Drought stress and rehydration affect the balance between MGDG and DGDG synthesis in cowpea leaves.
Membranes are main targets of drought, and there is growing evidence for the involvement of membrane lipid in plant adaptation to such an environmental stress. Biosynthesis of the galactosylglycerolipids, monogalactosyl-diacylglycerol (MGDG) and digalactosyl-diacylglycerol (DGDG), which are the main components of chloroplast envelope and thylakoid membranes, could be important for plant tolerance to water deficit and for recovery after rehydration. In this study, galactolipid (GL) biosynthesis in cowpea (Vigna unguiculata L. Walp) leaves was analysed during drought stress and subsequent rewatering. Comparison of two cowpea cutivars, one drought tolerant and the other drought susceptible submitted to moderate drought stress, revealed patterns associated with water-deficit tolerance: increase in DGDG leaf content, stimulation of DGDG biosynthesis in terms of (14)C-acetate incorporation and messenger accumulation corresponding to four genes coding for GL synthases (MDG1, MGD2, DGD1 and DGD2). Similar to phosphate starvation, lack of water enhanced DGDG biosynthesis and it was hypothesized that the drought-induced DGDG accumulated in extrachloroplastic membranes, and thus contributes to plant tolerance to arid environments.
Torres-Franklin
Maria-Lucia
ML
Laboratoire d'Ecophysiologie Moléculaire, UMR-IRD 137 BIOSOL, Université Paris XII -Val de Marne, 61 av. du Général de Gaulle, 94010 Créteil Cedex, France.
Gigon
Agnès
A
de Melo
Dirce Fernandes
DF
Zuily-Fodil
Yasmine
Y
Pham-Thi
Anh-Thu
AT
D000085:Acetates / Q000378:metabolism; D002250:Carbon Radioisotopes; D002736:Chloroplasts / Q000378:metabolism; D004190:Disasters; D007887:Fabaceae / Q000378:metabolism*; D038983:Galactolipids / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020524:Thylakoids / Q000378:metabolism; D014867:Water / Q000378:metabolism
D000085:Acetates; D002250:Carbon Radioisotopes; D038983:Galactolipids; D010940:Plant Proteins; C007388:digalactosyldiacylglycerol; C009909:monogalactosyldiacylglycerol; D014867:Water