Root colonization and systemic spreading of Azoarcus sp. strain BH72 in grasses.

摘要: The invasive properties of Azoarcus sp. strain BH72, an endorhizospheric isolate Kallar grass, on gnotobiotically grown seedlings Oryza sativa IR36 and Leptochloa fusca (L.) Kunth were studied. Additionally, spp. localized in roots field-grown grass. To facilitate localization to assure identity bacteria, genetically engineered microorganisms expressing beta-glucuronidase also used as inocula. beta-Glucuronidase staining indicated that the apical region root behind meristem was most intensively colonized. Light electron microscopy showed BH72 penetrated rhizoplane preferentially zones elongation differentiation colonized interior inter- intracellularly. In addition cortex, stelar tissue colonized; bacteria found xylem. No evidence obtained could reside living plant cells; rather, cells apparently destroyed after had cell wall. A common pathogenicity test tobacco leaves provided no representative strains are phytopathogenic. Compared with control, inoculation significantly promoted growth rice seedlings. This effect reversed when medium supplemented malate (0.2 g/liter). N2 fixation not involved, because same response a nifK mutant which has Nif- phenotype. Also, Western blot (immunoblot) analysis protein extracts from gave indication nitrogenase present. PCR immunoblotting, using primers specific for eubacteria antibodies recognizing type-specific antigens, respectively, colonize plants systemically, probably mediated by longitudinal spreading through vessels.