Table of Content

16 March 2023, Volume 56 Issue 6

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Identification of Excellent Wheat Germplasms and Classification of Source-Sink Types

NAN Rui, YANG YuCun, SHI FangHui, ZHANG LiNing, MI TongXi, ZHANG LiQiang, LI ChunYan, SUN FengLi, XI YaJun, ZHANG Chao

Scientia Agricultura Sinica. 2023, 56(6):  1019-1034.  doi:10.3864/j.issn.0578-1752.2023.06.001

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【Objective】 The aim of this study is to screen the evaluation indexes of wheat source-sink and classify the source-sink types. In addition, the relationships between different source-sink types and the agronomic traits, yield and grain quality of wheat were also clarified, which provides a better understanding of wheat source-sink metabolism and wheat breeding. 【Method】 In this study, the related agronomic traits of source metabolism and sink metabolism of 190 wheat varieties which from different regions were measured. Then, the source-sink metabolic capacity of wheat was evaluated by principal component analysis, and the superior wheat materials were selected according to the composite score. Furthermore, the hierarchical clustering was conducted based on the source size (leaf area), source activity, sink number and sink activity. Then, based on the clustering results, the source-sink types of wheat were classified and the source-sink characteristics of different region of wheats were analyzed. Meanwhile, the agronomic, yield and quality traits of different wheat source-sink types were compared and analyzed. 【Result】 For better understanding the results, six indicators related to source activity were converted into three independent indicators (photochemical quenching coefficient, maximum photosynthetic potential, chlorophyll content), and five indicators related to sink activity were converted into two independent indicators (maximum filling rate, filling duration) based on the principal component analysis. The cumulative contributions of three source activity indicators and two sink activity indicators were 82.80% and 92.90%, respectively. Then the top 10 wheat varieties were screened based on the source activity, source size (leaf area), sink activity, and sink number (number of spike grains). According to the source-library relationship, all the wheat varieties were divided into three major categories and eight subcategories, including sufficient source-weak sink type (medium source-weak sink type, strong source-medium sink type), weak source-sufficient sink type (medium source-strong sink type, weak source-medium sink type) and source-sink balance type (weak source-weak sink type limited by sink activity, weak source-weak sink type limited by source activity and grain number per spike, medium source-medium sink type, and strong source-strong sink type). 76.84% of wheat lines were contained in three subcategories (weak source-weak sink type, the medium source-strong sink type, and strong source-strong sink type), other wheat lines were distributed in other subcategories evenly. Most wheat varieties of China showed similar source-sink relationship, which presented the medium level of source activity, leaf area and grain number per spike, while the sink activity was high. But the sink activity of wheat varieties which were cultivated at the middle and lower reaches of the Yangtze River is low. The plant height, length of uppermost internode and spikelet number in different categories indicated that the sufficient source-weak sink type>source-sink balance type>weak source-sufficient sink type, and the dry protein content, dry wet gluten content and sedimentation value in different categories showed that source-weak sink type > source-sink balance type > weak source-sufficient sink type. Grain water absorption showed that the stronger the sink activity had the higher the water absorption rate. The yield of per plant was different among different source-bank groups, but it was positively correlated with the source activity and the number of grains per spike in the three subcategories which contained most wheat varieties. 【Conclusion】 In this study, photochemical quenching coefficient, maximum photosynthetic potential and chlorophyll content could be used as the main indexes to evaluate the activity of wheat source. The maximum filling rate and filling duration could be used as the main indexes to evaluate the activity of wheat sink. In practical production, the wheat yield could be improved by increasing the number of grains per spike and the activity of source. When the supply capacity of source is stronger than the absorption capacity of sink, the plant height, peduncle length, spikelet number, dry protein content, dry wet gluten content and sedimentation value would be increased. Strong sink activity would help us to improve the water absorption of wheat grains.

Investigation of Low Nitrogen Tolerance of ZmCCT10 in Maize

LI YiPu, TONG LiXiu, LIN YaNan, SU ZhiJun, BAO HaiZhu, WANG FuGui, LIU Jian, QU JiaWei, HU ShuPing, SUN JiYing, WANG ZhiGang, YU XiaoFang, XU MingLiang, GAO JuLin

Scientia Agricultura Sinica. 2023, 56(6):  1035-1044.  doi:10.3864/j.issn.0578-1752.2023.06.002

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【Objective】 The lack of soil nitrogen impacts the yield and quality of maize, which is a major problem of maize production in China. ZmCCT10 encodes the transcription factor, which is pleiotropic. ZmCCT10 is a very important co-factor regulating the growth, development and responding to abiotic stress of maize. The molecular mechanism of maize tolerance to low nitrogen is the basis for breeding maize varieties with low nitrogen tolerance and high nitrogen efficiency. 【Method】 In this study, we compared the traits those relate to low-nitrogen tolerance, expression pattern of ZmCCT10 and transcriptome results of ZmCCT10 near-isogenic lines under low-nitrogen stress and complete nutrient conditions. To analysis the characteristics of ZmCCT10 in response to low-nitrogen stress and the molecular mechanisms involved in low-nitrogen tolerance were explored. 【Result】 This study indicated that different alleles of ZmCCT10 showed significant differences in root length traits, biomass and nitrogen physiological traits under low nitrogen stress. The Y331-ΔTE haplotype without transposon insertion of ZmCCT10 had significantly longer total root length, main radicle length and lateral root length than Y331 after low nitrogen stress. What is more, root dry weight, shoot dry weight, nitrogen accumulation and nitrate reductase activity were also significantly higher than Y331. The expression levels of ZmCCT10 in roots and leaves were significantly higher than those in the control treatment. The expression level of ZmCCT10 in roots reached a peak at 3 hours after stress treatment. In leaves, the expression of ZmCCT10 continued to increase and peaked 6 hours after stress treatment. Root samples were collected under 0.04 mmol·L^-1 low nitrogen stress after 3h for transcriptome sequencing. The correlation coefficients between biological replicates are more than 0.9. GO enrichment analysis showed that the expression levels of amine synthesis process and cellular nitrogen compound catabolic process were significantly different in near-isogenic lines after low nitrogen stress. Combined with the amount and expression pattern of differential genes, ZmCCT10-regulated candidate genes involved in low-nitrogen tolerance were selected. qRT-PCR confirmed that the expression levels of ZmMPK5, ZmNS2 and other genes were significantly different after stress in near-isogenic lines. 【Conclusion】 ZmCCT10 is a candidate gene involved in low nitrogen tolerance in maize and it participates in the low-nitrogen tolerance response of maize as transcriptional regulation.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Difference in the Comprehensive Response of Dry Matter Accumulation of Rice at Tillering Stage to Rising Atmospheric CO₂ Concentration and Nitrogen Nutrition and Its Physiological Mechanism

HE Jiang, DING Ying, LOU XiangDi, JI DongLing, ZHANG XiangXiang, WANG YongHui, ZHANG WeiYang, WANG ZhiQin, WANG WeiLu, YANG JianChang

Scientia Agricultura Sinica. 2023, 56(6):  1045-1060.  doi:10.3864/j.issn.0578-1752.2023.06.003

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【Objective】 The aim of this study was to explore the comprehensive response difference and physiological mechanism of different rice cultivars in response to elevated atmospheric CO₂ concentration and nitrogen nutrition. 【Method】 In this study, a rice cultivar Liangyoupeijiu (LY) with high response to CO₂ (high-response rice cultivar) and a rice cultivar Nanjing 9108 (NJ) with low response to CO₂ (low-response rice cultivar) were selected as materials. Hydroponic experiments were carried out in the climate chamber. Two CO₂ treatments and two nitrogen treatments were set up with ambient CO₂ concentration (A-CO₂, 400 μmol·mol^-1) and elevated CO₂ concentration (E-CO₂, 600 μmol·mol^-1), and high nitrogen (HN, 1.25 mmol·L^-1 NH₄NO₃) and low nitrogen (LN, 0.25 mmol·L^-1 NH₄NO₃), respectively. The effects of elevated CO₂ concentration on root morphology and physiological activity, cytokinin (CTKs) content in leaves and roots, nitrogen assimilation enzyme activity, physiological characteristics of leaves, photosynthetic parameters, and dry matter accumulation of different rice cultivars were analyzed. 【Result】 (1) E-CO₂ significantly increased the total crown root number, total root length (except LN level), total root surface area, and average diameter of LY, improved root respiration rate and maintained high root oxidation power, but had no significant or opposite effects on NJ. (2) Regardless of nitrogen level, E-CO₂ significantly increased CTKs content in LY leaves and roots, but significantly decreased zeatin nucleoside (ZR) content in NJ roots at HN level. (3) At LN level, E-CO₂ significantly increased GOGAT and GDH activities in LY leaves, but significantly decreased NR activities in NJ leaves. At HN level, the activity of LY nitrogen assimilation enzyme increased under E-CO₂ condition, but only NR activity increased in NJ. (4) At LN level, E-CO₂ increased the net photosynthetic rate (P_n) of LY and NJ by 28.0% and 29.4%, respectively. At HN level, P_n of the two cultivars increased by 41.0% and 28.1%, respectively. The significant increase in photosynthetic response of LY was attributed to the significant increase in leaf maximum carboxylation efficiency (V_c,max), maximum photosynthetic electron transport efficiency (J_max), ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) content, chlorophyll content, and leaf nitrogen content. (5) E-CO₂ significantly increased the leaf area per plant of LY under different nitrogen levels, but had no significant effect on NJ. (6) E-CO₂ significantly increased the organs and total biomass of LY, and the increased level under HN was significantly higher than that under LN level. E-CO₂ did not significantly affect the total biomass of NJ under different nitrogen treatments, but significantly reduced the underground biomass of NJ under HN (-16.7%). 【Conclusion】 No matter at the HN or LN treatment, the response of dry matter production and physiological characteristics of LY to E-CO₂ was higher than that of NJ. In the early growth stage, LY had better root morphological characters and root activity, higher CTKs content, stronger nitrogen assimilation ability, larger green leaf area and photosynthetic response capacity, which were important reasons accounting for the higher response of dry matter production under E-CO₂ conditions.

Effects of Powdery Mildew on Photosynthetic Characteristics and Quantitative Simulation of Disease Severity in Winter Wheat

CHANG ChunYi, CAO Yuan, GHULAM Mustafa, LIU HongYan, ZHANG Yu, TANG Liang, LIU Bing, ZHU Yan, YAO Xia, CAO WeiXing, LIU LeiLei

Scientia Agricultura Sinica. 2023, 56(6):  1061-1073.  doi:10.3864/j.issn.0578-1752.2023.06.004

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【Objective】 The objective of this paper was to clearly demonstrate the effects of powdery mildew on photosynthetic characteristics of winter wheat and to establish a model for simulating effects of powdery mildew stress on wheat photosynthetic productivity. 【Method】 To clarify the effects of powdery mildew on wheat photosynthetic characteristics, the powdery mildew experiments of wheat were conducted under two initial inoculation degrees of wheat powdery mildew at jointing and booting stages. On this basis, a prediction model of wheat powdery mildew severity was established to quantify the physiological effects of powdery mildew on wheat. And then, based on the single leaf net photosynthetic rate (P_n) and leaf area index (LAI), the wheat powdery mildew severity prediction model was coupled with the crop growth model (WheatGrow). 【Result】 Under the stress of powdery mildew, P_n and LAI showed a decreasing trend. Compared with the control (CK), the averaged P_n and LAI decreased by 18.81% and 23.41%, respectively. Moreover, the effects of stages of powdery mildew on P_n and LAI were more serious than the initial inoculation degrees. In general, the development of wheat powdery mildew in the field had obvious gentle period, exponential outbreak period and stable period, and the temporal dynamic characteristics of wheat powdery mildew epidemic under each treatment accorded with Logistic function. Therefore, based on the Logistic fitting results, the wheat powdery mildew disease stress factor was established to reflect the stress effects of powdery mildew on wheat physiological indexes. In addition, based on the photosynthesis productivity sub-model of WheatGrow and the effect factor of wheat powdery mildew severity, the algorithms to simulate the effects of powdery mildew on P_n and LAI were established, and then the improved WheatGrow model was estimated by using the powdery mildew experimental datasets in independent years. 【Conclusion】 The integrated model with powdery mildew stress algorithms was better than the original WheatGrow model in predicting P_n, LAI, aboveground biomass and yield under powdery mildew stress condition, with the simulation accuracy improved by 53.29%, 43.61%, 60.09% and 67.57%, respectively. The improved model could provide the digital tool and technical support for prediction of wheat powdery mildew severity and the quantitative evaluation of wheat yield loss.

Effect of Nitrogen Rates on Yield Formation and Nitrogen Use Efficiency in Oilseed Under Different Cropping Systems

LI XiaoYong, HUANG Wei, LIU HongJu, LI YinShui, GU ChiMing, DAI Jing, HU WenShi, YANG Lu, LIAO Xing, QIN Lu

Scientia Agricultura Sinica. 2023, 56(6):  1074-1085.  doi:10.3864/j.issn.0578-1752.2023.06.005

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【Objective】 The aim of this study was to investigate the effects of nitrogen application on yield formation and nutrient utilization of oilseed (Brassica napus L.) under different cropping systems. 【Method】 A field experiment was carried out in Huanggang, Hubei Province. An oilseed variety ‘Zhongyouza19’ was used as the material, setting with two cropping systems (rice-oil rotation, RO; soybean-oil rotation, SO) and four nitrogen rates (N0, 0; N1, 90 kg·hm^-2; N2, 180 kg·hm^-2; N3, 270 kg·hm^-2) in this study. The yield and its components, dry matter accumulation, agronomic traits, nitrogen content and seeds quality were measured. 【Result】 (1) The oilseed yield of SO was significantly higher than that of RO, and the pods per plant, seeds per pod and 1000-seeds weight of oilseed in different cropping systems all tended to increase significantly by increasing the amount of nitrogen. Compared with N0, the seed yield of RO increased by 176.68%, 436.49% and 835.40% under N1, N2 and N3 treatments, respectively, while that of SO increased by 123.96%, 344.46% and 547.25%, respectively. Compared with RO, the seed yield under SO increased by 62.09%, 31.33%, 71.79% and 12.21% under N0, N1, N2 and N3 treatments, respectively. (2) The root crown diameter, plant height, first effective branch height and branch number of SO oilseed were significantly higher than those of RO at maturity stage, and the increase in each agronomic trait index was significant under different cropping systems with the increase in nitrogen application; the root biomass and above-ground biomass of SO were significantly higher than those of RO at all growth stages, but the root shoot ratio was lower than that of RO. The root shoot ratio decreased significantly after seedling stage in both cropping system with increasing nitrogen application. (3) Nitrogen content and nitrogen accumulation in the root, pod shell, stalk and seeds of SO were higher than those in RO, and the increases in nitrogen content and nitrogen accumulation in each part were significant with the increase in nitrogen application; the apparent nitrogen recovery efficiency under SO was higher than that under RO, and the apparent nitrogen recovery efficiency under RO increased with the increase in nitrogen application. (4) Compared with the RO, the soluble sugar content of pod shell under SO was lower, while the amino acid content and amino acid/soluble sugar content were higher with the same nitrogen application. The soluble sugar content decreased, but the amino acid content and amino acid/soluble sugar content increased with the increase of nitrogen application. Therefore, the oil content of oilseed under SO was lower than that under RO due to the limitation of fatty acid synthesis substrate, and the oil content of seeds decreased significantly with the increase of nitrogen application in cropping system. Oil yield was the maximum in both cropping system at 270 kg·hm^-2 nitrogen application level, 1 678.60 and 1 665.33 kg·hm^-2 for RO, and 1 684.03 and 1 687.10 kg·hm^-2 for SO, respectively, but the difference in oil yield between 180 and 270 kg·hm^-2 nitrogen application for SO was not significant. 【Conclusion】 In conclusion, the nitrogen rate for RO could be controlled at about 270 kg·hm^-2, but the nitrogen rate for SO could be controlled at about 180 kg·hm^-2 to ensure higher nitrogen use efficiency and higher oil yield.

PLANT PROTECTION

Screening of Differential Genes and Analysis of Metabolic Pathways in the Interaction Between Fusarium verticillioides and Maize Kernels

QU Qing, LIU Ning, ZOU JinPeng, ZHANG YaXuan, JIA Hui, SUN ManLi, CAO ZhiYan, DONG JinGao

Scientia Agricultura Sinica. 2023, 56(6):  1086-1101.  doi:10.3864/j.issn.0578-1752.2023.06.006

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【Objective】 Maize ear rot caused by Fusarium verticillioides is one of the most serious diseases in maize producing areas in China. The objective of this study is to understand the differences in gene expression during the plant-pathogen interaction at different stages, and to provide a basis for pathogenic mechanism of the pathogen infection and resistance mechanism of maize. 【Method】 Illumina platform was used to sequence the transcriptome of maize kernels infected with F. verticillioides at 0, 4, 12, and 72 h. The differentially expressed genes (DEGs) of maize and F. verticillioides were screened with |log₂FC|≥1, P-adjust<0.05 as threshold and clean reads were compared with genome of maize and F. verticillioides, separately. Functional annotation and enrichment analysis of DEGs were carried out by using GO and KEGG databases. Goatools software was used to analyze the expression changes of genes related to plant-pathogen interaction, MAPK signaling pathway and plant hormone signal transduction pathway. Sequencing results were verified by quantitative real-time PCR (qRT-PCR). 【Result】 A total of 140, 400 and 1 945 DEGs were up-regulated and 9, 302, and 1 784 DEGs were down-regulated in F. verticillioides after 4, 12 and 72 h interaction, respectively. A total of 293, 692, and 1 426 DEGs were up-regulated and 320, 482, and 153 DEGs were down-regulated in maize after 4, 12 and 72 h interaction, respectively. GO and KEGG enrichment analysis of DEGs showed that F. verticillioides grew in intercellular space at the early stage of pathogen infection. The DEGs were enriched in RNA biosynthesis, cell wall structural component, fatty acid biosynthesis, protein metabolism, carbohydrate metabolism, biological process, and metabolic process. Reactive oxygen species (ROS) was triggered in maize at the early stage of infection. The DEGs were enriched in response to ROS, hydrogen peroxide, chitinase activity, monooxygenase activity, lignin metabolism. At the later stage of infection, F. verticillioides colonized and expanded in maize, and the DEGs were enriched in carbohydrate and cell wall polysaccharide catabolic process, transmembrane transport and oxidoreductase activity. Maize responded to pathogen infection through phenylpropanoid, lignin, flavonoid biosynthesis, MAPK signaling pathway, plant-pathogen interaction and plant hormone signal transduction. Six DEGs of maize and six DEGs of F. verticillioides were randomly selected for qRT-PCR. The results were consistent with those of transcriptome sequencing, which confirmed the accuracy of RNA-seq. 【Conclusion】 At the early stage of infection, F. verticillioides grew in the intercellular space, triggering ROS outbreak in maize and the expression of related pathway differential genes. At the middle and late stages of infection, the pathogen further colonized and expanded in maize with starch as nutrient. Maize responded to the infection of F. verticillioides through biosynthesis of phenylpropanoid, lignin and chitinase. Meanwhile, plant-pathogen interaction, MAPK signaling pathway, and plant hormone signal transduction were involved in the resistance to the infection of F. verticillioides.

