A Munc13-like protein in Arabidopsis mediates H+-ATPase translocation that is essential for stomatal responses

Abstract

Plants control CO2 uptake and water loss by modulating the aperture of stomata located in the epidermis. Stomatal opening is initiated by the activation of H+-ATPases in the guard-cell plasma membrane. In contrast to regulation of H+-ATPase activity, little is known about the translocation of the guard cell H+-ATPase to the plasma membrane. Here we describe the isolation of an Arabidopsis gene, PATROL1, that controls the translocation of a major H+-ATPase, AHA1, to the plasma membrane. PATROL1 encodes a protein with a MUN domain, known to mediate synaptic priming in neuronal exocytosis in animals. Environmental stimuli change the localization of plasma membrane-associated PATROL1 to an intracellular compartment. Plasma membrane localization of AHA1 and stomatal opening require the association of PATROL1 with AHA1. Increased stomatal opening responses in plants overexpressing PATROL1 enhance the CO2 assimilation rate, promoting plant growth.

Overexpression of plasma membrane H + -ATPase in guard cells promotes light-induced stomatal opening and enhances plant growth

“…Our results show that manipulation of the plasma membrane H + -ATPase is very useful not only for promoting stomatal opening but also for enhancing photosynthesis and plant growth. In support of our results, control of H + -ATPase translocation to the plasma membrane by PATROL1, which is involved in intercellular membrane traffic, was recently reported to affect stomatal opening, photosynthesis, and plant growth (33). Note that other key components of light-induced stomatal opening investigated here (phototropins and K + in channels) had no effect on stomatal opening, photosynthesis, or plant growth under the conditions of this study (Fig.…”

Regulation of Photoassimilate Distribution between Source and Sink Organs of Crops through Light Environment Control in Greenhouses

“…Robbins •s −1 PPF [3]. The reason for these differences in photoassimilate translocation might be attributed to both the direct positive effects of light intensity on the activities of enzymes related to photoassimilate translocation and its indirect positive effects on stomata opening [6] [7].…”

The Role of the Primary Cell Wall in Plant Morphogenesis

“…The plasma membrane ATPase AHA1 and its translocator PATROL1 colocalise at the tips of Hechtian strands in plasmolyzed guard cells transformed with GFP-PATROL1 (D1) and RFP-AHA1 (D2) merged in (D3). Arrows show residual attachment to the plasma membrane Reprinted from [25]. ******************************************************* However, the Hechtian transduction hypothesis creates three dilemmas: 1.)…”

“…Mutants that lack amyloplast statoliths do not resolve the problem: While they decrease the gravitational response they do not eliminate it [92]. Finally, both plasma membrane H + -ATPases [25] (~11 in Arabidopsis) and PIN proteins recycle in response to mechanotransduction, thus an additional level of complexity.…”