Genome Wide Analysis of Citrus sinensis Heat Shock Proteins

Plant and animal cells possess a ubiquitous protein known as heat shock proteins (HSPs). Hsps were originally described in relation to heat shock and against abiotic and biotic stresses. Heat shock protein was classified in other crops on the bases of single classes or all classes but in Citrus sinensis Hsps groups, classes, subfamilies and members were not classified and characterized up to our knowledge.

Present study was focused on the identification and grouping of C. sinensis Hsps (CsHsps) classes, members among classes, their phylogenetic relationship, gene structure, conserved motifs and identification of proteins by using bioinformatics tools and analyses.

Genomic, Peptide and CDS sequences of CsHsps were downloaded from phytozome. MEGA 7 used for the phylogenetic analysis, GSDS for gene structure, UGENE for the multiple sequence alignment and MEME suite for the conserved motif analysis.

The genome size of C. sinensis was 367 Mb, Chromosome number (2n)18, having 151 Hsps with six groups CsHsp10, 20, 40, 60,70 and 90. CsHsp20 was the largest group having 54 members, followed by CsHsp60 and CsHsp70 both having 30 members respectively.

CsHsps members within a class shared more similar gene and protein structure. CsHsp 60, CsHsp 70 and CsHsp90 shared more conserved and similar amino acid pattern. Each class had some important proteins such as Cpn in CsHsp10, Hypothetical proteins in CsHsp20 and 40, Dnak in CsHsp60, Molecular chaperone in CsHsp70 and Hsp90 in CsHsp90. These proteins are produced by cells in response to stresses in citrus. Chaperonins and some hypothetical proteins identified in CsHsps, help in ATP synthesis and protein degradation. This is genome wide analysis and classification sets the groundwork for future investigations to fully characterize functionally the Citrus Hsps families and underscores the relevance of Hsps response to abiotic and biotic stresses in Citrus.