title: A rice calcium-dependent protein kinase OsCPK9 positively regulates drought stress tolerance and spikelet fertility.
abstract: BACKGROUND
  In plants, calcium-dependent protein kinases (CDPKs) are involved in tolerance to abiotic stresses and in plant seed development. However, the functions of only a few rice CDPKs have been clarified. At present, it is unclear whether CDPKs also play a role in regulating spikelet fertility.
  
  
  RESULTS
  We cloned and characterized the rice CDPK gene, OsCPK9. OsCPK9 transcription was induced by abscisic acid (ABA), PEG6000, and NaCl treatments. The results of OsCPK9 overexpression (OsCPK9-OX) and OsCPK9 RNA interference (OsCPK9-RNAi) analyses revealed that OsCPK9 plays a positive role in drought stress tolerance and spikelet fertility. Physiological analyses revealed that OsCPK9 improves drought stress tolerance by enhancing stomatal closure and by improving the osmotic adjustment ability of the plant. It also improves pollen viability, thereby increasing spikelet fertility. In OsCPK9-OX plants, shoot and root elongation showed enhanced sensitivity to ABA, compared with that of wild-type. Overexpression and RNA interference of OsCPK9 affected the transcript levels of ABA- and stress-responsive genes.
  
  
  CONCLUSIONS
  Our results demonstrated that OsCPK9 is a positive regulator of abiotic stress tolerance, spikelet fertility, and ABA sensitivity.
authors.forename: Shuya
authors.initials: S
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Deng
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhao
authors.forename: Qingchen
authors.initials: Q
authors.lastname: Luo
authors.forename: Zhengyi
authors.initials: Z
authors.lastname: Jin
authors.forename: Yin
authors.initials: Y
authors.lastname: Li
authors.forename: Shiyi
authors.initials: S
authors.lastname: Zhou
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.forename: Lianzhe
authors.initials: L
authors.lastname: Wang
authors.affiliation: The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science & Technology, Wuhan 430074, China. ygx@mail.hust.edu.cn.
authors.forename: Guangxiao
authors.initials: G
authors.lastname: Yang
authors.forename: Guangyuan
authors.initials: G
authors.lastname: He
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D003681:Dehydration; D055864:Droughts; D005298:Fertility / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D012275:Oryza / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D009995:Osmosis / Q000187:drug effects; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology; D030821:Plants, Genetically Modified; D011058:Pollen / Q000187:drug effects / Q000254:growth & development; D011392:Proline / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D034622:RNA Interference / Q000187:drug effects; D012995:Solubility; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D000040:Abscisic Acid; D011392:Proline; D011494:Protein Kinases; C454865:calcium-dependent protein kinase, rice; D017871:Calcium-Calmodulin-Dependent Protein Kinases