Overexpression of an Arabidopsis thaliana galactinol synthase gene improves drought tolerance in transgenic rice and increased grain yield in the field |
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| Authors: | Michael Gomez Selvaraj Takuma Ishizaki Milton Valencia Satoshi Ogawa Beata Dedicova Takuya Ogata Kyouko Yoshiwara Kyonoshin Maruyama Miyako Kusano Kazuki Saito Fuminori Takahashi Kazuo Shinozaki Kazuo Nakashima Manabu Ishitani |
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| Affiliation: | 1. International Center for Tropical Agriculture (CIAT), Cali, Colombia;2. Tropical Agriculture Research Front (TARF), Japan International Research Center for Agricultural Sciences (JIRCAS), Ishigaki, Okinawa, Japan;3. Japan Society for the Promotion of Science, The University of Tokyo, Bunkyo‐ku, Tokyo, Japan;4. Biological Resources and Post‐harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan;5. RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan;6. RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, Japan;7. Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan;8. Department of Molecular Biology and Biotechnology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan |
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| Abstract: | Drought stress has often caused significant decreases in crop production which could be associated with global warming. Enhancing drought tolerance without a grain yield penalty has been a great challenge in crop improvement. Here, we report the Arabidopsis thaliana galactinol synthase 2 gene (AtGolS2) was able to confer drought tolerance and increase grain yield in two different rice (Oryza sativa) genotypes under dry field conditions. The developed transgenic lines expressing AtGolS2 under the control of the constitutive maize ubiquitin promoter (Ubi:AtGolS2) also had higher levels of galactinol than the non‐transgenic control. The increased grain yield of the transgenic rice under drought conditions was related to a higher number of panicles, grain fertility and biomass. Extensive confined field trials using Ubi:AtGolS2 transgenic lines in Curinga, tropical japonica and NERICA4, interspecific hybrid across two different seasons and environments revealed the verified lines have the proven field drought tolerance of the Ubi:AtGolS2 transgenic rice. The amended drought tolerance was associated with higher relative water content of leaves, higher photosynthesis activity, lesser reduction in plant growth and faster recovering ability. Collectively, our results provide strong evidence that AtGolS2 is a useful biotechnological tool to reduce grain yield losses in rice beyond genetic differences under field drought stress. |
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| Keywords: | galactinol synthase drought transgenic rice grain yield confined field trial |
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