Genome wide characterization of Hsp 100 family genes from pigeonpea

Pigeon pea [Cajanus cajan] is an important grain legume of South-East Asia and East Africa. It is mainly grown as a kharif crop and is known to sustain prolonged drought and temperature stress. The Hsp 100family gene [ClpB] is one of the major and critical genes required for acquired thermo tolerance. The current study was taken up to identify and characterize the Hsp 100 family genes in pigeon pea since very little information is available for this thermo tolerant plant. In silico genome wide characterization was carried out and 5 Hsp100 like gene sequences were identified. Domains were predicted and three proteins were found to possess Class I type ClpB domains. Expression of these genes was observed at control 2, 6 and 24 h post heat stress conditions indicating their heat inducible nature. Out of the 5 genes predicted, two Clp genes show constant expression under heat stress and could be important components of the heat stress response in pigeon pea as they are targeted to the chloroplast. To identify additional members, candidate gene approach was taken up. Glycine max Hsp100 genes were downloaded and their expression studied under heat stress conditions in Asha, Pusa dwarf and C. platycarpus genotypes. Out of 23, 20 genes were expressed in pigeon pea indicating the presence of more Hsp100 family genes in the genome that need further investigation. This study would help in understanding the molecular components governing thermo tolerance in pigeon pea.