Dataset Information

Calcium regulates the mycophagous ability of Burkholderia gladioli strain NGJ1 in a type III secretion system-dependent manner.

ABSTRACT: BACKGROUND:A rice associated bacterium Burkholderia gladioli strain NGJ1 demonstrates mycophagy, a phenomenon wherein bacteria feed on fungi. Previously, we have reported that NGJ1 utilizes type III secretion system (T3SS) to deliver a prophage tail-like protein (Bg_9562) into fungal cells to establish mycophagy. RESULTS:In this study, we report that calcium ion concentration influences the mycophagous ability of NGJ1 on Rhizoctonia solani, an important fungal pathogen. The calcium limiting condition promotes mycophagy while high calcium environment prevents it. The expression of various T3SS apparatus encoding genes of NGJ1 was induced and secretion of several potential T3SS effector proteins (including Bg_9562) into extracellular milieu was triggered under calcium limiting condition. Using LC-MS/MS proteome analysis, we identified several calcium regulated T3SS effector proteins of NGJ1. The expression of genes encoding some of these effector proteins was upregulated during mycophagous interaction of NGJ1 with R. solani. Further, mutation of one of these genes (endo-?-1, 3- glucanase) rendered the mutant NGJ1 bacterium defective in mycophagy while complementation with full length copy of the gene restored its mycophagous activity. CONCLUSION:Our study provides evidence that low calcium environment triggers secretion of various T3SS effectors proteins into the extracellular milieu and suggests the importance of cocktail of these proteins in promoting mycophagy.

SUBMITTER: Yadav SK

PROVIDER: S-EPMC7372643 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Calcium regulates the mycophagous ability of Burkholderia gladioli strain NGJ1 in a type III secretion system-dependent manner.

Yadav Sunil Kumar SK Das Joyati J Kumar Rahul R Jha Gopaljee G

BMC microbiology 20200720 1

<h4>Background</h4>A rice associated bacterium Burkholderia gladioli strain NGJ1 demonstrates mycophagy, a phenomenon wherein bacteria feed on fungi. Previously, we have reported that NGJ1 utilizes type III secretion system (T3SS) to deliver a prophage tail-like protein (Bg_9562) into fungal cells to establish mycophagy.<h4>Results</h4>In this study, we report that calcium ion concentration influences the mycophagous ability of NGJ1 on Rhizoctonia solani, an important fungal pathogen. The calciu ...[more]

PMID: 32689944

Similar Datasets

Project description:Burkholderia gladioli strain NGJ1 exhibits mycophagous activity on a broad range of fungi, including Rhizoctonia solani, a devastating plant pathogen. Here, we demonstrate that the nicotinic acid (NA) catabolic pathway in NGJ1 is required for mycophagy. NGJ1 is auxotrophic to NA and it potentially senses R. solani as a NA source. Mutation in the nicC and nicX genes involved in NA catabolism renders defects in mycophagy and the mutant bacteria are unable to utilize R. solani extract as the sole nutrient source. As supplementation of NA, but not FA (fumaric acid, the end product of NA catabolism) restores the mycophagous ability of ΔnicC/ΔnicX mutants, we anticipate that NA is not required as a carbon source for the bacterium during mycophagy. Notably, nicR, a MarR-type of transcriptional regulator that functions as a negative regulator of the NA catabolic pathway is upregulated in ΔnicC/ΔnicX mutant and upon NA supplementation the nicR expression is reduced to the basal level in both the mutants. The ΔnicR mutant produces excessive biofilm and is completely defective in swimming motility. On the other hand, ΔnicC/ΔnicX mutants are compromised in swimming motility as well as biofilm formation, potentially due to the upregulation of nicR. Our data suggest that a defect in NA catabolism alters the NA pool in the bacterium and upregulates nicR which in turn suppresses bacterial motility as well as biofilm formation, leading to mycophagy defects. IMPORTANCE Mycophagy is an important trait through which certain bacteria forage over fungal mycelia and utilize fungal biomass as a nutrient source to thrive in hostile environments. The present study emphasizes that nicotinic acid (NA) is important for bacterial motility and biofilm formation during mycophagy by Burkholderia gladioli strain NGJ1. Defects in NA catabolism potentially alter the cellular NA pool, upregulate the expression of nicR, a negative regulator of biofilm, and therefore suppress bacterial motility as well as biofilm formation, leading to mycophagy defects.

Dataset Information

Calcium regulates the mycophagous ability of Burkholderia gladioli strain NGJ1 in a type III secretion system-dependent manner.

Publications

Calcium regulates the mycophagous ability of Burkholderia gladioli strain NGJ1 in a type III secretion system-dependent manner.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets