Table of Content

16 August 2024, Volume 57 Issue 16

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Preliminary Study on Appearance Quality Evaluation of Semi-Waxy Rice in Yangtze River Delta Region

FAN Peng, YANG TianLe, ZHU ShaoLong, WANG ZhiJie, ZHANG MingYue, WEI HaiYan, LIU GuoDong

Scientia Agricultura Sinica. 2024, 57(16):  3105-3115.  doi:10.3864/j.issn.0578-1752.2024.16.001

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【Objective】Due to the cloudy and translucent appearance characteristics of semi-waxy rice, there is a lack of effective evaluation methods in the industry at present. It is necessary to construct an evaluation method for the appearance quality of semi-waxy, and classify the appearance quality of semi-waxy rice, so as to provide technical support for the standardization and development of semi-waxy rice industry. 【Method】In this study, according to GB/T 15682-2008 "Grain and Oil Inspection of rice, Rice cooking and edible quality sensory evaluation method", the appearance quality score of semi-waxy rice was obtained by artificial evaluation method, and various appearance indexes of semi-waxy rice were measured, including chalkiness, transparency, grain type and color space related indexes. Pearson correlation coefficient, max-relevance and min-redundancy, competitive adaptive reweighted sampling and intersection feature selection methods were used to analyze the relationship between chalkiness, transparency, grain shape and color space related indicators and the appearance sensory score of semi-waxy rice, and select the core indicators that can determine the appearance quality of semi-waxy rice for constructing and verification of semi-waxy rice appearance evaluation model. Finally, the model was used to estimate the overall appearance quality of semi-waxy rice in the Yangtze River Delta region and graded according to the estimated score. 【Result】Through comparing the estimation accuracy and stability of four models, this study found that the semi-waxy rice appearance evaluation model, represented by the equation Y=5.68＋0.17X₄＋0.19X₆-0.03X₉-0.12X₁₀, demonstrated the highest accuracy and stability. This model was constructed using chalk rice transparency (X₄), overall transparency (X₆), chalkiness (X₉), and L*(X₁₀), which were selected by the intersection feature selection method. Notably, this model incorporates the fewest number of indicators, with a coefficient of determination (R²) of 0.86 during model validation and a simulated root mean square error (RMSE) of 0.32. After using this model to estimate the appearance of most of the semi-waxy rice in the three rice-growing areas of the Yangtze River Delta, It was found that the appearance scores of the first 20%, 20%-50%, 50%-90% and last 10% of semi-waxy rice materials in the Yangtze River Delta region in this study were greater than 0.23, -0.48-0.23, -1.68--0.48 and less than -1.68, respectively, which can represent four levels of appearance quality of semi-waxy rice in practical applications: Level 1, Level 2, Level 3, Out of level. At the same time, it was found that there were significant gradient differences in grain type, chalkiness, transparency and color space among different appearance grades of semi-waxy rice, but there were different degrees of crossover between their value ranges.【Conclusion】Using chalk rice transparency (X₄), overall transparency (X₆), chalkiness (X₉), and L*(X₁₀), an effective estimation model of semi-waxy rice appearance could be established: Y=5.68＋0.17X₄＋0.19X₆-0.03X₉-0.12X₁₀. With reference to the scoring range of each appearance grade of semi-waxy rice in Yangtze River Delta region, the appearance of a single semi-waxy rice material can be quickly determined by the appearance estimation score. The evaluation of semi-waxy rice by appearance estimation model is beneficial to take into account the different appearance phenotypes of semi-waxy rice, and can accurately reflect the actual situation of semi-waxy rice appearance.

Genetic Effects of the 1BL·1RS Chromosome on Wheat Yield and Quality-Related Traits

ZHAO ZhuoChao, CAO HaoTian, ZHOU ZiXin, QU JiaLe, LI Ze, XU MingYang, YANG QiWei, ZHANG Bin, WANG NingZe, WU YongZhen, SUN Han, QIN Ran, ZHAO ChunHua, CUI Fa

Scientia Agricultura Sinica. 2024, 57(16):  3116-3126.  doi:10.3864/j.issn.0578-1752.2024.16.002

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【Objective】1BL·1RS translocation lines are widely used in wheat breeding programs. The genetic effects of 1BL·1RS on yield and quality related traits will be characterized under different backgrounds, and its application in breeding programs will be evaluated. The study will provide therotical references for the selection of high-yield and high-quality wheat varieties.【Method】 The natural mapping population comprised by 244 varieties/advanced lines and the 188 recombinant inbred lines (KJ-RIL-F₈) derived from the cross between Kenong9204 (KN9204) and Jing411 (J411) were used in this study. Their genotypes were detected by the 1RS diagnostic markers. Combining with the phenotypic values, the genetic effects of 1BL·1RS translocation on yield and quality were characterized. The selection and utilization of 1BL·1RS translocation in breeding programs were clarified by analyzing its proportion in the approved varieties among different decades and cultivate locations.【Result】Of the 188 KJ-RILs, 74 were 1BL·1RS translocation lines. The yield-related traits analysis showed that, under both high and low nitrogen conditions, the 1BL·1RS translocation lines significantly prolonged the heading date, increased grain nitrogen content ratio, increased flag leaf length and flag leaf area; while it significantly reduced kernel number per spike. The 1BL·1RS translocation had no significant effect on the spikes number per plant, thousand kerner weight or flag leaf width. Under both high nitrogen and low nitrogen conditions, 1BL·1RS translocation could significantly increase water absorption rate, wet gluten content, protein content and grain hardness; it had no significant effect on testweight, tractility or sedimentation value. Of the 244 varieties/advanced lines in the natural population, 76 were 1BL·1RS translocation lines. The 1BL·1RS translocation could significantly increase kernel number per spike, spike length and spikelet number, but it could significantly reduce plant height. However, it had no significant effect on spikes number per plant, thousand kerner weight, flag leaf length, flag leaf width or flag leaf area. The 244 varieties/advanced lines in the natural mapping population were classified and grouped according to wheat cultivation locations and variety certification time. The results showed that there were significant differences in the proportion of 1BL·1RS among different wheat cultivation locations. The proportion of the 1BL·1RS translocation lines began to increase from the 1990s in breeding programs.【Conclusion】There is no significant difference for the effects of 1BL·1RS translocation on yield and quality traits under high and low nitrogen conditions. The 1BL·1RS translocation showed inconsistent effects on yield related traits in the KJ-RIL mapping population and the natural mapping population, probably due to the different genetic backgrounds among them.

Function Analysis of bHLH93 Transcription Factor in Tartary Buckwheat in Response to Aluminum Stress

LIU Tong, WANG ZhiRong, LI Wei, LIU Yang, WANG XiangRu, LAI DiLi, HE YuQi, ZHANG KaiXuan, ZHAO ZhenJun, ZHOU MeiLiang

Scientia Agricultura Sinica. 2024, 57(16):  3127-3141.  doi:10.3864/j.issn.0578-1752.2024.16.003

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【Objective】Buckwheat is an important cereal and economic crop. Compared with other crops, buckwheat has strong aluminum tolerance. A transcription factor FtbHLH93 in response to aluminum stress was identified in transcriptome data of aluminum treatment. Exploring the function of FtbHLH93 will provide ideas and clues for solving the problem of aluminum toxicity in acidic soil and molecular breeding of new varieties of buckwheat with aluminum tolerant, and provide theoretical basis for the molecular mechanism of tolerance aluminum in buckwheat.【Method】 The cDNA of Pinku1 was used as a template to clone FtbHLH93. qRT-PCR was used to detect the expression of FTbHLH93 in different tissues of Tartary buckwheat and at different time points after aluminum treatment. Yeast system was used to identify the transcriptional activation activity. The localization of intracellular expression was determined by subcellular localization. The flavonoid content of the overexpressed materials was examined, and SOD and POD activities were measured under untreated and Al-treated conditions. The differentially expressed genes were analyzed by transcriptome analysis, potential downstream target genes were screened, and their promoters were predicted. The dual luciferase reporter gene assay was used to verify the results.【Result】The coding region of FtbHLH93 transcription factor was 573 bp in length, encoding 190 amino acid residues. The predicted molecular weight of FtbHLH93 was 21.759 kDa, and its isoelectric point was 8.64. qRT-PCR results showed that FtbHLH93 was highly expressed in roots. The expression level of FtbHLH93 is highest at 24 h after aluminum treatment. FtbHLH93 is localized in the nucleus without self-activating activity. Overexpression of FtbHLH93 in Tartary buckwheat hairy roots enhanced aluminum tolerance, and the activities of SOD and POD were significantly higher than those of the control group. The detection results of flavonoid metabolites in the overexpressed FtbHLH93 hairy roots showed that the contents of rutin, catechin, and fireworks were significantly higher than those of the control group. GO enrichment analysis showed that it was related to metal ion transport and cadmium and manganese ion entries, and KEGG enrichment analysis showed that it was related to ABC transporter. Three genes responsive to aluminum stress may be downstream target genes of FtbHLH93, and co-expression analysis showed that two of the candidate downstream target genes had a similar expression pattern to FtbHLH93.【Conclusion】FtbHLH93 transcription factor may alleviate aluminum toxicity by promoting the accumulation of flavonoids and the increase of SOD and POD activities. FtbHLH93 may act as an upstream regulator to regulate the expression of FtPinG0100930100.01, FtPinG0303102000.01 and FtPinG0403996200.01.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Agricultural Climatic Factors and Their Thresholds for Winter Wheat Cultivation in Northern China

CHEN Shi, HUANG YinLan, JIN YunXiang, XU ChengLin, ZOU JinQiu

Scientia Agricultura Sinica. 2024, 57(16):  3142-3153.  doi:10.3864/j.issn.0578-1752.2024.16.004

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【Background】To determine the safe planting limit of winter wheat based on agricultural climate indicators is crucial for the scientific and rational utilization of resources, avoiding freezing disasters, and ensuring stable and high yields of winter wheat. However, in the north of China, which is located in the sensitive area of winter wheat planting, the fluctuation of safe winter wheat planting has been intensified due to the increase of extreme weather events caused by global climate change. It is urgent to clarify the agroclimatic factors affecting the safe planting of winter wheat on a large regional scale and to determine their threshold ranges. 【Objective】The research on the agricultural climatic factors and their thresholds for the safe planting of winter wheat was conducted to provide a scientific basis for the sustainable production and planning of winter wheat in response to climate change. 【Method】The northern China was selected as the research area, which was highly sensitive to the safe planting of winter wheat. Based on the spatial distribution of winter wheat with medium and high spatial resolution and ground meteorological observation data, this research utilized methods such as kernel density estimation, geographic detector to reveal the spatial pattern characteristics of the actual northern limit of winter wheat planting, to quantitatively analyze the influence of agricultural climate factors on the formation of the actual northern limit of winter wheat planting, and to explore the threshold of key climate factors. 【Result】(1) The actual northern limit of winter wheat planting, with a total length of about 2 200 km, fluctuated from southwest to northeast. However, agricultural climate factors exhibited more significant fluctuations along the line of Pingning-Xunyi-Tongchuan-Baishui- Heyang-Hancheng-Jishan. (2) The negative accumulative temperature during winter, average temperature of the coldest month, extreme minimum temperature of the year, and accumulative temperature before winter were crucial factors (q >0.45) in shaping the actual northern limit of winter wheat planting. Agricultural precipitation factors had a minor effect (q <0.19) on winter wheat planting, but interacted strongly with temperature factors (q >0.57). (3) Specific meteorological parameters for the northern limit of winter wheat safe planting in northern China were established: negative accumulated temperature in overwintering period≥-620 ℃·d, coldest monthly mean temperature≥-8 ℃, annual extreme minimum temperature≥-22 ℃, and accumulated temperature before overwintering≥529 ℃·d. (4) The potential northern limit for winter wheat planting has moved about 107 km northward compared to the actual limit, with approximately 23.39×10³ km² of expansion area. 【Conclusion】This study identified the key agricultural climate indicators and thresholds influencing safe winter wheat planting in northern China, which provided a basis for determining potential safe planting areas for winter wheat. The research results could provide the theoretical reference and technical support for how winter wheat planting could adapt to climate change and adjust agricultural planting layout reasonably.

Nitrogen Nutrition Estimation of Maize Based on UAV Spectrum and Texture Information

YUN BinYuan, XIE TieNa, LI Hong, YUE Xiang, LÜ MingYue, WANG JiaQi, JIA Biao

Scientia Agricultura Sinica. 2024, 57(16):  3154-3170.  doi:10.3864/j.issn.0578-1752.2024.16.005

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【Objective】Crop nitrogen nutrition status is a key indicator to characterize the green degree and health status of maize canopy. In order to compare the accuracy of single spectral index model and texture information fusion model in maize nitrogen nutrition estimation model, this investigated the accuracy and reliability of maize nitrogen nutrition estimation model based on UAV multispectral information and texture information fusion. 【Method】 Matrice-300 RTK multi-rotor aircraft equipped with MS600 Pro multi-spectral sensor was used to obtain multi-spectral images of maize tasseling-silking stages under six nitrogen levels in two years. By extracting vegetation index and texture features, the correlation between vegetation index, single texture feature, combined texture index and fusion information of vegetation index and texture index, was comprehensively analyzed. The vegetation index, normalized difference texture index (NDTI) and their combined parameters with the largest amount of information were selected. Four nitrogen nutrition parameters of maize leaf nitrogen content (LNC), plant nitrogen content (PNC), leaf nitrogen accumulation (LNA), and plant nitrogen accumulation (PNA) were compared and estimated by multiple stepwise regression (MSR), random forest (RF), support vector machine (SVM), and grey wolf optimized convolutional neural network ( GWO-CNN ). 【Result】 (1) There were differences in the original spectral reflectance of maize under different nitrogen treatments, and the differences in the red band R (660 nm), blue band B (450 nm) and near-infrared band NIR (840 nm) were significant. (2) The vegetation indices (EVI, GARI, REOSAVI, SIPI, and MCARI), single texture features (var₄₅₀, var₆₆₀, mean₈₄₀, dis₇₂₀, and hom₈₄₀) and combined texture index NDTI extracted from UAV multispectral images could be used for LNC, PNC, LNA and PNA estimation of maize in VT-R1 stage. The GWO-CNN model based on vegetation index had better estimation effect on LNC, PNC, LNA and PNA than single texture feature and texture index model, and its R² were 0.831, 0.761, 0.826 and 0.770, respectively. (3) The accuracy of GWO-CNN model with vegetation index and texture index for LNC, PNC, LNA and PNA estimation was significantly higher than that of vegetation index and texture index, and its R² was 0.921, 0.901, 0.917 and 0.892, respectively, which was 9.77%, 15.54%, 9.92% and 13.68% higher than that of single spectral information optimal estimation model. 【Conclusion】 Fusion of multi-spectral vegetation index and texture index could effectively improve the estimation accuracy of maize nitrogen nutrition, and better evaluate the distribution of maize nitrogen distribution, which provided new ideas for precise maize nitrogen fertilizer management based on UAV platform at field scale.

PLANT PROTECTION

Analysis of the Relationship Between Aphid-Damage and Fusarium Composition, Mycotoxin Pollution on Maize Ears

CHAI HaiYan, PAN YiYuan, BAI Xue, MENG LingMin, ZHANG Wei, WU HongBin, WANG YiSheng, GAO YueBo, JIA Jiao, SU QianFu

Scientia Agricultura Sinica. 2024, 57(16):  3171-3181.  doi:10.3864/j.issn.0578-1752.2024.16.006

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【Objective】The objective of this study is to clarify the relationship between maize aphids damage and the occurrence of maize ear rot and the level of mycotoxin pollution in maize kernels, and to provide a reference for establishing a comprehensive control system of maize ear rot and exploring the effective control technology of main Fusarium toxins.【Method】The 105 aphid-damaged maize ears were collected from 46 cities and counties in Jilin Province in 2021. Pathogenic fungi were isolated and identified using tissue isolation and molecular biology methods for aphids, bracts and kernels. The isolation frequency of different Fusarium species on each sample and the proportion of the same Fusarium number isolated from different sample combinations in aphid-infested samples were calculated. The distribution of pathogens in different regions of Jilin Province and the correlation between the species of Fusarium carried by aphids, bracts and kernels were analyzed. Additionally, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was employed to determine the presence of Fusarium toxin species and content of maize kernels with and without aphid infestation. The detection rate of fumonisin (FB), deoxynivalenol (DON) and zearalenone (ZEA) in samples exceeding the standard was calculated, and the effect of aphid damage on the toxin secretion of Fusarium in kernels was analyzed.【Result】Aphids, bracts and kernels from 105 ears were tested for the Fusarium, the infection rate of aphids was 57.14%, and that of bracts and kernels was 81.90% and 82.86%, respectively. A total of 1 394 Fusarium strains, including 16 pathogenic Fusarium species, were obtained through single spore isolation and purification. Among them, 8, 13 and 12 Fusarium species were isolated from aphids, bracts and kernels, respectively. The dominant Fusarium species on aphids, bracts and kernels were F. verticillioides and F. proliferatum. Three species including F. andiyazi, F. incarnatum and F. temperatum were detected for the first time on maize kernels in Jilin Province. The results of mycotoxin analysis revealed a higher incidence of positive mycotoxin contamination in aphid-damaged maize ears compared to aphid-undamaged ones. All maize samples exhibiting excessive mycotoxin content were damaged by aphids. The identification of corresponding mycotoxin-producing strains was possible in the majority of cases where mycotoxins were detected in aphid-damaged maize ears.【Conclusion】F. verticillioides and F. proliferatum were the dominant Fusarium species isolated from aphids, bracts and kernels. The main Fusarium species isolated from aphids, bracts and kernels on the same maize ear were the same. Aphid damage significantly increased toxin accumulation levels in maize kernels, and the type of toxin was highly correlated with the detection of Fusarium species.

Optimization and Application of Rapid Evaluation System for Citrus Huanglongbing Resistance Mediated by Agrobacterium rhizogenes

CAO Peng, ZHOU JinHuan, WANG XinLiang, LI ChuXin, LI JiaXIN, JIANG Pei, LIU JinXiang, SONG Zhen

Scientia Agricultura Sinica. 2024, 57(16):  3182-3191.  doi:10.3864/j.issn.0578-1752.2024.16.007

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【Objective】Citrus Huanglongbing (HLB) is a destructive citrus disease primarily caused by Candidatus Liberibacter asiaticus (CLas). The objective of this research is to investigate the growth pattern of CLas in citrus hairy roots at the initial stage of infection, optimize the rapid evaluation system of Agrobacterium rhizogenes-mediated HLB resistance and apply it to the resistance evaluation of antimicrobial peptides.【Method】A plant expression vector, pGNGM1300, was employed to transform different citrus varieties via the hairy root transformation system, which was mediated by A. rhizogenes K599. Subsequently, varieties with rapid induction and high transformation rate were then selected. Following inoculation with CLas, the presence of CLas in hairy roots was consistently demonstrated through the use of real-time quantitative PCR (qPCR), which allowed for the monitoring of its growth pattern. Further, the optimization of the HLB resistance evaluation system permitted the HLB resistance evaluation of antimicrobial peptides to be conducted via (RT-) qPCR analysis of CLas and related genes, quantification of callose deposition, microstructure observation, and symptom assessment.【Result】Among the 11 tested citrus varieties, citron (Citrus medica) exhibited the fastest induction of hairy roots (15 d), accompanied by the highest induction rate (73.75%) and a substantial transgene positivity rate (53.54%) in hairy roots. The results of regular qPCR monitoring indicated that CLas began to colonize roots on 20-30 days post-inoculation (dpi). At 30-50 dpi, there was a notable increase in the CLas content. The content of the CLas exhibited a slight fluctuation at a range of 60 to 120 dpi, though the discrepancy with 50 dpi was not statistically significant. The results of the antimicrobial peptide resistance evaluation, conducted on MaSAMP (stable antimicrobial peptide), HBD-4 (homo sapiens defensin beta 4), and CB (cecropin B), revealed that at 50-120 dpi, the content of CLas in both MaSAMP- and CB-expressing plants was significantly lower than that of the control. However, except that at 90 dpi, the CLas content was also significantly lower in HBD-4-expressing plants than the control. The callose content in all three plants expressing antimicrobial peptides was significantly lower than that of the control (60 dpi). There was no visible cell wall thickening in the phloem, and no significant deposition of starch grains or callus was observed. Furthermore, none of the plants exhibited signs of root death at 90 dpi.【Conclusion】This study elucidates the growth dynamics of CLas in citrus hairy roots during the early stages of infection and optimizes a rapid scoring system for A. rhizogenes-mediated HLB resistance. In addition, the results show that overexpression of MaSAMP, HBD-4 and CB effectively suppresses CLas proliferation, reduces callose deposition and alleviates HLB symptoms. These findings have the potential to be used in the prevention and control of HLB.

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

Effects of Phosphorus Fertilization on the Yield and Phosphorus Absorption and Utilization of Dryland Winter Wheat Under Different Precipitation Year Types

JIA BingLi, LI YanXing, YANG WenJie, YU Jie, YUAN AiJing, LI NingNa, QIU WeiHong, WANG ZhaoHui

Scientia Agricultura Sinica. 2024, 57(16):  3192-3206.  doi:10.3864/j.issn.0578-1752.2024.16.008

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【Objective】 The effects of phosphorus (P) fertilization on the yield, P uptake and utilization of dryland wheat under different precipitation patterns and summer-season precipitation were investigated to provide the theoretical basis and practical guidance for optimizing the management of P fertilizer application and increasing yield of dryland winter wheat.【Method】 This study was based on a winter wheat P fertilization experiment that started in July 2018 at three sites in Weibei dryland area of Plateau Loess, China. The field experiment included two treatments: optimized P application (+P), and no P application (-P). The precipitation, winter wheat yield, precipitation efficiency, soil water storage, P fertilizer use efficiency, wheat P uptake, and soil P budget under different precipitation years were analyzed over three years. 【Result】 The wheat yields in dry and intermediate years were 3 432 and 4 549 kg·hm^-2, respectively, while the wheat yield in wet year was 7 634 kg·hm^-2. Compared with the -P treatment, the +P treatment significantly increased the wheat yield by 5.8%. Overall, the winter wheat yield showed a linear plus platform correlation with annual precipitation and precipitation in the summer fallow season. In the dry years, the annual and summer-seasonal precipitation use efficiency under +P treatment were significantly lower than those in the -P treatment, with a decrease of 9.5% and 8.0%, respectively; however, in the wet year, they were significantly higher by 13.1% and 12.9% than those under -P treatment. Soil water storage in 0-100 cm soil layers in intermediate year was significantly lower by 10.5% and 10.8% than that under the dry and wet years, respectively, while in the wet year, the application of P fertilizer had no significant effects on soil water storage in 0-300 cm soil layers. Additionally, in the dry and intermediate years, the +P treatment significantly increased the topsoil available phosphorus contents by 29.1% and 17.8%, respectively. The P use efficiency increased with the increasing annual precipitation and summer-season precipitation and the partial factor productivity and agronomic efficiency of P fertilizer were the highest in the wet year, with increases of 74.0% and 176.3%, respectively, compared with the dry year. The soil P budget under +P treatment in the wet year was the lowest, significantly reduced by 67.9% and 62.9% than that in the dry and intermediate years, respectively. The soil P budget under -P treatment was deficient, and it was significantly higher in wet year than that in dry year and intermediate year. 【Conclusion】 Under P fertilizer input, winter wheat yield and P uptake and utilization had different effects in different precipitation year patterns. Therefore, it was necessary to consider the changes in precipitation when applying P fertilizer in dryland winter wheat production. Based on the similar results under the precipitation in summer season and annual precipitation, more attention should be paid to the precipitation in summer season, by which it could predict the target yield and optimize the P fertilizer application rate, in order to ensure the reasonable application of P fertilizer and improve crop yield.

Different Manures Affect Soil Nutrients and Bacterial Community Structure in Mining Reclamation Area

LI HaiPeng, DU WuYan, WU HanQian, ZHANG Jie, MENG HuiSheng, HONG JianPing, XU MingGang, HAO XianJun, GAO WenJun

Scientia Agricultura Sinica. 2024, 57(16):  3207-3219.  doi:10.3864/j.issn.0578-1752.2024.16.009

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【Objective】The purpose of this study was to explore the characteristics of nutrient and bacterial communities and function in reclaimed soil under different manures and to provide a theoretical basis for fertilization transformation and health management of reclaimed soil.【Method】Based on the located fertilization test base (coal mining subsidence area in Piancheng Village, Xiaoyi City, Shanxi Province), this experiment analyzed the soil nutrients, bacterial community structure and function, and maize yield of reclaimed soil in the mining area under different manures (chicken manure, pig manure, and cow manure) and chemical fertilizer treatments for three consecutive years,.【Result】(1) After three consecutive years of fertilization, the application of manures significantly reduced soil pH (0.03-0.08 units) compared with chemical fertilizer, but significantly increased soil organic carbon (11.0%-15.5%), total nitrogen (14.9%-19.1%), available nitrogen (20.3%-43.4%) and available potassium (12.3%-13.6%), among them, chicken manure treatment had the greatest increase in soil organic carbon and available nitrogen content. In addition, the application of chemical fertilizer and manures significantly increased crop yield (16.7%-21.1%), and pig manure had the greatest increase in crop yield. (2) The manures application significantly increased the bacterial richness of reclaimed soil and affected the composition of soil bacterial community structure. At the phylum level, the manures application considerably enhanced the relative abundance of Proteobacteria and Firmicutes, with the relative richness of Firmicutes significantly higher under pig manure and chicken manure treatments than that under cow manure treatment. At the genus level, different manures treatments significantly increased the relative abundance of beneficial bacteria, such as Lechevalieria, Sphingomonas, and Bacillus. (3) The ecological function of reclaimed soil bacteria was mainly chemoheterotrophy and aerobic chemoheterotrophy. Various manures treatments significantly increased the relative abundance of chemoheterotrophy and fermentation populations, with the relative abundance of fermentation populations considerably higher under the pig manure treatment than under the chicken manure and cow manure treatments. (4) The mantel test study revealed a substantial positive correlation between soil bacterial diversity and function and soil organic carbon, total nitrogen, total phosphorus, and crop yield. 【Conclusion】The application of various manures significantly increased the nutrient content of reclaimed soil, improved the structure and function of the bacterial community in reclaimed soil, and then increased crop yield. Nevertheless, there were differences in the soil nutrients, bacterial community structure, and crop yields among the various manures, with chicken manure offering the highest enhancement in soil nutrients, pig manure providing the highest enhancement in functional flora related to carbon and crop yields, but cow manure providing the lesser improvement in soil nutrients and crop yields.

Effects of Magnesium Fertilizer Dosage on Nutrient Absorption and Photosynthetic Characteristics in Peanuts

HU JiaYu, GAO BingYang, GAO YiFan, YUAN ShiLun, QI Xin, HUANG YuFang, YAN JunYing, ZHAO YaNan, YE YouLiang

Scientia Agricultura Sinica. 2024, 57(16):  3220-3233.  doi:10.3864/j.issn.0578-1752.2024.16.010

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【Objective】The aim of this study was to explore the impact of an appropriate amount of magnesium (Mg) fertilizer on nutrient absorption and photosynthetic characteristics of peanuts for high yield and high efficiency, so as to provide the theoretical support for peanut high yield and high efficiency. 【Method】Field experiments were carried out from 2021 to 2022 to study the effects of four MgSO₄ dosages (0, 20, 40, 60 kg·hm^-2, referred to as T1, T2, T3, T4) on the growth and development, yield and nutrient absorption, photosynthetic characteristics, photosynthetic rate-limiting enzymes, and antioxidant enzymes of peanuts.【Result】The rational application of Mg showed a significant effect on peanut plant height, with the maximum value observed at 40 kg·hm^-2 in different periods. The flower needle stage showed a significant effect of Mg on branching, with an average increase of 8.8% than that under T1. The treatments with Mg application had 3.5%-15.1% higher dry matter accumulation than that under T1. The yields, pods per plant, 100-pod weight, and 100-kernel weight significantly increased within the ranges of 7.6%-15.5%, 2.4%-18.1%, 1.5%-11.1%, and 3.5%-10.9%, respectively, reaching the maximum value under T3. At the maturity stage, the nutrient absorption of different treatments as follows: nitrogen (197.3, 206.8, 217.9, and 204.8 kg·hm^-2), phosphorus (37.1, 40.1, 42.3, and 39.4 kg·hm^-2), potassium (75.6, 79.7, 81.1, and 78.5 kg·hm^-2), calcium (38.5, 45.4, 46.8, and 42.3 kg·hm^-2), and Mg (20.9, 25.4, 26.6, and 23.6 kg·hm^-2). The nutrient absorption reached the maximum under T3, which were 10.4%, 14.0%, 7.3%, 21.6%, and 27.3% higher than under T1, respectively. Reasonable application of Mg increased the SPAD, net photosynthetic rate, activity of rubisco enzyme, and antioxidant enzymes in peanut leaves. The SPAD value reached the maximum under T3 in each growth stage. At the pod-setting stage, the changes in Pn, Gs, Tr, and Ci due to Mg application were within the ranges of 2.7%-10.3%, -3.7%-15.8%, -6.6%-5.9%, and -8.2%- -3.0%, respectively. The activities of Rubisco, SOD, and CAT increased by 2.7%-9.1%, 0.6%-5.3%, and 2.1%-7.3%, respectively, while the PRO decreased by 3.3%-10.3%. 【Conclusion】Rational application of Mg fertilizer promoted peanut growth, increased nutrient absorption and yield, improved photosynthetic characteristics, and delayed leaf senescence. The recommended Mg application rate in soils with exchangeable Mg of 243 mg·kg^-1 was 40 kg·hm^-2.

HORTICULTURE

Genome-Wide Identification of GST Gene Family and Functional Analysis of the BcGSTF6 Gene Related to Anthocyanin in Pak Choi

YIN YuQin, XU HuanHuan, TANG LiPing, WANG XinYa, HU ChunMei, HOU XiLin, LI Ying

Scientia Agricultura Sinica. 2024, 57(16):  3234-3249.  doi:10.3864/j.issn.0578-1752.2024.16.011

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【Background】Anthocyanin is one of the important nutritional components in purple pak choi (Brassica campestris ssp. chinensis), and the glutathione S-transferase (GST) plays an important role in anthocyanin transport. 【Objective】This study aimed to identify the genes encoding GST in pak choi and to elucidate the role of BcGSTF6 in anthocyanin transport through transcriptome and molecular biology methods, which would help to elucidate the molecular basis of anthocyanin accumulation in pak choi. 【Method】Using bioinformatics methods to identify members of the GST gene family and to analyze their positions and motifs on chromosomes. The transcriptome analysis was performed in purple and green pak choi to screen genes involving in anthocyanin transport. To further validate the functions of BcGSTF6 and BcTT19, the expression pattern analysis, subcellular localization, and heterologous expression of BcGSTF6 and BcTT19 in the Arabidopsis tt19 mutant were conducted. By comparing the amino acid sequences of BcGSTF6 and BcTT19 with anthocyanin transporters in other species, the differences between BcGSTF6 and others were analyzed. In vitro binding experiments and gene silencing experiments of the BcGSTF6 protein with cyanidin (Cya) demonstrated whether BcGSTF6 played a crucial role in anthocyanin transport and accumulation in pak choi.【Result】In total, 83 members of the GST gene family were identified. They were divided into 8 subfamilies, and they were distributed on all 10 chromosomes of the pak choi. The transcriptome analysis results showed that BcGSTF6 and BcTT19 may be important genes involved in anthocyanin transport in pak choi. Furthermore, qRT-PCR analysis revealed that both BcGSTF6 and BcTT19 were highly expressed during the anthocyanin accumulation; subcellular localization results indicated that both BcGSTF6 and BcTT19 were located in the endoplasmic reticulum (ER) and tonoplast; multiple comparisons of amino acid sequences revealed high homology between BcTT19 and other anthocyanin transport proteins in other species, while BcGSTF6 showed significant differences in the conserved domain; the overexpression of BcGSTF6 and BcTT19 in the Arabidopsis tt19 mutant rescued the phenotype that seedlings could accumulate anthocyanin, but the brown color of the seed coats was not rescued. These results suggested that both BcGSTF6 and BcTT19 were involved in anthocyanin transport but could not transport proanthocyanidins (PAs); In vitro binding assay showed that BcGSTF6 protein could increase the solubility of Cya at room temperature; gene silencing of BcGSTF6 in pak choi not only resulted a significant decrease in anthocyanin content in the leaves, but also led to a decrease in the expression of genes related to anthocyanin synthesis and regulation. These results demonstrated that BcGSTF6 was involved in anthocyanin transport and accumulation in pak choi, and played an important role in the coloring process of pak choi leaves. 【Conclusion】 This study identified the GST gene family and further elucidated the functions of BcTT19 and BcGSTF6 in anthocyanin transport in pak choi. This experiment elucidated the partial mechanism of BcGSTs regulation of anthocyanin transport and accumulation in pak choi.

Crucial Factors Impacting Carrot Flavor Analysis Based on Broad Target Metabolomics

QI XiaoYu, KONG XiaoPing, ZHOU HongWei, YAN XiangPing

Scientia Agricultura Sinica. 2024, 57(16):  3250-3263.  doi:10.3864/j.issn.0578-1752.2024.16.012

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【Objective】 Terpenoid metabolites serve as primary indicators for assessing the quality of carrot flavor, which influence the taste and overall flavor quality of carrots significantly. This study compared the metabolites of flavor components in mature fleshy carrot roots exhibiting pronounced sweetness group and bitterness group, which could offer valuable insights for identifying key flavor components and enhancing the cultivation and exploitation of superior genetic resources.【Method】Efficient methods for detecting and identifying metabolites were established for carrot metabolomics research. Initially, a high-throughput metabolomic analysis platform was developed using UPLC-MS/MS to analyze terpene metabolites in carrots and to identify those influencing flavor quality. Differential metabolites were screened based on OPLS-DA results using VIP and log2FC values, with thresholds set at VIP>1 and fold changes of ≥2 and ≤0.5. 【Result】 A total of 50 terpenoid metabolites were screened out and exhibited significant differences, with 12 up-regulated and 2 down-regulated. Notable upregulated metabolites included Genipine (0.754), Japonicumin B (0.936), oxyphyllanene A (1.03), carvyl acetate (1.04), and 3-(3'-hydroxybutyl)-2, 4, 4-trimethylcyclohexan-2, 5-dienone (0.662). Dehydrodigitoxin (0.617) was significantly down-regulated. In terms of terpene content, those bitter carrots showed higher levels of Normelanothyrsin A (16.98), Curcumenol (17.57), and Genipin (15.32), while sweet carrots exhibited higher levels of Normelanothyrsin A (17.61), isothyrsin alcohol (16.01), and Curcuma alcohol (18.73). Top metabolites based on p-values included micrantholide (0.994), pyrodialdehyde (0.991), methyl (E)-5, 11-dihydroxy-4-(((Z)-2-2-enoyl methylbut-)foxy)-, 10-dimethylene-2-3 oxo-2 filling a, 4, 5, 8, 9, 10, 11, 11a-decahydrocyclodeca[b]furan-6-carboxylate (0.978), (3R)-3-hydroxy-ionone (0.974), and Blumenol A (0.969). Cluster analysis was employed to compare metabolite profiles between the two carrot groups, revealing significantly higher metabolite content in group 3 than that in group -3. Differential metabolite annotation and enrichment analysis were performed using the KEGG database.【Conclusion】Terpenoid metabolites, including Gennipine, Japonicumin B, oxyphyllanene A, carvyl acetate, Normelanothyrsin A, curcumenol, isocarbamol, dehydrodigitoxin, and micrantholide, were the primary compounds influencing the flavor of carrots. These compounds were believed to play a crucial role in determining the characteristic taste of carrots.

FOOD SCIENCE AND ENGINEERING

Effects of Cell-to-Cell Contact Between Torulaspora delbrueckii and Saccharomyces cerevisiae on the Flavor and Quality of Cabernet Sauvignon Wine

ZHOU DeGang, XU BinYan, WANG QingXia, ZHU Xia, YANG XueShan

Scientia Agricultura Sinica. 2024, 57(16):  3264-3282.  doi:10.3864/j.issn.0578-1752.2024.16.013

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【Objective】The mixed fermentation of Saccharomyces cerevisiae and Non-Saccharomyces yeast could improve the complexity and richness of wine aroma. In order to accurately control the mixed fermentation, it is necessary to deeply elucidate the regulatory effects of the contact between yeast cells in the co-culture on alcohol fermentation and metabolites.【Method】Torulaspora delbrueckii (T. delbrueckii) and S. cerevisiae was inoculated in the sterilized Cabernet Sauvignon grape juice to conduct pure fermentation, mixed fermentation, and double-compartment fermentation, respectively, and the differences in fermentation kinetics and volatile aroma compounds were analyzed. In addition, the effects of mixed fermentation and double-compartment fermentation on the vinification parameters and flavor quality of Cabernet Sauvignon wine under different inoculation time modes were investigated.【Result】T. delbrueckii strain was unable to complete the alcoholic fermentation independently, resulting in a final reducing sugar content of 89.00 g∙L^-1 in its fermented wine. S. cerevisiae maintained high growth activity in pure fermentation, mixed fermentation as well as double-compartment fermentation, and successfully completed alcohol fermentation. Cell-to-cell contact during mixed fermentation significantly reduced the viability of T. delbrueckii. Compared with the pure fermentation of S. cerevisiae, the mixed and the double-compartment fermentation were characterized by high content of the total acid and low level of ethanol and pH value. The content of volatile acid detected in each treated wine sample was between 0.2-0.7 g∙L^-1. The content of volatile acid and anthocyanin in the mixed fermentation group was significantly lower than those in S. cerevisiae pure fermentation and double-compartment fermentation. The results of GC-MS showed that the content of aroma compounds in T. delbrueckii strain pure fermentation group was the lowest among all wine samples. Compared with the S. cerevisiae pure fermentation, the content of esters in the mixed fermentation and the double-compartment fermentation significantly increased, while the content of higher alcohols and C₆ compounds significantly decreased. The content of ester compounds, such as isoamyl acetate, hexyl acetate, ethyl caproate and ethyl caprylate in the mixed fermentation group, showed a significant increase trend compared with those in the double-compartment fermentation group. Meanwhile, there was a significant decrease in the levels of higher alcohols and benzene derivatives. In addition, the inoculation time of S. cerevisiae also had a significant effect on the formation of isoamyl acetate and hexyl acetate during mixed fermentation. The results of sensory analysis showed that the simultaneous inoculation (0 h) strategy could significantly reduce the green flavor and enhance the fruity and floral aroma of wine samples compared with S. cerevisiae pure fermentation.【Conclusion】During the mixed alcoholic fermentation, the yeast cell-to-cell contact not only limited the growth of T. delbrueckii, but also significantly affected the aroma characteristics and sensory quality of Cabernet Sauvignon wine.

ANIMAL SCIENCE·VETERINARY SCIENCE

Development and Application of Indirect ELISA Kits for Antibody Detection of Porcine Proliferative Enteropathy

ZHANG CongYue, ZHOU Hong, LIN HuiXing, FAN HongJie

Scientia Agricultura Sinica. 2024, 57(16):  3283-3293.  doi:10.3864/j.issn.0578-1752.2024.16.014

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【Objective】 The objective of this study was to develop an indirect ELISA kits to detect Lawsonia intracellularis (LI) antibodies in pig, so as to provide a tool for the monitoring of LI infection and vaccine evaluation.【Method】 The outer membrane protein (Omp2) of LI was expressed and purified, and an indirect ELISA method based on it to detect LI antibodies was established. The reaction conditions of the indirect ELISA and assemble the test kit was further optimized. Based on this, the prototype kit was used to test the sensitivity of the kit with serially diluted LI-positive sera, and other pathogen-positive sera were tested to study the specificity of the kit. The practicality of the kit was evaluated by testing 1 000 clinical pig serum samples collected at different times from different farms. From these clinical serum samples, the positive or negative effect of 50 sampleswere tested for by imported commercial kits, and the conformity of the kit were compared and verified.【Result】 The Omp2 protein was successfully expressed and purified, with a purity of 90.31%, and was identified to react with LI-positive serum via Western blot. The optimal ELISA conditions were: coating with Omp2 at 200 ng/well at 4 °C for 12-16 hours; serum diluted 1﹕50 and incubated at 37 °C for 30 minutes; goat anti-pig IgG-HRP diluted 1﹕20 000, and incubated at 37°C for 30 minutes; TMB substrate developed at 37 °C for 15 minutes, and the reaction was stopped with 0.5 mol·L^-1 sulfuric acid. The highest detection dilution of LI-positive sera was 8-fold, indicating that the established ELISA method had the good sensitivity. The test kit tested negative for E. coli, App, Mhp, SS2, PRRSV, and PRV, demonstrating the good specificity of the ELISA method. Sensitivity and specificity testing standards for the kit have been established. The kit remains stable in terms of appearance, sensitivity, and specificity for 15 months when stored at 4 °C. The criteria for the kit were set as follows: OD_450nm ≥1.25 for positive standard sera and OD_450nm <0.3 for negative standard sera. The intra-batch and inter-batch variability coefficients of the prototype kit were all less than 10%. The concordance rate with foreign commercial ELISA test kits reached 86%. The developed ELISA test kit detected LI-positive samples at a rate of 59.90% among 1 000 clinical pig serum samples from the eastern part of China, indicating the widespread presence of LI in the region. 【Conclusion】 The LI indirect ELISA antibody test kit in pig developed in this study had high specificity and sensitivity, and a high concordance rate with commercial test kits, making it suitable for clinical detection of LI antibodies.

STM2503 Regulates Biofilm Formation and Stress Adaptability of S. Typhimurium

WANG NanWei, LI LiLi, CHEN KaiFeng, ZHOU ZhouPing, PAN Peng, GUAN Jin, XU ChengGang, LIAO Ming, ZHANG JianMin

Scientia Agricultura Sinica. 2024, 57(16):  3294-3304.  doi:10.3864/j.issn.0578-1752.2024.16.015

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【Objective】S. Typhimurium is an important zoonotic pathogen, and its strong pressure adaptability brings great challenges to its prevention and control. In this study, the mechanism related to c-di-GMP pathway gene STM2503 regulating the biofilm formation, and thereby affects environmental stress capacity of S. Typhimurium, were investigated, so as to excavate the key factors regulating the stress adaptation of S. Typhimurium, and provide a theoretical basis for the formulation of new prevention and control strategies.【Method】The STM2503 gene deletion strain was constructed by λ-Red homologous recombination, and plasmid PBAD was used to express STM2503 to construct the gene complementation strain. Then, the effect of STM2503 on the intracellular c-di-GMP level of bacteria was revealed by detecting the signaling molecule c-di-GMP content in strains with different STM2503 expression levels. Next, the effect of STM2503 on bacterial motility and biofilm formation ability were detected by bacterial motility detection and crystal violet staining experiments, furthermore, the real-time fluorescence quantitative PCR was employed to elucidate its regulatory mechanism on bacterial motility and biofilm formation at the genetic level. Finally, the effect of STM2503 on the stress adaptability of S. Typhimurium was investigated through antibiotic treatment, oxidative stress, and disinfectant stress tests.【Result】Compared with the wild strain (WT269), the deletion of STM2503 increased the intracellular c-di-GMP content of the strain by 37.51%, and did not affect the normal growth of the strain. In addition, the deletion of STM2503 increased the expression level of extracellular matrix synthesis genes, and increased the content of extracellular polysaccharide, extracellular DNA and extracellular protein by 10.30% (P<0.01), 33.59% (P<0.001) and 27.60% (P<0.01), respectively, which ultimately led to a significant enhancement of biofilm formation ability by 1.63-fold (P<0.01). Moreover, 269ΔSTM2503 reduced the motile diameter by 17.22% (P<0.01) compared with the wild strain (WT269) at 6 h via decreasing the expression of flagella synthesis related genes fliA and flhC. These changes eventually led to a 1-3 fold reduction in the sensitivity of the 269ΔSTM2503 strain to β-lactam antibiotics, such as cefotaxime, cefepime, and amoxicillin, along with showed stronger adaptability under oxygen stress and SDS disinfectant stress. 【Conclusion】 In conclusion, STM2503 was involved in the degradation of the signaling molecule c-di-GMP and reduced the biofilm formation ability of S. Typhimurium by inhibiting the synthesis of extracellular substances and enhanced the motility of strains by upregulating the expression of flagellar synthesis genes, thereby reducing the drug resistance and environmental stress adaptability of S. Typhimurium. This study provided a theoretical basis for the excavation of the key targets for the prevention and control of S. Typhimurium.