AUTHOR=Wang Hongman , Dong Zuqi , Chen Jianbing , Wang Meng , Ding Yuting , Xue Qingyun , Liu Wei , Niu Zhitao , Ding Xiaoyu 

TITLE=Genome-wide identification and expression analysis of the Hsp20, Hsp70 and Hsp90 gene family in Dendrobium officinale

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.979801

DOI=10.3389/fpls.2022.979801

ISSN=1664-462X

ABSTRACT=<p><italic>Dendrobium officinale</italic>, an important orchid plant with great horticultural and medicinal values, frequently suffers from abiotic or biotic stresses in the wild, which may influence its well-growth. Heat shock proteins (<italic>Hsp</italic>s) play essential roles in the abiotic stress response of plants. However, they have not been systematically investigated in <italic>D. officinale</italic>. Here, we identified 37 <italic>Hsp20</italic> genes (<italic>DenHsp20</italic>s), 43 <italic>Hsp70</italic> genes (<italic>DenHsp70</italic>s) and 4 <italic>Hsp90</italic> genes (<italic>DenHsp90</italic>s) in <italic>D. officinale</italic> genome. These genes were classified into 8, 4 and 2 subfamilies based on phylogenetic analysis and subcellular predication, respectively. Sequence analysis showed that the same subfamily members have relatively conserved gene structures and similar protein motifs. Moreover, we identified 33 pairs of paralogs containing 30 pairs of tandem duplicates and 3 pairs of segmental duplicates among these genes. There were 7 pairs in <italic>DenHsp70</italic>s under positive selection, which may have important functions in helping cells withstand extreme stress. Numerous gene promoter sequences contained stress and hormone response <italic>cis</italic>-elements, especially light and MeJA response elements. Under MeJA stress, <italic>DenHsp20</italic>s, <italic>DenHsp70</italic>s and <italic>DenHsp90</italic>s responded to varying degrees, among which <italic>DenHsp20-5,6,7,16</italic> extremely up-regulated, which may have a strong stress resistance. Therefore, these findings could provide useful information for evolutional and functional investigations of <italic>Hsp20</italic>, <italic>Hsp70</italic> and <italic>Hsp90</italic> genes in <italic>D. officinale</italic>.</p>