title: A Raf-like MAPKKK gene, GhRaf19, negatively regulates tolerance to drought and salt and positively regulates resistance to cold stress by modulating reactive oxygen species in cotton.
abstract: Mitogen-activated protein kinase kinase kinases (MAPKKKs) function at the top level of MAPK cascades and play important roles in plant development and stress responses. Although MAPKKKs comprise the largest family in the MAPK cascades, very few Raf-like MAPKKKs have been functionally identified, especially in the economically important crop cotton. In this study, a Raf-like MAPKKK gene, GhRaf19, was characterized for the first time in cotton. Our data show that the expression of GhRaf19 was inhibited by PEG and NaCl and induced by cold (4°C) and H2O2. Furthermore, when GhRaf19 was silenced in cotton using virus-induced gene silencing (VIGS), tolerance to drought and salt stress were enhanced, the accumulation of reactive oxygen species (ROS) was reduced, and ROS-related gene expression was increased. Consistent with these results, in N. benthamiana, overexpressing-GhRaf19 reduced tolerance to drought and salt. However, GhRaf19-silenced plants showed lowered resistance to cold in cotton, and this effect was correlated with the accumulation of ROS. In contrast, overexpressing GhRaf19 in N. benthamiana increased resistance to cold by inducing higher levels of expression and activity of ROS-related antioxidant genes/enzymes. These results indicate that GhRaf19 negatively regulates tolerance to drought and salt and positively regulates resistance to cold stress by modulating cellular ROS in cotton.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China.
authors.forename: Haihong
authors.initials: H
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China.
authors.forename: Lili
authors.initials: L
authors.lastname: Hao
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China.
authors.forename: Xulei
authors.initials: X
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China.
authors.forename: Shuchang
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, PR China. Electronic address: xqguo@sdau.edu.cn.
authors.forename: Xingqi
authors.initials: X
authors.lastname: Guo
mesh_terms: D003080:Cold Temperature; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D003368:Gossypium / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020935:MAP Kinase Signaling System; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species / Q000378:metabolism*; D055049:Salt Tolerance / Q000235:genetics; D020539:Sequence Analysis, Protein; D013312:Stress, Physiological / Q000235:genetics*; D014867:Water / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014867:Water; D020930:MAP Kinase Kinase Kinases
keywords: Cold; Cotton (Gossypium hirsutum); Drought; GhRaf19; Salt