Variabilidade genética de Ralstonia solanacearum (smith) Yabucchi et al. utilizando marcadores AFLP e avaliação de respostas bioquímicas de defesa à murcha bacteriana em capsicum spp. nativo

Abstract

Bacterial wilt caused by Ralstonia solanacearum is one of the most important diseases of solanaceous. Present in all national territory, causes rapid wilting of plants and affects several crops of agronomic interest. In Amazonas, the high temperature and humidity combined with the genetic diversity of this pathogen diversity of hosts favor the development and aggressiveness of the pathogen and complicate the management of this disease. The aim of this study was to evaluate the genetic diversity of R. solanacearum using AFLP markers and evaluate defense responses submitted by Capsicum spp. natives of the Amazon region, verifying the expression of pathogenesis-related proteins, resulting from infection by the pathogen. Samples were collected in four counties vegetable growers in the metropolitan area of Manaus to establish a collection of 30 isolates of the pathogen. We performed classical biochemical characterization of the isolates and characterization of genetic diversity using AFLP molecular markers. The 24 primer combinations were tested and selected the six best informative combinations . The six combinations of primers generated a 432 bands , ranging from 47 to 103 loci in the combination E + AT / M + C. The Jaccard similarity coefficient estimated between 30 isolates ranged from 0.01 to 0.98. From the similarity matrix a dendrogram was generated by UPGMA method being possible separate the isolates into six groups with cophenetic correlation coefficient of r = 0.98. The defense response submitted by Capsicum spp. were also evaluated by biochemical methods for the determination of total protein, phenylalanine ammonia lyase activity and peroxidase activity phenoloxidases. The enzymatic activity varied according to the level of resistance of the evaluated accessions, being higher in the first hours after inoculation and decreased after 72 hours. It was possible to identify two resistant accessions ( BC 05 and NT ) showed that grade point average of 1.17 xi and 0.94 . The BC had access resistance of accessions was associated with increased activity of PPO and FAL, indicating that these enzymes make up the defense mechanism in plants of Capsicum. The POX activity was lower when compared with the activity of PPO and FAL