The role of Arabidopsis 5PTase13 in root gravitropism through modulation of vesicle trafficking.
Inositol polyphosphate 5-phosphatases (5PTases) are enzymes of phosphatidylinositol metabolism that affect various aspects of plant growth and development. Arabidopsis 5PTase13 regulates auxin homeostasis and hormone-related cotyledon vein development, and here we demonstrate that its knockout mutant 5pt13 has elevated sensitivity to gravistimulation in root gravitropic responses. The altered responses of 5pt13 mutants to 1-N-naphthylphthalamic acid (an auxin transport inhibitor) indicate that 5PTase13 might be involved in the regulation of auxin transport. Indeed, the auxin efflux carrier PIN2 is expressed more broadly under 5PTase13 deficiency, and observations of the internalization of the membrane-selective dye FM4-64 reveal altered vesicle trafficking in 5pt13 mutants. Compared with wild-type, 5pt13 mutant seedlings are less sensitive to the inhibition by brefeldin A of vesicle cycling, seedling growth, and the intracellular cycling of the PIN1 and PIN2 proteins. Further, auxin redistribution upon gravitropic stimulation is stimulated under 5PTase13 deficiency. These results suggest that 5PTase13 may modulate auxin transport by regulating vesicle trafficking and thereby play a role in root gravitropism.
Wang
Yuan
Y
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Lin
Wen-Hui
WH
Chen
Xu
X
Xue
Hong-Wei
HW
D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020126:Brefeldin A / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D055786:Gene Knockout Techniques; D018522:Gravitropism / Q000502:physiology*; D007210:Indoleacetic Acids / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010797:Phthalimides / Q000494:pharmacology; D018517:Plant Roots / Q000254:growth & development; D011726:Pyridinium Compounds / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology
D029681:Arabidopsis Proteins; D020126:Brefeldin A; D005456:Fluorescent Dyes; D007210:Indoleacetic Acids; D010744:Phosphoric Monoester Hydrolases; D010797:Phthalimides; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; C092350:FM 4-64; C117013:AT5G57090 protein, Arabidopsis; C002687:alpha-naphthylphthalamic acid; C499855:5PTase13 protein, Arabidopsis