Oil is the main energy storage substance and an important membrane component of plant. Oil is also involved in the signal transduction, stomatal opening and closing, pollination and fertilization, seed germination, and stress response. WRINKLED 1 (WRI1), a member of the AP2 transcription factor family, is master regulator in transcriptional control of plant oil biosynthesis. This paper reviewed recent advances in regulatory mechanism of WRI1 on plant oil biosynthesis, including (1) the discovery, origin, and evolutionary characteristics of WRI1; (2) gene expression characteristics, gene structure, protein structure, and promoter cis-acting elements of WRI1; (3) regulation mechanism of transcription level and translation level, and downstream target genes of WRI1; (4) the future research direction and application prospects. This review is expected to provide a reference for further understanding the molecular mechanism of WRI1 regulating plant oil synthesis, and also provide a theoretical basis for improving oil crops with WRI1.
Glycerolipids are the main constituents of biological membranes, which participate in a variety of biological processes including energy and signal transduction and protein transport, thereby playing many important roles during plant growth and development. Glycerol-3-phosphate acyltransferase （GPAT） catalyzes the initial committed step in de novo biosynthesis of phosphatidic acid （PA）. PA not only serves as a general precursor for the biosynthesis of membrane glycerolipids and the neutral lipid triacylglycerols, but also acts as an important signal molecule. So far, however, it has remained unclear how many genes encoding GPATs are present in plants, mainly due to the lack of convenient and effective methods for identification of this enzyme. In this review, we analyze and summarize the recent advance in studies on glycerolipid biosynthesis as well as on cloning and characterization of GPAT genes, then introduce the methods used for characterizing GPATs, especially for the development and application of yeast genetic complementation, and finally present our prospects for future studies on the initial step of the glycerolipid biosynthetic pathway.
Tigernut (Cyperus esculentus L.) received increasing attention in recent years because of its comprehensive utilization potentials. As a new source of food, vegetative oil, feed for the consumption of humans and livestock, it accumulates great nutrients including oil, starch, sugars, protein, dietary fibers etc. in its underground tubers. The aboveground grass could also be utilized as high-quality forage for livestock. As a multi-purpose crop originated in the desert area, tigernut has the characteristics of wide adaptability, higher biomass yield and value added chain, and shows great potential for the verstile applications in agricultural and industrial sectors. Abundant marginal land with sandy texture provides a basis for the development of tigernut industry in China. Currently, foundation of tigernut industry has been established in China, and the essentials of the industrial chain are also in place. The present paper reviewed the characteristics and utilization of tigernut as a cultivated crop in China, and analyzed its current status of research and industrial development. Potential, problems and adaptive suggestions related to the industry were also discussed.
Grain, oilseed and their products are important for human beings, which provide the three most essential nutrients. Their quality and safety are hot issues, which draws more attentions from governments and consumers. Thus their detection methods are important to ensure the safety. Among them, solid phase extraction （SPE） is one of the most scientific method to extract targets from samples, and the extraction material is the key factor to influence the efficiency of both extraction and separation. This review summarized the research progress of SPE based pretreatment methods for grain, oilseed and their products, analyzed the advantages and disadvantages of different materials, and prospected development trends of new extraction materials in analytical methods for grain, oilseed and their products.
Aflatoxins are mainly produced by toxin-producing fungi such as Aspergillus flavus. They are biological hazards and are extremely toxic mycotoxins. Historically, consumption of aflatoxin-contaminated products caused many deaths of humans and domestic animal groups. Aflatoxin enters the food chain through contaminated agricultural products and animal feed, seriously threatening global food safety and human health. In order to reduce the hazards of aflatoxin pollution, it is very necessary to grasp the main types of agricultural products and foods polluted by aflatoxin. Therefore, by studying relevant literature reports at home and abroad, this article has comprehensively summarized the main types of aflatoxin-contaminated agricultural products and their products in recent years, including 12 categories of cereals and their products, condiments, and feeds, totaling 143 products. The summary of the types of products contaminated by aflatoxin can provide important scientific basis for the prevention and control of aflatoxin pollution in agricultural products and food, and has important guiding significance for ensuring consumer safety and the healthy development of the industry.
