Anotação e caracterização preliminar de genes de celulose sintase em diferentes espécies de Eucalyptus

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Universidade Federal de Goiás


Cellulose is the world s most abundant polymer, being the main constituent of plant biomass. Genes from CesA family, that encodes the cellulose synthase enzyme, was identified in several plant species, especially in Arabidopsis thaliana, in which three of them (AtCesA4, AtCesA7 e AtCesA8) were associated with secondary cell wall cellulose production. Eucalyptus species represent an important target of genetic improvement studies, since it is the most planted forest genus in the world, beyond deserving a special place in the international market of cellulose and paper. The molecular breeding technology enables that gene characterization can be applied to forest species genetic improvement programs with the aim to improve the quality and productivity of its products. In this work, 320 Eucalyptus ESTs, separated in four genes related with cellulose production in secondary cell wall, using AtCesA4, AtCesA7 e AtCesA8 genes as reference. For these genes, primers were designed in order to screen an Eucalyptus BACs library. An emphasis was given to genes that are orthologs to AtCesA7 from Arabidopsis thaliana for witch it was sequenced a 1197 base pairs region from the BACs library and this served as a support to expression level studies of this genes in different species/tissues, showing that this is preferentially expressed in xylem and weakly expressed in leaves. The expression level of this gene was higher in E. urophylla than in other species studied. Sequences from approximately 500bp was obtained from different Eucalyptus species and in these, with one intron between two exons, the amount of SNPs in the intron (4), as waited, was higher than that found in exons (1 in each), although the intron nucleotide diversity index (π) (0,0824) were less than in the exon (0,2029). In this manner, one expects that this work can contribute for one better understanding of the mechanisms involved in biosynthesis and regulation of the cellulose pathway in Eucalyptus species, as well as subsidize genetic mapping studies and linkage disequilibrium analysis for this genus.



SALAZAR, Marcela Mendes. Annotation and preliminary characterization of cellulose synthase genes in different species of Eucalyptus. 2006. 120 f. Dissertação (Mestrado em Ciências Biolóicas) - Universidade Federal de Goiás, Goiânia, 2006.