Altered Architecture and Enhanced Drought Tolerance in Rice via the Down-Regulation of Indole-3-Acetic Acid by TLD1/OsGH3.13 Activation

Publication Type:Journal Article
Year of Publication:2009
Authors:Zhang, S-W, Li, C-H, Cao, J, Zhang, Y-C, Zhang, S-Q, Xia, Y-F, Sun, D-Y, Sun, Y
Journal:Plant Physiology
Date Published:2009
ISBN Number:00320889

Plant architecture is determined by genetic and developmental programs as well as by environmental factors. Sessile plants have evolved a subtle adaptive mechanism that allows them to alter their growth and development during periods of stress. Phytohormones play a central role in this process; however, the molecules responsible for integrating growth-and stressrelated signals are unknown. Here, we report a gain-of-function rice (Oryza sauva) mutant, tld1-D, characterized by (and named for) an increased number of tillers, enlarged leaf angles, and dwarfism. TLD1 is a rice GH3.13 gene that encodes indole-3-acetic acid (IAA)-amido synthetase, which is suppressed in aboveground tissues under normal conditions but which is dramatically induced by drought stress. The activation of TLD1 reduced the IAA maxima at the lamina joint, shoot base, and nodes, resulting in subsequent alterations in plant architecture and tissue patterning but enhancing drought tolerance. Accordingly, the decreased level of free IAA in tld1-D due to the conjugation of IAA with amino acids greatly facilitated the accumulation of late-embryogenesis abundant mRNA compared with the wild type. The direct regulation of such drought-inducible genes by changes in the concentration of IAA provides a model for changes in plant architecture via the process of drought adaptation, which occurs frequently in nature.

Short Title:Plant Physiology
Taxonomic name: 
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