title: Secretory low molecular weight phospholipase A2 plays important roles in cell elongation and shoot gravitropism in Arabidopsis.
abstract: To elucidate the cellular functions of phospholipase A(2) in plants, an Arabidopsis cDNA encoding a secretory low molecular weight phospholipase A(2) (AtsPLA(2)beta) was isolated. Phenotype analyses of transgenic plants showed that overexpression of AtsPLA(2)beta promotes cell elongation, resulting in prolonged leaf petioles and inflorescence stems, whereas RNA interference-mediated silencing of AtsPLA(2)beta expression retards cell elongation, resulting in shortened leaf petioles and stems. AtsPLA(2)beta is expressed in the cortical, vascular, and endodermal cells of the actively growing tissues of inflorescence stems and hypocotyls. AtsPLA(2)beta then is secreted into the extracellular spaces, where signaling for cell wall acidification is thought to occur. AtsPLA(2)beta-overexpressing or -silenced transgenic plants showed altered gravitropism in inflorescence stems and hypocotyls. AtsPLA(2)beta expression is induced rapidly by auxin treatment and in the curving regions of inflorescence stems undergoing the gravitropic response. These results suggest that AtsPLA(2)beta regulates the process of cell elongation and plays important roles in shoot gravitropism by mediating auxin-induced cell elongation.
authors.affiliation: Kumho Life and Environmental Science Laboratory, Gwangju 500-712, Korea.
authors.forename: Hyoung Yool
authors.initials: HY
authors.lastname: Lee
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Bahn
authors.forename: Yoon-Mi
authors.initials: YM
authors.lastname: Kang
authors.forename: Kyu Hee
authors.initials: KH
authors.lastname: Lee
authors.forename: Hae Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Eun Kyeung
authors.initials: EK
authors.lastname: Noh
authors.forename: Jiwan P
authors.initials: JP
authors.lastname: Palta
authors.forename: Jeong Sheop
authors.initials: JS
authors.lastname: Shin
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Ryu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018522:Gravitropism / Q000235:genetics / Q000502:physiology*; D018546:Hypocotyl / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D007210:Indoleacetic Acids / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010741:Phospholipases A / Q000235:genetics / Q000378:metabolism*; D054467:Phospholipases A2; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified; D021382:Protein Sorting Signals / Q000235:genetics / Q000502:physiology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D007210:Indoleacetic Acids; D021382:Protein Sorting Signals; D010741:Phospholipases A; D054467:Phospholipases A2