Table of Content

01 November 2023, Volume 56 Issue 21

Previous Issue    Next Issue

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

QTL Mapping and Molecular Marker Development of Traits Related to Grain Weight in Wheat

ZHANG ZeYuan, LI Yue, ZHAO WenSha, GU JingJing, ZHANG AoYan, ZHANG HaiLong, SONG PengBo, WU JianHui, ZHANG ChuanLiang, SONG QuanHao, JIAN JunTao, SUN DaoJie, WANG XingRong

Scientia Agricultura Sinica. 2023, 56(21):  4137-4149.  doi:10.3864/j.issn.0578-1752.2023.21.001

Abstract ( 456 )   HTML ( 47 )   PDF (4065KB) ( 287 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The yield of wheat, the second-highest-yielding food product in the world, has a major impact by grain weight. This research used materials from a recombinant inbred line (RIL) population derived from Heshangtou (HST) and Longchun 23 (LC23). Based on 55K SNP genotype data, QTL mapping was performed for traits related to grain weight of wheat, and co-segregation markers of major grain length QTL were developed and verified to provide reference for molecular marker assisted selection breeding.【Method】The wheat 55K SNP microarray was used to genotype parents and RIL populations, and a high density genetic linkage map was constructed, and its correlation with Chinese spring reference genome IWGSC RefSeq v1.0 was analyzed. QTL mapping of traits related to grain weight in multiple environments based on inclusive composite interval mapping method. The analysis of variance of major effect QTLs were performed to judge the additive interaction effect among different QTLs, and to analyse its effect on traits related to grain weight. At the same time, the corresponding kompetitive allele specific PCR marker was developed according to the closely linked SNP loci of major QTL for grain length, and verified in 242 wheat accessions worldwide.【Result】In this study, a high density genetic map of Heshangtou/Longchun 23 RIL population was constructed, with full length 4 543 cM, including 22 linkage groups, covering 21 chromosomes of wheat, and the average genetic distance was 1.7 cM. There was a significant correlation between genetic map and physical map, and the Pearson correlation coefficient were 0.77-0.99 (P<0.001). A total of 51 QTLs related to grain weight were detected, among them, 4 stable major QTLs were found in multi-environments (three or more environments) and distributed on 2D, 5A, 6B and 7D chromosomes. According to the physical interval and functional markers, it is inferred that stable major QTLs Qtkw.nwafu-2D.1 and Qtkw.nwafu-7D are photoperiod gene Ppd-D1 and flowering gene FT-D1, respectively. The analysis of variance shows that there is a significant interaction between them. The favorite alleles polymerization of Qtkw.nwafu-2D.1 and Qtkw.nwafu-7D can significantly increase thousand grain weight and grain width of wheat. In addition, the corresponding KASP molecular detection marker AX-111067709 was developed based on the co-segregated SNP of the major locus Qgl.nwafu-5A for grain length, which was significantly correlated with grain length and grain weight traits in a diversity panel comprising of 242 wheat accessions, and could increase grain length by 3.33% to 4.59% and grain weight 5.70% to 10.35% in different environments (P<0.001).【Conclusion】There are several genetic loci that affect traits linked to grain weight in Heshangtou (HST) and Longchun 23 (LC23), and Qtkw.nwafu-2D.1 and Qtkw.nwafu-7D dramatically increased thousand grain weight and grain width through additive interaction effects. Qgl.nwafu-5A is significantly correlated with grain weight and grain length, and its co-segregated molecular marker AX-11106770 can be used in molecular marker assisted selection breeding.

Screening of Low Phosphorus Tolerant Germplasm in Cotton at Seedling Stage and Comprehensive Evaluation of Low Phosphorus Tolerance

KAYOUMU MiReZhaTiJiang, WUMAIERJIANG XiErAiLi, LI XiaoTong, WANG XiangRu, GUI HuiPing, ZHANG HengHeng, ZHANG XiLing, DONG Qiang, SONG MeiZhen

Scientia Agricultura Sinica. 2023, 56(21):  4150-4162.  doi:10.3864/j.issn.0578-1752.2023.21.002

Abstract ( 253 )   HTML ( 29 )   PDF (2662KB) ( 229 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】To establish an evaluation system for low phosphorus tolerance in cotton varieties (lines), screen low phosphorus tolerant cotton germplasm and evaluate different types of phosphorus efficiency, and lay the foundation for studying the physiological mechanisms of low phosphorus tolerance in cotton and mining low phosphorus tolerance genes.【Method】Using 140 cotton cultivars (lines) from different cotton regions at home and abroad, 21 traits such as biomass, root-related indexes and phosphorus efficiency-related indexes were measured under low (10 μmol·L^-1 KH₂PO₄) and normal (500 μmol·L^-1 KH₂PO₄) phosphorus treatments in a hydroponic experiment. The index of low phosphorus stress tolerance was calculated for each index. Using the integrated affiliation function method, principal component analysis, regression analysis and cluster analysis were conducted to classify the low phosphorus tolerance of each cotton variety and to comprehensively evaluate the low phosphorus tolerance and phosphorus efficiency type of each cotton variety.【Result】Compared with the normal phosphorus treatment, the mean values of total phosphorus accumulation, total phosphorus content, aboveground dry weight and total dry matter weight of the tested cotton varieties decreased more under the low phosphorus treatment, while the mean values of root average diameter, specific root area, root tips number and phosphorus use efficiency increased. Under low phosphorus treatment, the coefficients of variation of each index ranged from 6.04% to 47.79%，the coefficients of variation of root indexes such as specific root tips density, root tips number, specific root length and root average diameter were higher than those of normal phosphorus treatment, and the coefficients of variation were 47.49%, 42.13%, 40.19% and 19.16%, respectively; the principal component analysis of the 21 indexes of low phosphorus stress tolerance showed that the cumulative variance contribution of the six principal components reached 77.21%, and the comprehensive low phosphorus tolerance value (D) was calculated using the affiliation function method. The D-value regression equation was established by multiple regression analysis to determine the six low phosphorus tolerance indices and perform systematic clustering to classify different cotton varieties (lines) into three categories: low phosphorus tolerant, intermediate and low phosphorus sensitive.【Conclusion】Total dry matter weight, phosphorus use efficiency, root fresh weight, total root length, root surface area and total phosphorus accumulation were identified as indicators for the evaluation of low phosphorus tolerance in cotton.

Identification and Evaluation of Drought Tolerance and Screening of Drought-Tolerant Germplasm for Core Germplasms in Proso Millet at Adult Stage

WANG Qian, DONG KongJun, XUE YaPeng, LIU ShaoXiong, WANG RuoNan, YANG JiaQi, LU Ping, WANG RuiYun, YANG TianYu, LIU MinXuan

Scientia Agricultura Sinica. 2023, 56(21):  4163-4174.  doi:10.3864/j.issn.0578-1752.2023.21.003

Abstract ( 174 )   HTML ( 24 )   PDF (989KB) ( 207 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Drought is one of the major constraints influencing on the growth, development, and yield of proso millet. To screen excellent drought-tolerant accessions and identification indicators will promote the drought-tolerant varieties breeding and drought tolerance molecular mechanisms analysis of proso millet.【Method】In this study, 200 core germplasm accessions of proso millet were used to identify field drought tolerance at adult stage in 2021-2022 at Dunhuang, Gansu province, with two treatments of normal irrigation and drought stress. Eleven morphological indicators, such as leaf area (LA), main stem diameter (MSD), number of main stem nodes (NMSN), main panicle length (MPL), peduncle length (PL), plant height (PH), straw weight per plant (SWPP), panicle weight per plant (PWPP), grain weight per plant (GWPP), thousand grain weight (TGW), and yield per plot (YPP) were determined. Comprehensive drought tolerance coefficient (CDTC value), drought resistance index (DRI value), and drought resistance comprehensive evaluation value (D value) were combined to identify the drought tolerance of proso millet at adult stage.【Result】There were significant differences in all eleven indexes among different accessions under different water treatments, including leaf area, main stem diameter, number of main stem nodes, main panicle length, peduncle length, plant height, straw weight per plant, panicle weight per plant, grain weight per plant, thousand grain weight, and yield per plot. The growth of proso millet was inhibited under drought stress treatments. Compared with the normal irrigation treatments, all the eleven indexes under drought treatments were significantly reduced, and yield per plot was more sensitive to drought treatments. The correlation analysis found that certain degrees of correlation existed among the drought tolerance coefficients of all traits, the correlation between panicle weight per plant and grain weight per plant was strongest, with a correlation coefficient of 0.943. Eleven evaluation indexes were converted into six comprehensive indexes by principal component analysis, with a cumulative variance contribution of 80.667%. The drought tolerance ranking of proso millet accessions based on CDTC value, DRI value and D value was generally consistent. The 200 proso millet accessions were classified into four categories according to D value cluster analysis, 10 of cluster Ⅰ were highly drought tolerant, 70 of cluster Ⅱ were drought tolerant, 81 of cluster Ⅲ were drought sensitive, and 39 of cluster Ⅳ were highly drought sensitive. Plant height, grain weight per plant, panicle weight per plant and main panicle length were highly correlated with D value, with correlation coefficients of 0.756, 0.697, 0.696 and 0.679, respectively. The regression equation for the drought tolerance evaluation was constructed by stepwise regression analysis: Y=-1.509+0.362X₁+0.174X₂+0.349X₃+0.389X₄+0.307X₅+ 0.251X₆+0.218X₇.【Conclusion】The drought resistance comprehensive evaluation value method could be suitable for evaluating the drought resistance of proso millet at adult stage. Ten accessions with highly drought tolerance, such as Balinzuogedashu (00000525), Gaotaiwumizi (00002677) and Minlehongmizi (00002687). Plant height, panicle weight per plant and main panicle length could be used as primary evaluation indexes for drought tolerance of proso millet at adult stage.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Non-Destructive Monitoring of Rice Growth Key Indicators Based on Fixed-Wing UAV Multispectral Images

WANG WeiKang, ZHANG JiaYi, WANG Hui, CAO Qiang, TIAN YongChao, ZHU Yan, CAO WeiXing, LIU XiaoJun

Scientia Agricultura Sinica. 2023, 56(21):  4175-4191.  doi:10.3864/j.issn.0578-1752.2023.21.004

Abstract ( 288 )   HTML ( 25 )   PDF (2299KB) ( 374 )   Save

Figures and Tables | References | Related Articles | Metrics

【Background】In recent years, with the rapid development of remote sensing technology, real-time and non-destructive monitoring of crop growth status has become a research hotspot. Remote sensing-derived agricultural information will provide guidance for the precise management of large-scale crops. Among various remote sensing monitoring platforms, unmanned aerial vehicles (UAVs) have attracted wide attention due to their simple operation and low cost. UAVs equipped with multispectral cameras can quickly obtain crop growth conditions.【Objective】This study attempted to combine texture information and spectral information of multispectral images of fixed-wing UAVs to explore the monitoring effect of “atlas” information on rice growth indicators.【Method】A two-year rice field experiment involving different sowing dates, varieties, planting methods and nitrogen levels was conducted. During the key growth stages of rice, remote sensing images of the rice canopy were obtained using a Sequoia multispectral camera mounted on a fixed-wing UAV. Shoot destructive sampling was conducted simultaneously to obtain leaf area index (LAI), aboveground biomass (AGB), plant nitrogen content (PNC) and other agronomic indexes of rice. Simple regression, partial least squares regression and artificial neural network algorithms were used to construct rice growth index monitoring model based on multispectral images of fixed-wing UAV. The monitoring effects of spectral texture information in different models were compared and analyzed.【Result】The quantitative relationship between vegetation index (VI), single-band texture features and rice LAI, AGB, and PNC was explored using simple linear regression. The results showed that vegetation indexes had strong correlations with LAI and AGB, with the best-performing indexes being CIRE and NDRE, with R² values of 0.80 and 0.76, respectively. However, for PNC monitoring, vegetation indexes did not achieve ideal results, with the best-performing RESAVI and NDRE having R² values of only 0.13 with PNC. Further analysis using simple linear regression revealed that single-band texture features did not perform well in monitoring rice growth indicators. In order to further analyze the monitoring effect of image texture on the above three indexes, normalized texture indexes (NDTI), ratio texture indexes (RTI), and difference texture indexes (DTI) were constructed by referring to the construction method of VI. Correlation analysis showed that the newly constructed texture index (TI) improved the monitoring accuracy of rice growth indicators compared to single-band texture feature but did not perform better than vegetation indexes. To combine spectral and texture information, partial least squares and artificial neural network modeling methods were adopted in this paper. VI and VI+TI were used as different input parameter combinations to construct rice LAI, AGB and PNC monitoring models. The results showed that both partial least squares and artificial neural network modeling methods significantly improved the monitoring accuracy compared to simple linear regression. The best performance was achieved using VI+TI as input variables and an artificial neural network model for validation, with validation R² values for LAI, AGB, and PNC models increasing from 0.75, 0.72, and 0.26 to 0.86, 0.92, and 0.86, respectively, while RMSE values were significantly reduced.【Conclusion】The monitoring accuracy of rice LAI, AGB and PNC can be effectively improved by using the fixed-wing UAV to collect multispectral images of rice canopy and using the texture features and reflectance information as input parameters of the model through the model construction method of artificial neural network. The research results will provide a theoretical basis for rapid monitoring of large area crop growth.

Effects of Straw Mulching and Nitrogen Application on the Improvement of Wheat Root Architecture and the Absorption and Utilization of H⁺ and NO₃^- in Hilly Dry Land

AI DaiLong, LEI Fang, ZOU QiaoSheng, HE Peng, YANG HongKun, FAN GaoQiong

Scientia Agricultura Sinica. 2023, 56(21):  4192-4207.  doi:10.3864/j.issn.0578-1752.2023.21.005

Abstract ( 147 )   HTML ( 13 )   PDF (1241KB) ( 137 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】In order to further study the root architecture and root tip nitrogen transport process of wheat after straw mulching in the wheat-maize rotation system in the dry land of southwest China, and to elucidate the physiological basis of straw mulching and nitrogen application to promote the efficient absorption and utilization of wheat nitrogen.【Method】The experiment was a two-factor split plot experiment of straw mulching (SM: straw mulching; NSM: no straw mulching) and nitrogen application (N0: 0; N1: 120 kg·hm^-2), which was conducted at Sichuan Renshou Modern Agricultural Test Station from 2020-2022. The effects of straw mulching and nitrogen application on soil physicochemical properties, wheat root architecture, nitrogen absorption in root tips, plant biomass and aboveground nitrogen accumulation and utilization were analyzed according to the current situation that soil drought inhibited root elongation in dry land of southwest hills, resulting in low wheat biomass and nutrient use efficiency.【Result】The soil nitrate nitrogen content of straw mulching treatment increased by 43.1% and 30.8%, and the ammonium nitrogen content increased by 21.8% and 18.8%, respectively, in 2020-2021 and 2021-2022 compared with the no straw mulching treatment. Straw mulching increased the root length, root surface area, and root volume of the 0-10 cm soil layer at jointing stage, booting stage and anthesis stage of wheat, and nitrogen application significantly increased the 0-10 cm soil root length, root surface area and root volume. In addition, straw mulching and nitrogen application could significantly increase the absorption rate and net absorption rate of H⁺ and NO₃^- at the root tips of wheat, and reduce the H⁺ efflux rate at the root tips of 0-20 cm soil layer. Straw mulching and nitrogen application significantly increased the activities of nitrate reductase and glutamine synthetase in roots, and the nitrogen accumulation and biomass in the aboveground part of wheat increased by 25.8% and 35.8% on average, respectively, in two years. H⁺ absorption rate, NO₃^- absorption rate, nitrate reductase activity, glutamine synthetase activity, and nitrogen accumulation were positively correlated with root length, root surface area and root volume of 0-10 cm soil layer (P<0.05).【Conclusion】In the southwest hilly dry land wheat-maize rotation system, maize straw mulching and nitrogen application can increase the content of inorganic nitrogen in the soil during the wheat season, the root distribution in the soil surface and the absorption rate of H⁺ and NO₃^- at the root tips, promote nitrogen uptake and root tip nitrogen transport, and then promote aboveground nitrogen assimilation and accumulation; Under the conditions of this experiment, straw mulching combined with 120 kg N·hm^-2 is a green production mode suitable for high yield and high nitrogen use efficiency in Sichuan hilly dry land.

Application of Trehalose Enhances Drought Resistance in Sugarcane Seedlings and Promotes Plant Growth

LUO ZhengYing, HU Xin, LIU XinLong, WU CaiWen, WU ZhuanDi, LIU JiaYong, ZENG QianChun

Scientia Agricultura Sinica. 2023, 56(21):  4208-4218.  doi:10.3864/j.issn.0578-1752.2023.21.006

Abstract ( 173 )   HTML ( 13 )   PDF (1735KB) ( 223 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】This study aims to investigate whether application of trehalose could mitigate the adverse effects of drought stress by enhancing the defense response in sugarcane (Saccharum spp. hybrid), and to provide a theoretical basis for stable high yield of sugarcane under drought conditions.【Method】The present investigation was conducted to assess ameliorative effects of adding trehalose on the growth, malondialdehyde (MDA) content, and antioxidant responses of two sugarcane cultivars ROC22 and YZ05-51 under the treatment of 30% PEG6000 and 12% PEG6000. In the preliminary experiment, four treatment concentrations of trehalose were set at 0, 10, 100 and 200 mg·L^-1. The dry weight, fresh weight and adventitious roots of tissue-cultured sugarcane seedlings were measured at 9 d after treatment to clarify the optimal concentration of trehalose in promoting sugarcane growth under drought stress. Then, the MDA content and the activity of antioxidant enzyme peroxidase (POD) and superoxide dismutase (SOD) were determined under control, drought stress and drought stress combined with optimal trehalose treatment. Finally, the expression level of drought-resistance genes ScTPS1, ScSnRK2.3, ScSnRK2.4 and ScDREB2b-1 was quantified by qRT-PCR at 0, 12, 24 and 48 h in YZ05-51 after exposed to 30% PEG6000 and 30% PEG6000 adding with optimal trehalose concentration, respectively.【Result】Application of trehalose could alleviate the drought-induced decrease of fresh weight and dry weight of two sugarcane cultivars, and the growth recovery of plantlet was better in 100 mg·L^-1 trehalose group than that in 10 and 200 mg·L^-1 trehalose groups. Under 30% PEG6000 stress, the MDA content was notably increased, and a considerable improvement was recorded in the activity of the antioxidant enzymes POD and SOD. Adding trehalose significantly reduced the content of drought-induced MDA, and enhanced the activity of POD and SOD, respectively. However, external trehalose had little effect on the MDA content and antioxidant enzyme activity of tissue-cultured sugarcane seedlings under 12% PEG6000 stress. Compared with drought controls, the expression of drought-resistance genes ScTPS1, ScSnRK2.3, ScSnRK2.4 and ScDREB2b-1 was up-regulated in the trehalose-treated plantlet.【Conclusion】Application of trehalose can alleviate the negative impact of drought on the growth of sugarcane seedlings, and promote adventitious root growth. External addition of trehalose may reduce the oxidative toxicity caused by drought stress by increasing the activity of antioxidant enzymes POD and SOD. Meanwhile, application of trehalose induces the expression of drought-resistance genes ScTPS1, ScSnRK2.3, ScSnRK2.4, and ScDREB2b-1, indicating that applying trehalose can improve the drought resistance of sugarcane. The results will provide a reference for developing drought resistance strategies in sugarcane breeding and productive practice.

