Altering endogenous cytokinin content by GmCKX13 as a strategy to develop drought-tolerant plants
Dung Tien Le,
Chien Van Ha,
Kien Huu Nguyen,
Ha Duc Chu,
Chenbo Zhu,
Weiqiang Li,
Yasuko Watanabe,
Mikiko Kojima,
Yumiko Takebayashi,
Hitoshi Sakakibara,
Keiichi Mochida,
Lam-Son Phan Tran
Affiliations
Dung Tien Le
VK Tech Research Center, NTT Hi-Tech Institute, Nguyen Tat Thanh University, 298-300A Nguyen Tat Thanh Street, District 4, Ho Chi Minh City 754000, Vietnam
Chien Van Ha
Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas 79409, USA
Kien Huu Nguyen
Department of Genetic Engineering, Agricultural Genetics Institute, Pham Van Dong Street, North Tu Liem District, Hanoi City 122300, Vietnam
Ha Duc Chu
Faculty of Agricultural Technology, University of Engineering and Technology, Vietnam National University Ha Noi, 144 Xuan Thuy Street, Cau Giay District, Hanoi City 122300, Vietnam
Chenbo Zhu
Jilin Da'an Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
Weiqiang Li
Jilin Da'an Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
Yasuko Watanabe
Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
Mikiko Kojima
Mass Spectrometry and Microscopy Unit, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
Yumiko Takebayashi
Mass Spectrometry and Microscopy Unit, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
Hitoshi Sakakibara
Mass Spectrometry and Microscopy Unit, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
Keiichi Mochida
Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan; School of Information and Data Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan; Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa 244-0813, Japan; RIKEN Baton Zone Program, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
Lam-Son Phan Tran
Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas 79409, USA; Corresponding author.
Climate-resilient crops are essential to meet the growing food demands of an ever-increasing world population. The phytohormone cytokinins (CKs) have been well established to regulate plant adaptation to drought. Previously, we reported that GmCKX13, encoding a CK oxidase/dehydrogenase in soybean (Glycince max), was differentially expressed under drought. Here, we further characterized its in planta function to assess if GmCKX13 could be a candidate gene to develop drought-tolerant crops. Transgenic Arabidopsis 35S:GmCKX13 plants ectopically and constitutively expressing GmCKX13 using the 35S promoter had an increase in root length, while showing a reduction in shoot height and biomass. CK contents were reduced in 35S:GmCKX13 plants, coupled with the reduced expression of all AtCKX genes and increased expression of all Arabidopsis isopentenyl transferase (AtIPT) genes, except AtIPT2 and AtIPT9 that are responsible for the production of cis-zeatin-type CKs. The 35S:GmCKX13 plants showed improved tolerance to drought and more sensitivity to the treatment with exogenous abscisic acid (ABA). Under the control of the drought-responsive promoter RD29A, the transgenic RD29A:GmCKX13 Arabidopsis plants had a similar phenotype as that of the wild-type (WT) plants under normal conditions. Under dehydration, we found a significant increase in the expression of the transgene coupled with a higher leaf relative water content in RD29A:GmCKX13 plants when compared with WT plants. In consistence with this finding, the RD29A:GmCKX13 plants exhibited higher survival rates and 30 % higher seed yield than the WT plants under drought conditions. Taken together, our results demonstrated that GmCKX13 is an excellent gene for developing drought-tolerant crops by altering endogenous CK levels and ABA responsiveness when being driven by a drought-responsive promoter.
