Analysis of genomic-transcriptomic dynamics delineates key molecular signatures modulating seed size and weight in lentil

Abstract

Delineating key genetic determinants associated with seed size/weight is crucial for increasing productivity. In this study, the advantages of an integrated approach combining QTL mapping, GWAS and transcriptomics to identify robust candidates governing seed size and weight were demonstrated in lentil, an important grain legume. QTL mapping identified three stable QTLs harbouring 5113 genes. GWAS identified 42 MTAs (5 consistent) containing 192 underlying genes. Comparative transcriptome analysis identified 1202 differentially expressed transcripts. Integrated analysis of the results obtained from QTL mapping and GWAS revealed nine SNPs located in the three robust QTLs harbouring 32 candidate genes. Upon integration with transcriptome data, only one (LcWDL1) was identified as the most promising candidate. LcWDL1 (a member of TPX2 family involved in microtubule organisation and cell expansion) and its predicted interacting partners that is, LcGLIPs are known to function as regulators of seed size. Candidate gene-based association analysis identified a SNP on second exon of LcWDL1 to be significantly associated with seed size and weight of lentil. The genomic loci/candidate gene identified in the study will serve to expedite the molecular breeding and gene editing programs for enhancing seed size and seed weight in lentils.