PLANT PROTECTION

Development and Application of Specific Molecular Markers for Six Homologous Rice Blast Resistance Genes in Pi9 Locus of Rice

YANG Hao, HUANG YanYan, YI ChunLin, SHI Jun, TAN ChuTian, REN WenRui, WANG WenMing

Scientia Agricultura Sinica. 2023, 56(21):  4219-4233.  doi:10.3864/j.issn.0578-1752.2023.21.007

Abstract ( 293 )   HTML ( 26 )   PDF (4029KB) ( 238 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The Pi9 resistance gene locus, conferring a broad-spectrum resistance against Magnaporthe oryzae, is consist by several tandem homologous genes. Over 10 resistance genes have been cloned from this gene locus. This study aims to clarify the R gene composition at Pi9 locus in rice resource materials and promote the application of those genes in rice resistance breeding.【Method】Comparing the DNA sequence of cloned R genes at Pi9 locus, the specific nucleotide polymorphism sites were screened as the candidate sites. Subsequently, each R gene was blasted with 155 rice genomes in the database of Rice Resource Center. The most specific nucleotide polymorphism sites were picked out from the candidate site in each gene to develop primer pair of molecular markers. The PCR product of primer pairs was used to mark indicated R gene in tested rice materials via parameter optimization. To verify the results, the R genes were cloned from indicated rice variety randomly and examined by Sanger sequencing, or analyzed the R genes from the genome database if the genome sequence of indicated rice variety exists in Rice Resource Center. The R genes in Pi9 locus have high homology, which cause same specific nucleotide polymorphism sites existing in different R genes. Therefore, some R genes are hardly identified by one molecular marker. For this case, several molecular markers were employed to identify the indicated R gene simultaneously. Moreover, some specific nucleotide polymorphism sites are single nucleotide polymorphism (SNP), in where the primers of molecular markers have a mismatched base. In order to improve the specificity of PCR amplification, the adjacent base of SNP was mutated to generate two mismatched bases at 3′ site of primer.【Result】Finally, the valid molecular markers were developed for each R gene and identified 32.09% tested materials containing R genes at Pi9 locus. Pi9, Pid4, PigmR, Piz-t, Pi2 and Pi9-type5 are present in 1, 7, 8, 14, 23 and 33 tested materials, respectively. The Pi9 only presents in monogenic line but not in rice parent lines. The other genes are usually present in two or more gene combinations in rice parent lines. The Pi9-type5 often presents in pair with Pi2 and Piz-t, and presents alone in three rice parents, Chenghui 993, HR2168 and Mianhui 365. Yuhui 38 contains the most R genes at Pi9 locus, including Pi2, Pi9-type5, PigmR and Pid4. Chuangu B, Chuannong 4B, Neixiang 6B and Shuang 1B contain Piz-t, PigmR and Pid4. Qianxiang 654B contains Piz-t and Pid4.【Conclusion】This study successfully developed specific molecular markers for six homologous rice blast resistance genes in Pi9 locus and identified the R gene composition in Pi9 locus for 110 rice parent lines that used in rice breeding in Sichuan basin. It also discovered different types of R genes combination at Pi9 locus and provided a clear reference for choosing the resistance source in rice breeding.

The Variation of GRSPaV in Different Parts of Shine Muscat Grapevines During Their Phenological Periods

LI MeiXuan, ZHANG XiangKun, WANG Li, QIAO YueLian, SHI XiaoXin, DU GuoQiang

Scientia Agricultura Sinica. 2023, 56(21):  4234-4244.  doi:10.3864/j.issn.0578-1752.2023.21.008

Abstract ( 118 )   HTML ( 16 )   PDF (1938KB) ( 185 )   Save

Figures and Tables | References | Related Articles | Metrics

【Background】Grapevine rupestris stem pitting associated virus (GRSPaV) is the most common virus causing rugose wood disease. It is mainly transmitted via asexual reproduction. Sensitive detection technology and cultivation of virus-free plants are essential for preventing GRSPaV.【Objective】The purpose of this study was to establish a GRSPaV detection system, and to determine the appropriate periods and sites of sample collection for virus detection, so as to provide a reference for virus detection and obtaining virus-free materials.【Method】An RT-qPCR detection method was established using the AugeGreen dye method and primers according to the coat protein gene (CP) region. The detection rate and gene expression of GRSPaV in samples from different parts of Shine Muscat grapevines during various phenological stages were examined.【Result】The RT-qPCR detection method for GRSPaV using GRS q CP1 as primer showed 10 times higher sensitivity than that of RT-PCR method. The detection rates of GRSPaV were 100% during the budbreak, shoot growing period, and florescence, 91.7% during the fruit enlargement stage, 94.4% for mature tendrils, and 100% for mature leaves, mature petioles, and tender shoots. Samples showing negative results were all from the young parts of the plants. The young tendrils at florescence showed the highest level of GRSPaV CP gene expression, followed by the mature leaves at florescence. The expression level in mature leaves was the highest among the parts in the same phenological period from berry expansion to maturity. The expression levels in secondary winter buds at the budbreak stage and the secondary laterals at the shoot growing period were both relatively low.【Conclusion】The detection rate of GRSPaV and the GRSPaV CP gene expression level of Shine Muscat grape varied with the progression of phenological periods. The detection rate was the highest from budbreak to florescence, while which was the lowest at berry maturity period. The GRSPaV CP gene expression level was the highest at florescence. Based on both the detection rate and the expression level factors, it could be concluded that the mature leaves at florescence were suitable as samples for GRSPaV virus detection, and the winter buds from the berry expansion to maturity period and the lateral shoots germinated from these buds was appropriate for obtaining virus-free materials.

SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT

Characteristics and Succession of Rhizosphere Soil Microbial Communities in Continuous Cropping Watermelon

GUO HanYue, WANG DongSheng, RUAN Yang, QIAO YiZhu, ZHANG YunTao, LI Ling, HUANG QiWei, GUO ShiWei, LING Ning, SHEN QiRong

Scientia Agricultura Sinica. 2023, 56(21):  4245-4258.  doi:10.3864/j.issn.0578-1752.2023.21.009

Abstract ( 150 )   HTML ( 20 )   PDF (3190KB) ( 378 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The aim of this study was to investigate the effects of continuous cropping on the construction and potential functions of bacterial and fungal communities in the rhizosphere soil of watermelon, and to clarify the adaptability of rhizosphere microorganisms to environmental changes, so as to provide a theoretical basis for ecological control of watermelon continuous cropping obstacles and healthy maintenance of farmland.【Method】In this study, the rhizosphere soil of watermelon without continuous cropping (CK), continuous cropping for 2 times and continuous cropping for 6 times was used as the research object. 16S rRNA and ITS high-throughput sequencing were used to analyze the effects of continuous cropping on the bacterial and fungal communities of rhizosphere soil of watermelon.【Result】With the increasing continuous cropping times, the bacterial diversity index in the rhizosphere soil of watermelon showed a trend of first decreasing and then increasing, while the fungal diversity index decreased significantly. At the bacterial genus level, multiple times of continuous cropping decreased the relative abundance of Sphingomonas and Lysobacter in watermelon rhizosphere soil; at the fungal genus level, the relative abundance of Fusarium increased with the continuous cropping times. Compared with CK, the network complexity of continuous cropping was higher, but the stability of network structure was lower. In addition, compared with CK, the relative abundance of biodegradation pathways of harmful substances and metabolic pathways of amino acids could be significantly reduced after continuous cropping for 6 times; the relative abundance of pathogenic fungi significantly increased in the fungal community after continuous cropping for 6 times. During community succession, the stochastic processes dominated rhizosphere bacterial community construction in watermelon under continuous cropping, while the deterministic processes dominated rhizosphere fungal community construction in watermelon.【Conclusion】Continuous cropping caused changes in community characteristics, functional composition and succession process of rhizosphere bacteria and fungi. The decrease of key functions of bacterial community, the increase of pathologic fungi and the decrease of stability of microbial community network might be the important factors leading to occurrence of watermelon continuous cropping obstacles.

Spatial-Temporal Variability Characteristics and Main Controlling Factors of Soil Fertility in Shouyang County of Cinnamon Soil Area

SHEN Tong, WANG HengFei, DU WenBo, ZHOU HuaiPing, WANG Rui, ZHANG JianJie, JIN DongSheng, XU MingGang

Scientia Agricultura Sinica. 2023, 56(21):  4259-4271.  doi:10.3864/j.issn.0578-1752.2023.21.010

Abstract ( 186 )   HTML ( 7 )   PDF (4832KB) ( 193 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The main controlling factors of soil fertility and temporal and spatial evolution characteristics in typical county of cinnamon soil region were investigated, so as to provide the basis for scientific management of nutrients and soil fertilization.【Method】Based on the data of soil fertility, including soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), available potassium (AK) and pH, at Shouyang County in 1983, 2007 and 2017, the Nemerow index method was used to calculate the comprehensive index of soil fertility, the random forest method was used to explore the main controlling factors of soil fertility, and the combined method of GIS and geostatistics was used to determine the temporal and spatial variability characteristics and the distribution patterns of the comprehensive index of soil fertility and its main factors.【Result】(1) The overall level of cultivated land soil fertility showed an upward trend in Shouyang County during the past 34 years, and the comprehensive index of soil fertility increased by 0.26, which changed from 1.16 to 1.42. The changes of soil fertility index were characterized by stages. From 1983 to 2007, the average annual increases of SOM, TN and AK were 0.09 g·kg^-1, 0.0021 g·kg^-1 and 1.61 mg·kg^-1, respectively, while the changes of AP were not significant. From 2007 to 2017, SOM, TN and AP increased significantly, with the average annual increases of 0.25 g·kg^-1, 0.01 g·kg^-1 and 0.31 mg·kg^-1, respectively, while the changes of AK were not significant. (2) The analysis results of the random forest model showed that, the main controlling factors of soil fertility were TN and SOM in 1983, with the importance of 75.3% and 17.8%, respectively. In 2007, the main controlling factors of soil fertility became AK, AP and TN, with the importance of 31.8%, 27.1% and 26.8%, respectively. In 2017, the main controlling factors were TN, AK and AP, and the importance for the three factors were 31.8%, 27.1% and 26.8%, respectively. (3) There were certain spatial differences in the main controlling factors of soil fertility. From 1983 to 2007, SOM increased in the whole county; TN decreased in the northwest and central regions, but increased in other regions; AP decreased in the north regions, but increased in the south regions; AK increased in the whole county. From 2007 to 2017, SOM increased fast in the southeast regions but slow in other regions; TN decreased in the middle regions but increased in other regions; AP decreased in the east regions, but increased in other regions; AK decreased in the east and west regions, but increased in the central region.【Conclusion】After 34 years, the cultivated land soil fertility of Shouyang County has been improved, and SOM, TN, AP and AK were the main controlling factors affecting the soil fertility variability. SOM, TN and AP increased fast in the south regions, while AK increased fast in the east regions. It was suggested that the whole Shouyang County still needed to increase the application of nitrogen fertilizer moderately, especially in the central region, and stabilize the application of phosphate fertilizer, while control the application of potassium fertilizer in the future.

