M. Nagaraju, Anuj Kumar, N. Jalaja, D. Manohar Rao* and P.B. Kavi Kishor* Pages 137 - 155 ( 19 )
Background: Sorghum, the C4 dry-land cereal, important for food, fodder, feed and fuel, is a model crop for abiotic stress tolerance with smaller genome size, genetic diversity, and bioenergy traits. The heat shock proteins/chaperonin 60s (HSP60/Cpn60s) assist the plastid proteins, and participate in the folding and aggregation of proteins. However, the functions of HSP60s in abiotic stress tolerance in Sorghum remain unclear.Methods: Genome-wide screening and in silico characterization of SbHSP60s were carried out along with tissue and stress-specific expression analysis. Results: A total of 36 HSP60 genes were identified in Sorghum bicolor. They were subdivided into 2 groups, the HSP60 and HSP10 co-chaperonins encoded by 30 and 6 genes, respectively. The genes are distributed on all the chromosomes, chromosome 1 being the hot spot with 9 genes. All the HSP60s were found hydrophilic and highly unstable. The HSP60 genes showed a large number of introns, the majority of them with more than 10. Among the 12 paralogs, only 1 was tandem and the remaining 11 segmental, indicating their role in the expansion of SbHSP60s. Majority of the SbHSP60 genes expressed uniformly in leaf while a moderate expression was observed in the root tissues, with the highest expression displayed by SbHSP60-1. From expression analysis, SbHSP60- 3 for drought, SbHSP60-9 for salt, SbHSP60-9 and 24 for heat and SbHSP60-3, 9 and SbHSP10- 2 have been found implicated for cold stress tolerance and appeared as the key regulatory genes. Conclusion: This work paves the way for the utilization of chaperonin family genes for achieving abiotic stress tolerance in plants.
HSP60, HSP10, abiotic stress-responsive, phylogenetic tree, gene expressions.
Department of Genetics, Osmania University, Hyderabad 500 007, Advance Center for Computational & Applied Biotechnology, Uttarakhand Council for Biotechnology (UCB), Silk Park, Prem Nagar, Dehradun248 007, Department of Biotechnology, Vignan’s Foundation for Science, Technology and Research, Vadlamudi, Guntur 522 213, Andhra Pradesh, Department of Genetics, Osmania University, Hyderabad 500 007, Department of Biotechnology, Vignan’s Foundation for Science, Technology and Research, Vadlamudi, Guntur 522 213, Andhra Pradesh