Integrated genomic approaches delineate a novel role of ROP1 ENHANCER1 in controlling seed protein content of chickpea.

Abstract

Utilizing a combinatorial approach of quantitative trait locus (QTL)-Seq and candidate gene-based association mapping, the QTLs and genes responsible for seed protein content (SPC), a major quality trait in chickpea, were identified. Whole genome re-sequencing based QTL-Seq analysis of bulked recombinant inbred lines from a mapping population contrasting for SPC led to the identification of two QTLs [0.94 Mb on Linkage Group (LG)5 and 1.16 Mb on LG6] encompassing three SNPs, displaying the highest ΔSNP index. These highly significant SNPs and their associated genes were validated in 211 chickpea mini-core accessions varying in SPC, revealing a tightly associated marker affecting CaREN1 (ROP1 ENHANCER1) and explaining a phenotypic variation of 23%. This SNP was subsequently converted into a cost effective allele-specific PCR-based marker that could be utilized for rapid screening of SPC during marker assisted breeding. Furthermore, in planta functional validation via knockdown of CaREN1 transcripts led to significant reduction in SPC of chickpea. This decrease in seed protein is likely due to disruption in the formation of CaREN1 protein complexes comprising chaperones, phosphopeptide-binding proteins, and GTPases that mediate folding, transport and accumulation of seed storage proteins, as indicated through affinity purification-mass spectrometry. Taken together, our data will expedite tailoring of chickpea cultivars with augmented SPC.