Identification and expression analysis of the SBP gene family in Rhododendron henanense subsp. lingbaoense under abiotic stress

Abstract

Abstract [Objective] The SQUAMOSA promoter binding protein (SBP) plays an important role in plant development and abiotic stress. The aim of the study is to provide basis for understanding the function and regulation of abiotic stress response of the SBP gene family of Rhododendron henanense subsp. lingbaoense and lay foundation for species protection. [Methods] SBP gene family members in the genome of R. henanense subsp. lingbaoense was identified and analyzed by bioinformatics method. Tissue specificity was analyzed based on transcriptome data and qRT-PCR was used to detect the response of SBP gene expression to abiotic stress. [Results] (1) 19 SBP genes containing SBP conserved domains were identified in the reference genome of Lingbao rhododendron, the length of amino acids encoded by the genes ranged from 179-1 072 aa with molecular weight ranging from 20.26-118.73 kD. The proteins were located in the nucleus, and the genes were unevenly distributed on 8 chromosomes. (2) 19 RhlSBPs were divided into 5 subfamilies by phylogenetic analysis and most RhlSBPs were clustered with Arabidopsis AtSPL family members. (3) All RhlSBPs shared motif 1, motif 2, and motif 4, and the number of introns in subfamilies Ⅳ and Ⅴ was much higher than that in subfamilies Ⅰ, Ⅱ, and Ⅲ. (4) RhlSBP promoters contained a large number of light responsive elements, hormone responsive elements, and stress responsive elements, suggesting that RhlSBPs may play an important role in response to light regulation and abiotic stress. (5) The orthology of SBP genes between Lingbao rhododendron and R. williamsianum and R. molle which were in the same family was higher. (6) The RhlSBP gene subfamily members had similar tissue expression patterns. (7) RhlSBP genes functioned in response to abiotic stress, but members responded differently to different stresses. Under methyl jasmonate (MeJA) and low temperature treatments, gene expression was up-regulated, while salt treatment inhibited RhlSBP expression. Under drought conditions, RhlSBP expression was up-regulated and then down-regulated. [Conclusion] RhlSBP1 and RhlSBP8 may be the key genes induced by drought, low temperature, and MeJA.

Keywords

• rhododendron henanense subsp. lingbaoense
• sbp gene family
• bioinformatics
• abiotic stress