Project description:Gluconacetobacter diazotrophicus has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis of the early transcriptional response of exponentially growing G. diazotrophicus to iron, an essential cofactor for many enzymes involved in various metabolic pathways. RNA-seq, targeted gene mutagenesis and computational motif discovery tools were used to define the G. diazotrophicus Fur regulon. The data analysis showed that genes encoding functions related to iron homeostasis, were significantly upregulated in response to iron limitation. Certain genes involved in the secondary metabolism were overexpressed under iron-limited conditions. In contrast, it was observed that the expression of genes involved in Fe-S cluster biosynthesis, flagellar biosynthesis and type IV secretion systems were downregulated in an iron-depleted culture medium. Our results support a model that control transcription in G. diazotrophicus by Fur function. The G. diazotrophicus Fur protein was able to complement an E. coli fur mutant. These results provide new insights into the effects of iron on the metabolism of G. diazotrophicus, as well as demonstrating the essentiality of this micronutrient for the main characteristic of plant growth promotion by G. diazotrophicus.
Project description:Heavy metal accumulation in agricultural areas is a global environmental problem that affects microorganisms and plants, with serious implications for human health. This study aimed to investigate the molecular responses of the plant growth-promoting bacterium Gluconacetobacter diazotrophicus PAL5 to cobalt stress. We evaluated bacterial growth and cell viability under cobalt stress and performed comparative proteomic and reverse genetics analyses. Cobalt significantly inhibited bacterial growth but did not cause cell death. Proteomic analysis in the presence of 2.5 mM CoCl2, which caused approximately 50% growth inhibition, revealed the induction of pathways related to iron uptake, carbohydrate metabolism, amino acid metabolism, quality control, and efflux. Knockout mutants for genes involved in these pathways (∆tbdR, ∆zwf, ∆pdhB, ∆argH and ∆czcC) confirmed the essential role of the CzcC efflux system in cobalt tolerance. Cobalt stress triggers molecular responses in G. diazotrophicus PAL5, with efflux systems playing a crucial role in stress tolerance.
2025-06-03 | PXD062750 | Pride
Project description:Transcriptomic analysis of tomato during endophytic bacterial colonisation and humic acid treatment
Project description:Investigation of whole genome gene expression level changes in a Gluconacetobacter xylinus NBRC 3288 delta-fnrG mutant, compared to the wild-type strain.
2021-07-16 | GSE41775 | GEO
Project description:Arabidopsis thaliana response to endophytic colonization by Gluconacetobacter diazotrophicus
Project description:The Fusarium incarnatum strain K23, originally isolated from a habit-adapted wild plant Thapsia species, colonized the roots and shoots of tomato seedlings and protected them against salt stress. Comparison of expression and metabolite profile changes uncovered that the fungus completely reprogramed the tomato response to salt stress. Barely any overlap was observed among the genes and metabolites which are regulated by salt stress in uncolonized and colonized tomato seedlings. In colonized seedlings exposed to salt stress, less stress- related genes are activated than in un-colonized seedlings. Furthermore, K23 produced gibberellin and gibberellin-responsive genes were detected in all RNA samples. Our analysis demonstrates that K23 colonisation completely alters the salt-responsive gene and metabolite profiles in tomato seedlings.
