AUTHOR=Rana Kusum , Atri Chhaya , Akhatar Javed , Kaur Rimaljeet , Goyal Anna , Singh Mohini Prabha , Kumar Nitin , Sharma Anju , Sandhu Prabhjodh S. , Kaur Gurpreet , Barbetti Martin J. , Banga Surinder S. 

TITLE=Detection of First Marker Trait Associations for Resistance Against Sclerotinia sclerotiorum in Brassica juncea–Erucastrum cardaminoides Introgression Lines

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01015

DOI=10.3389/fpls.2019.01015

ISSN=1664-462X

ABSTRACT=<p>A set of 96 <italic>Brassica juncea</italic>–<italic>Erucastrum cardaminoides</italic> introgression lines (ILs) were developed with genomic regions associated with <italic>Sclerotinia</italic> stem rot (<italic>Sclerotinia sclerotiorum</italic>) resistance from a wild <italic>Brassicaceous</italic> species <italic>E. cardaminoides</italic>. ILs were assessed for their resistance responses to stem inoculation with <italic>S. sclerotiorum</italic>, over three crop seasons (season I, 2011/2012; II, 2014/2015; III, 2016–2017). Initially, ILs were genotyped with transferable SSR markers and subsequently through genotyping by sequencing. SSR based association mapping identified six marker loci associated to resistance in both A and B genomes. Subsequent genome-wide association analysis (GWAS) of 84 ILs recognized a large number of SNPs associated to resistance, in chromosomes A03, A06, and B03. Chromosomes A03 and A06 harbored the maximum number of resistance related SNPs. Annotation of linked genomic regions highlighted an array of resistance mechanisms in terms of signal transduction pathways, hypersensitive responses and production of anti-fungal proteins and metabolites. Of major importance was the clustering of SNPs, encoding multiple resistance genes on small regions spanning approximately 885 kb region on chromosome A03 and 74 kb on B03. Five SNPs on chromosome A03 (6,390,210-381) were associated with LRR-RLK (receptor like kinases) genes that encode LRR-protein kinase family proteins. Genetic factors associated with pathogen-associated molecular patterns (PAMPs) and effector-triggered immunity (ETI) were predicted on chromosome A03, exhibiting 11 SNPs (6,274,763-994). These belonged to three R-Genes encoding TIR-NBS-LRR proteins. Marker trait associations (MTAs) identified will facilitate marker assisted introgression of these critical resistances, into new cultivars of <italic>B. juncea</italic> initially and, subsequently, into other crop <italic>Brassica</italic> species.</p>