Abstract
Protein phosphorylation by kinase is an important mechanism for adapting to drought stress conditions. Here, we isolated the CaDIMK1 (Capsicum annuum drought-induced MAP kinase 1) from dehydrated pepper leaf tissue and functionally characterized it. Subcellular localization analysis revealed that the CaDIMK1 protein was localized in the cytoplasm and nucleus. CaDIMK1-silenced pepper plants exhibited drought-susceptible phenotypes that were characterized by increased transpiration rates, low leaf temperatures, and decreased stomatal closure. In contrast, CaDIMK1-overexpressing (OX) transgenic Arabidopsis plants were hypersensitive to abscisic acid (ABA) from germination to adult growth stages. Furthermore, the CaDIMK1-OX plants were tolerant to drought stress. The transcript levels of several stress-related genes were high in CaDIMK1-OX plants than in wild-type plants. Taken together, our data demonstrate that CaDIMK1 acts as a positive modulator of drought tolerance and ABA signal transduction in pepper plants.
Highlights
Sessile plants are exposed to various environmental stresses that can lead to decreased crop yields
When measuring the water loss rate in rosette leaf tissues during 0–7 h after leaf detachment, we found that the fresh weight loss of CaDIMK1-OX leaves was significantly lower than that in the wild-type leaves (Figure 6B)
To determine if this enhanced drought resistance is associated with abscisic acid (ABA)-mediated regulation of stomatal closure, we analyzed changes in leaf surface temperatures and stomatal apertures in response to ABA
Summary
Sessile plants are exposed to various environmental stresses that can lead to decreased crop yields. Plants have adapted to water-deficit conditions by altering many survival processes such as stomatal closure, stress-related gene expression, and abscisic acid (ABA) accumulation (Golldack et al, 2014; Basu et al, 2016; Ullah et al, 2018). The core ABA signal transduction pathway is composed of ABA receptors (PYR/PYL/RCAR) that directly bind to ABA and perceive ABA signals (Gonzalez-Guzman et al, 2012; Dittrich et al, 2019). This complex recognizes clade A protein phosphatase 2Cs (PP2Cs), including AHG1, PP2CA, HAB1, HAB2, ABI1, ABI2, AIP1, AIP2, and AIP3, and in turn inhibits phosphatase activity
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