Genome-wide analysis of the Populus Hsp90 gene family reveals differential expression patterns, localization, and heat stress responses

Abstract

BackgroundMembers of the heat shock protein 90 (Hsp90) class of proteins are evolutionarily conserved molecular chaperones. They are involved in protein folding, assembly, stabilization, activation, and degradation in many normal cellular processes and under stress conditions. Unlike many other well-characterized molecular chaperones, Hsp90s play key roles in signal transduction, cell-cycle control, genomic silencing, and protein trafficking. However, no systematic analysis of genome organization, gene structure, and expression compendium has been performed in the Populus model tree genus to date.ResultsWe performed a comprehensive analysis of the Populus Hsp90 gene family and identified 10 Populus Hsp90 genes, which were phylogenetically clustered into two major groups. Gene structure and motif composition are relatively conserved in each group. In Populus trichocarpa, we identified three paralogous pairs, among which the PtHsp90-5a/PtHsp90-5b paralogous pair might be created by duplication of a genome segment. Subcellular localization analysis shows that PtHsp90 members are localized in different subcellular compartments. PtHsp90-3 is localized both in the nucleus and in the cytoplasm, PtHsp90-5a and PtHsp90-5b are in chloroplasts, and PtHsp90-7 is in the endoplasmic reticulum (ER). Furthermore, microarray and semi-quantitative real-time RT-PCR analyses show that a number of Populus Hsp90 genes are differentially expressed upon exposure to various stresses.ConclusionsThe gene structure and motif composition of PtHsp90s are highly conserved among group members, suggesting that members of the same group may also have conserved functions. Microarray and RT-PCR analyses show that most PtHsp90s were induced by various stresses, including heat stress. Collectively, these observations lay the foundation for future efforts to unravel the biological roles of PtHsp90 genes.

The chaperone MeHSP90 recruits MeWRKY20 and MeCatalase1 to regulate drought stress resistance in cassava

“…Except for mutant analysis, two protein inhibitors (geldanamycin (GDA) and radicicol (RAD)) are also widely used to reveal the functions of HSP90s in plants (Baro et al , ; Queitsch et al , ; Samakovli et al , ; Wang et al , ; Watanabe et al , ). So far, the HSP90 gene family has been reported on a genome‐wide basis in several plant species, including Arabidopsis (Krishna & Gloor, ), Populus trichocarpa (Zhang et al , ), tomato (Zai et al , ), chickpea and pigeonpea (Agarwal et al , ), foxtail millet (Singh et al , ), and Brachypodium distachyon (Zhang et al , ). However, cassava HSP90 genes have not been identified and their functions remain to be further characterized.…”

Genome-Wide Analysis of the PvHsp20 Family in Switchgrass: Motif, Genomic Organization, and Identification of Stress or Developmental-Related Hsp20s

“…Most HSPs function by aiding protein folding and refolding under stress conditions, protein assembly, translocation, and degradation in cellular processes to maintain stabilization of proteins and membranes (Mayer and Bukau, 2005; Zhang, 2013). …”

Rapid induction of small heat shock proteins improves physiological adaptation to high temperature stress in peanut

“…Definite role of small HSP for preventing wrong aggregation or irreversible unfolding of partially denatured proteins was established in many crops under heat stress (Goswami et al., ; Lee et al., ; Xu, Zhan, & Huang, ). Besides, both HSP 70 and 90 play key role as molecular chaperon and known to modulate downstream gene expression under heat stress (Duan et al., ; Zhang et al., ).…”

“…In addition, larger HSPs, especially HSP 70 and HSP 90, were reported to act as molecular chaperone as they involved in up‐regulation of several downstream genes associated with heat tolerance in plants (Kumar et al. ; Zhang et al., ).…”