NITRIC OXIDE-MEDIATED ANTIOXIDANT ENZIMES CHANGES PROTECTSOYBEAN LEAVESAGAINSTUV-B RADIATION

SANTA CRUZ DM; POLIZIO AH; ZILLI CG; ML TOMARO; BALESTRASSE KB

Mendoza

Congreso; 48 Annual Meeting XLVIII Reunión Anual th Argentine Society for Biochemistry and Molecular Biology Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

In previous reports we demonstrated that heme oxygenase 1 (HO)plays a protective role against oxidative stress in soybean. Here weinvestigated the effect of nitric oxide (NO) on oxidative stressmarkers and classical antioxidant enzymes activities, isoformprofile and gene expression in soybean leaves subjected to a highdose UV-B radiation (30 KJ m ). Pretreatments with 0.8 mMsodium nitroprussiate (SNP), a NO donor, applied as an sprayprevented chlorophyll loss, H O and O . accumulation and ionleakage in UV-B-treated plants. The antioxidant response of plantleaves was evaluated analyzing the activities and isoform profile ofsuperoxide dismutase (SOD), catalase (CAT), ascorbateperoxidase (APX) and unspecific peroxidases. UV-B treatmentdecreased CAT andAPX specific activities 50 and 48 % respect tocontrol values. On the other hand, we performed quantitative RTPCRof HO, CAT, SOD andAPX genes.UV-B treatment decreasedsignificantly HO, CAT andAPX gene expression levels, respect tocontrol values. SNP pretreatments assays showed that NO revertsthis response. SOD gene expression increased 2-fold respect tocontrol. HO and CAT activities showed a positive correlation withHO-1 gene expression.Our results indicate that NO protects against high doses UV-Bradiation by regulating the response of classical antioxidantenzymes.