Characterization on the water deprivation-associated physiological traits as well as the related differential genes during seed filling stage in wheat (T. aestivum L.)

Abstract

Improvement on water use efficiency of the plants contributes to the sustainable crop production worldwide. In this study, we reported the physiological and growth traits at late stage, transcriptome profiling during seed filling period, and the function of TaMPK16 (encoding mitogen-activated protein kinase 16), a drought-inducible gene in wheat plants, in mediating drought adaptation of plants upon water deprivation. Compared with those grown under normal condition, the plants underlying deficit irrigation displayed increased proline and soluble sugar contents whereas lowered plant biomass and grain yields in tested cultivars. Shimai 22, a drought-tolerant cultivar, exhibited improved osmolytes and improved agronomic traits under DI relative to Jimai 585, an affluent water-acclimated cultivar. A total of 1712 genes were differentially expressed (DE) in leaves of Shimai 22 under water deprivation condition; they were categorized into the functional groups of biological process, cellular components, and molecular function and concentrated into the GO terms of metabolic process, metal ion binding, oxidation–reduction process, and catalytic activity, involving major biochemical metabolisms of glyoxylate and dicarboxylate, pyruvate, starch and sucrose, and amino and nucleotide sugars. Transgene analysis on TaMAPK16, a significantly upregulated DE gene, confirmed its role in mediating plant drought tolerance; the lines with TaMAPK16 overexpression conferred plants enhanced biomass, osmolytes biosynthesis, antioxidant enzyme activities, and photosynthetic function. These results suggested that plant water-deficit response during seed filling stage is associated with drastically modified transcription of huge genes that are involved in diverse physiological processes. TaMPK16 can be acted as a valuable target for breeding drought-tolerant varieties of T. aestivum. Quantities of differentially expressed genes categorized into diverse functional groups contribute plant growth and agronomic traits in wheat plants upon water deprivation, via modulation of various physiological and biochemical processes associated with plant water deficit adaptation.