Changes in membrane-associated H+-ATPase activities and amounts in young grape plants during the cross adaptation to temperature stresses

Proton pumps make a critical contribution to the physiology of plants, although it remains unclear whether or not membrane-associated H+-ATPase is involved in the cross adaptation to different temperature stresses. This experiment investigated the changes in membrane-associated H+-ATPase activities that associated with chilling-treated plants after heat acclimation (HA, 38 °C/10 h) and with heat-treated plants after cold acclimation (CA, 8 °C/2.5 days) in annual young grape plants (Vitis vinifera L. cv. Jingxiu) using biochemical and electron microscopic cytochemical assay methods in which cerium trichloride (CeCl3) precipitation was adopted. The results indicated that plasma membrane H+-ATPase activity increased as a result of both pretreatments, while V-type and F-type H+-ATPase activity hardly changed. Under subsequent cross temperature stresses, however, the three H+-ATPase types did maintain higher activity levels than that of the control. This finding suggests that either a HA or CA pretreatment may promote stability in membrane-associated H+-ATPase. A western-blotting assay of the plasma membrane H+-ATPase (P-H+-ATPase) indicated that the immuno-signal intensity of a 100 kDa peptide was visibly stronger in the HA and CA pretreated plants than in the control both before and after stress. This suggests that the HA- or CA-induced P-type H+-ATPase activation can be partly attributed to a new synthesis of the enzyme protein. Further, the results also suggested that membrane-associated H+-ATPase was involved in the HA-induced chilling resistance and the CA-induced thermo-tolerance in grape plants and that they had a similar regulating mechanism.