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.