Application Evaluation of the Whole-Process Biological Management Scheme for Apple Pests in the Weibei Dry Highland

SUN Zheng, LAI ZhongXiao, ZHAO XiaoMin, JIANG ZhiLi, CHEN GuangYou, MA ZhiQing

Scientia Agricultura Sinica. 2023, 56(6):  1102-1112.  doi:10.3864/j.issn.0578-1752.2023.06.007

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【Objective】 One of the key problems restricting the green development of apple industry in China lies in the lack of green prevention and control technology of pests. In this paper, the application effect of the whole-process biological management technology for apple pests (WBTAP) in Weibei Dry Highland was comprehensively evaluated, hoping to provide a basis for the extension of the technology system. 【Method】 In the apple orchards of Ecological Agriculture Science and Technology Experiment and Demonstration Station in the highland of Northwest A&F University (Chengcheng County, Weinan City), the biological management area and the conventional management area were set up. The biological management area adopted WBTAP (from March to the end of November, all biopesticides were applied according to the occurrence of pests), while the conventional management area adopted the current local control technology which mainly based on chemical pesticides. The yield and quality of apple and the dynamics of natural enemy insects in orchard were determined by publicly reported methods, and pesticide residues in apple leaf, fruit and orchard soil were detected by third-party organizations. The experiment has been carried out for two consecutive years in 2019 and 2020. 【Result】 The apple yields of orchards with WBTAP in 2019 and 2020 were 51 585 and 53 639 kg·hm^-2, respectively, which were not significantly different from those of conventional chemical management technology of apple pests (CCTAP). There was no significant difference in the general physical properties of apples, such as fruit shape, firmness and edible rate between the two management technologies, but the single fruit weight of WBTAP orchard was better than that of CCTAP orchard, reaching 342.89 and 377.89 g in two years, respectively. In 2019, the soluble solid, pH, Vc content and soluble sugar content of apples in the WBTAP orchard were significantly higher than those in the CCTAP orchard, while the titratable acid content was significantly lower than that in the CCTAP orchard, and the indexes were 17.06%, 4.69, 9.23 mg/100 g, 16.60% and 0.26%, respectively. The results of two years showed similarity and consistency. No pesticide residue was found in apple fruits, leaves and soil in the WBTAP orchard during the two years, while many chemical pesticide residues such as tebuconazole, lambda-cyhalothrin and chlorpyrifos were detected in the CCTAP orchard. In addition, the number of natural enemy insects in the WBTAP orchard was significantly higher than that in the CCTAP orchard. Taking Coccinella septempunctata as an example, on May 24th, 2019, there were 1.5 ladybirds per shoot in the WBTAP orchard, while there was only 0.5 ladybird in the CCTAP orchard. The natural enemy insects in the WBTAP orchard also existed longer than in the CCTAP orchard. From May 3rd to July 12th, 2019, C. septempunctata appeared for 71 days in the WBTAP orchard, but only for 50 days in the CCTAP orchard. 【Conclusion】 There was no significant difference in apple yield between the WBTAP orchard and CCTAP orchard, but the apple quality of WBTAP orchard was better. No pesticide residues were found in apple fruits, leaves and soil in the WBTAP orchard, and the number of natural enemy insects (C. septempunctata, Harmonia axyridis and Chrysopa) in the WBTAP orchard was significantly higher than that in the CCTAP orchard. The technology system shows excellent economic, environmental and ecological benefits, and the fruit quality reaches the requirements of food safety. It can provide technical reference for organic apple production, and has the value of further popularization and application.

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

Effects of Different Varieties of Phosphate Fertilizer Application on Soil Phosphorus Transformation and Phosphorus Uptake and Utilization of Winter Wheat

WANG XiaoXuan, ZHANG Min, ZHANG XinYao, WEI Peng, CHAI RuShan, ZHANG ChaoChun, ZHANG LiangLiang, LUO LaiChao, GAO HongJian

Scientia Agricultura Sinica. 2023, 56(6):  1113-1126.  doi:10.3864/j.issn.0578-1752.2023.06.008

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【Objective】 Effects of different phosphorus (P) fertilizers application on soil P transformation as well as P uptake and utilization in wheat were investigated, so as to provide a theoretical basis for precise matching and efficient utilization of P fertilizer in soil - P fertilizer - crop system. 【Method】 The pot experiment was conducted in lime concretion black soil and red soil including six treatments: no P fertilizer (CK); application of calcium superphosphate (SSP), calcium magnesium phosphate (FMP), diammonium phosphate (DAP), calcium superphosphate (TSP) and ammonium polyphosphate (APP). The relationship between the P transformation in rhizosphere as well as non-rhizosphere soils with P accumulation in wheat at the jointing and anthesis stages was analyzed. 【Result】 Soil Olsen-P concentration increased by 194%-662% after application of P fertilizer in lime concretion black soil. Soil Olsen-P concentration in wheat rhizosphere soil followed the order: APP, TSP, DAP, FMP, SSP, and CK. The H₂O-P and NaHCO₃-Pi concentration was significantly increased, whereas the Residual-P concentration was significantly reduced after phosphate fertilizer application. Both H₂O-P and NaHCO₃-Pi concentration was positively correlated with soil Olsen-P. At the jointing stage, in comparison to that of the control, TSP and APP application increased NaHCO₃-Pi concentration by 41.0 and 36.0 mg·kg^-1, respectively. For the red soil, soil Olsen-P concentration in rhizosphere soil increased by 84%-791% as P fertilizer was applied. And soil Olsen-P concentration under DAP and TSP treatments was significantly higher than that under other P fertilizer treatments. The NaHCO₃-Pi and NaOH-Pi concentration increased by 275.2%-848.3% and 26.9%-58.3%, respectively, which was positively correlated with rhizosphere soil Olsen-P concentration. After P fertilizer application, the most significant effects were found under DAP and TSP treatments. At the jointing stage, there was a significant positive correlation between shoot P accumulation and soil Olsen-P concentration in lime concretion black soil and red soil. When soil Olsen-P concentration increased by 1 mg·kg^-1, shoot P accumulation increased by 0.87 and 0.37 mg/pot respectively in lime concretion black soil and red soil. In lime concretion black soil, shoot P accumulation significantly increased by 15.44%-50.9% compared with the control as different P fertilizers addition, and the APP and TSP significantly increased shoot P accumulation and utilization efficiency in shoot than other P fertilizers. After P fertilizer application in red soil, shoot P accumulation and grain yield of wheat increased by 123.7%-643.9% and 75.5%-337.2%, respectively. The grain yield, shoot P accumulation and P utilization efficiency under TSP treatments were significantly higher than that under other P fertilizer treatments. 【Conclusion】 In lime concretion black soil, the concentration of H₂O-P and NaHCO₃-Pi was significantly increased after application of APP and TSP. In red soil, the NaHCO₃-Pi and NaOH-Pi concentration was significantly increased after the application of DAP and TSP. Therefore, in order to increase wheat P efficiency, APP or DAP was recommended as a proper fertilizer in lime concretion black soil, while DAP or TSP was recommended as a proper P fertilizer in red soil.

Decomposition Characteristics of Straw and Organic Fertilizer Mixed Soil After Landfill in Typical Area

LI DeJin, MA Xiang, SUN Yue, XU MingGang, DUAN YingHua

Scientia Agricultura Sinica. 2023, 56(6):  1127-1138.  doi:10.3864/j.issn.0578-1752.2023.06.009

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【Objective】 Straw and manure are the main sources of organic materials in China, and rotary tillage is the main way of returning farmland. In this study, the characteristics and driving factors of their decomposition process in typical farmland soils in China were investigated to provide a scientific basis for better utilization of straw resources and rational application of manure. 【Method】 The landfill experiment of field organic material mixed with soil was carried out on a typical black soil, fluvo-aquic soil, and red soil in China. Four treatments were set up: wheat straw plus soil (WS+Soil), maize straw plus soil (MS+Soil), pig manure plus soil (PM+Soil), and cow manure plus soil (CM+Soil). All the organic materials (8 g carbon) were mixed with 200 g of soil in a nylon mesh bag buried in soil, six samples were taken within one year after landfilling, once from 2 to 2.5 years after landfilling, and once in 3 years, then a total of eight samples were taken. The decomposition differences of organic materials in different mixtures were analyzed. The double exponential equation was used to clarify the proportion and decomposition rate of easy-to-decompose carbon pool and refractory organic carbon pool, and to clarify the fast decomposition rate, slow decomposition rate and accumulated temperature turning point of organic materials in each soil. The random forest model was used to quantify the relative contribution of material composition and environmental factors to the decomposition rate. 【Result】 The humification coefficient of straw pluil was ranged from 22% to 43%, and that of manure plus soil was ranged from 45% to 58%. The decomposition rate of manure plus soil was slower than straw plus soil, and there was little difference between regions. Besides, the decomposition of organic materials was accelerated from north to south, and the decomposition of straw was faster than that of organic fertilizers. The proportion of decomposable organic carbon poor of straw (70%-87%) was higher than that of organic fertilizer (57%-83%), and the decomposition rate of straw decomposable carbon pool k₁ (1.0%·a^-1-4.9%·a^-1) was higher than that of organic fertilizer k₁ ( 0.7%·a^-1-1.1%·a^-1). There was little difference in the turning point of accumulated temperature of straw in the three types of soil. Before 3 700℃, it was the stage of rapid decomposition, and then it was the stage of slow decomposition. On the other hand, the difference in accumulated temperature at the turning point of rapid decomposition and slow decomposition of organic fertilizer gradually increased from north to south, and the accumulated temperature at the turning point of organic fertilizer was 2-5 times higher that of straw. Soil accumulated temperature and soil organic carbon content were the main driving factors of mixed soil straw and organic fertilizer, contributing about 17% and 13% of the decomposition rate, respectively. In addition, the main driving factor for mixed soil straw was the ratio of soil carbon to nitrogen, but the main driving factor for mixed soil organic fertilizer was the time. 【Conclusion】 Straw returning to the field decomposed faster than organic fertilizer, and the high proportion of easily decomposable organic carbon pool with fast decomposition rate of straw was one of the main reasons for the difference. For straw, the ratio of carbon to nitrogen was the main factor affecting its decomposition, and for organic fertilizer, it was time. Therefore, the ratio of carbon to nitrogen of soil and material should be considered to regulate the decomposition of straw, and the long-term effect of organic fertilizer should be fully considered.

HORTICULTURE

Regulation Mechanism of Brassinolide on Anthocyanins Synthesis and Fruit Quality in Wine Grapes Under High Temperature Stress Based on Transcriptome Analysis

WANG YueNing, DAI HongJun, HE Yan, WEI Qiang, GUO XueLiang, LIU Yan, YIN MengTing, WANG ZhenPing

Scientia Agricultura Sinica. 2023, 56(6):  1139-1153.  doi:10.3864/j.issn.0578-1752.2023.06.010

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【Objective】 The aims of the study were to analyze the genes involved in the regulation of grape anthocyanin accumulation and fruit quality by 2,4-Epibrassinolide (EBR) under high-temperature stress, and to explore the molecular mechanism of EBR regulation anthocyanin accumulation in grapes under high-temperature stress. 【Method】 Cabernet Sauvignon grapes were treated with high-temperature stress using infrared emitter, and sprayed 0.6 mg∙L^-1 of EBR before the veraison. The content of total anthocyanins, total sugar, reducing sugar and sucrose were quantified using the ultraviolet visible spectrophotometer. The mechanism of EBR-mediated accumulation of anthocyanin under high-temperature stress was analyzed by transcriptome sequencing. 【Result】 Starting from veraison, the anthocyanin content increased gradually under various treatments. At maturity, the total anthocyanin content in the high temperature group (HT) was significantly lower than that in the control group (CK), and the anthocyanin content in the high temperature and EBR group (HTE) was higher than that in the HT group, but lower than CK group. Under HT treatment, the accumulation pattern of total sugar, reducing sugar and sucrose was similar to that of anthocyanins and lower than those of CK group at maturity stage. Compared with HT group, the contents of various sugars in HTE group were increased. The differences in transcriptome levels of Cabernet Sauvignon fruits under the three treatments were analyzed. Through GO and KEGG enrichment, 14 differential genes related to sucrose and starch metabolic pathways, among which 10 genes were significantly up-regulated and 4 genes were significantly down-regulated under HT and HTE treatments. The expressions of 11 genes were different in the phenylpropane metabolic pathway. Seven genes involved in anthocyanin synthesis were up-regulated under the HT treatment, and 4 genes involved in lignin synthesis were significantly up-regulated under the HT treatment, indicating that high temperature might promote lignin synthesis and reduce the accumulation of anthocyanins. In the endogenous hormone signaling pathway, the expression of the ABA signaling receptor genes PP2C and SnRK2 was significantly increased under high-temperature stress, and might be involved in regulating the synthesis of grape anthocyanin under high-temperature stress together with EBR. The expression patterns of some differential genes were verified by qRT-PCR, which confirmed the accuracy of transcriptome data. 【Conclusion】 EBR alleviated the inhibitory effect of high temperature stress on grapevine anthocyanin accumulation, probably due to the fact that EBR reduced the expression of lignin-related genes and changed the expression pattern of grape endogenous hormone signal transduction genes.

Effects of Exogenous Abscisic Acid Treatment on Periderm Suberification of Postharvest Mini-Tuber Potato from Aeroponic System and Its Possible Mechanisms

ZHANG ZhiPeng, TAN YunXiu, LI BaoJun, LI YongCai, BI Yang, LI ShouQiang, WANG XiaoJing, ZHANG Yu, HU Dan

Scientia Agricultura Sinica. 2023, 56(6):  1154-1167.  doi:10.3864/j.issn.0578-1752.2023.06.011

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【Objective】 The aim of this study was to evaluate the effect of exogenous abscisic acid treatment on periderm suberification of postharvest potato mini-tuber from aeroponic system, and to further explore its mechanism. 【Method】 The original seed potato mini-tubers of Tongshu No. 1, free of artificial damage, were pre-stored at 15℃ (RH86-88%) respectively in dark environment for wound healing after dipping in exogenous abscisic acid (ABA) for 10 min. The weight loss rate of tuber during wound healing was measured, the accumulation of suberin and cork in pericardium cells was observed, and the phenylpropane and reactive oxygen metabolism in pericardium tissue of potato tuber were also analyzed. 【Result】 25 mg∙L^-1 ABA treatment and prestorage at 15℃ significantly reduced weight loss rate of microtuber, accelerated the accumulation of suberin and corkification in perituber tissue. Further studies showed that the key enzyme activities of phenylpropane metabolism and the content of total phenols, flavonoids and lignin of tuber tissues were significantly increased after ABA treatment, the enzyme activities of phenylalnine ammonia-lyase (PAL), 4-coumarate coenzyme A ligase (4CL), cinnamic acid 4-hydroxylase (C4H) and cinnamyl alcohol dehydrogenase (CAD) were significantly increased by 79.02%, 3.21%, 12.99% and 11.54%, respectively, compared with that of the control 21 days after storage. At the same time, ABA treatment decreased cell membrane permeability and malondialdehyde content, and increased $\mathrm{O}_2^{\bar{.}}$ and H₂O₂ content and enzyme activities of NADPH oxidase (NOX), super oxide dismutase (SOD), catalase (CAT) and peroxidase (POD), the enzyme activities of NOX, SOD, CAT and POD in treated tubers were increased by 47.33%, 8.61%, 27.27% and 14.50%, respectively, 21 days after storage. In addition, ABA treatment also activated antioxidant system AsA-GSH cycle and effectively maintained the intracellular redox balance. 【Conclusion】 Postharvest ABA treatment could promote the accumulation of suberin and corkification in perituber tissue by activating the metabolism of phenylpropanoid and reactive oxygen species in periderm tissue, and accelerated the postharvest suberification process of aeroponic cultivated micro-potato tubers.

FOOD SCIENCE AND ENGINEERING

Apparent Matrix Effect of Yeast Polysaccharides from S. cerevisiae on the Hydrolysis of Wine Fruity Esters

KONG CaiLin, XU YinHu, HUANG Jie, FENG Lin, YAN XinYi, TAO YongSheng

Scientia Agricultura Sinica. 2023, 56(6):  1168-1176.  doi:10.3864/j.issn.0578-1752.2023.06.012

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【Objective】 The aim of this study was to investigate the apparent matrix effect of yeast polysaccharide (YP) from S. cerevisiae on the hydrolysis of fruity ester, and to explore the potential application of yeast polysaccharide in stabilizing wine aroma profile and expand shelf life of product. 【Method】 YP was extracted from S. cerevisiae by hot water extraction and alkali methods, and the basic components of YP were analyzed by ultraviolet spectrophotometer (UV), gas chromatography (GC) and high- performance liquid chromatography (HPLC). The model wine containing the conventional concentration of fruity esters was prepared and treated with YP, and the concentration of YP was set in the range of 0-2.0 g·L^-1. The effect of YP on the volatility of fruity esters was analyzed by the static headspace method. Next, the model wines with different treatments were stored at 4℃ for 6 months, and the content of fruity esters in model wine was regularly monitored. Finally, sensory analysis was used to evaluate the aroma notes of model wine stored 6-months. 【Result】 Instrumental analysis showed that the total polysaccharide content of YP was (72.61±3.29)%, and the protein contents accounts for (11.20±0.02)%. The main monosaccharide composition of YP was mannose and glucose, and their molar ratio was 1.790:1. The high molecular weight components of YP are 18, 163 and 21 819 kD, and the low molecular weight components are 576 Da. Static headspace analysis indicated that YP treatment could reduce the volatility of acetate esters in model wine, especially 0.8 g∙L^-1. While YP treatment could increase the volatility of ethyl esters. Data of regular sampling found that the hydrolysis rate of ethyl esters was significantly higher than that of acetate esters during 6 months storage. Compared with the control, 0.4-0.8 g∙L^-1 YP slowed down the hydrolysis of acetate esters and ethyl esters by 10%-40% and 3.7%-26.7%, respectively. Sensory analysis showed that model wine added with YP showed higher MF% of temperate sour and sweet fruity, and preserved fruit and floral aroma notes of wine samples compared with the control. 【Conclusion】 From the study of model wine system, it was concluded that adding 0.4-0.8 g∙L^-1 YP during wine storage slowed down the hydrolysis of fruity esters, stabilized wine fruity aroma profile, and showed potential application value for prolonging wine shelf life.

ANIMAL SCIENCE·VETERINARY SCIENCE

Comparing Methods for Correcting Days to 100 kg of Sows in Licha Black Pig and Its Intercross with Berkshire

CUI DengShuai, XIONG SanYa, ZHENG Hao, LI LongYun, YU NaiBiao, HUANG ZhiYong, XIAO ShiJun, GUO YuanMei

Scientia Agricultura Sinica. 2023, 56(6):  1177-1188.  doi:10.3864/j.issn.0578-1752.2023.06.013

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【Objective】 The aims of this study were to compare the powers of three correction coefficients for days to 100 kg (D_100kg), so as to provide the reference for pig breeding farms to select the appropriate correction coefficient for D_100kg according to the data they have. 【Method】 A total of 1 344 pigs were used in this study, including Licha black pig, F₁ (BL₁) and F₂ (BL₂) from its intercross with Berkshire boars. Body weight and age in days for each pig were recorded everyday during its growth and fattening period. The data were qualified according to following criteria: the start body weight ≥25kg, the final body weight among 80 - 125 kg, the slope of the regression equation of body weight to age in days within±2 standard deviations of its average and so on. Three methods described as following were used to estimate the correction coefficient of the days to 100 kg (CF) into Licha Black pig, BL₁, BL₂ and their mixed population. First one was the regressive correction coefficient (CF_reg): b_1i was the slope of the simple regression equation of body weight to age in days for the ith individual, and b_2i was the slop of the straight line through the testing end point of the ith individual and the origin (age and weight were both 0), then the average of b_1i/b_2i in the population was CF_reg. Second one is the two-point correction coefficient (CF_2point): b_1i was the slope of the straight line through the testing start and end points of the ith individual, and the methods to calculate b_2i and CF_2point were as same as those of CF_reg. The last one was the single-point correction coefficient (CF_1point): b₁ was the slope of the simple regression equation of body weight to age in days at the testing end point for all pigs, and the methods to calculate b_2i and CF_1point were as same as those of CF_reg. Put CF_reg, CF_2point and CF_1point into the correction equation, respectively, and got D_100kg.CF.reg, D_100kg.2point and D_100kg.1point. The simple regression of age in days to body weight was used to calculate the regressive age in days to 100 kg (D_100kg.reg), and the correlation coefficients and deviations between D_100kg.reg and other D_100kg were calculated. The merits and demerits of the three methods were evaluated according to their correlation coefficients and deviations to D_100kg.reg. D_100kg of a population was estimated by using the correction coefficients from another population, and its correlation coefficient with D_100kg.reg of the population was calculated to evaluate whether the correction coefficient estimated from one population could be used in other populations. The relationship between body weight at the end of performance test (BW_end) and correction error was also investigated to explore whether BW_end had an effect on D_100kg. Taking consideration of the strong linear relationship between BW_end and the correction error of CF_1point, BW_end was used to correct D_100kg.1point to improve the correction accuracy of CF_1point. 【Result】 A total of 1 181 sows were used for following analyses after quality control. In the same population, the values of CF_reg and CF_2point were almost the same, and both of which were highly significantly greater than CF_1point. D_100kg.CF.reg and D_100kg.2point of each pig were very close to its D_100kg.reg, and all of the correlation coefficients among D_100kg.CF.reg, D_100kg.2point and D_100kg.reg were greater than 0.98, indicating that the correction powers of CF_reg and CF_2point were very good. The difference between D_100kg.1point and D_100kg.reg was large, and their correlation coefficient was 0.89, so the correction power was not very good. CF_reg and CF_2point had good population transplantations, and could be used to correct D_100kg of other populations, while CF_2point had poor population transplantations, and it was unsuitable to correct D_100kg of other populations. With the difference of BW_end to the target body weight increasing, the correction error of D_100kg.CF.reg was also increasing in the three populations, and the correction error of D_100kg.2point was no significant changing. D_100kg.1point was significant negative correlation with BW_end, the correlation coefficients were -0.9812, -0.9627, -0.9786 and -0.9352 in the four populations, respectively. The correction power of CF_1point has been significantly improved after adjusting with BW_end, but CF_reg was still better than CF_1point, and it was preferred. 【Conclusion】 The correction powers and transplantations of correction coefficients CF_reg and CF_2point were very good, so CF_reg and CF_2point were suitable to be used to correct D_100kg in practice. The correction power of CF_1point was not very good, therefore, CF_1point was unsuitable to be used in practice. According to the datum amount of a pig, its D_100kg was estimated with the appropriate correction coefficient in order to improve the estimation accuracy and reduce the estimation error.

Formation and Function of Paraspeckle During Pre-implantation Embryos Development in Yak

PAN YangYang, WANG JingLei, WANG Meng, WANG LiBin, ZHANG Qian, CHEN Rui, ZHANG TianTian, CUI Yan, XU GengQuan, FAN JiangFeng, YU SiJiu

Scientia Agricultura Sinica. 2023, 56(6):  1189-1203.  doi:10.3864/j.issn.0578-1752.2023.06.014

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【Objective】 The aim of present study was to identify of paraspeckle formation stages during the early embryonic development in yak (Bos grunniens). Furthermore, the long non-coding RNAs (LncRNAs) involved in paraspeckle formation were determined, and the effects and regulatory mechanism of their formation on the subsequent developmental ability of yak embryos were studied. 【Method】 The yak embryos were produced by in vitro fertilization (IVF), DAPI staining of embryonic nuclei combined with paraspeckle protein 1 (PSPC1) mRNA detection were done by quantitative real-time fluorescence PCR (qRT-PCR) at different stages in order to confirm paraspeckle formation. PSPC1 protein in embryos was verified by immunofluorescence technique. The levels of encoding nuclear paraspeckle assembly transcript 1 (NEAT1), coactivator associated arginine methyl transferase 1 (CARM1) and non-POU domain containing octamer-binding protein (p54nrb) mRNAs were also detected by qRT-PCR at different stages. The mRNA level of PSPC1 in zygote was inhibited by RNA interference technology, and the developmental rate of embryos in subsequent stages was compared. The blastocyst quality was evaluated by analyzing the number of total cells, trophoblast cells (TE) and inner cell mass (ICM). B-cell lymphoma/leukemia-2 (Bcl-2) and b-cell lymphoma/leukemia associated X protein (Bax) in blastocysts form in the control and PSPC1 mRNA interference groups was detected. 【Result】 (1) Paraspeckle could be observed in the nuclei of embryos at all different stages; however, nuclei could be more clearly seen at 2-cell stage and 4-cell stage. The PSPC1 mRNA was higher in yak embryos from 2-cell to morula stage, which was the highest in embryos at 4-cell embryos and morula. The fluorescence intensity of PSPC1 protein was the strongest in embryos from those stages. (2) The levels of NEAT1, CARM1 and p54nrb mRNA were higher from 2-cell to morula stage than that from other stages. NEAT1 and p54nrb were found to be highest in embryos at 4-cell stage, while CARM1 was not significantly different from 2-cell to morula stage (P>0.05). (3) The developmental rates of morula and blastocyst in PSPC1 mRNA interference group were reduced, which was more significantly reduced in morula rate. The total number of blastocyst cells in PSPC1 mRNA interference group was significantly lower than that in the control group, which was mainly caused by ICM reduction. There was no significant difference in number of TE between the two groups. (4) The levels of Bax mRNA and protein were enhanced in blastocyst form PSPC1 mRNA interference group, while the levels of Bcl-2 mRNA and protein were reduced in blastocyst, and the cell lysis was observed in ICM. 【Conclusion】 The paraspeckle was formed at 2-cell to morula stage transition in the yak embryo, which was more prominent in 4-cell stage. The expression of PSPC1, NEAT1, CRAM1 and p54nrb in the stages of paraspeckle formation were on high levels. Interference with PSPC1 mRNA in yak zygotes resulted in decreased developmental ability of subsequent embryo. The blastocyst quality was also reduced by inducing apoptosis of inner cell mass, which was also involved in the regulation of cell fate determination in early embryo development.

Isolation and Genotyping of Mycobacterium avium subsp. paratuberculosis from Sheep in Inner Mongolia

ZHAO WeiHong, HAN WenXiong, YANG Bo, MENG WeiKang, CHAI HaiLiang, MA YiMin, ZHANG ZhanSheng, WANG LiFeng, WANG Yan, WANG MingYuan, ZHANG Shan, DING YuLin, WANG JinLing, JIRINTAI Sulijid, WANG FengLong, ZHAO Li, LIU YongHong

Scientia Agricultura Sinica. 2023, 56(6):  1204-1214.  doi:10.3864/j.issn.0578-1752.2023.06.015

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【Objective】 Paratuberculosis is listed in the must-report at the list of “World Organization for Animal Health (OIE) diseases, infections and Invasion” by OIE. It is classified as the second kind of animal disease in China. It causes chronic and proliferative enteritis in many ruminants. The infected animals become a continuous source of infection in farms through intestinal intermittent excretion, which has brought great economic losses to aquaculture. The pathogen of Mycobacterium avium subsp. paratuberculosis (MAP) belongs to intracellular parasitic Gram-positive bacteria, and is a third group of zoological pathogenic microorganisms, including type C (also designated as type II) and type S. Type C also includes type B. Type S can be further subdivided into sub-group types I and III. And sub-lineages of camelid isolates Studies have shown that each subtype of MAP has no host specificity, but is regional. Inner Mongolia is the first region of the disease in China. It is of great significance to obtain and accurately identify the subtype and genetic characteristics of MAP strains in Inner Mongolia for the prevention and control of paratuberculosis. 【Method】 28 MAP-positive sheep disease samples collected in Inner Mongolia were isolated and cultured by MAP, and the colonies were stained with Ziehl-Neelsen. The positive bacteria were propagated and the genomic DNA was extracted. IS900 gene, IS1311 gene and DMC gene were amplified, sequenced, and analyzed. The PCR products of IS1311 gene were identified by Hinf I and Mse I double digestion. 【Result】 28 samples were cultured for 7- 2 weeks, a total of 9 mediums grew colonies, and the colonies were translucent milky white smooth surface. Single colonies were selected for acid-fast staining, and irregular (single or branched), red-stained Brevibacterium was observed under the microscope, which was consistent with the morphological characteristics and acid-fast staining characteristics of Mycobacterium. The PCR products of IS900, IS1311 and DMC genes of 9 isolates were consistent with the expected size of the target gene fragment. 9 isolates were identified as MAP strains, named MAP-NM1 to MAP-NM9. DMC gene amplification product size of 310bp, which was consistent with type II MAP characteristics. IS1311 gene amplification products were digested by Hinf I and Mse I restriction endonucleases, and 4 target bands were obtained in 9 strains of MAP, which were consistent with type II MAP. The sequencing results of IS1311 gene and the analysis of MAP representative strains of type I, type II, type III, Indian Buffalo and American Buffalo showed that the nucleotide sites at positions 64, 65, 68, 223, 236, 422, 527 and 628 of the nine MAP IS1311 gene fragments were conformed to the characteristics of type C and type B MAP. Sequence analysis of IS900 gene sequencing results showed that the 169th and 216th nucleotides of the nine MAP IS900 gene fragments were C (cytosine) and A (adenine), and accorded with Type II and type III MAP. The phylogenetic tree of 17 MAP IS900 gene reference sequences from GenBank database with 9 isolates in this study showed that the 9 isolates in this study were all in the type II MAP branch. Blast online analysis was performed on the sequencing results of the three genes. The reference sequences with the highest homology with the isolates obtained in this study were all type II MAP, and the homology was higher than 98%. In conclusion, all the 9 MAP isolates were type II MAP. 【Conclusion】 To the best of our knowledge, this was the first isolate of the MAP type Ⅱ strains in sheep in Inner Mongolia.