Analysis of the Characteristics and Influencing Factors of Soil Particle Composition in Ningxia

ZHOU Lei, QU XiaoLin, ZHOU Tao, MA ChangBao, LI JianBing, LONG HuaiYu, XU AiGuo, ZHANG RenLian, LI Ge

Scientia Agricultura Sinica. 2023, 56(21):  4272-4287.  doi:10.3864/j.issn.0578-1752.2023.21.011

Abstract ( 114 )   HTML ( 10 )   PDF (2196KB) ( 229 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The aim of this study was to clarify the characteristics and influencing factors of soil particle composition in Ningxia, so as to provide the scientific reference for local land use and agricultural production planning.【Method】Based on the soil particle composition test data at 114 sites in Ningxia, the effects of environmental factors on soil particle composition, the statistical characteristics of soil particle composition, soil texture type, particle size of soil control layer, and the spatial distribution characteristics of soil particle composition were studied.【Result】(1) The content of sand, silt and clay in Ningxia soil were 2.4%-97.2%, 0.8%-86.0% and 0.7%-43.3%, respectively, and the average content were 34.9%, 49.6% and 15.5%, respectively; Soil texture was mainly composed of silty loam (46.5%), sandy loam (17.6%) and loam (13.3%), and the variation of soil texture types was mainly attributed to the change of sand and silt content. (2) A number of environmental factors jointly affect the soil particle composition in Ningxia, and the influential factors were geomorphic factors, parental material type factors, small topographic factors, thermal factors, soil type factors, land use type factors and wind speed factors in turn from large to small. (3) There were 11 types of particle sizes in the control interval, among which loamy (46.5%), clay (19.3%) and sandy (16.7%) were the main ones. (4) It was difficult to develop argic horizon in Ningxia. Among 114 sections, 26 clay particles were consistent with cohesive layer, but only 2 were exact argic horizon. (5) Siltigic epipedon of Ningxia produced obvious texture differentation.【Conclusion】The soil particle composition in Ningxia was mainly sand and silt, while landform and parental material were the most important factors affecting the particle composition.

HORTICULTURE

Sequencing and Functional Analysis of Tomato circRNA During Flowering Stage

YIN ZiHe, YANG ChengCheng, ZHAO YuHui, ZHAO Li, LÜ XiuRong, YANG ZhenChao, WU YongJun

Scientia Agricultura Sinica. 2023, 56(21):  4288-4303.  doi:10.3864/j.issn.0578-1752.2023.21.012

Abstract ( 114 )   HTML ( 9 )   PDF (4532KB) ( 267 )   Save

Figures and Tables | References | Related Articles | Metrics

【Background】As one of the most important periods in plant growth and development, the flowering period directly affects fruit ripening and seed development. circRNAs are a class of covalent closed-loop RNA molecules that are ubiquitous in eukaryotic cells and play an important role in the regulation of tomato development and stress response. However, the current circRNA studies on tomato mainly focus on fruit and leaves, and there is a lack of systematic studies on tomato circRNA at flowering stage.【Objective】Identification and analysis of circRNs in flowering tomato could be of great significance for the functional study of miRNA and circRNA in tomato, and also layed a foundation for the study of tomato growth, development and stress response mechanism.【Method】circRNA sequencing was performed on 3 tissue samples of flowers, roots and leaves of flowering tomato plants, with 3 replicates for each sample. circRNAs were identified and their basic characteristics were analyzed. The cycle-forming ability of tissue-specific circRNAs was screened, and the host genes of identified circRNAs were analyzed by GO analysis and KEGG analysis. The mode and site of action of circRNAs were predicted and analyzed by bioinformatics methods to construct a potential circRNA-miRNA-mRNA interaction regulatory network in response to tomato growth and development.【Result】A total of 532 circRNAs were obtained by high-throughput sequencing, 83% of which were exon types. The distribution of circRNA in each chromosome of flowering tomato was uneven, among which chromosome 1 produced the most circRNAs and chromosome 5 produced the least. circRNAs differentially expressed in flower, leaf and root tissues of flowering tomato showed that 79 circRNAs were differentially expressed in flower and leaf, 133 circRNAs were differentially expressed in flower and root, and 132 circRNAs were differentially expressed in leaf and root tissues. Among them, 14 circRNAs were differentially expressed in flower, leaf and root tissues. The cyclization ability of 8 circRNAs randomly selected from 14 differentially expressed circRNAs was tested, and the results showed that all 8 circRNAs had cyclization ability. GO analysis and KEGG analysis showed that circRNAs in flowering tomato were mainly related to the binding of nucleic acids, proteins and other small molecules, as well as the synthesis and metabolism of various biological macromolecules. Finally, the tomato circRNA-miRNA-mRNA interaction regulatory network composed of 14 circRNAs, 10 miRNAs and 136 mRNAs was constructed.【Conclusion】A total of 342 tissue-specific circRNAs were identified, among which 14 were significantly expressed, and 8 were successfully identified. A circRNA-miRNA-mRNA interaction regulatory network was constructed for tomato at flowering stage. This study laid a foundation for the subsequent research of circRNA in flowering period.

Identification of the Transcription Factor WRKY75 of CmPR4A in Citron C-05 and Its Function Analysis in Resistance to Citrus Canker Disease

YAN PeiHan, LUO JianMing, HAO ChenXing, SUN ZiQing, YE RongChun, LI Yi, LIU Lian, SHENG Ling, MA XianFeng, DENG ZiNiu

Scientia Agricultura Sinica. 2023, 56(21):  4304-4317.  doi:10.3864/j.issn.0578-1752.2023.21.013

