title: Cyclic GMP is involved in auxin signalling during Arabidopsis root growth and development.
abstract: The second messenger cyclic guanosine 3',5'-monophosphate (cGMP) plays an important role in plant development and responses to stress. Recent studies indicated that cGMP is a secondary signal generated in response to auxin stimulation. cGMP also mediates auxin-induced adventitious root formation in mung bean and gravitropic bending in soybean. Nonetheless, the mechanism of the participation of cGMP in auxin signalling to affect these growth and developmental processes is largely unknown. In this report we provide evidence that indole-3-acetic acid (IAA) induces cGMP accumulation in Arabidopsis roots through modulation of the guanylate cyclase activity. Application of 8-bromo-cGMP (a cell-permeable cGMP derivative) increases auxin-dependent lateral root formation, root hair development, primary root growth, and gene expression. In contrast, inhibitors of endogenous cGMP synthesis block these processes induced by auxin. Data also showed that 8-bromo-cGMP enhances auxin-induced degradation of Aux/IAA protein modulated by the SCF(TIR1) ubiquitin-proteasome pathway. Furthermore, it was found that 8-bromo-cGMP is unable to directly influence the auxin-dependent TIR1-Aux/IAA interaction as evidenced by pull-down and yeast two-hybrid assays. In addition, we provide evidence for cGMP-mediated modulation of auxin signalling through cGMP-dependent protein kinase (PKG). Our results suggest that cGMP acts as a mediator to participate in auxin signalling and may govern this process by PKG activity via its inﬂuence on auxin-regulated gene expression and auxin/IAA degradation.
authors.affiliation: Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Nan
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Hu
authors.forename: Yuantao
authors.initials: Y
authors.lastname: Wei
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Liang
authors.forename: Lina
authors.initials: L
authors.lastname: Mao
authors.forename: Yurong
authors.initials: Y
authors.lastname: Bi
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D007210:Indoleacetic Acids / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D030821:Plants, Genetically Modified; D046988:Proteasome Endopeptidase Complex; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid; D017869:Cyclic GMP-Dependent Protein Kinases; D046988:Proteasome Endopeptidase Complex; D006152:Cyclic GMP
keywords: Arabidopsis thaliana; PKG; TIR1-Aux/IAA interaction.; auxin signalling; cGMP; guanylate cyclase