Suppression of phospholipase Dalpha1 induces freezing tolerance in Arabidopsis: response of cold-responsive genes and osmolyte accumulation.
Phospholipase D (PLD; EC 3.1.4.4) plays an important role in membrane lipid hydrolysis and in mediation of plant responses to a wide range of stresses. PLDalpha1 abrogation through antisense suppression in Arabidopsis thaliana resulted in a significant increase in freezing tolerance of both non-acclimated and cold-acclimated plants. Although non-acclimated PLDalpha1-deficient plants did not show the activation of cold-responsive C-repeat/dehydration-responsive element binding factors (CBFs) and their target genes (COR47 and COR78), they did accumulate osmolytes to much higher levels than did the non-acclimated wild-type plants. However, a stronger expression of COR47 and COR78 in response to cold acclimation and to especially freezing was observed in PLDalpha1-deficient plants. Furthermore, a slower activation of CBF1 was observed in response to cold acclimation in these plants compared to the wild-type plants. Typically, cold acclimation resulted in a higher accumulation of osmolytes in PLDalpha1-deficient plants than in wild-type plants. Inhibition of PLD activity by using lysophosphatidylethanolamine (LPE) also increased freezing tolerance of Arabidopsis, albeit to a lesser extent than did the PLD antisense suppression. Exogenous LPE induced expression of COR15a and COR47 in the absence of cold stimulus. These results suggest that PLDalpha1 plays a key role in freezing tolerance of Arabidopsis by modulating the cold-responsive genes and accumulation of osmolytes.
Rajashekar
C B
CB
Division of Horticulture, Kansas State University, Manhattan, KS 66506, USA. crajashe@ksu.edu
Zhou
Han-E
HE
Zhang
Yuwen
Y
Li
Weiqi
W
Wang
Xuemin
X
D000064:Acclimatization / Q000187:drug effects / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D008246:Lysophospholipids / Q000494:pharmacology; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; C104387:CBF1 protein, Arabidopsis; C116166:COR15 protein, Arabidopsis; D004268:DNA-Binding Proteins; D008246:Lysophospholipids; D015534:Trans-Activators; C008301:lysophosphatidylethanolamine; C072393:COR47 protein, Arabidopsis; D010739:Phospholipase D