Caracterização estrutural e funcional dos genes de Tiorredoxinas em Eucalyptus grandis

Abstract

Tree genomes have been sequenced over the last ten years and constitute basic information for plant gene characterization. Comparative genomics once complete genome sequences are made available in public data is a powerful tool to enabe progress within the study of gen function. In this work the interest is concentrated in the genes coding for thioredoxins and considers the diversity, structure and expression of these genes in the genome of Eucalyptus grandis. Bioinformatics tools on public domain platforms (Phytosome; Eucgenie.org; NCBI; PREDOTAR) have been used to identify the coding sequences and to validate data and specific softwares (MEGA7, BEAST3) were employed to characterize the structure and in silico expression of the genes. RT-PCR assays were performed for 6 cytoplasmic thioredoxin genes from leaf tissue, phloem, xylem and apical meristem to confirm the expression observed in silico. Twenty-one thioredoxins with a characteristic active site were identified, confirming the existence of all three major groups already defined in cytoplasmic (h), mitochondrial (m, f, x, y, z) and cytidine plants in the eucalyptus genome. Differences in the number of genes per group were observed in comparison with other genomes of already grown trees such as Populus trichocarpa and Vitis vinifera. The expression of these thioredoxin genes was shown to be divergent for some genes observed in A. thaliana, suggesting a function specificity in eucalyptus, such as the Eucgr.F01604 gene coding for a h1 cytoplasmic Trx with strong expression in conducting tissues. RT-PCR analysis validate Bioinformatics and the approach employed here involving structural and functional analysis through the profile of the gene expression contributed significantly to progress in elucidating the function of Trxs in plants, especially in tree genomes.