Early PLD-mediated events in response to progressive drought stress in Arabidopsis : a transcriptome analysis

Author： Mane Shrinivasrao P. Vasquez-Robinet Cecilia Sioson Allan A. Heath Lenwood S. Grene Ruth

ISSN： 1460-2431

Source： Journal of Experimental Botany, Vol.58, Iss.2, 2007-01, pp. : 241-252

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Abstract

Phospholipase D (PLD) has been implicated in a variety of stresses including osmotic stress and wounding. PLD1-derived phosphatidic acid interacts with ABI1 phosphatase 2C and promotes abscisic acid signalling. It has also been shown to regulate proline biosynthesis negatively. Plants with abrogated PLD show insensitivity to abscisic acid (ABA) and impaired stomatal conductance. The goal in the present study was to identify early PLD-mediated events in response to progressive drought stress in Arabidopsis. Water was withheld from 7-week-old Arabidopsis thaliana (Col-0) and antisense-PLD1 (anti-PLD) in a controlled environment chamber. Diurnal leaf water potential (LWP) and photosynthesis measurements were recorded five and three times a day, respectively. Quantitative reverse transcriptionpolymerase chain reaction (qRTPCR) and microarray analyses were conducted using RNA from shoots collected at the fourth LWP time point on the ninth day after stress imposition. Anti-PLD experienced severe water stress (1.28MPa) at the same time period that Col-0 experienced less water stress (0.31MPa). Diurnal LWP measurements showed that anti-PLD had a lower LWP than Col-0 in both control and drought-stress conditions. Photosynthesis was also more affected in anti-PLD than in Col-0. Anti-PLD plants recovered fully following rehydration after 10d of stress. qRTPCR revealed up to 18-fold lower values for PLD transcripts in stressed anti-PLD plants when compared with stressed Col-0. Microarray expression profiles revealed distinct gene expression patterns in Col-0 and anti-PLD. No differences in gene expression were detected between the two genotypes in the absence of drought stress. ROP8, PLD, and lipid transfer proteins were among the differentially expressed genes between the two genotypes.