Arabidopsis Growth-Promotion and Root Architecture Responses to the Beneficial Rhizobacterium Strain STM196 Are Independent of the Nitrate Assimilatory Pathway.

STM196, a plant growth-promoting rhizobacterium isolated from roots of oilseed rape, stimulates growth. We have previously shown that the and genes are required for this growth promotion response. Since these genes are members of the family of nitrate transporters, the nitrogen assimilatory pathway could be involved in growth promotion by STM196.

The ethylene pathway contributes to root hair elongation induced by the beneficial bacteria Phyllobacterium brassicacearum STM196.

In Arabidopsis roots, some epidermal cells differentiate into root hair cells. Auxin regulates root hair positioning, while ethylene controls cell elongation. Phyllobacterium brassicacearum STM196, a beneficial strain of plant growth promoting rhizobacteria (PGPR) isolated from the roots of field-grown oilseed rape, stimulates root hair elongation in Arabidopsis thaliana seedlings.