Poly(ADP-ribose) polymerase in plants affects energy homeostasis, cell death and stress tolerance.
Plants contain two genes that code for poly(ADP-ribose) polymerase (PARP): parp1 and parp2. Both PARPs are activated by DNA damage caused by, example reactive oxygen species. Upon activation polymers of ADP-ribose are synthesized on a range of nuclear enzymes using NAD(+) as substrate. Here, we show that in plants stresses such as drought, high light and heat activate PARP causing NAD(+) breakdown and ATP consumption. When the PARP activity is reduced by means of chemical inhibitors or by gene silencing, cell death is inhibited and plants become tolerant to a broad range of abiotic stresses like high light, drought and heat. Plant lines with low poly(ADP-ribosyl)ation activity maintain under stress conditions their energy homeostasis by reducing NAD(+) breakdown and consequently energy consumption. The higher energy-use efficiency avoids the need for a too intense mitochondrial respiration and consequently reduces the formation of reactive oxygen species. From these results it can be concluded that breeding or engineering for a high energy-use efficiency under stress conditions is a valuable, but until today nearly unexploited, approach to enhance overall stress tolerance of crops.
De Block
Marc
M
Bayer BioScience N.V., Technologiepark 38, 9052 Gent, Belgium.
Verduyn
Christoph
C
De Brouwer
Dirk
D
Cornelissen
Marc
M
D017360:Arabidopsis / Q000201:enzymology / Q000378:metabolism; D001241:Aspirin / Q000494:pharmacology; D029688:Brassica napus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D016923:Cell Death; D006706:Homeostasis; D020287:In Situ Nick-End Labeling; D018384:Oxidative Stress; D010944:Plants / Q000201:enzymology* / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D011065:Poly(ADP-ribose) Polymerases; D001241:Aspirin