title: Patatin-related phospholipase pPLAIIIδ influences auxin-responsive cell morphology and organ size in Arabidopsis and Brassica napus.
abstract: BACKGROUND
  The members of the patatin-related phospholipase subfamily III (pPLAIIIs) have been implicated in the auxin response. However, it is not clear whether and how these genes affect plant and cell morphogenesis. Here, we studied the roles of the patatin-related phospholipase pPLAIIIδ in auxin-responsive cell morphology and organ size in Arabidopsis and Brassica napus.
  
  
  RESULTS
  We show that overexpression of pPLAIIIδ inhibited longitudinal growth but promoted transverse growth in most organs of Arabidopsis and Brassica napus. Compared to wild-type plants, pPLAIIIδ-KO plants exhibited enhanced cell elongation in hypocotyls, and pPLAIIIδ-OE plants displayed broadened radial cell growth of hypocotyl and reduced leaf pavement cell polarity. For the hypocotyl phenotype in pPLAIIIδ mutants, which resembles the "triple response" to ethylene, we examined the expression of the ACS and ACO genes involved in ethylene biosynthesis and found that ACS4 and ACS5 were up-regulated by 2.5-fold on average in two OE lines compared with WT plants. The endogenous auxin distribution was disturbed in plants with altered pPLAIIIδ expression. pPLAIIIδ-OE and KO plants exhibited different sensitivities to indole-3-acetic acid-promoted hypocotyl elongation in both light and dark conditions. Gene expression analysis of auxin-induced genes in the dark showed that OE plants maintained a higher auxin response compared with WT and KO plants after treatment with 1 μM IAA for 12 h. Following treatment with 10 μM IAA for 30 min in the light, early auxin-induced genes were significantly up-regulated in two OE plant lines.
  
  
  CONCLUSIONS
  These data suggest that the PLAIIIδ gene plays an important role in cell morphology and organ size through its involvement in the regulation of auxin distribution in plants.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Dong
authors.forename: Maoyin
authors.initials: M
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Xuemin
authors.initials: X
authors.lastname: Wang
authors.forename: Chuchuan
authors.initials: C
authors.lastname: Fan
authors.forename: Yongming
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D029688:Brassica napus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D049108:Cell Enlargement; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D009154:Mutation; D010741:Phospholipases A / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; C585189:pPLAIIIdelta protein, Arabidopsis; D010741:Phospholipases A