In order to explore the response characteristics of growth point to low temperature, and to understand its relationship with cold resistance, growth point morphology of 4 rapeseed （Brassica napus L.） materials (cold resistant VHTSG10 and VHTS309-4; cold susceptive VH Tianyou 2288 and VH Xinyou 23) was observed by microscopy, paraffin section and scanning electron microscope. Cold resistance of the materials was identified by measuring the semi-lethal temperature (LT50). Their growth point regulation genes were cloned. Morphology results showed that, under cold treatment before winter, growth points at seedling of VHTSG10 and VHTS309-4 had smooth surface and lower relative height, while those of VH Tianyu 2288 and VH Xinyou 23 had small protuberant structures and higher relative height. LT50 was positively correlated with the relative height of growth point. Relative expression of BnSTM was significantly positively correlated with the relative height of growth points, while relative expression of BnCUC2 was significantly negatively correlated with the relative height of seedling growth points. BnSTM gene has a complete open reading frame of 1149 bp and encodes 382 amino acids, including KNOX1, KNOX2, ELK and Homeobox_KN domains. BnSTM was closely related to B. rapa, and the protein sequence similarity was 98.69%. Subcellular localization analysis showed that BnSTM protein was found in nucleus and involved in growth and development of shoot apical meristem. Thus could be concluded that, the stronger the wintering, the lower the relative height of seedling growth point, and the stronger the cold resistance.
There is a similarity on gene expression and physiological / biochemical adaptation between the low phosphorus and low temperature stresses in plants. PHR1, one of MYB-CC family transcription factors, is a core regulator of low phosphorus stress in plants. Up to now, the function of PHR1 in low temperature stress in plants is not clear. In this study, the function of BnPHR1 in low temperature was analyzed with BnPHR1 overexpressing transgenic rapeseed. Compared with wild-type rapeseed, the tolerance
Cotyledon yellowing lethality directly affects seed emergence and seedling rate in Brassica napus. It is convenient to investigate the molecular mechanism of cotyledon yellowing lethal mutants for the basic research on plant physiology. In this paper, we reported the results of gene localization and candidate gene prediction related to the mutant ytl (yellow to lethal) in B. napus. The mutant isolated from the progenies of the restorer recurrent selection population did not return to green after germination, and the cotyledons remained in a state of yellowing and died in 9-15 days after sowing. The chlorophyll and lutein contents of the ytl mutant were significantly reduced compared with the wild-type plants. Transmission electron microscopic observations showed that the chloroplasts of the mutant still stopped at the plastid stage and the basal lamellae of the cystoid were blurred. The results of genetic analysis indicated that the cotyledon yellowing trait of the mutant was controlled by a recessive nuclear gene. The candidate gene was located between the marker SSR-140 and PBZIN-1 on chromosome C09 using B. napus 60K Illumina Infinium SNP microarray combined with molecular marker analysis, corresponding to a physical distance of 198 kb. This study laid the foundation for further cloning of the candidate gene BnaC09.YTL and subsequent functional researches.
The multi-carpel trait of rapeseed can significantly increase the number of seeds per silique of rapeseed, which has a potential application value for high-yield breeding. Previous studies have found that the multilocualr Brassica juncea, J163-4, can form a stable four-carpel trait, and the small G protein gene BjROP10 might be involved in regulating the formation of the multiloculus, but the molecular mechanism is still unclear. In this study, using CRISPR/Cas9 technology, a dual-target vector of BjROP10 was constructed and genetically transformed into J163-4. In the T0 generation, 20 transgenetic positive seedlings were obtained, 13 of which showed changes of the number of carpels. The mutation sites of the target gene in 7 transgenic positive plants which showed the carpel number variation were analyzed by sequencing technology. The gene sequences of BjROP10 in the 7 transgenic positive plants were mutated, resulting in the inability of encoding a normal BjROP10 protein. This study provides a material basis for further analysis of the function of BjROP10 gene in regulating the development of carpel number of rapeseed in response to CLV signals, and provides experimental basis and experimental materials for studying the molecular mechanism of the development of multilocualr trait in rapeseed too.
In order to accelerate soybean varieties improvement, this study analyzed the evolution of main agronomic traits, yield, quality and resistance of 101 soybean varieties (including 60 Huaibei varieties and 41 Huainan varieties) released in Jiangsu Province from 1982 to 2021. The results showed that plant height and node number of released varieties decreased with the year, and pods per plant, 100-seed weight increased with the year extremely significantly. Among them, the plant height of Huaibei varieties showed a extremely significant decrease. The yield of released varieties increased extremely significantly with the year of an average annual improvement of 21.08 kg·hm-2, and R2 greater than 0.600, showing an obvious ascending linear relationship. The protein content and oil content increased with the year, and the total protein and oil content increased significantly. Among them, the protein content, the total protein and oil content of Huaibei varieties increased extremely significantly. Correlation analysis found that yield appeared extremely significant negative correlation with growth periods, node number and pod height, significant negative correlation with plant height, but appeared extremely significant positive correlation with total protein and oil content, significant positive correlation with protein content, oil content and 100-seed weight. It means the reasonable shortening the growth period, reducing node number, plant height and podding height could promote yield, and the positive correlation between yield and quality could provide an effective way to high yield and quality soybean breeding.
ERD15 （Early Responsive to Dehydration 15）, as a transcription factor, binds to NRP-B promoter and activates NRP-B-mediated cell death. This family consists of six members, of which two members, GmERD15a and GmERD15b, are mainly studied in this study. The functions of GmERD15a and GmERD15b genes were preliminarily explored through cloning, bioinformatics analysis, tissue expression analysis and stress resistance identification in yeast transient system. The results show that the full length of GmERD15a is 378 bp, and the full length of GmERD15b is 318 bp. GmERD15a has the highest homology with GmERD15c, followed by JrERD15. GmERD15b has the highest homology with GmERD15f, followed by VaERD15. Both GmERD15a and GmERD15b are hydrophilic proteins. GmERD15a and GmERD15b were the highest expression levels in 20 d embryos and roots. GmERD15a and GmERD15b were sensitive to drought stress and salt stress. The study was expected to provide a theoretical basis for further study of the function and mechanism of the two genes.
MIKC MADS-box is a biological function rich family of transcription factors, and involved in regulating plant growth and development. In order to study the biological characteristics of MIKC-type MADS-box family genes in legumes, 92 and 45 MADS-box genes were identified in soybean and Medicago truncatula by bioinformatics method, and they were divided into 15 subfamilies. Motif analysis showed that the motifs of soybean and Medicago were different, and the gene structure and function changed. Collinearity and Ks analysis showed that 90.5% of the MIKC gene pairs in soybean and 87.1% of the MIKC-type gene pairs in Medicago were generated before the whole genome triplication in dicotyledons. Expression pattern analysis of genes in soybean showed that the MIKC MADS-box genes in soybean seedling stage were expressed higher than other stages, especially the expression of SVP, SOC1 and AGL12 subfamilies. Protein interaction network showed that soybean protein SVP interacted with CO, FT and TFL1 to regulate plant flowering. This study will lay a foundation for the further biological functions of MADS-box gene family.
Cultivated peanut was used to develop haploid plant including dedifferentiation of detached anthers for callus induction, callus differentiation to form shoot, induction of adventitious shoots and roots, identification of plant ploidy and transplantation. By comparison of sterilization period, different additives and media for cali induction and shoot induction, and plant regeneration, a protocol suitable for peanut anther culture was established including 1% NaClO disinfection for 9 min, dedifferentiation induction culture using B5N1 or B3N1 medium, differentiation culture using B5N1-2 medium, plant regeneration using CM medium or SG medium. One plant, named 15B8-8, were first obtained from cultivated peanut through anther culture. Result from fluorescence in situ hybridization (FISH) showed that 15B8-8 was the target haploid line for having 20 chromosomes with 9 A chromosomes and 11 B. The result indicated that Shanyou 52 had stronger ability of anther culture, which can be considered as a bridge variety for anther culture of peanut in the future.
The composition of three major fatty acids, oleic, linoleic and palmitic acids together determine peanut oil quality. Increasing oleic acid content and decreasing linoleic acid and palmitic acid content is one of the important projects for peanut quality improvement. In this study, 292 peanut germplasm resources from China and their 583 SSR markers were used to analyze the association between fatty acid composition and molecular markers in four environments. There were 14, 14, and 9 stable associated markers repeatedly detected in multiple environments for oleic acid, linoleic acid, and palmitic acid content, respectively. Among them, 8 stable markers were simultaneously associated with the three fatty acids, distributing on chromosomes A02, A03, A08 and A09. AHGS2050-226bp and AHGS3647-253bp were two favorable alleles of novel associated markers for three major fatty acids. In peanut mini-core germplasm, AHGS2050-226bp was verified to stably increase oleic acid content （9.79%-11.26%）, and reduce the contents of linoleic acid （8.04%-9.31%） and palmitic acid （1.81%-1.97%）. AHGS3647-253bp could gain oleic acid content （9.79%-11.26%）, and decrease the contents of linoleic acid （8.04%-9.31%） and palmitic acid （1.81%-1.97%） in mini-core germplasm. Stable associated markers （AHGS2050 and AHGS3647） have potential value in assisting variety selection of high oleic acid and low linoleic acid and palmitic acid in peanut breeding.
Elsinochrome (ESC) of Elsino? arachidis causing peanut scab is a photosensitive activity and nonhost-selective toxin which is an important virulence factor in the infection progress and lesion formation. Based on the whole genome sequencing, the secondary metabolism PKS gene cluster mining, gene clone and bioinformatics analysis of the toxin biosynthesis gene ESCB1 were conducted. The results showed that E. arachidis genome contained six PKS and PKS-NRPS gene clusters. Sequence analysis showed that ESCB1 contains an open reading frame (ORF) of 6636 bp length and encoding a protein of 2212 amino acid. The molecular weight of the protein is 238.8 kDa, the theoretical isoelectric point is 5.65. Subcellular localization analysis showed that ESCB1 was localized in chloroplasts. This hydrophilic protein mainly composed by α-helix and random coil. Quantitative PCR analysis showed that the expression pattern of ESCB1 was similar to that of ESC production, which was significantly higher in light than that in dark. These results would provide a theoretical basis for the analysis of ESC biosynthesis pathways, the construction of regulatory networks and the further study of pathogenesis in E. arachidis.
In order to investigate root metabolism changes of peanut seedling under aluminum （Al） stress, 2 peanut cultivars Huayu 23 （Al-sensitive） and Yueyou 7 （Al-tolerant） were used as materials. 416 metabolites were detected from peanut roots by ultra-performance liquid chromatography/ tandem mass spectrometry （UPLC-MS/MS）. Among them, 155 differential metabolites were found from Huayu 23, with 27 metabolites up-regulated and 128 down-regulated. And 109 differential metabolites were found from Yueyou 7, with 28 metabolites up-regulated and 81 down-regulated. 145 differential metabolites were found between Huayu 23 and Yueyou 7 in aluminum stressed roots, of them 76 were up regulated and 69 down regulated. These metabolites were belonged to phenolic acids, flavonoids, organic acids, lignans and coumarins, amino acids and their derivatives, and nucleotides and their derivatives. KEGG pathway metabolic analysis showed that the different metabolites were enriched in isoflavone biosynthesis pathway. The significant changes of root metabolites of peanut seedling under aluminum stress were expected to provide a scientific basis for peanut production with lower Al toxicity.
To better understand the regulatory mechanism of MYB transcription factor in peanut anthocyanin accumulation, AhMYB113 gene was cloned from the hybrid of Luhua 11 （green leaves） and 056 （purple leaves）. Conserved domains, phylogenetic tree, expression patterns of the gene were analized using bioinformatics method and quantitative real-time PCR. In addition, AhMYB113 was genetically transformed into tobacco for ectopic expression. Result showed that ORF of AhMYB113 was 864 bp in length and encoded 287 amino acids, with 2 highly conserved MYB domains at N-terminal, indicating that AhMYB113 belonged to R2R3-MYB transcription factor. AhMYB113 showed high homologous with the same conserved motif of R2R3-MYB in Arabidopsis, Antirrhinum, petunia, apple and grape. Its expression was significantly higher in purple hybrid plants （PH, PS） than in green hybrids （GH, GS）. Phenotype analysis result showed that, AhMYB113 ectopic expression could promote anthocyanin accumulation in transgenic tobacco NC89. Tobacco leaves changed from green to purple, and was deepened gradually with the growth. Petals, stamens （anthers and filaments）, pistil （stigmas and style） and sepals were maroon or purple-black, respectively.
The Sclerotinia disease, caused by the Sclerotinia sclerotiorum fungi, is an important disease in most of cruciferous plants including Brassica napus. The disease has a serious impact on the yield quality of B. napus. In this study, we screened a Sclerotinia gene, named Ss160 (Sscle04g035160) based on the transcriptome analysis, and we found that Ss160 was highly expressed in S. sclerotiorum when inoculated them on leaves of B. napus. The bioinformatics analysis indicated that Ss160 contained a signal peptide and the amino sequence were well-conserved across fungi species. The subcellular location of Ss160 was not specific. Furthermore, the tobacco leaves transient expressed of Ss160, showed significant smaller disease lesion than the control, suggesting that heterologous expression of Ss160 in plant can enhance its Sclerotinia disease resistance. We further verified the transcript activation activity of Ss160 by yeast proteins interaction system in vitro. Our results lay the foundation for further research of the functional mechanisms of Ss160, and also provide the reference for Sclerotinia disease resistance study in B. napus.
To improve castor hybrid breeding, correlation between harvest index and plant traits was investigated using 133 castor hybrid combinations. 13 traits were invstigated, including harvest index, plant height, stem diameter, main stem node number, primary branch length, bearing height of primary spike, number of effective spikes, number of primary branches, yield per plant, hundred-grain weight, biomass, SPAD and Pn. Results showed that harvest index of the 133 combinations varied from 0.126 to 0.644, with an average value of 0.398. Among the 133 castor combinations, those with harvest index above 0.5 accounted for 16.54%. Correlation analysis revealed that harvest index had extemely significant positive correlation with the yield per plant, and extemely significant negative correlation with length of primary branch. Regression analysis showed that, yield per plant, plant height, length of primary branch and number of effective spikes had a greater impact on the harvest index. Thus in breeding process, selection of plants with longer main panicle inflorescences, relatively high plants and more number of primary branches could increase yield.
In order to investigate the regulative role of ABA on cadmium (Cd) toxicity in rapeseed seedlings, Fengyou 737, the main cultivars planted in southern China, were used through hydroponic experiments. Results indicated that Cd detrimented seedling growth, decreased plant biomass, SPAD content and root activity through inhibiting superoxide dismutase (SOD) activity and causing oxidative stress. Application of ABA significantly alleviated the inhibitory effect of Cd on rapeseed growth, kept the seedlings from Cd-induced leaf chlorosis, and decreased shoot and root Cd accmulation by 31.17% and 34.89% respectively. In comparison with Cd treatment, exogenous ABA also decreased malondialdehyde and O2?– content by 20.89% and 38.89%, increased the activity of SOD, catalase and peroxidase by 158.05%, 28.59% and 34.62% respectively. However, ABA addtion barely affected the Cd translocation factor. The above results suggested that ABA application might mitigate Cd toxicity through inhibiting Cd uptake and accumulation, enhancing antioxidant enzymes’ activity, and maintaing the redox homeostasis, thereby alleviating Cd toxcity to rapeseed seedlings.
In order to investigate the effect of nitrogen fertilizer on enzymes activities relating to nitrogen metabolism, nitrogen accumulation and utilization efficiency, yield and its components, Nonghua 5 was used, taking no nitrogen fertilizer as control, three different application periods were set with equal total amount nitrogen fertilizer, including N 135 kg·hm-2, applied as basal fertilizer （T1）, N 67.5 kg·hm-2, applied as basal fertilizer and as the topdressing fertilize in seedling stage respectively （T2）, N 45 kg·hm-2, applied as basal fertilizer and as the topdressing fertilize in seedling and flowering stages respectively （T3）. The results showed that under different nitrogen application periods, the same trends of nitrogen metabolism-related enzyme activities and nitrogen accumulation were observed, while the level of activity and content had varied. T3 treatment had significantly increased the activities of nitrate reductase, glutamine synthetase and glutamate dehydrogenase in leaves of the later growth stage of peanut. Similarly, the total nitrogen content of plant, root and pod nitrogen accumulation in T3 treatment was the highest, but there was no significant difference among different fertilization treatments. Agronomic utilization rate of nitrogen fertilizer and partial productivity of nitrogen fertilizer of peanut were peaked in the T3 treatment, whilst there was significant difference among the fertilization treatments. The highest yield was in T3 at 5361.11 kg·hm-2, which was 20.79%, 3.27% and 5.66% higher than CK, T1 and T2 treatments, respectively. From the analysis of yield components, the yield increase of T3 treatment was mainly dependent on the increase of fruit weight per plant and satiation rate of peanut.
In order to analyze the influence of waterlogging on the morphological characteristics of peanut root system, a tolerant variety Xianghua 2008 and a sensitive variety Zhonghua 4 were used as materials, and pot experiment was carried out with the self-made root rack system. After 0, 3, 6, 9, and 12 days of waterlogging stresses in the seedling stage, the root morphological characteristics were studied based on the fresh （dry） weight, microscopic and ultrastructure of the root system. The results showed that the root system of Zhonghua 4 was greatly damaged by waterlogging stress. As the days of flooding prolonged, the root color of Zhonghua 4 became darker and smelled bad, while, for Xianghua 2008, only the middle-and-upper roots was slightly yellow and lighter odor. Waterlogging tolerance cofficient of fresh weight of the root system was higher than that of Zhonghua 4. In addition, aerenchyma appeared in Xianghua 2008, the number and cross-sectionalarea of aerenchyma increased with flooding time. Xylem of the middle section of the main root remained basically normal, and the ducts were generally distributed in rays. On the contrary, no obvious aerenchyma was formed in roots of Zhonghua 4, and the xylem and ducts were irregularly distributed. Although the nucleus and mitochondria in the main root cells of Xianghua 2008 are affected, they could still maintain cell activity and root growth. The organelles of Zhonghua 4 were more sensitive to waterlogging stress and accelerate senescence and death. In summary, the root of Xianghua 2008 were less affected under waterlogging stress, aerenchyma appeared in the main root, the xylem and the nucleus and mitochondria in cells in the middle of the main root were basically normal. However, the roots of Zhonghua 4 were severely damaged, and no obvious aerenchyma was formed. The xylem and ducts in the middle of the main root were irregularly distributed, the cytoplasm of the cells in the middle of the main root was dissolved, and the mitochondria were abnormal. This study could provide a basis for analyzing the waterlogging resistance mechanism of peanut.
In order to study the effect of exogenous melatonin treatment on the degradation of pesticide residues in vegetable soybean, Zhexian12 was used as test material, chlorothalonil and carbendazim were used as test fungicides. Effects of exogenous melatonin treatment on pesticide residues, antioxidant system and detoxification system of vegetable soybean were determined to explore the effect of exogenous melatonin on the degradation of vegetable soybean pesticides. Results showed that exogenous melatonin increased the content of ascorbic acid and glutathione and activities of antioxidant enzymes （superoxide dismutase, peroxidase, catalase, ascorbate peroxidase） in vegetable soybean, effectively eliminated the reactive oxygen species in vegetable soybean, induced the expression of detoxification related genes of vegetable soybean, enhanced the detoxification metabolism of carbendazim and chlorothalonil, and promoted the degradation of residual pesticides, and thus reduced the residues of carbendazim and chlorothalonil in vegetable soybean.
In order to investigate the occurrence and distribution of aflatoxin by Aspergillus flavus in soils, 36 soil samples were collected from 4 main peanut planting areas in Xiangyang for A. flavus isolation, identification and aflatoxin detection. Results demonstrated that the average colony number of A. flavus was 5997.6 cfu in one gram soil generally. But the populations of A. flavus in soil samples from 4 peanuts areas were significantly different. The order of colony numbers of 4 peanuts areas was Xiangzhou, Zaoyang, Yicheng, Gucheng, ranking from high to low. Among the strains，aflatoxigenic strains accounted for 63.6%, with AFT content of ND - 304.9μg/L，and proportion of atoxigenic strains was 36.4%. According to the aflatoxin types, there were 7 types of aflatoxigenic strains and the proportion of strains which producing AFB1+AFB2 +AFG1 was the highest, reaching 54%. Studies on aflatoxin production in different planting areas showed that with proper culture conditions, the highest amount of AFT contamination per gram of soil was from Xiangzhou, reaching 2080.0×103 μg/L. And the average aflatoxin production of strains isolated from soils of Xiangzhou was the highest （218.7 μg/L）. Results illustrated that the average population of A. flavus in soil samples from main peanuts planting fields in Xiangyang was significantly higher than that in both south and north peanuts planting areas in China. But the ability of aflatoxin producing of A. flavus isolated from soils in Xiangyang were much lower than those from other areas in China. This study was expected to provide a theoretical base for predicting and controlling of aflatoxin contamination in typical peanut planting areas in Xiangyang．
Corynespora leaf spot is sesame common disease, seriously affecting the yield and quality of the sesame. To determine the optimal period of prevention and control of Corynespora leaf spot and formulate effective pesticide control measures, the occurrence of Corynespora leaf spot in Pingyu County was monitored from 2017 to 2019. The indoor toxicity and field control efficiency of 16 fungicides were determined. The results showed that the initial occurrence stage of Corynespora leaf spot was the squaring stage-early flowering stage, and the turning stage of disease development was the early flowering stage-full flowering stage （20-31, July, in Huanghuai region, the incidence was less than 3% or the disease index was less than 1）. Among the 16 fungicides, hexaconazole, prochloraz, flusilazole, tebuconazole, difenoconazole, procymidone, thiofuramide and fludioxonil were the stronger toxicity to Corynespora leaf spot, EC50 is 1.5734×10-4, 0.1248, 0.7128, 1.3922, 2.0014, 2.7323, 5.4327 and 6.1285 mg/L. Thiofuramide, hexaconazole, azoxystrobin, tebuconazole and difenoconazole had well field efficacy both on disease control and yield improvement. The control efficacies were 67.19%, 65.86%, 61.17%, 60.87% and 61.83%, the increase rates were 38.96%, 36.86%, 39.72%, 34.96% and 38.56%, respectively. The control efficacy and yield increase efficacy of difenoconazole, hexaconazole, azoxystrobin and tebuconazole were the best when applied twice. According to the results, the optimal control period of Corynespora leaf spot in sesame was from early flowering stage to full flowering stage as 20-31 July in Huanghuai region, or before the disease incidence reached 3% or disease index reached 1. Thus it is supposed to select thiofuramide, hexaconazole, azoxystrobin, tebuconazole and difenoconazole as fungicides. The same fungicide should not be applied for more than twice with an interval of 10 days. In order to reduce fungicide residues and prevent pathogens from producing resistance （tolerance）, different fungicides could be used alternately.
