Abstract
The Heat shock protein-70 (Hsp70) gene family is one of the protective mechanisms; however, it has not been widely studied in tomatoes. Therefore, the current study provides the first report genome-wide analysis of the Hsp70 gene family in tomato (Solanum lycopersicum L.) under five heavy metals (Cd2+, Co2+, Mn2+, Zn2+, and Fe2+) stresses. We identified 23 candidate genes of the Hsp70 gene family based on the PF00012 domain through bioinformatics studies, including gene structure, distribution, synteny, phylogenetic tree, protein-protein interactions, gene ontology, and previous RNA-seq data analysis followed by qRT-PCR analysis. Based on the phylogenetic analysis, the 23 candidate genes were classified into five subfamilies where the same subfamily contains similar SlHsp70 proteins. Many pairs of SlHsp70 gene duplications have appeared, consisting of tandem and segment duplication. In addition, analysis of previous RNA-seq besides the gene ontology gave us significant evidence about the vital roles of these genes during tomato development and growth. The SlHsp7s showed different responses, which were varied depend on different plant tissues and types of heavy metal. Some of the SlHsp70s were up-regulated after heavy metal exposure, such as Cd2+/SlHsp70-23 and Mn2+/ SlHsp70-8. Still, down-regulated others such as Fe2+/ SlHsp70-18. Finally, our gene expression analysis revealed the significant roles of the Hsp70s, especially, SlHsp70- 3, SlHsp70-8, SlHsp70-12, SlHsp70-19, and SlHsp70-23, with the different heavy metals treatments.
Genome-Wide Identification and Expression Analysis of the Protease Inhibitor Gene Families in Tomato
