Ectopic Overexpression of Histone H3K4 Methyltransferase CsSDG36 from Tea Plant Decreases Hyperosmotic Stress Tolerance in Arabidopsis thaliana

Abstract

Histone methylation plays an important regulatory role in the drought response of many plants, but its regulatory mechanism in the drought response of the tea plant remains poorly understood. Here, drought stress was shown to induce lower relative water content and significantly downregulate the methylations of histone H3K4 in the tea plant. Based on our previous analysis of the SET Domain Group (SDG) gene family, the full-length coding sequence (CDS) of CsSDG36 was cloned from the tea cultivar ‘Fuding Dabaicha’. Bioinformatics analysis showed that the open reading frame (ORF) of the CsSDG36 gene was 3138 bp, encoding 1045 amino acids and containing the conserved structural domains of PWWP, PHD, SET and PostSET. The CsSDG36 protein showed a close relationship to AtATX4 of the TRX subfamily, with a molecular weight of 118,249.89 Da, and a theoretical isoelectric point of 8.87, belonging to a hydrophilic protein without a transmembrane domain, probably located on the nucleus. The expression of CsSDG36 was not detected in the wild type, while it was clearly detected in the over-expression lines of Arabidopsis. Compared with the wild type, the over-expression lines exhibited lower hyperosmotic resistance by accelerating plant water loss, increasing reactive oxygen species (ROS) pressure, and increasing leaf stomatal density. RNA-seq analysis suggested that the CsSDG36 overexpression caused the differential expression of genes related to chromatin assembly, microtubule assembly, and leaf stomatal development pathways. qRT-PCR analysis revealed the significant down-regulation of stomatal development-related genes (BASL, SBT1.2(SDD1), EPF2, TCX3, CHAL, TMM, SPCH, ERL1, and EPFL9) in the overexpression lines. This study provides a novel sight on the function of histone methyltransferase CsSDG36 under drought stress.

Genome-wide identification and expression analysis of the SET domain-containing gene family in potato (Solanum tuberosum L.)

“…The analysis of cis-elements in the promoter regions allowed the prediction of potential mechanisms of StSET gene regulation. Our results showed that a diverse set of cis-elements were present in most StSET genes (Table 4), indicating that the StSET genes are involved in several diverse biological processes, including drought [39], anaerobic induction, auxin responsiveness, defense, stress responsiveness, wound, and low-temperature responsiveness (Fig. 4).…”

Genome-wide identification and expression analysis of the SET domain-containing gene family in potato (Solanum tuberosum L.)

“…The analysis of cis-elements in the promoter regions allowed the prediction of potential mechanisms of StSET gene regulation. Our results showed that a diverse set of cis-elements were present in most StSET genes (Table 3), indicating that the StSET genes are involved in several diverse biological processes, including drought [45], anaerobic induction, auxin responsiveness, defense, stress responsiveness, wound, and low-temperature responsiveness (Fig. 4).…”

Singlet oxygen induces cell wall thickening and stomatal density reducing by transcriptome reprogramming

“…The phenotype of stomatal density reduction and cell wall thickening induced by singlet oxygen has important implications for agricultural industry. Declines in stomatal density would enhance plant's tolerance to drought ( 36 , 37 , 38 , 39 , 40 ), salinity/osmotic stress ( 38 , 39 , 40 , 41 , 42 ), and heat stress ( 40 , 43 , 44 ) by reducing water transpiration. There are interests in developing crop varieties that require less water yet still maintain the grain yield.…”