Abscisic acid is involved in the response of grape (Vitis vinifera L.) cv. Malbec leaf tissues to ultraviolet-B radiation by enhancing ultraviolet-absorbing compounds, antioxidant enzymes and membrane sterols.
We investigated the interactions of abscisic acid (ABA) in the responses of grape leaf tissues to contrasting ultraviolet (UV)-B treatments. One-year-old field-grown plants of Vitis vinifera L. were exposed to photosynthetically active radiation (PAR) where solar UV-B was eliminated by using polyester filters, or where PAR was supplemented with UV-B irradiation. Treatments combinations included weekly foliar sprays of ABA or a water control. The levels of UV-B absorbing flavonols, quercetin and kaempferol were significantly decreased by filtering out UV-B, while applied ABA increased their content. Concentration of two hydroxycinnamic acids, caffeic and ferulic acids, were also increased by ABA, but not affected by plus UV-B (+UV-B) treatments. Levels of carotenoids and activities of the antioxidant enzymes, catalase, ascorbate peroxidase and peroxidase were elevated by +ABA treatments, but only if +UV-B was given. Cell membrane beta-sitosterol was enhanced by ABA independently of +UV-B. Changes in photoprotective compounds, antioxidant enzymatic activities and sterols were correlated with lessened membrane harm by UV-B, as assessed by ion leakage. Oxidative damage expressed as malondialdehyde content was increased under +UV-B treatments. Our results suggest that the defence system of grape leaf tissues against UV-B is activated by UV-B irradiation with ABA acting downstream in the signalling pathway.
Facultad de Ciencias Agrarias-CONICET, Universidad Nacional de Cuyo, Almirante Brown 500, Chacras de Coria, Argentina.
Federico J
FJ
Berli
Daniela
D
Moreno
Patricia
P
Piccoli
Leandro
L
Hespanhol-Viana
M Fernanda
MF
Silva
Ricardo
R
Bressan-Smith
J Bruno
JB
Cavagnaro
Rubén
R
Bottini
D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000872:Anthocyanins / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D044949:Kaempferols / Q000378:metabolism; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D011794:Quercetin / Q000378:metabolism; D012855:Sitosterols / Q000378:metabolism; D014466:Ultraviolet Rays; D027843:Vitis / Q000378:metabolism / Q000528:radiation effects*
D000872:Anthocyanins; D000975:Antioxidants; D044949:Kaempferols; D012855:Sitosterols; D002734:Chlorophyll; D002338:Carotenoids; C025473:gamma-sitosterol; D000040:Abscisic Acid; C006552:kaempferol; D011794:Quercetin; D010544:Peroxidases; D002374:Catalase