Abstract ( 172 )   HTML ( 24 )   PDF (2450KB) ( 236 )   Save

Figures and Tables | References | Related Articles | Metrics

【Background】Citrus canker is one of the serious citrus diseases caused by Xanthomonas citri subsp. citri (Xcc). There is currently no radical cure method for it, and few of the existing cultivars have sufficient resistance to citrus canker. Therefore, the breeding for resistant varieties is crucial for the radical cure of the disease, and the identification of resistant genes is beneficial to disease-resistant cultivar breeding.【Objective】The aim of this study was to use the resistance related gene CmPR4A to screen its upstream transcription factors, and to explore the role of transcription factors in resistance to Xcc, which could provide genetic information for the breeding of citrus disease resistant varieties.【Method】Based on the transcriptome results of Citron C-05 (resistant) and Bingtang Sweet orange (susceptible) after inoculated with Xcc, and combined with the results of qRT-PCR, PR4A was differentially expressed in resistant and susceptible genotypes. Differential analysis on PR4A promoter sequence of Citron C-05 and Bingtang Sweet orange was performed using PlantCARE. Yeast one hybrid was used to screen the upstream transcription factors of PR4A. Further interaction between CmPR4A and candidate transcription factors was verified by yeast gyration test and dual-Luciferase. The expression of candidate transcription factors was detected among 8 resistant and susceptible citrus genotypes after inoculation with Xcc at 0, 2, 4, 6, and 8 days to verify their relationship with disease resistance. By transient overexpression of candidate transcription factors in Citron C-05 and Bingtang sweet orange leaves, the expression of transcription factors and PR4A were analyzed using qRT-PCR. Xcc bacterial quantification and symptom observation were executed in transgenic leaves after 24 h inoculated with Xcc.【Result】The expression of PR4A was significantly higher in resistant Citron C-05 than that in the susceptible Bingtang sweet orange at 4, 6, and 8 dpi after inoculated with Xcc. There was a difference in the cis acting element W-box in PR4A promoter between Citron C-05 and Bingtang sweet orange at -236 bp location. Therefore, the CmPR4A promoter was truncated and the bait vector was constructed. Yeast one hybrid screening was conducted using Citron C-05 yeast library induced by Xcc, resulting in CmWRKY75 could interact with proCmPR4A-2. Further dual Luciferase reporting system also confirmed that the interaction between CmWRKY75 and CmPR4A, and CmWRKY75 was positive regulating the expression of CmPR4A. Additionally, the expression of WRKY75 was significantly upregulated in resistant genotypes Citron C-05, American citron and Aiguo citron after inoculation with Xcc, while it was only slight upregulation in susceptible genotypes Bingtang Sweet orange, Shatian Yu pummelo, lemon, Nanchuan and Danna citron. Transient overexpression WRKY75 in Citron C-05 and Bingtang Sweet orange leaves revealed a significant upregulation expression of PR4A at 4 dpi of Xcc and enhanced leaf resistance to Xcc.【Conclusion】CmWRKY75 could bind to the W-box in CmPR4A promoter and positively regulate the expression of CmPR4A, resulting in enhancing leaf resistance to Xcc. Moreover, the expression of WRKY75 was induced by Xcc and showed significant upregulation in disease-resistant genotypes, which was consistent with the expression pattern of PR4A. These results indicated that the differential expression of WRKY75 in different disease-resistant and susceptible citrus genotypes influenced the expression of PR4A, which made it play a role in the resistance of Citron C-05 to canker disease.

FOOD SCIENCE AND ENGINEERING

Effects of Different Salt Ions on the Gel Properties and Molecular Interactions of Quinoa Protein

FENG Xiao, WU ChaoSheng, YANG YuLing, FU LiXiao, CHEN LongWei, TANG XiaoZhi

Scientia Agricultura Sinica. 2023, 56(21):  4318-4329.  doi:10.3864/j.issn.0578-1752.2023.21.014

Abstract ( 127 )   HTML ( 11 )   PDF (2091KB) ( 120 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】This research studied the effects of different salt ions on the gel properties of quinoa protein, and explored its molecular mechanisms, so as to provide a theoretical basis for the processing of quinoa protein gels.【Method】Quinoa protein was extracted by alkali extraction and acid precipitation. Quinoa protein solution (20%, w/v) was prepared at pH 7.0. NaCl, CaCl₂, CaSO₄ and MgCl₂ was added in quinoa protein solution till the concentration was 50 mmol∙L^-1, and then the solution was heated in a water bath to prepare quinoa protein gels. The effects of salt ions on the texture, water retention, color properties and water distribution of quinoa protein gels were analyzed. Meanwhile, the effects of salt ions on the microstructure and rheological properties of quinoa protein gels were studied by scanning electron microscopy and rheometer. The effects of salt ions on the molecular interactions and secondary structure of protein gels were also analyzed.【Result】The addition of salt ions significantly decreased the hardness and water holding capacity, while increased the springiness of quinoa protein gels under pH 7.0. Quinoa protein gels with MgCl₂ showed the lowest hardness and water holding capacity. NaCl addition had no significant influence on the color properties of protein gels. However, the addition of bivalent salt ions significantly improved the lightness and whiteness of quinoa protein gels, and their whiteness increased from 59.62 to 67.80 with the addition of CaCl₂. Furthermore, the addition of salt ions promoted granular aggregation of quinoa protein, which made the gel network structure become coarse. Coarse and larger gaps were observed in the microstructure of quinoa protein gels when divalent salt ions were added. Meanwhile, compared with blank gels and gels added with NaCl, the addition of divalent salt ions significantly decreased the content of disulfide bond, and weakened the electrostatic interactions within quinoa protein gels. Furthermore, the addition of salt ions decreased the contents of β-sheets and β-turns, increased the contents of α-helix and random coil, which affected the orderliness of protein secondary structure.【Conclusion】Under neutral conditions, the gel properties of quinoa protein and microstructure of gels were affected by the presence of different salt ions to various degrees. Compared with the gel prepared with NaCl, quinoa protein gels with the same concentration of CaCl₂, CaSO₄, and MgCl₂ showed rougher microstructure, lower gel hardness and water holding capacity, as divalent salt ions significantly decreased the disulfide bond content and weakened the electrostatic interactions within quinoa protein gels.

ANIMAL SCIENCE·VETERINARY SCIENCE

NAC Affects Proliferation and Differentiation of Adipose-Derived Mesenchymal Stem Cells by Regulating Reactive Oxygen Species

LIU PeiPei, DING ShiJie, SONG WenJuan, TANG ChangBo, LI HuiXia, TANG Hong

Scientia Agricultura Sinica. 2023, 56(21):  4330-4343.  doi:10.3864/j.issn.0578-1752.2023.21.015

