Drought priming evokes essential regulation of Hsp gene families, Hsfs and their related miRNAs and induces heat stress tolerance in chickpea

Abstract

Optimum temperature is crucial for plant's survival. During high temperature stress, heat shock proteins (Hsps) are expressed many folds essentially controlled by explicit heat shock factors (Hsfs).We have narrowed key HSPs, related HSFs and miRNAs regulated after priming with drought stress and consequent heat stress in chickpea. Firstly, we identified Hsf and Hsp gene families in desi and kabuli chickpea using Genome-wide analysis. Thereafter, selected Hsfs, Hsps and related miRNAs were analyzed using qRT-PCR in contrasting chickpea varieties (PBG1 and PBG5) after drought priming and exposing at 32 °C 24 hrs, 35 °C 12 hrs, and 38 °C 6 hrs. An interaction network between Hsfs and Hsps was generated. 18 & 17 Hsfs and 42 & 34 Hsps were identified in the desi and kabuli, respectively. The gene structure and motif composition of the genes were found to be conserved in all subfamilies. A total of 32 heat shock genes were found to have undergone duplication. Most of the CaHsf and CaHsp genes were differentially expressed on exposure to a combination of drought priming and heat stress in both in-silico and qPCR analysis. Targeted miRNAs expression was coordinated with the respective genes. miR156, miR166, miR319, miR171, and miR5213 were identified to be targets of sHsps, Hsfs, and Hsps. The protein-protein interaction revealed that CaHsp18.2 and CaHsp70 might be controlled by CaHsfsA1. Drought priming strongly correlated with less membrane damage and better leaf water content. Higher harvest index and root shoot ratio significantly indicated effectiveness of priming and essential role of Hsf and Hsp and related miRNAs in heat stress tolerance.