Identification and characterisation of heat shock protein gene (HSP70) family and its expression in Agave sisalana under heat stress

Heat shock Protein (HSP) expression is the plants' responses to high temperature. We analysed the HSP70 gene family in Agave sisalana transcriptome to understand its expression under heat stress. A total of 167 genes were identified as heat shock protein genes. Among them; 74, 39 and 25 belong to the HSP70, HSP20 HSP90 respectively and multiple sequence alignment of conserved domain proteins of AsHSP70 showed that they are highly conserved. Fifty-two AsHSPs were classified into three major classes according to their structural characteristics. Phylogenetic analysis indicated that orthologs from Agave deserti and Agave tequilana species were distributed among the three classes; which revealed the diverse expression of HSP70 gene family. In silico subcellular localisation of AsHSP, suggested that its interaction is quite diverse in target cells and active signalling pathways. Transcripts identified and named as B1, B3, B5, B7, B9, B11, B13, B15, B17 and B19 were validated through Nested PCR. Significant difference in the expression pattern of target gene was revealed after normalisation with GAPDH. Gene expression was up-regulated with some exceptions as down-regulated. In silico analysis of HSP70 gene family identified from A. sisalana suggests that genetic transformation of this gene will induce heat tolerance in transgenic crops.