Overexpression of WRKY30 transcription factor confers tolerance to oxidative stress in Arabidopsis

SCARPECI, TE; ZANOR, MI; VALLE, EM

Mar del Plata

Congreso; XLIII Reunión Anual SAIB; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

In plants, oxidative stress is one of the major causes of damage as a result of various environmental stresses. Oxidative stress arises from an imbalance in the generation and removal of reactive oxygen species (ROS). Despite the deleterious effects of ROS, recent studies indicate that ROS act as signalling molecules. WRKY30 transcription factor, which was early induced under oxidative conditions, was overexpressed in Arabidopsis plants (35S::WRKY30). Seeds from these lines were germinated in MS/2 agar plates containing MV (0.25 and 0.50 mM), NaCl (150 mM) and ABA (0.50 mM) and per cent of seedlings at growth stage 0.7 was scored. Under these conditions, 35S::WRKY30 plants showed to be more tolerant than wild type plants, being able to germinate and develop cotyledons. The antioxidant response of Arabidopsis plants under MV treatment was followed by determining ascorbate peroxidase (APX), glutathione reductase (GR) and catalase (CAT) activities in solution. These activities were markedly increased in 35S::WRKY30 after 6 h MV treatment, while wild type plants were unaffected. Tolerance of transgenic plants could be correlated with an increment in antioxidant enzymes activity. We  suggest that WRKY30 could regulate downstream genes involved in the defense against ROS damage during Arabidopsis seed germination.