Heat responsive proteome changes reveal molecular mechanisms underlying heat tolerance in chickpea

Abstract

Understanding the molecular differences in plant genotypes contrasting for heat sensitivity can provide useful insights into the mechanisms that confer heat tolerance in plants. This study focuses on comparative physiological and proteomic analyses of heat-sensitive (ICC16374) and heat-tolerant (JG14) genotypes of chickpea (Cicer arietinum L.) under heat stress impositions at anthesis. Heat stress reduced leaf water content, chlorophyll content and membrane integrity with a greater impact on the sensitive genotype compared to the tolerant one that had higher total antioxidant capacity and osmolyte accumulation, and consequently less oxidative damage. This study identified a set of 482 heat-responsive proteins in the tolerant genotype using comparative gel-free proteomics. Besides heat shock proteins, proteins such as acetyl-CoA carboxylase, pyrroline-5-carboxylate synthase (P5CS), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), phenylalanine ammonia-lyase (PAL) 2, ATP synthase, glycosyltransferase, sucrose synthase and late embryogenesis abundant (LEA) proteins were strongly associated with heat tolerance in chickpea. Several crucial proteins were induced by heat exclusively in the heat-tolerant genotype. Comparative proteome profiling and pathway analysis revealed mitigating strategies including, accumulation of osmoprotectants, protected membrane transport, ribosome and secondary metabolite synthesis, activation of antioxidant and defense compounds, amino acid biosynthesis, and hormonal modulation that might play key roles in chickpea heat tolerance. This study potentially contributes to improved stress resilience by advancing our understanding on the mechanisms of heat tolerance in chickpea.