title: MAPK-mediated enhanced expression of vacuolar H(+)-ATPase confers the improved adaption to NaCl stress in a halotolerate peppermint (Mentha piperita L.).
abstract: Vacuolar H(+)-ATPase (V-H(+)-ATPase) has been proved to be of importance in maintenance of ion homeostasis inside plant cells under NaCl stress. In this study, the expression levels and salt-tolerate function of V-H(+)-ATPase genes were investigated in the roots and leaves of a halotolerate peppermint (Mentha × piperita L.) Keyuan-1 treated with different concentrations of NaCl. Results showed that the expressions of V-H(+)-ATPase in the transcriptional, protein and activity levels were significantly enhanced in the halotolerate peppermint Keyuan-1 compared to the wild-type (WT) peppermint under 50, 100, and 150 mM NaCl treatment. Moreover, inhibition experiments exhibited that V-H(+)-ATPase activity played vital roles in the salt tolerance of peppermint Keyuan-1 to 150 mM NaCl stress through increasing the vacuolar H(+) pumping activity and Na(+) compartmentalization capacity. Furthermore, results of Western blots showed that the activity of a mitogen-activated protein kinase (MAPK) was significantly increased under different concentrations of NaCl in the halotolerate peppermint Keyuan-1, which was much higher than that of WT peppermint. Further experiments with inhibitors suggested that this MAPK protein was responsible for the enhanced expression of V-H(+)-ATPase in the halotolerate peppermint Keyuan-1. In response to NaCl stress, increase of cytoplasmic calcium concentration ([Ca(2+)]cyt) occurred upstream of MAPK activation in the halotolerate peppermint Keyuan-1. In all, these findings demonstrated that increased V-H(+)-ATPase activity was positively correlated with the enhanced salt tolerance in the halotolerate peppermint Keyuan-1, providing the theoretic basis for the further development and utilization of peppermint in saline areas.
authors.affiliation: Biotechnology Center, Shandong Academy of Sciences, Jinan, 250014, China. lizh@sdas.org.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Botany, Chinese Academy of Science, Beijing, 100093, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhen
authors.affiliation: Biotechnology Center, Shandong Academy of Sciences, Jinan, 250014, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Guo
authors.affiliation: Biotechnology Center, Shandong Academy of Sciences, Jinan, 250014, China.|Division of Ecosystem Science, Commonwealth Scientific and Industrial Research Organization, Clayton South, VIC, 3169, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Harvey
authors.affiliation: Biotechnology Center, Shandong Academy of Sciences, Jinan, 250014, China.
authors.forename: Jishun
authors.initials: J
authors.lastname: Li
authors.affiliation: Biotechnology Center, Shandong Academy of Sciences, Jinan, 250014, China.
authors.forename: Hetong
authors.initials: H
authors.lastname: Yang
mesh_terms: D000222:Adaptation, Physiological; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D020935:MAP Kinase Signaling System; D036142:Mentha piperita / Q000201:enzymology*; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000502:physiology*; D018517:Plant Roots / Q000201:enzymology*; D055049:Salt Tolerance; D055051:Salt-Tolerant Plants; D025262:Vacuolar Proton-Translocating ATPases / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D025262:Vacuolar Proton-Translocating ATPases
keywords: Calcium; H+ pumping activity; MAPK cascade; Na+ compartmentalization; Peppermint; Vacuolar H+-ATPase