Screening For Peanut Resistance To Aspergillus Flavus Infection And Aflatoxin Production

Peanuts are not only an important oilseed,but also a popular food among consumers in the international market.Aflatoxin contamination poses a serious threat to human and animal health.Much research has been conducted both domestically and internationally on peanuts resistance to Aspergillus flavus infection and aflatoxin production,and some progresses have been achieved,but a permanent solution has not been found.In China,related research is concentrated in the southern region.With the warming climate,aflatoxin contamination in the northern region is showing an increasing trend.Therefore,in this study,a wide range of peanut materials were used to identify resistance to Aspergillus flavus infection and aflatoxin production.The following main results were obtained:1.227 peanut entries were screened for resistance to Aspergillus flavus infection.One resistant,88 intermediate-resistant,72 intermediate-susceptible,38 susceptible and28 highly susceptible peanut genotypes were identified,accounting for 0.44%,38.77%,31.72%,16.74% and 12.33% of the total,respectively.No peanut genotype with high resistance was found.2.Aflatoxin(AFT B1)detection showed that the peanut entries with the lowest content were Guihua 36(intermediate-susceptible material,infection index 30.67)and21L94(intermediate-resistant material,infection index 24.33),both with a content of11.25 ppm.Infection index was significantly correlated with AFT B1 content(r=0.4748).3.Infection index of peanut materials from different regions in China was analyzed,and it was found that as the breeding source of tested peanuts gradually moved southward,the severity of their susceptibility to Aspergillus flavus infection decreased.This may be related to the higher environmental selection pressure for peanut in southern regions.The proportion of wild peanut accessions with resistance to infection was 53.85%,significantly higher than that of cultivated materials(37.31%).There is no linear trend between the high and low categories of oleic acid content in the tested peanut breeding materials and resistance to aspergillus flavus infection.Genetic improvement of oleic acid content may not affect resistance to aspergillus flavus infection4.Genome-wide association analysis identified 4 Ah MITE tab loci,Ah TE0151,Ah TE0489,Ah TE0046 and Ah TE0047,significantly associated with resistance to invasion,located on four linkage groups(LG02,LG011,LG13,LG17),with contribution rates of 5.1% ～ 12.8% and P values of 0.0024～0.0429.Among these 4Ah MITE tab loci,Ah TE0046,with a contribution rate higher than 10.00% and a P value of 0.0024,was the most significant.Three Ah MITE tab loci(Ah TE0489,Ah TE0052,Ah TE0019)were associated with toxin production,located on three linkage groups(LG11,LG14,LG17),with a contribution rate of 4.2% ～ 11.1% and P values of0.0106～0.0488.Among these 3 Ah MITE tab loci,only Ah TE0019 had a contribution rate exceeding 10% One Ah MITE tab marker associated with infection index was identified by whole-genome association analysis.The marker was on the A13 linkage group,with a phenotypic variation explanation percentage of 12.8%.5.90 of the peanut materials were assessed for genetic diversity.Intermediatesusceptible peanut entries were found to have the highest genetic diversity,followed by intermediate-resistant entries,thus necessitating enhanced resistance screening to broaden the genetic basis of peanut resistance to Aspergillus flavus infection.