Evolutionary analysis of pathogenicity genes from Erwinia psidii infecting Eucalyptus spp.

• Ano de defesa: 2019
• Autor(a) principal: Pereira, Isadora Cristófoli
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Fitopatologia
• Palavras-chave em Português: Erwinia psidii; Eucalipto; Goiaba; Secreção; Fitopatologia
• Link de acesso: https://locus.ufv.br//handle/123456789/30083

Erwinia psidii is a Gram-negative bacterium that threatens both guava and eucalypt production. Despite the importance of both trees to the Brazilian economy, little is known about the mechanisms underlying this bacterium pathogenicity. Thus, in this study we used bioinformatic approaches to determine the gene composition of the hrp/hrc cluster of E. psidii, which encodes for the Type III secretion system, a well-known apparatus for its importance to the pathogenicity of many plant pathogenic Gram-negative bacteria. Computational methods were also used to predict both type II and III effector protein repertoires of E. psidii. In addition, evolutionary analyses were performed for the candidate type III effector proteins, in order to gain a better understanding on how this bacterium pathogenicity system evolved over time. Here, we characterized and compared the gene composition of E. psidii hrp/hrc cluster with those of other Enterobacteriaceae, and predicted 11 type III effector proteins, two of which, DspA/E and Eop1, are known important effector proteins secreted by the closely related species E. amylovora. Interestingly, these two candidate type III effectors seem to have been acquired by E. psidii through horizontal gene transfer between Erwinia and Pantoea species. Also, we identified 47 candidate type II effector proteins, most of which were annotated as enzymes, with hydrolytic or non- hydrolytic activities. These results provide important knowledge for further in vivo analysis, through construction of mutant strains and functional characterization of the effector candidates during plant-bacteria interactions.