Análise molecular e proteômica de Lasiodiplodia theobromae associado a fruteiras tropicais

Abstract

Lasiodiplodia theobromae is a plant pathogenic fungus responsible for many diseases in various plants, is a fungus typically tropical and subtropical regions. The fungus attacks many tropical plants, among them, including mango, Spondias sp., coconut, cashew, and many others. His control is basically genetic performed by planting resistant clones, however to obtain it becomes necessary to know the pathogen characteristics. The information available on the genetic variability of L. theobromae is restricted to ensure success in any breeding program for resistance to this pathogen. Taking into account that proteins are functional products of genes, it is important to know them, to improve the understanding of the mode of action of pathogens, with this understanding, useful as a strategy to be used in plant breeding seeking genetic resistance. The objective of this study were to conduct a genetic study molecular in a population of L. theobromae and a differential proteomic analysis of the fungus among isolates, more and less aggressive, to identify proteins responsible for this aggressivity. A population consisting of 105 strains was used for molecular characterization, extracting the DNA from mycelia grown in liquid medium. Each sample was subjected to polymerase chain reaction (PCR) with 15 pairs of primers specific for the species, and a primer pair of the ITS region and other EF-1α region. The amplified products were visualisados agarose gel, stained with ethidium bromide and spreadsheet data in binary tabulated and analyzed by unbalanced grouping method based on the arithmetic mean (UPGMA) using the MVSP program. Genetic similarities were estimated by Jaccard’s coefficient. The results indicated a high genetic variability of the studied population. Since the proteomic study was conducted to assess qualitative differences, that is, the presence/absence of a specific protein in relation to the opposite group. To this end, we used two isolates of the same fungus, differing as their aggressiveness, in which one was highly aggressive, whereas the other had a low aggressiveness when inoculated seedlings of cashew. When the electrophoretic profile was analyzed, 96 were detected differentially expressed spots. By LC-ESI-Q-TOF MS / MS, 84 proteins were identified having the most diverse cellular functions. With this approach it was possible preliminary characterization of the protein profile of this fungus to give some evidence of the mechanisms involved in their aggressiveness. This is the first study seeking to know the proteins responsible for the aggressiveness L. theobromae.