Abstract ( 121 )   HTML ( 4 )   PDF (3356KB) ( 96 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Cells are sensitive to oxidative stress and elevated levels of intracellular reactive oxygen species during in vitro culture, which affects cell function. In this research, the regulation of reactive oxygen species in porcine adipose mesenchymal stem cells by N-acetyl-L cysteine (NAC) was evaluated, and the effects on their proliferation and differentiation were further clarified, which could provide a theoretical basis and reference for cultured fat seed cells to expand in vitro in large numbers and improve differentiation efficiency.【Method】In this research, to model oxidative stress, the different concentrations of H₂O₂ (0, 25, 50, and 100 μmol·L^-1) were added during the proliferation of adipose-derived mesenchymal stem cells (ADSCs). The added concentration of H₂O₂ was identified by cell counting results, cell morphology, cell viability and intracellular reactive oxygen species levels detected by a High-throughput High-content Live Cells Confocal Imaging System. To select the appropriate addition concentration of NAC to promote the proliferation of ADSCs, the different concentrations of NAC (0, 1, 2, and 3 mmol·L^-1) were added during the proliferation of ADSCs, and the appropriate addition concentration of NAC was determined by cell counting results and cell morphology. To further explore the effect of NAC on the proliferation of oxidatively stressed ADSCs, cell proliferation under different treatment conditions (Control, 1 mmol·L^-1 NAC, 50 μmol·L^-1 H₂O₂, and 1 mmol·L^-1 NAC + 50 μmol·L^-1 H₂O₂) was analyzed by EdU staining and cell counting. To investigate the level of reactive oxygen species in ADSCs under different treatment conditions, ADSCs proliferated under different treatment conditions for 3 d were stained by CellRox, and the intracellular reactive oxygen species content was detected by High-throughput High-inclusion Live Cell Confocal Imaging System to clarify the relationship between ADSCs proliferation and intracellular reactive oxygen species level. To explore the effect of reactive oxygen species levels within ADSCs on their differentiation, ADSCs were stained with Oil Red O after 10 d of differentiation under different treatment conditions, and the amount of differentiated lipid accumulation in ADSCs was assessed by Image J analysis of stained area, and the relative expression of ADSCs differentiation-related genes was examined by RT-qPCR.【Result】During the proliferation of ADSCs, ADSCs in the group with 50 μmol·L^-1 H₂O₂ were shuttle-shaped and had significantly higher intracellular reactive oxygen species content compared with the control group (P<0.05), and the oxidative stress model was successfully established. Compared with the control group, when 50 μmol·L^-1 H₂O₂ was added during proliferation of ADSCs, the number of ADSCs proliferation was significantly decreased (P<0.05), but the lipid accumulation of ADSCs was significantly higher (P<0.05) when 50 μmol·L^-1 H₂O₂ was added during the differentiation of ADSCs. During the proliferation of ADSCs, ADSCs in the group with the addition of 1 mmol·L^-1 NAC had a shuttle shape, the intracellular reactive oxygen species content was significantly lower (P<0.05), and proliferation number of ADSCs was significantly higher (P<0.05) compared with the control group, but the addition of 1 mmol·L^-1 NAC during the differentiation of ADSCs had no significant effect on the lipid accumulation of ADSCs (P>0.05).【Conclusion】When ADSCs were affected by oxidative stress, the level of reactive oxygen species in ADSCs increases, which was detrimental to the massive expansion of ADSCs in vitro, inducing cell differentiation and accelerating cellular senescence. The addition of 1 mmol·L^-1 NAC to the in vitro expansion system of ADSCs could reduce the oxidative stress damage brought about by long-term culture and exogenous stimulation, and had a protective effect on oxidatively stressed ADSCs, which could effectively promote cell proliferation and did not affect the differentiation ability of the cells.

Effect of Interaction Between Vitamin A and Acetic Acid on the Expression of Genes Related to Milk Composition Synthesis in Bovine Mammary Epithelial Cells

GUO YongMei, LIU Yang, WU Rui, YAN SuMei, ZHAO YanLi, GUO XiaoYu

Scientia Agricultura Sinica. 2023, 56(21):  4344-4358.  doi:10.3864/j.issn.0578-1752.2023.21.016

Abstract ( 93 )   HTML ( 6 )   PDF (602KB) ( 114 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Our previous research found that vitamin A (VA) has a significant effect on promoting the expression of genes related to milk fat and milk protein synthesis in bovine mammary epithelial cells (BMECs). Based on this, this experiment was conducted by adding acetic acid (AA) to explore whether there is an interaction between VA and AA in the expression of genes related to milk composition synthesis, then gaining a more systematic understanding of the regulatory mechanism of VA involvement in milk fat and protein synthesis, this study would provide scientific basis for the rational addition of VA to feed for dairy cows and the improvement of milk quality.【Method】In this experiment, cells were cultured using digestive method of collagenase. Two factor completely randomized trial design was used in this study. The third generation BMECs was randomly divided into 6 treatment groups, with 6 replicates in each group. After starvation treatment of serum-free medium for 24 hours, medium with VA and AA at different concentrations was added, respectively. The six treatment groups were sequentially named as control group (0 mg·mL^-1VA+0 mol·L^-1 AA), AA treatment group 1 (0 mg·mL^-1VA+0.006 mol·L^-1 AA), AA treatment group 2(0 mg·mL^-1VA+0.01 mol·L^-1 AA), VA treatment group(0.001 mg·mL^-1VA+0 mol·L^-1 AA), VAAA1 group(0.001 mg·mL^-1VA+0.006 mol·L^-1 AA), and VAAA2 group(0.001 mg·mL^-1VA+0.01 mol·L^-1 AA). After 24 hours of continuous culture, the cells and culture medium were collected as required, and the cell proliferation rate was measured using MTT method; the content of triglycerides and the activities of key enzymes in milk fat and protein synthesis were measured using kits. The relative expression of genes related to milk fat and milk protein synthesis was measured and calculated by real-time quantitative PCR.【Result】The results showed that adding VA significantly increased the cell proliferation rate (P<0.001), but no significant effect on the cell proliferation rate was found followed by addition of AA or VA and AA (P>0.05). There was an interaction effect between VA and AA on milk fat synthesis. AA increased the triglyceride (TG) content in BMECs (P=0.01), but the addition of VA inhibited TG synthesis in the meantime (P=0.01). AA up-regulated the activities of fatty acid synthase (FASN) and acetyl CoA carboxylase (ACACA) as well as peroxisome proliferator-activated receptor γ (PPARG) gene expression in BMECs (P<0.05; P<0.05; P<0.001), while significant inhibitory effect of VA was observed (P<0.001; P=0.01; P<0.01). AA significantly increased the content of mammalian rapamycin target protein (mTOR) (P=0.05), ribosome S6 protein kinase (S6K1) enzyme activity (P<0.001), and the gene expression of CSN3 in BMECs (P=0.02). VA and AA had an interaction effect on the gene expression of mTOR and CSN2, because the simultaneous addition of VA and AA attenuated the down-regulatory effect on mTOR and CSN2 gene expression after addition of VA or AA alone.【Conclusion】To sum up, AA treatment group 2 had a better promoting effect on milk fat synthesis, while VAAA2 group had a weaker effect; AA treatment group 1 had a better promoting effect on milk protein synthesis, while VAAA1 group had a weaker effect. Therefore, 0.01 mol·L^-1 of AA alone is better for promoting milk fat synthesis, while 0.006 mol·L^-1 of AA is more conducive to milk protein synthesis.