LcMKK, a novel group A mitogen-activated protein kinase kinase gene in Lycium chinense, confers dehydration and drought tolerance in transgenic tobacco via scavenging ROS and modulating expression of stress-responsive genes

Abstract

The mitogen-activated protein kinase (MAPK) cascades have been previously implicated in signal transduction during plant responses to various environmental stresses. As the convergent point of the MAPK cascades, MAPKKs play paramount roles in amplifying, integrating, and channeling information between the extracellular stimuli and intracellular responses. However, the functional role of MAPKKs in Lycium chinense has never been explored. In this study, a novel MAPKK gene, LcMKK, in L. chinense belonging to group A MAPKKs was isolated and functionally characterized. The transcript level of LcMKK rapidly increased in L. chinense after drought treatments. Overexpression of LcMKK in tobacco conferred dehydration and drought tolerance. Under dehydration and drought conditions, the transgenic tobacco lines exhibited better water status, less accumulation of reactive oxygen species (ROS), higher levels of germination rate and antioxidant enzyme activity than the wild type. In addition, overexpression of LcMKK enhanced the expression of ROS-related and stress-responsive genes under drought conditions. Taken together, these data demonstrate that LcMKK acts as a positive regulator in dehydration/ drought stress responses by either regulating ROS homeostasis through the activation of the cellular antioxidant defense system or modulating transcriptional levels of a variety of stress-associated genes.

PscCYP716A1-Mediated Brassinolide Biosynthesis Increases Cadmium Tolerance and Enrichment in Poplar

“…The supernatant was used for analyzing the activities of antioxidant enzymes including ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, E.C.1.15.1.1), and peroxidase (POD, EC 1.11.1.7). The activities of POD and SOD were determined by the method of Wu et al ( 2015 ). According to the manufactural instructions of detection kits (BC0200-50, Solarbio, Beijing, China, A123-1-1, Jiancheng, Nanjing, China), the activities of CAT and APX were determined with the spectrophotometry method.…”

StMAPKK5 Positively Regulates Response to Drought and Salt Stress in Potato

“…Reactive oxygen species (ROS) are produced by plants and stimulated by abiotic factors such as salt, low temperature, and drought lead to the activation of MEKK1-MKK4/5-MPK3/6 in response to adverse stress conditions [19]. Tomato (Solanum lycopersicum) SlMKK2/5 [20], rice (Oryza sativa) OsMKK1 [21,22], land cotton (Gossypium hirsutum) GhMKK1/5 [23,24], and Chinese wolfberry (Lycium chinense) LcMKK, all in MKK genes' family, respond positively to drought and salt stress [25]. However, the role of StMAPKK5 in drought and salt stress is still not fully understood.…”

Genes and pathways associated with drought tolerance in Populus wutunensis under drought stress

“…The expression of the MAPK signaling pathway-plant related genes and plant hormone signal transduction in P. wutunensis are basically consistent. The MAPK cascade can transform environmental signals into molecular and cellular reactions [32,33], which can regulate the expression of ROS-related genes, increasing the levels of ROS-scavenging enzymes and the drought resistance of plants [34]. Oxidative signal-inducible1 (OXI1) can promote the production of reactive oxygen species [35].…”