Biology subjects

de Oliveira, L. O.

Publications and source records attributed to de Oliveira, L. O..

2 recordsLinked to original sources

bioRxiv2024

Acquisition, Evolution, and Diversification of Genomic Islands: A Case Study of a Virulence Gene Cluster in Pseudomonas syringae

Genomic islands are widely distributed among bacteria, facilitating the dissemination of genes relevant to human, animal, and plant health. Herein, we explore the evolutionary history of a genomic island (Tox island) composed of a novel mobile genetic element (GInt) carrying an [~]25 kb gene cluster (Pht cluster) responsible for the biosynthesis of the phytotoxin phaseolotoxin, a virulence factor of the plant pathogen Pseudomonas syringae. The Pht cluster has been acquired, either naked or associated with a GInt, on seven independent occasions by four phylogroups of P. syringae and the distant rhizobacterium Pseudomonas sp. JAI115. The Pht cluster was independently captured by three distinct GInt elements, suggesting specific mechanisms for gene capture. Once acquired, the Tox island tends to be stably maintained, evolving with the genome. An array of molecular analyses delineated the likely evolutionary trajectory of the Pht cluster within P. syringae pv. actinidiae (Psa) and P. amygdali pv. phaseolicola (Pph), involving: 1) acquisition by Pph; 2) transfer of haplotype G to Psa biovar 1; 3) acquisition or replacement by a haplotype of haplogroup D in Psa biovar 1; 4) acquisition of haplotype C by Psa biovar 6; and 5) replacement of the Tox island in Pph by a distantly related GInt. These findings underscore the potential role of phaseolotoxin in bacterial fitness and contribute to our understanding of virulence evolution in plant pathogens. Furthermore, GInts provide a model for studying the evolutionary dynamics of mobile genetic elements and the dissemination of adaptive genes among bacterial pathogens.

microbiology↗

bioRxiv2022

The Necrosis- and Ethylene-inducing peptide 1-like protein (NLP) gene family of the plant pathogen Corynespora cassiicola

Effectors are secreted by plant-associated microorganisms in order to modify the host cell physiology. As effectors, the Necrosis- and Ethylene-inducing peptide 1-like proteins (NLPs) are involded in the early phases of plant infection and may trigger host immune responses. Corynespora cassiicola is a polyphagous plant-pathogen that causes target spot on many agriculturally important crops. Using genome assembly, gene prediction, and proteome annotation tools, we retrieved 135 NLP-encoding genes from proteomes of 44 isolates. We explored the evolutionary history of NLPs using Bayesian phylogeny, gene genealogies, and selection analyses. We accessed the expression profiles of the NLP genes during the early phase of C. cassiicola-soybean interaction. Three NLP effector genes (Cc_NLP1.1, Cc_NLP1.2A, and Cc_NLP1.2B) were maintained in the genomes of all isolates tested. A non-effector NLP gene (Cc_NLP1.3) was found in three isolates that had been originally obtained from soybean. NLP effectors were under different selective constraints: Cc_NLP1.1 was under stronger selective pressure, while Cc_NLP1.2A was under a more relaxed constraint. Meanwhile, Cc_NLP1.2B likely evolved under either positive or balancing selection. Despite highly divergent, the effector NLPs maintain conserved the residues necessary to trigger plant immune responses, suggesting they are potentially functional. Only the Cc_NLP1.1 effector gene was significantly expressed at the early hours of soybean colonization, while Cc_NLP1.2A and Cc_NLP1.2B showed much lower levels of gene expression.

microbiology↗