Proceedings of the XLVI Italian
Society of Agricultural Genetics - SIGA Annual Congress
Giardini
Naxos, Italy - 18/21 September, 2002
ISBN 88-900622-3-1
Poster Abstract
- 1.27
Characterisation of
catalase genomic structure by PCR analysIs in Prunus and Populus species
Santucci S., Caparrini S., Turchi A., De Blasi P.,
Racchi M.L.
Dip.
Biotecnologie Agrarie Laboratorio di Genetica Università degli Studi di
Firenze, P.le delle Cascine 24, 50144 Firenze, Italia
catalase, intron, Prunus, Populus, PCR
Catalase, which is an ubiquitous
peroxisomal matrix enzyme, dismutates H2O2 into water and oxygen. Together with
superoxide dismutase and hydroperoxidase, catalase is part of a defence system
for scavenging superoxide radicals and hydroperoxides and protecting cells from oxidative
stress. Plant catalases are encoded by a small gene family, usually three or at
most four isoenzyme genes in one species. Each catalase isoenzymes shows a
distinct spatial and temporal pattern of expression through the entire life
cycle of the plants, which may account for the diverse roles played by plant
catalases. Catalase activity is a determining factor for the protection of
cells against oxidative stress induced during abiotic stress conditions such as
chilling, drought, salt and ozone. Nevertheless catalase may play an important
role in the signal transduction of the defence response in the plants leading
to the development of SAR. Therefore, the interest in plant catalase has
increased considerably in recent years.
In particular, in order to understand the
molecular evolution of catalase genes, studies about genomic structures are
performed comparing the exon-intron structures of known genomic sequences.
Comparison of position and numbers of introns sequences indicates that intron
positions are conserved, and suggests the existence of an ancestral catalase
gene which contained seven introns. During evolution in plant species, the duplication
of the primordial gene followed by the differential loss and gain of introns
occurred to form three or four different isozyme genes.
Biochemical and molecular aspects of catalase
multiplicity have been thoroughly studied in herbaceous plants. However, on
woody plants biochemical aspects of catalase have been studied in gymnosperms
and more recently in horse chestnut and oak, but few molecular data on genes
coding for these enzymes are available on woody plants.
In this study, we compared the exon-intron
structures of catalase genes of Prunus and Populus
species, using the polymerase chain reaction (PCR). We analysed differences in
the position, size and sequence of the introns, to characterise genotypes of
species or cultivar. In particular, we compared Populus nigra with P. deltoides and Prunus persica with P. armeniaca, P. avium, P. domestica.
To obtain detailed informations about the structures of introns of these
plants, we cloned and sequenced the PCR products. The results obtained show
that the position of introns of primordial catalase gene is conserved among the
species analysed, but with some interesting differences in the number and
sequence of introns.