Water deficit is a key limiting factor for maize (Zea mays L.) productivity. Elucidating the molecular regulatory networks of stress tolerance is crucial for genetic enhancement of drought tolerance. Two genotypes of maize contrasting in their yield response to water deficit were evaluated for tolerance traits of water relations, net CO₂ assimilation rate, antioxidative metabolism and grain yield in relation to the expression levels, based on transcription profiling of genes involved in stress signaling, protein processing and energy metabolism to identify functional tolerance mechanisms. In the genotype SNJ201126 upregulation of calcium mediated signaling, plasma membrane and tonoplast intrinsic proteins and the membrane associated transporters contributed to better maintenance of water relations as evident from the higher relative water content and stomatal conductance at seedling and anthesis stages coupled with robust photosynthetic capacity and antioxidative metabolism. Further the protein folding machinery consisting of calnexin/calreticulin (CNX/CRT) cycle was significantly upregulated only in SNJ201126. While the down regulation of genes involved in photosystems and the enzymes of carbon fixation led to the relative susceptibility of genotype HKI161 in terms of reduced net CO₂ assimilation rate, biomass and grain yield. Our results provide new insight into intrinsic functional mechanisms related to tolerance in maize.

缺水是玉米 ( Zea mays L.) 生产力的一个关键限制因素。阐明胁迫耐受性的分子调控网络对于遗传增强耐旱性至关重要。评估了两种玉米对缺水反应的产量反应不同的基因型的水分关系耐受性状，净 CO ₂同化率、抗氧化代谢和与表达水平相关的谷物产量，基于参与应激信号传导、蛋白质加工和能量代谢的基因的转录谱，以确定功能耐受机制。在基因型 SNJ201126 中，钙介导的信号传导、质膜和液泡内源蛋白以及膜相关转运蛋白的上调有助于更好地维持水分关系，这从幼苗和开花期较高的相对含水量和气孔导度以及强大的光合能力和抗氧化代谢。此外，由钙连接蛋白/钙网蛋白 (CNX/CRT) 循环组成的蛋白质折叠机制仅在 SNJ201126 中显着上调。₂同化率、生物量和粮食产量。我们的研究结果为与玉米耐受性相关的内在功能机制提供了新的见解。