Molecular Plant Advance Access originally published online on February 8, 2008
Molecular Plant 2008 1(2):262-269; doi:10.1093/mp/ssm025
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
Dual Functions of Phospholipase D
1 in Plant Response to Drought
Department of Biology, University of Missouri, St Louis, MO 63121, USA
Donald Danforth Plant Science Center, St Louis, MO 63132, USA
1 To whom correspondence should be addressed. E-mail swang{at}danforthcenter.org, fax 314–587–1519, tel. 314–587–1419.
Phospholipase D
1 (PLD
1) has been shown to mediate the abscisic acid regulation of stomatal movements. Arabidopsis plants deficient in PLD
1 increased, whereas PLD
1-overexpressing tobacco decreased, transpirational water loss. In the early stage of drought, the decrease in water loss was associated with a rapid stomatal closure caused by a high level of PLD in PLD
1-overexpressing plants. However, in the late stage of drought, the overexpressing plants displayed more susceptibility to drought than control plants. PLD
1 activity in the overexpressing plants was much higher than that of control plants in which drought also induced an increase in PLD
1 activity. The high level of PLD
1 activity was correlated to membrane degradation in late stages of drought, as demonstrated by ionic leakage and lipid peroxidation. These findings indicate that a high level of PLD
1 expression has different effects on plant response to water deficits. It promotes stomatal closure at earlier stages, but disrupts membranes in prolonged drought stress. These findings are discussed in relation to the understanding of PLD functions and potential applications.
Key Words: drought phospholipase phosphatidic acid lipid oxidation lipid signaling