Diversidade genética de Physalis L. e análise molecular in silico de putrescine n-methyltransferase em espécies da família Solanaceae

Abstract

Physalis is a genus belonging to the Solanaceae family, which comprises about one hundred species, almost all of which occur in the Americas. Its species have been widely used in human food, in the production of pharmacological substances and for ornamentation. Currently, the Physalis fruit cultivation is the most commercially important, being used as a source of vitamin A, B and C, of micronutrients such as phosphorus, and high levels of soluble solids. Studies have revealed the identification of chemical substances found in Physalis, which have important biological activities, with immunomodulatory, antimicrobial, anticancer, antiflammatory, and molluscicidal actions, among others. Despite the expressive economic potential, only a small part of the genetic variability of its species has been studied, with a large number of genotypes not yet genetically characterized. The genetic breeding of the species is carried out empirically, over the years, by the farmers themselves. Therefore, the present study aims to perform a preliminary evaluation of the genetic diversity among Physalis L. accessions belonging to the Active Germplasm Bank (BAG) of the Federal Rural University of Pernambuco (UFRPE), using morphological characters. The work was conducted in the Laboratory of Plant Biotechnology and Weeds and in a greenhouse of the Phytotechnology Area, Agronomy Department, UFRPE. The evaluated materials originated from seeds commercially obtained from the species Physalis peruviana L., and from genotypes from six states of Brazil, which are part of the Physalis germplasm bank of UFRPE. Ten accessions were characterized using 21 qualitative descriptors (Growth habit; Stem color; Stem pubescence; Stem shape; Leaf shape; Leaf margin shape; Leaf base shape; Leaf apex shape; Anthocyanin in the leaf venation; Color of the corolla; Color of the maculae of the corolla; Position of the flower; Color of the immature calyx; Color of the mature calyx; Shape of the calyx; Color of the immature fruit; Color of the mature fruit; Fruit shape; Presence of wax in the fruit; Seed shape; Seed color). The use of morphological descriptors was efficient in estimating the genetic variability existng among the accessions. This information will serve as a basis for managing the germplasm bank, identifying of possible duplicates, and reducing maintenance costs, also helping in the evaluation and selection of individuals of interest for plant breeding programs for the crop. In the bioinformatics part, the present study aimed to perform in silico molecular analysis of the enzyme putrescine Nmethyltransferase (PMT) in species of the Solanaceae family, characterizing structurally and functionally the amino acid sequences with bioinformatics methodologies, to develop three-dimensional models of this protein, based on homology modeling methodology. A total of 48 PMT sequences present in public databases were characterized. The results obtained indicated a hydrophilic character of PMT for all species, and a small variation of pI among the analyzed species, indicating an acidic character. The presence of four functional domains was observed in the PMT sequences. Clustering analysis by Neighbour Joining showed consistency with recent taxonomic classifications of the evaluated species. The generated 3D models can be considered a close representation of the real structure of the protein.