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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 3.10

MOLECULAR EVOLUTION OF CATALASE GENE FAMILY IN THE GENUS POPULUS

S. CAPARRINI, P. DE BLASI, M. L. RACCHI

Dip. Biotecnologie Agrarie, Università degli Studi di Firenze, p.le delle Cascine 24, 50144 Firenze

catalase, multigene family, phylogeny, Populus

Plant catalases are encoded by a small gene family. Studies performed comparing the exon-intron structures of known genomic sequences, indicate that intron positions are conserved and suggest the existence of an ancestral catalase gene containing 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 isoenzyme genes. Unlike herbaceous plants, few molecular data on the catalase gene structure are available on woody plants. In this study we investigated the intron-exon structure of catalases of Populus species.

Because of its fast growth, ease for clonal propagation, strong heterosis upon interspecific hybridization, its small genome size (550 Mb) and its amenability for genetic transformation, Populus has become a model system for fundamental research on trees.

Using PCR approaches, three catalase genes have been identified and characterized in P. deltoides (section Aigeiros). Two catalase sequences contain seven introns in conserved positions, while one gene lacks the last four introns. Exon-intron structure of catalases was analysed for four species of the section Aigeiros (P. deltoides P. nigra, P. wislizenii, P. fremontii) and for three Leuce species (P. tremula, P. tomentosa, P. alba).

The results indicate that the position of introns of each catalase is conserved, both in Aigeiros and Leuce sections. On the contrary, interesting differences were found in the size and sequence of introns of the same catalases, between the sections, and within each section, which will be used to examine the phylogenetic relationships among different species of the genus Populus.