title: Down-regulation of GIGANTEA-like genes increases plant growth and salt stress tolerance in poplar.
abstract: The flowering time regulator GIGANTEA (GI) connects networks involved in developmental stage transitions and environmental stress responses in Arabidopsis. However, little is known about the role of GI in growth, development and responses to environmental challenges in the perennial plant poplar. Here, we identified and functionally characterized three GI-like genes (PagGIa, PagGIb and PagGIc) from poplar (Populus alba × Populus glandulosa). PagGIs are predominantly nuclear localized and their transcripts are rhythmically expressed, with a peak around zeitgeber time 12 under long-day conditions. Overexpressing PagGIs in wild-type (WT) Arabidopsis induced early flowering and salt sensitivity, while overexpressing PagGIs in the gi-2 mutant completely or partially rescued its delayed flowering and enhanced salt tolerance phenotypes. Furthermore, the PagGIs-PagSOS2 complexes inhibited PagSOS2-regulated phosphorylation of PagSOS1 in the absence of stress, whereas these inhibitions were eliminated due to the degradation of PagGIs under salt stress. Down-regulation of PagGIs by RNA interference led to vigorous growth, higher biomass and enhanced salt stress tolerance in transgenic poplar plants. Taken together, these results indicate that several functions of Arabidopsis GI are conserved in its poplar orthologues, and they lay the foundation for developing new approaches to producing salt-tolerant trees for sustainable development on marginal lands worldwide.
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), Daejeon, Korea.
authors: Qingbo
authors: Q
authors: Ke
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.
authors: Ho Soo
authors: HS
authors: Kim
authors: Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Northwest A & F University, Shaanxi, China.
authors: Zhi
authors: Z
authors: Wang
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), Daejeon, Korea.
authors: Chang Yoon
authors: CY
authors: Ji
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), Daejeon, Korea.
authors: Jae Cheol
authors: JC
authors: Jeong
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), Daejeon, Korea.
authors: Haeng-Soon
authors: HS
authors: Lee
authors: Division of Forest Biotechnology, Korea Forest Research Institute, Suwon, Korea.
authors: Young-Im
authors: YI
authors: Choi
authors: Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Northwest A & F University, Shaanxi, China.
authors: Bingcheng
authors: B
authors: Xu
authors: Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Northwest A & F University, Shaanxi, China.
authors: Xiping
authors: X
authors: Deng
authors: Division of Applied Life Science (BK21plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Korea.
authors: Dae-Jin
authors: DJ
authors: Yun
authors: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), Daejeon, Korea.
authors: Sang-Soo
authors: SS
authors: Kwak
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics; D032107:Populus / Q000187:drug effects / Q000235:genetics*; D034622:RNA Interference; D055049:Salt Tolerance / Q000235:genetics* / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D012965:Sodium Chloride
keywords: 
  Arabidopsis
  ; 
  PagGI
  ; RNAi; poplar; salt tolerance; transgenic plants