ROLE OF CATALASE IN PROTECTING TOMATO FRUITS (CV. MICRO-TOM) FROM CHILLING INJURY.

RE, MARTIN DAMIAN; BOGGIO, SILVANA BEATRIZ

SAN MIGUEL DE TUCUMAN - TUCUMAN - ARGENTINA

Congreso; SAIB; 2009

Cold storage of fruits can alter the normal ripening process because of their susceptibility to chilling injury. Oxidative stress has been associated with the appearance of this physiological disorder and some antioxidants or free radical scavengers have been shown to reduce it. Catalase (CAT) in plants has been associated with the removal of H202 during stress conditions. We have evidence suggesting that CAT could be responsible for chilling tolerance observed in dwarf tomato cultivar Micro-Tom. The aim of this study was to elucidate the role of different CAT genes during postharvest chilling stress in Micro-Tom fruits. We found a new putative CAT gene by bioinformatics screening which has high homology with other plant catalase genes and we named it cat3 from S. lycopersicum. Mature green fruits were harvested, stored at 4ºC during four weeks and transferred to 25ºC. There was an increase in CAT activity one day after the fruits were transferred to room temperature but not during the cold storage. Also, we have analyzed the expression of cat3 and three different CAT genes previously identified (cat1, cat2 and ER60). cat1 was the most abundant CAT gene expressed in mature green fruits and we observed a great increase of cat1 transcripts one day after the fruits were transferred to 25ºC. Our results suggest that cat1 plays a key role in chilling stress tolerance, scavenging H2O2 after the cold storage of Micro-Tom fruits.