title: SIZ1 controls cell growth and plant development in Arabidopsis through salicylic acid.
abstract: The post-translational conjugation of small ubiquitin-related modifiers (SUMOs) to other proteins is involved in regulation of many processes in eukaryotic development; although its role in plant development is beginning to be dissected. Previously, we demonstrated that the siz1 mutant, which is impaired in SUMO E3 ligase, showed a dwarf-like shoot phenotype with accumulation of salicylic acid (SA), and the expression of nahG, a bacterial salicylate hydroxylase that catabolizes SA, in siz1 reduced the SA level and suppressed dwarfism. Herein, we provide evidence that the SIZ1 gene controls cell division and elongation through regulation of the SA level. Mature siz1-2 and siz1-3 plants exhibited a dwarf-like shoot phenotype that is attributable to decreased leaf cell volume and number relative to the wild type. Cell division and expansion defects caused by siz1 were also suppressed by the expression of nahG. Expression of XTH8 and XTH31, encoding xyloglucan endotransglycosylase/hydrolase, which are thought to facilitate leaf cell expansion, was down-regulated in siz1 leaves. However, reduced XTH8 and XTH31 expression in siz1 plants was restored in nahG siz1-2 plants. These results indicate that SIZ1 regulates cell growth and plant development with regulation of SA accumulation. Also, XTH8 and XTH31 genes may be responsible for reduced leaf cell expansion.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan. kmiura@gene.tsukuba.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Miura
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Tomoko
authors.initials: T
authors.lastname: Miura
authors.forename: Paul M
authors.initials: PM
authors.lastname: Hasegawa
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049108:Cell Enlargement; D048708:Cell Growth Processes / Q000502:physiology*; D049109:Cell Proliferation; D048429:Cell Size; D004392:Dwarfism / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D006899:Mixed Function Oxygenases; C022619:salicylate 1-monooxygenase; D016695:Glycosyltransferases; C000603582:XTH31 protein, Arabidopsis; C473049:xyloglucan - xyloglucosyltransferase; D006026:Glycoside Hydrolases; D008025:Ligases; C502552:SIZ1 protein, Arabidopsis; D020156:Salicylic Acid