Regulation of reactive oxygen species generation under drought conditions in arabidopsis

Abstract

Reactive oxygen species (RO S) are produced when plants are exposed to environmental stresses, such as drought and heat conditions. Oxidative stress imposed by ROS under drought conditions profoundly affects plant growth and development. However, RO S production and scavenging mechanisms under adverse environmental conditions are largely unknown. We have recently reported that a NAM /ATA F1/2/CUC2 (NA C) transcription factor NT L4 is required for generation of RO S under drought conditions in Arabidopsis. 35S:4ΔC transgenic plants overexpressing a truncated NT L4 form (4ΔC) lacking the C-terminal transmembrane (TM) motif were hypersensitive to drought stress, and RO S accumulated to a high level in the transgenic plants. In contrast, NTL4-deficient ntl4 mutants were less sensitive to drought stress and contained reduced levels of RO S. Furthermore, the plasma membrane-associated NT L4 transcription factor is proteolytically activated by treatments with drought and abscisic acid (ABA) and nuclear-localized, where it induces expression of NA DPH oxidase genes involved in RO S biosynthesis. Notably, the 35S:4ΔC transgenic plants showed accelerated leaf senescence and cell death under drought conditions. Taken together, these observations indicate that NT L4 regulation of RO S generation underlies the drought-induced leaf senescence. © 2012 Landes Bioscience.