Genome-Wide Association Analysis of 14 Glucosinolate Compounds Reveals the Multiple Association Loci’s and Related Candidate Genes in Chinese Cabbage

Glucosinolates (GSLs) are naturally found high in Brassicacea family particularly in Chinese cabbage (Brassica rapa ssp. pekinensis) and their degradation products plays an key role in human health, special taste and flavors. Also many GSL compounds are involved in the resistance to several pathogens and insects. Earlier we have performed a conventional QTL analysis using a B. rapa segregated population combined with candidate gene association approach by using natural population in order to identify the genomic region and genes which regulating glucosinolates biosynthesis in B. rapa crops. Both QTL and gene based association mapping results revealed that paralogous of R2R3, MYB transcription factor, MAM gene family and BCAT-4 on A02, A03, A04, A07 syntenic region regulated the individual, three types and total aliphatic glucosinolate with gene redundancy function, guaranteeing the effective biosynthesis and metobolisam of glucosinolate. Recently we have re-sequenced 145 Chinese cabbage accessions and identified ~1.7 million high quality SNPs for the association studies. Results suggest several alleles with very high association for important compounds like gluconapin, neoglucobrassicin, sinigrin and glucobrassicanapin. Additionally the comparative analyses of several association results were completely matching with previous analyzed QTL maps. Potential candidate genes are identified for many loci which showed convincing association with each phenotypes. Association and comparative analysis of pathogenic resistant gluconapin compound shown strong association with four loci’s located on RLP and PAP genes which previously identified as a resistance gene for the bacterial pathogens in Brassicacea crops.