Many plant pathogenic Pseudomonas savastanoi pv glycinea isolates possess an inactive quorum sensing ahlR gene via a point mutation. Issue 12 (4th July 2019)

• Record Type: Journal Article
• Authors: Degrassi, Giuliano; Mortato, Valentina; Devescovi, Giulia; Hoshino, Rodrigo; Chatnaparat, Tiyakhon; Kojic, Milan; Carpentieri-Pipolo, Valeria; Zhao, Youfu; Venturi, Vittorio
• Is Part Of: FEMS microbiology letters. Volume 366:Issue 12(2019)
• Publication Date: 2019-07-04
• Subjects: soybean -- Pseudomonas -- quorum sensing -- transcriptional regulator -- autoinduction -- swarming; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fnz149
• Languages: English
• ISSNs: 0378-1097

Abstract

ABSTRACT: Many plant bacterial pathogens monitor their group behaviour and their population density via production of N -acyl homoserine lactone signals which regulate the expression of several genes via the LuxI/R homologs. This regulatory network, termed quorum sensing (QS), is present in the soybean bacterial pathogen Pseudomonas savastanoi pv glycinea (Psg) . The sequenced genomes of two strains of Psg, race 4 and B076, contain an N -acyl homoserine lactone (AHL) based LuxI/R QS system named AhlI/R. While studying the QS system of Psg strains race 4 and B076 isolated in USA, LMG5066 in New Zealand and IBSBF355 in Brazil, we found that B076, LMG5066 and IBSBF355 possess a point mutation in the ahlR gene that causes a frameshift resulting in a truncated AhlR protein. Psg race 4 does not possess the mutation in ahlR and the QS system is functional. The same mutation in the ahlR gene was found to be also present in 9 of 19 Psg strains isolated from diseased soybean in Illinois. Phenotypic analysis of strains showed that swarming motility is repressed whereas phosphate solubilisation was activated by QS in Psg . Analysing the secretome, we also found that four proteins were under QS regulation. Abstract : Conservation of an inactive mechanism of regulation of gene expression, namely quorum sensing, was observed in Pseudomonas savastanoi pv glycinea, a soybean bacterial pathogen. Data for its significance are provided.