An apigenin-induced decrease in K-antigen production by Sinorhizobium sp. NGR234 is y4gM- and nodD1-dependent.

Cultured cells of Sinorhizobium sp. NGR234 produce an abundance of capsular polysaccharides, or K antigens; however, cells that are cultured in the presence of apigenin, a nod gene inducer, exhibited a significant reduction in K-antigen production. The flavonoid-induced modulation in capsule production appeared to be related to the phase-shift changes associated with bacteroid differentiation.

Strain-ecotype specificity in Sinorhizobium meliloti-Medicago truncatula symbiosis is correlated to succinoglycan oligosaccharide structure.

Molecular signals, including Nod factors and succinoglycan, are necessary for the establishment of nitrogen-fixing nodules (Fix+) in Medicago truncatula-Sinorhizobium meliloti symbiosis. This report shows that M. truncatula-S.

Structural characterization of a flavonoid-inducible Pseudomonas aeruginosa A-band-like O antigen of Rhizobium sp. strain NGR234, required for the formation of nitrogen-fixing nodules.

Rhizobium (Sinorhizobium) sp. strain NGR234 contains three replicons, the smallest of which (pNGR234a) carries most symbiotic genes, including those required for nodulation and lipo-chito-oligosaccharide (Nod factor) biosynthesis. Activation of nod gene expression depends on plant-derived flavonoids, NodD transcriptional activators, and nod box promoter elements.

The type III-dependent Hrp pilus is required for productive interaction of Xanthomonas campestris pv. vesicatoria with pepper host plants.

The plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria expresses a type III secretion system that is necessary for both pathogenicity in susceptible hosts and the induction of the hypersensitive response in resistant plants. This specialized protein transport system is encoded by a 23-kb hrp (hypersensitive response and pathogenicity) gene cluster.

TtsI, a key regulator of Rhizobium species NGR234 is required for type III-dependent protein secretion and synthesis of rhamnose-rich polysaccharides.

Formation of nitrogen-fixing nodules on legume roots by Rhizobium sp. NGR234 requires an array of bacterial factors, including nodulation outer proteins (Nops) secreted through a type III secretion system (TTSS). Secretion of Nops is abolished upon inactivation of ttsI (formerly y4xI), a protein with characteristics of two-component response regulators that was predicted to activate transcription of TTSS-related genes.