Insight into the mechanisms of terminal HS-tolerance in wheat mutant with improved nutritional quality through de novo transcriptome sequencing

Abstract Terminal HS is one of the main bottle-neck in wheat yield and grain-quality. Here, we have developed wheat mutant (M3) for HS-tolerance [parent-MP3054- C-306/CB.SPRING BW/CPAN2072 (Parentage)]. To elucidate the mechanism of thermotolerance in mutant, we performed de novo transcriptomic sequencing of mutant (M3), parent (P3), and mutant exposed to HS (M3H). We sequenced 6.5, 7.5, and 7.0 million reads in P3, M3 and M3H and generated 3,05,537 genes and 5,88,788 transcripts with an N50 of 1,349 bp. We observed 6,120 upregulated and 4,428 downregulated transcripts (M3 vs P3), 11,354 upregulated and 12,408 downregulated genes (M3H vs P3) and 4817 upregulated and 9085 downregulated genes (M3H vs M3). Some of the highly upregulated genes observed were HSP20, SOD, ABC transporters, HSF, etc. and downregulated genes were starch synthase, sucrose synthase, etc. Gene Ontology analysis showed ‘ATP-binding’ to be most enriched category. Carbon metabolism pathway was observed most altered under HS. We identified 41940 SSRs, 1,10,772 SNPs and 2432 InDels. Potential markers were observed lying on HSP, SOD, STK, and starch synthase. Biochemical markers based characterization showed wheat mutant to be better in HS-tolerance and grain-quality, as compared to parent.