title: Enhanced expression of vacuolar H+-ATPase subunit E in the roots is associated with the adaptation of Broussonetia papyrifera to salt stress.
abstract: Vacuolar H(+)-ATPase (V-H(+)-ATPase) may play a pivotal role in maintenance of ion homeostasis inside plant cells. In the present study, the expression of V-H(+)-ATPase genes was analyzed in the roots and leaves of a woody plant, Broussonetia papyrifera, which was stressed with 50, 100 and 150 mM NaCl. Moreover, the expression and distribution of the subunit E protein were investigated by Western blot and immunocytochemistry. These showed that treatment of B. papyrifera with NaCl distinctly changed the hydrolytic activity of V-H(+)-ATPase in the roots and leaves. Salinity induced a dramatic increase in V-H(+)-ATPase hydrolytic activity in the roots. However, only slight changes in V-H(+)-ATPase hydrolytic activity were observed in the leaves. In contrast, increased H(+) pumping activity of V-H(+)-ATPase was observed in both the roots and leaves. In addition, NaCl treatment led to an increase in H(+)-pyrophosphatase (V-H(+)-PPase) activity in the roots. Moreover, NaCl treatment triggered the enhancement of mRNA levels for subunits A, E and c of V-H(+)-ATPase in the roots, whereas only subunit c mRNA was observed to increase in the leaves. By Western blot and immunocytological analysis, subunit E was shown to be augmented in response to salinity stress in the roots. These findings provide evidence that under salt stress, increased V-H(+)-ATPase activity in the roots was positively correlated with higher transcript and protein levels of V-H(+)-ATPase subunit E. Altogether, our results suggest an essential role for V-H(+)-ATPase subunit E in the response of plants to salinity stress.
authors.affiliation: Jiangsu Academy of Forestry, Dongshanqiao, Jiangning, Nanjing, Jiangsu, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Yanming
authors.initials: Y
authors.lastname: Fang
authors.forename: Zhenhai
authors.initials: Z
authors.lastname: Liang
authors.forename: Libin
authors.initials: L
authors.lastname: Huang
mesh_terms: D031623:Broussonetia / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007425:Intracellular Membranes / Q000378:metabolism; D007477:Ions; D015233:Models, Statistical; D009711:Nucleotides / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011522:Protons; D012492:Salts / Q000737:chemistry; D014018:Tissue Distribution; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D017931:DNA Primers; D007477:Ions; D009711:Nucleotides; D011522:Protons; D012492:Salts; D025262:Vacuolar Proton-Translocating ATPases