Genome-Wide Identification and Characterization of HSP90-RAR1-SGT1-Complex Members From Arachis Genomes and Their Responses to Biotic and Abiotic Stresses

Abstract

The molecular chaperone complex HSP90-RAR1-SGT1 (HRS) plays important roles in both biotic and abiotic stress responses in plants. A previous study showed that wild peanut Arachis diogoi SGT1 (AdSGT1) could enhance disease resistance in transgenic tobacco and peanut. However, no systematic analysis of the HRS complex in Arachis has been conducted to date. In this study, a comprehensive analysis of the HRS complex were performed in Arachis. Nineteen HSP90, two RAR1 and six SGT1 genes were identified from the allotetraploid peanut Arachis hypogaea, a number close to the sum of those from the two wild diploid peanut species Arachis duranensis and Arachis ipaensis. According to phylogenetic and chromosomal location analyses, thirteen orthologous gene pairs from Arachis were identified, all of which except AhHSP90-A8, AhHSP90-B9, AdHSP90-9, and AiHSP90-9 were localized on the syntenic locus, and they shared similar exon-intron structures, conserved motifs and expression patterns. Phylogenetic analysis showed that HSP90 and RAR1 from dicot and monocot plants diverged into different clusters throughout their evolution. Chromosomal location analysis indicated that AdSGT1 (the orthologous gene of AhSGT1-B3 in this study) might provide resistance to leaf late spot disease dependent on the orthologous genes of AhHSP90-B10 and AhRAR1-B in the wild peanut A. diogoi. Several HRS genes exhibited tissue-specific expression patterns, which may reflect the sites where they perform functions. By exploring published RNA-seq data, we found that several HSP90 genes play major roles in both biotic and abiotic stress responses, especially salt and drought responses. Autoactivation assays showed that AhSGT1-B1 could not be used as bait for yeast two-hybrid (Y2H) library screening. AhRAR1 and AhSGT1 could strongly interact with each other and interact with AhHSP90-B8. The present study represents the first systematic analysis of HRS complex genes in Arachis and provides valuable information for functional analyses of HRS complex genes. This study also offers potential stress-resistant genes for peanut improvement.

Genomics Associated Interventions for Heat Stress Tolerance in Cool Season Adapted Grain Legumes

“…In addition, complete transcriptome analysis of heat-responsive genes in heat-sensitive genotypes (ICC 5912, ICC 4567, and ICC 10685) and heat-tolerant genotypes (ICC 15614, ICC 1356, and ICC 92944) has been also reported in chickpea [ 165 ]. Major gene families for heat stress like AP2/ERF gene family has also been reported in an earlier study [ 166 ]. One AP2 domain and three ERFs clustered with AP2 sequences have also been identified in chickpea [ 166 ].…”

“…Major gene families for heat stress like AP2/ERF gene family has also been reported in an earlier study [ 166 ]. One AP2 domain and three ERFs clustered with AP2 sequences have also been identified in chickpea [ 166 ]. Deokar et al [ 167 ], also identified 16 AP2 and 120 putative ERF TFs in chickpea.…”

“…This study strictly identified and characterized the AP2s through the presence of two AP2 domains [ 167 ]. Furthermore, transcription factors (TFs) for heat tolerance have been reported in chickpea [ 166 , 168 ]. Car-WRKY has been reported to be a multi-stress responsive transcription factor and plays a crucial role in stress signal transduction pathways [ 169 ].…”

“…In cool season grain legumes, protein sequences have been examined for the presence of histidine kinase-like ATPases (HATPase c) and HSP90 motifs. In chickpea, five HSP90 genes have been identified [ 166 ] and the proteins encoded by these genes ranged from 648 to 818 amino acids in length with isoelectric points ranging from 4.79 to 5.45 suggesting the conserved nature of HSP90 proteins across the different legumes. Expression pattern of AP2/ERF and HSP90 in chickpea under heat stress and RNA-seq data generated from leaf, root and flower tissues at vegetative and reproductive stages revealed a unique set of AP2/ERF genes that expressed in different tissues [ 166 ].…”

“…In chickpea, five HSP90 genes have been identified [ 166 ] and the proteins encoded by these genes ranged from 648 to 818 amino acids in length with isoelectric points ranging from 4.79 to 5.45 suggesting the conserved nature of HSP90 proteins across the different legumes. Expression pattern of AP2/ERF and HSP90 in chickpea under heat stress and RNA-seq data generated from leaf, root and flower tissues at vegetative and reproductive stages revealed a unique set of AP2/ERF genes that expressed in different tissues [ 166 ]. In the same study, genes Ca_01566 , Ca_14133 and Ca_22585 were down regulated, whereas Ca_14133 , Ca_02170 , Ca_02170 and Ca_23799 were up-regulated in the vegetative tissues of heat-tolerant and heat-sensitive genotypes.…”