Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

DIFFERENTIAL EXPRESSION OF MN-SUPEROXIDE DISMUTASE AND CATALASE GENES OF PEACH DURING DEVELOPMENT AND IN RESPONSE TO PATHOGENS

DANTI S., MAGHERINI V., BAGNOLI F., RACCHI M.L.

Dip. Biotecnologie Agrarie Laboratorio di Genetica, P.le delle Cascine 24, Firenze

milvia.racchi@unifi.it

catalase, oxidative stress, Prunus persica, superoxide dismutase, pathogen infection

The increased production of toxic oxygen derivatives is considered to be a universal or common feature of stress conditions. Plants and other organisms have evolved a wide range of mechanisms to contend with this problem. The antioxidant defence system of the plant comprises a variety of antioxidant molecules and enzymes. Catalases and superoxide dismutases are important part of the defence system for scavenging superoxide radicals and protecting cells from oxidative stress their combined action converts the superoxide radical and hydrogen peroxide to water and molecular oxygen and thereby prevents cellular damage from occurring. Moreover recently evidence has been presented that catalase may play a crucial role in the salicylic acid (SA) mediated induction of systemic acquired resistance (SAR). In addition, the expression of superoxide dismutase was demonstrated to increase dramatically in plant cells during the pathogenesis response. Studying catalase and superoxide dismutase expression during stress conditions could therefore contribute to our understanding of stress induced resistance in plants. As a first step to study the function of catalases and superoxide dismutase in peach (Prunus persica L.), we have isolated three different catalase and one Mn-superoxide dismutase cDNAs. These were used to investigate expression profile during vegetative development and stress responses induced by Taphrina deformans and Coryneum beijerinckii. The expression of Cat1 and Cat2 and MnSod was analysed during tree development in different tissues and during seasonal growth in the leaf. MnSod transcript was particularly abundant in juvenile leaf, Cat1 mRNA predominates in leaves as well and the peak in its abundance occurred in the mature fully expanded leaf during the summer. On the other hand, Cat2 is highly expressed in buds, stem and micropropagated shoots. Expression profile of MnSod, Cat1 and Cat2 in leaves during stress condition changes dramatically according to pathogen. Our findings support the hypothesis that suppression of reactive oxygen intermediate scavenging enzymes as catalases plays an important role in defence response and furthermore suggest a specific protective role for MnSod during conditions of increased mithocondrial respiration.