The role of the plasma membrane H+-ATPase in plant-microbe interactions

Abstract

Plasma membrane (PM) H+-ATPases are the primary pumps responsible for the establishment of cellular membrane potential in plants. In addition to regulating basic aspects of plant cell function, these enzymes contribute to signaling events in response to diverse environmental stimuli. Here, we focus on the roles of the PM H+-ATPase during plant-pathogen interactions. PM H+-ATPases are dynamically regulated during plant immune responses and recent quantitative proteomics studies suggest complex spatial and temporal modulation of PM H+-ATPase activity during early pathogen recognition events. Additional data indicate that PM H+-ATPases cooperate with the plant immune signaling protein RIN4 to regulate stomatal apertures during bacterial invasion of leaf tissue. Furthermore, pathogens have evolved mechanisms to manipulate PM H+-ATPase activity during infection. Thus, these ubiquitous plant enzymes contribute to plant immune responses and are targeted by pathogens to increase plant susceptibility.

Figure 1

Regulation of PM H⁺-ATPases by Phosphorylation. ClustalW alignment of the C-terminal regulatory domain of Arabidopsis (AHA) and Nicotiana (PMA) PM H⁺-ATPases. Underlined residues have been identified in planta as phosphorylated. Phosphorylation status of shaded residues significantly changes during PTI responses (upper). Phosphorylation (+P) effect on enzyme activity is indicated below the alignment. Protein functional domains are indicated at the bottom. (+), increase in phosphorylation or activity. (−), decrease in phosphorylation or activity. (nd), not determined. R-I and R-II are inhibitory domains.