Guard cell-specific silencing of Arabidopsis plasma membrane proton pumps

Abstract

Stomata are structures in the plant epidermis consisting of two specialized guard cells and a stomatal pore between them. The gas exchange occurs through stomata, making these cells vital for plants. Stomatal aperture is regulated by the activity of plasma membrane proton pumps (AHAs), which is encoded by 11 isoforms in Arabidopsis. Previously, mutants with overexpressed or hyperactive single AHAs have been analysed, which have failed to answer the questions about the regulation and functions of proton pumps in guard cells. However, aha double mutants demonstrated embryo lethality and the single aha loss-of-function mu-tants have no growth impairments, making the function of AHAs hard to test. To address these problems, transgenic lines where three major AHAs were silenced in the guard cells by a novel amiRNA approach was applied in this thesis.