Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

mBio, Journal Year: 2024, Volume and Issue: 15(7)

Published: June 4, 2024

ABSTRACT Stenotrophomonas maltophilia expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report structure TfcB, comprising an N-terminal domain similar to catalytic glycosyl hydrolase (GH-19) chitinases C-terminal for recognition translocation T4SS. Utilizing two-hybrid assay measure interactions with T4SS coupling VirD4, documented existence five more substrates. One these was 20845, annotated nuclease. A S. mutant lacking gene 20845 impaired Escherichia coli , Klebsiella pneumoniae Pseudomonas aeruginosa . Moreover, cloned conferred robust toxicity, recombinant E. being rescued when co-expressed its cognate immunity protein. The 899 amino-acid protein, comprised GHH-nuclease in N-terminus, large central region indeterminant function, C-terminus secretion. Engineered variants had mutations predicted site did not impede indicating antibacterial effect involves nuclease activity. Using flow cytometry DNA staining, determined but variants, confers loss content target bacteria. Database searches revealed uncharacterized homologs occur within range These data indicate interbacterial competition through action multiple toxic effectors, including potent, novel DNase. IMPORTANCE is multi-drug-resistant, Gram-negative bacterium emerging pathogen humans. Patients cystic fibrosis are particularly susceptible infection. In hospital water systems various types infections, co-exists bacteria, pathogens such as We previously demonstrated has functional VirB/D4 VI Since most work on system, this observation remains noteworthy. currently stands alone model human expressing biochemical, genetic, cell biological approaches, now both discovery (TfdA) first structural determination bactericidal (TfcB).

Language: Английский

Xanthomonas sontii, and not Xanthomonas sacchari, is the predominant, vertically transmitted core rice seed endophyte

Phytopathology, Journal Year: 2024, Volume and Issue: 114(9), P. 2017 - 2023

Published: June 25, 2024

Seed endophytes, particularly the abundant, core, and vertically transmitted species, are major areas of focus in host microbiome studies. Apart from being first members to colonize, they accompany plant throughout its development stages next generation. Recently published studies have reported keystone species be Xanthomonas sacchari, a core endophyte that is rice with probiotic properties. Furthermore, was involved assembly beneficial bacteria after early inoculation seeds. However, strains discussed these were misclassified as X. well-known pathogen sugarcane. By including nonpathogenic plant-protective functions seeds, we correctly established phylogenetic taxonomic identity sontii. This will enable researchers use correct reference or lab strain sontii for further systematic in-depth model plant–microbe interactions apart exploitation seed health.

Language: Английский

Xanthomonas protegens sp. nov., a novel rice seed-associated bacterium, provides in vivo protection against X. oryzae pv. oryzae, the bacterial leaf blight pathogen

FEMS Microbiology Letters, Journal Year: 2024, Volume and Issue: 371

Published: Jan. 1, 2024

Historically, Xanthomonas species are primarily known for their pathogenicity against plants, but recently, there have been more findings of non-pathogenic xanthomonads. In the present study, we report isolates from healthy rice seeds that belong to a new species, protegens, protector plants serious pathogenic counterpart, i.e. X. oryzae pv. upon leaf clip co-inoculation. The member is and lacks type III secretion system. pangenome investigation revealed large number unique genes, including novel lipopolysaccharide biosynthetic gene cluster, might be important in its adaptation. phylo-taxonogenomic analysis protegens taxonomic outlier sontii, core, vertically transmitted seed endophyte with numerous probiotic properties. Interestingly, sontii also reported as keystone microbiome. resources will help development markers evolutionary studies successful symbiont pathogen. Here, propose sp. nov. genus PPL118 = MTCC 13396 CFBP 9164 ICMP 25181 strain. PPL117, PPL124, PPL125, PPL126 other strains species.

Language: Английский