Journal Article

Ectopic expression of specific GA2 oxidase mutants promotes yield and stress tolerance in rice

Chen, Ku‐Ting, Hsieh, Kun‐Ting, Liu, Yi‐Lun, Yu, Lin‐Chih, Sakakibara, Hitoshi, Ho, Tuan‐Hua David, Chen, Chi‐yu, Jiang, Mirng‐Jier, Lee, Miin‐Huey, Chen, Liang‐Jwu, Yu, Su‐May, Lo, Shuen‐Fang, Kojima, Mikiko, Huang, Tzu‐Pi

2017

Overview

Summary A major challenge of modern agricultural biotechnology is the optimization of plant architecture for enhanced productivity, stress tolerance and water use efficiency (WUE). To optimize plant height and tillering that directly link to grain yield in cereals and are known to be tightly regulated by gibberellins (GAs), we attenuated the endogenous levels of GAs in rice via its degradation. GA 2‐oxidase (GA2ox) is a key enzyme that inactivates endogenous GAs and their precursors. We identified three conserved domains in a unique class of C20 GA2ox, GA2ox6, which is known to regulate the architecture and function of rice plants. We mutated nine specific amino acids in these conserved domains and observed a gradient of effects on plant height. Ectopic expression of some of these GA2ox6 mutants moderately lowered GA levels and reprogrammed transcriptional networks, leading to reduced plant height, more productive tillers, expanded root system, higher WUE and photosynthesis rate, and elevated abiotic and biotic stress tolerance in transgenic rice. Combinations of these beneficial traits conferred not only drought and disease tolerance but also increased grain yield by 10–30% in field trials. Our studies hold the promise of manipulating GA levels to substantially improve plant architecture, stress tolerance and grain yield in rice and possibly in other major crops.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Agricultural biotechnology / Agricultural practices / Amino acids / Attenuation / Biotechnology / biotic stress / Cereals / Crop yield / Crop yields / Crops / Degradation / disease resistance / Disease tolerance / Drought / Ectopic expression / Ectopic Gene Expression - genetics / Ectopic Gene Expression - physiology / Efficiency / field experimentation / Food / GA 2 oxidase 6 / Gene Expression Regulation, Plant - genetics / gene regulatory networks / Genetic engineering / Genetically engineered foods / gibberellin / Gibberellins / Gibberellins - metabolism / Grain / grain yield / mutants / Mutation - genetics / N-Acetylgalactosaminyltransferases - genetics / N-Acetylgalactosaminyltransferases - metabolism / Networks / Optimization / Oryza - enzymology / Oryza - genetics / Oryza sativa / Oxidase / Photosynthesis / Photosynthesis - genetics / Photosynthesis - physiology / photosynthesis rate / plant architecture / plant height / Plant Proteins - genetics / Plant Proteins - metabolism / Plants (botany) / Plants, Genetically Modified - genetics / Plants, Genetically Modified - metabolism / Productivity / Rice / root systems / stress tolerance / Stresses / tillering / Tillers / Transcription / transgenic plants / Water use / Water use efficiency / yield