Synthetic Biology Toolbox for Nitrogen-Fixing Soil Microbes.

The soil environment adjacent to plant roots, termed the rhizosphere, is home to a wide variety of microorganisms that can significantly affect the physiology of nearby plants. Microbes in the rhizosphere can provide nutrients, secrete signaling compounds, and inhibit pathogens. These processes could be manipulated with synthetic biology to enhance the agricultural performance of crops grown for food, energy, or environmental remediation, if methods can be implemented in these nonmodel microbes.

Plant-Pathogenic Phylotypes Evolved Divergent Respiratory Strategies and Behaviors To Thrive in Xylem.

Bacterial pathogens in the Ralstonia solanacearum species complex (RSSC) infect the water-transporting xylem vessels of plants, causing bacterial wilt disease. Strains in RSSC phylotypes I and III can reduce nitrate to dinitrogen via complete denitrification. The four-step denitrification pathway enables bacteria to use inorganic nitrogen species as terminal electron acceptors, supporting their growth in oxygen-limited environments such as biofilms or plant xylem.

Trehalose increases tomato drought tolerance, induces defenses, and increases resistance to bacterial wilt disease.

Ralstonia solanacearum causes bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in the disaccharide trehalose.

Depends on Catabolism of Myo-Inositol, Sucrose, and Trehalose for Virulence in an Infection Stage-Dependent Manner.

The soilborne pathogen causes a lethal bacterial wilt disease of tomato and many other crops by infecting host roots, then colonizing the water-transporting xylem vessels. Tomato xylem sap is nutritionally limiting but it does contain some carbon sources, including sucrose, trehalose, and myo-inositol. Transcriptomic analyses revealed that expresses distinct catabolic pathways at low cell density (LCD) and high cell density (HCD).

Trehalose Synthesis Contributes to Osmotic Stress Tolerance and Virulence of the Bacterial Wilt Pathogen .

The xylem-dwelling plant pathogen changes the chemical composition of host xylem sap during bacterial wilt disease. The disaccharide trehalose, implicated in stress tolerance across all kingdoms of life, is enriched in sap from -infected tomato plants. Trehalose in xylem sap could be synthesized by the bacterium, the plant, or both.

Complete Genome Sequences of the Plant Pathogens Type Strain K60 and Race 3 Biovar 2 Strain UW551.

is a globally distributed plant pathogen that causes bacterial wilt diseases of many crop hosts, threatening both sustenance farming and industrial agriculture. Here, we present closed genome sequences for the type strain, K60, and the cool-tolerant potato brown rot strain UW551, a highly regulated U.S.

Extracellular DNases of Ralstonia solanacearum modulate biofilms and facilitate bacterial wilt virulence.

Ralstonia solanacearum is a soil-borne vascular pathogen that colonizes plant xylem vessels, a flowing, low-nutrient habitat where biofilms could be adaptive. Ralstonia solanacearum forms biofilm in vitro, but it was not known if the pathogen benefits from biofilms during infection. Scanning electron microscopy revealed that during tomato infection, R.

Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum.

Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner.