Identification of Two Novel Peanut Genotypes Resistant to Aflatoxin Production and Their SNP Markers Associated with Resistance

Abstract

Aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) are the most common aflatoxins produced by Aspergillus flavus in peanuts, with high carcinogenicity and teratogenicity. Identification of DNA markers associated with resistance to aflatoxin production is likely to offer breeders efficient tools to develop resistant cultivars through molecular breeding. In this study, seeds of 99 accessions of a Chinese peanut mini-mini core collection were investigated for their reaction to aflatoxin production by a laboratory kernel inoculation assay. Two resistant accessions (Zh.h0551 and Zh.h2150) were identified, with their aflatoxin content being 8.11%–18.90% of the susceptible control. The 99 peanut accessions were also genotyped by restriction site-associated DNA sequencing (RAD-Seq) for a genome-wide association study (GWAS). A total of 60 SNP (single nucleotide polymorphism) markers associated with aflatoxin production were detected, and they explained 16.87%–31.70% of phenotypic variation (PVE), with SNP02686 and SNP19994 possessing 31.70% and 28.91% PVE, respectively. Aflatoxin contents of accessions with “AG” (existed in Zh.h0551 and Zh.h2150) and “GG” genotypes of either SNP19994 or SNP02686 were significantly lower than that of “AA” genotypes in the mean value of a three-year assay. The resistant accessions and molecular markers identified in this study are likely to be helpful for deployment in aflatoxin resistance breeding in peanuts.

Comprehensive Evaluation of Chinese Peanut Mini-Mini Core Collection and QTL Mapping for Aflatoxin Resistance

“…Zh.h1312 was resistant to both seed infection and toxin production, meanwhile the shell infection resistance of Zh.h1312 was also much better than the susceptible control, showing being an ideal parent in breeding. As for the screening of resistant germplasm, ve accessions were screened for a atoxin production resistance in this study are not exactly the same as Yu's [23] study due to the different methods used in screening. More research would be conducted to reveal the role of these resistant accessions in reducing post-harvest infection under eld conditions.…”

“…The above peanut accessions were normally maintained in the genebank at the Oil Crops Research Institute of Chinese Academy of Agricultural Sciences (OCRI-CAAS), China. The materials were planted in the same experimental eld as in the previous study [23] in Wuhan, China in two growing seasons (2018-2019). After harvest, all peanut pods were dried to 5%-8% moisture content.…”

“…The SNP variation of the Chinese peanut mini-mini core collection was identi ed based on the combination of two genome assembles of the two diploid progenitors of cultivated peanut [23]. Therefore, the previously generated sequencing datasets were re-analyzed using the published genome sequence of the cultivated peanut cultivar Tifrunner (https://www.peanutbase.org/data/public/Arachis_hypogaea/Tifrunner.gnm2.J5K5/) [25] as reference to identify both SNP and InDel variations.…”

“…Han [22] performed a GWAS of 313 maize inbred lines which were inoculated with A. avus and identi ed four associated loci and 16 candidate genes. In peanut, Yu et al [23] identi ed 60 associated SNPs through GWAS in the Chinese peanut mini-mini core collection. It is worth to mention that the identi ed resistant loci for SDII and a atoxin accumulation were different, indicating the potential of pyramiding these two different resistances by marker-assisted breeding.…”

Dissection of the Genetic Basis of Yield-Related Traits in the Chinese Peanut Mini-Core Collection Through Genome-Wide Association Studies

“…Assemblies of the reference genome have also become available for cultivated peanut ( Bertioli et al, 2019 ; Chen et al, 2019 ; Zhuang et al, 2019 ) and will increase the efficiency of such studies in the future. In this study, we have used progenitor genome sequence assemblies for calling SNPs in the Chinese peanut mini-core collection as reported in some recent publications ( Chavarro et al, 2019 ; Gangurde et al, 2020 ; Huang et al, 2020 ; Yu et al, 2020 ). Finally, 105,814 high-quality genome-wide SNPs were retained in this study, which is, so far, the highest number of markers used for performing association analysis in peanut.…”