title: Heterotrimeric G protein alpha subunit is involved in rice brassinosteroid response.
abstract: Heterotrimeric G proteins are known to function as messengers in numerous signal transduction pathways. The null mutation of RGA (rice heterotrimeric G protein alpha subunit), which encodes the alpha subunit of heterotrimeric G protein in rice, causes severe dwarfism and reduced responsiveness to gibberellic acid in rice. However, less is known about heterotrimeric G protein in brassinosteroid (BR) signaling, one of the well-understood phytohormone pathways. In the present study, we used root elongation inhibition assay, lamina inclination assay and coleoptile elongation analysis to demonstrated reduced sensitivity of d1 mutant plants (caused by the null mutation of RGA) to 24-epibrassinolide (24-epiBL), which belongs to brassinosteroids and plays a wide variety of roles in plant growth and development. Moreover, RGA transcript level was decreased in 24-epiBL-treated seedlings in a dose-dependent manner. Our results show that RGA is involved in rice brassinosteroid response, which may be beneficial to elucidate the molecular mechanisms of G protein signaling and provide a novel perspective to understand BR signaling in higher plants.
authors.affiliation: Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Yun-Yuan
authors.initials: YY
authors.lastname: Xu
authors.forename: Qi-Bin
authors.initials: QB
authors.lastname: Ma
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Xu
authors.forename: Kang
authors.initials: K
authors.lastname: Chong
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000502:physiology*; D012275:Oryza / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D010840:Phytosterols / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D044385:GTP-Binding Protein alpha Subunits; D010840:Phytosterols; D010940:Plant Proteins; D011494:Protein Kinases; C519615:BRI1 protein, Oryza sativa; C108270:BRI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases