title: Overexpression of an Arabidopsis thaliana galactinol synthase gene improves drought tolerance in transgenic rice and increased grain yield in the field.
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.
authors.affiliation: International Center for Tropical Agriculture (CIAT), Cali, Colombia.
authors.forename: Michael Gomez
authors.initials: MG
authors.lastname: Selvaraj
authors.affiliation: Tropical Agriculture Research Front (TARF), Japan International Research Center for Agricultural Sciences (JIRCAS), Ishigaki, Okinawa, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Ishizaki
authors.affiliation: International Center for Tropical Agriculture (CIAT), Cali, Colombia.
authors.forename: Milton
authors.initials: M
authors.lastname: Valencia
authors.affiliation: International Center for Tropical Agriculture (CIAT), Cali, Colombia.|Japan Society for the Promotion of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
authors.affiliation: International Center for Tropical Agriculture (CIAT), Cali, Colombia.
authors.forename: Beata
authors.initials: B
authors.lastname: Dedicova
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Ogata
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan.
authors.forename: Kyouko
authors.initials: K
authors.lastname: Yoshiwara
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan.
authors.forename: Kyonoshin
authors.initials: K
authors.lastname: Maruyama
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.|RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, Japan.|Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Kusano
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.|RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, Japan.|Department of Molecular Biology and Biotechnology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.|RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Takahashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.|RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nakashima
authors.affiliation: International Center for Tropical Agriculture (CIAT), Cali, Colombia.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ishitani
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D055864:Droughts; D002523:Edible Grain / Q000235:genetics / Q000254:growth & development*; D005700:Galactosyltransferases / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D013312:Stress, Physiological / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D014157:Transcription Factors; D005700:Galactosyltransferases; C096645:inositol 1-alpha-galactosyltransferase
keywords: confined field trial; drought; galactinol synthase; grain yield; transgenic rice