title: Nonspecific phospholipase C NPC4 promotes responses to abscisic acid and tolerance to hyperosmotic stress in Arabidopsis.
abstract: Diacyglycerol (DAG) is an important class of cellular lipid messengers, but its function in plants remains elusive. Here, we show that knockout of the Arabidopsis thaliana nonspecific phospholipase C (NPC4) results in a decrease in DAG levels and compromises plant response to abscisic acid (ABA) and hyperosmotic stresses. NPC4 hydrolyzes various phospholipids in a calcium-independent manner, producing DAG and a phosphorylated head group. NPC4 knockout (KO) plants display decreased ABA sensitivity in seed germination, root elongation, and stomatal movement and had decreased tolerance to high salinity and water deficiency. Overexpression of NPC4 renders plants more sensitive to ABA and more tolerant to hyperosmotic stress than wild-type plants. Addition of a short-chain DAG or a short-chain phosphatidic acid (PA) restores the ABA response of NPC4-KO to that of the wild type, but the addition of DAG together with a DAG kinase inhibitor does not result in a wild-type phenotype. These data suggest that NPC4-produced DAG is converted to PA and that NPC4 and its derived lipids positively modulate ABA response and promote plant tolerance to drought and salt stresses.
authors.affiliation: Department of Biology, University of Missouri, St. Louis, Missouri 63121, USA.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Peters
authors.forename: Maoyin
authors.initials: M
authors.lastname: Li
authors.forename: Rama
authors.initials: R
authors.lastname: Narasimhan
authors.forename: Mary
authors.initials: M
authors.lastname: Roth
authors.forename: Ruth
authors.initials: R
authors.lastname: Welti
authors.forename: Xuemin
authors.initials: X
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D016254:Mutagenesis, Insertional; D010712:Phosphatidic Acids / Q000378:metabolism; D054712:Salinity; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism; D014867:Water / Q000502:physiology
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D004075:Diglycerides; D010712:Phosphatidic Acids; D010738:Type C Phospholipases; D014867:Water; C000731236:AT3G03530 protein, Arabidopsis