Dataset Information

Synergistic interaction between the type III secretion system of the endophytic bacterium Pantoea agglomerans DAPP-PG 734 and the virulence of the causal agent of olive knot Pseudomonas savastanoi pv. savastanoi DAPP-PG 722.

ABSTRACT: The endophytic bacterium Pantoea agglomerans DAPP-PG 734 was previously isolated from olive knots caused by infection with Pseudomonas savastanoi pv. savastanoi DAPP-PG 722. Whole-genome analysis of this P. agglomerans strain revealed the presence of a Hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To assess the role of the P. agglomerans T3SS in the interaction with P. savastanoi pv. savastanoi, we generated independent knockout mutants in three Hrp genes of the P. agglomerans DAPP-PG 734 T3SS (hrpJ, hrpN, and hrpY). In contrast to the wildtype control, all three mutants failed to cause a hypersensitive response when infiltrated in tobacco leaves, suggesting that P. agglomerans T3SS is functional and injects effector proteins in plant cells. In contrast to P. savastanoi pv. savastanoi DAPP-PG 722, the wildtype strain P. agglomerans DAPP-PG 734 and its Hrp T3SS mutants did not cause olive knot disease in 1-year-old olive plants. Coinoculation of P. savastanoi pv. savastanoi with P. agglomerans wildtype strains did not significantly change the knot size, while the DAPP-PG 734 hrpY mutant induced a significant decrease in knot size, which could be complemented by providing hrpY on a plasmid. By epifluorescence microscopy and confocal laser scanning microscopy, we found that the localization patterns in knots were nonoverlapping for P. savastanoi pv. savastanoi and P. agglomerans when coinoculated. Our results suggest that suppression of olive plant defences mediated by the Hrp T3SS of P. agglomerans DAPP-PG 734 positively impacts the virulence of P. savastanoi pv. savastanoi DAPP-PG 722.

SUBMITTER: Moretti C

PROVIDER: S-EPMC8435235 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The olive knot disease (Olea europea L.) is caused by the bacterium Pseudomonas savastanoi pv. savastanoi. P. savastanoi pv. savastanoi in the olive knot undergoes interspecies interactions with the harmless endophyte Erwinia toletana; P. savastanoi pv. savastanoi and E. toletana colocalize and form a stable community, resulting in a more aggressive disease. P. savastanoi pv. savastanoi and Etoletana produce the same type of the N-acylhomoserine lactone (AHL) quorum sensing (QS) signal, and they share AHLs in planta In this work, we have further studied the AHL QS systems of P. savastanoi pv. savastanoi and Etoletana in order to determine possible molecular mechanism(s) involved in this bacterial interspecies interaction/cooperation. The AHL QS regulons of P. savastanoi pv. savastanoi and Etoletana were determined, allowing the identification of several QS-regulated genes. Surprisingly, the P. savastanoi pv. savastanoi QS regulon consisted of only a few loci whereas in Etoletana many putative metabolic genes were regulated by QS, among which are several involved in carbohydrate metabolism. One of these loci was the aldolase-encoding gene garL, which was found to be essential for both colocalization of P. savastanoi pv. savastanoi and Etoletana cells inside olive knots as well as knot development. This study further highlighted that pathogens can cooperate with commensal members of the plant microbiome.IMPORTANCE This is a report on studies of the quorum sensing (QS) systems of the olive knot pathogen Pseudomonas savastanoi pv. savastanoi and olive knot cooperator Erwinia toletana These two bacterial species form a stable community in the olive knot, share QS signals, and cooperate, resulting in a more aggressive disease. In this work we further studied the QS systems by determining their regulons as well as by studying QS-regulated genes which might play a role in this cooperation. This represents a unique in vivo interspecies bacterial virulence model and highlights the importance of bacterial interspecies interaction in disease.

Dataset Information

Synergistic interaction between the type III secretion system of the endophytic bacterium Pantoea agglomerans DAPP-PG 734 and the virulence of the causal agent of olive knot Pseudomonas savastanoi pv. savastanoi DAPP-PG 722.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets