Overexpression of the Wheat TaPsb28 Gene Enhances Drought Tolerance in Transgenic Arabidopsis

Abstract

Psb28 is a soluble protein in the photosystem II (PSII) complex, but its role in the drought stress response of wheat remains unclear. Here, we functionally characterized the TaPsb28 gene, which positively regulates drought tolerance in wheat. When the full-length 546-bp TaPsb28 cDNA was transferred into Arabidopsis thaliana, it was located in the guard cell chloroplast around the stroma. Overexpression of TaPsb28 conferred drought tolerance, as exhibited by the increases in the survival rate. Transgenic plants maintained lower MDA content and higher chlorophyll content by inducing chlorophyll synthase (ChlG) gene transcription. The content of abscisic acid (ABA) and zeatin increased significantly in wild-type (WT) plants under drought stress, and the transcriptional expression levels of RD22, dihydroflavonol 4-reductase (DFR) and anthocyanin reductase (ANR) genes were induced, thus enhancing the contents of endogenous cyanidin, delphinidin, and proanthocyanidins. However, in transgenic plants, although anthocyanins were further aggregated, the ABA increase was inhibited, zeatin was restored to the control level under drought stress, and stomatal closure was promoted. These findings indicate ABA and zeatin have opposite synergistic effects in the process of drought tolerance caused by TaPsb28 because only after the effect of zeatin is alleviated can ABA better play its role in promoting anthocyanin accumulation and stomatal closure, thus enhancing the drought tolerance of transgenic plants. The results suggest that overexpression of TaPsb28 exerts a positive role in the drought response by influencing the functional metabolism of endogenous hormones. The understanding acquired through the research laid a foundation for further in-depth investigation of the function of TaPsb28 in drought resistance in wheat, especially its relationship with anthocyanidin accumulation.

The Role of Anthocyanins in Plant Tolerance to Drought and Salt Stresses

“…However, in the expression of the wheat Psb28 gene in transgenic Arabidopsis plants, the content of ABA and zeatin were restored to the control level under drought stress treatment and stomatal closure was promoted. These data suggest that Psb28 exerted a positive function in the drought response by influencing the metabolism of ABA and zeatin hormones, which acted through stomatal closure and promoted anthocyanin accumulation [58].…”

“…The Psb28, a soluble protein in the photosystem II (PSII) complex, acted as a positive regulator of drought tolerance in wheat (Triticum aestivum L.) through increased expression of the chlorophyll synthase (ChlG) gene, and higher chlorophyll and lower MDA contents [58]. In wild-type plants, drought increased ABA and zeatin content, up-regulated expression of RD22, DFR, and ANR, and enhanced content of proanthocyanidins, delphinidin and cyanidin, delphinidin, and proanthocyanidins.…”

Differential Transcription Profiling Reveals the MicroRNAs Involved in Alleviating Damage to Photosynthesis under Drought Stress during the Grain Filling Stage in Wheat

“…The results of the photosynthetic and oxidative index test revealed that Zhengmai 1860 had an obviously greater tolerance to drought than Bainong 207 and Zhoumai 18 [20]. Therefore, a GO functional enrichment analysis was carried out for the DE genes of Zhengmai 1860.…”

Yellow-Green Leaf 19 Encoding a Specific and Conservative Protein for Photosynthetic Organisms Affects Tetrapyrrole Biosynthesis, Photosynthesis, and Reactive Oxygen Species Metabolism in Rice

“…Studies have shown that the light-harvesting protein LHca can participate in light-harvesting activities as well as chloroplast metabolism [61]. PSB28 is a soluble protein in the PSII complex, and the Psb28 gene positively regulates drought tolerance in wheat [62]. In photosynthesis and photorespiration, Rubisco catalyzes the first step of CO 2 assimilation, and it is a decahexameric protein consisting of eight small subunits (RBCS) and eight large subunits (RBCL) in higher plants [63].…”