How bacteria get into plants

Legumes form a unique symbiotic relationship with bacteria known as rhizobia, which they allow to infect their roots. This leads to root nodules being formed in which the bacteria convert nitrogen from the air into ammonia that the plant can use for growth.
Exactly how these plants are able to distinguish and welcome compatible rhizobia for this self-fertilising activity - while halting infection by incompatible bacteria - has been a mystery.
The researchers have determined how legumes perceive and distinguish compatible bacteria based on the exopolysaccharides featuring on the invading cells' surfaces.The researchers have identified the first known exopolysaccharide receptor gene, called Epr3.
They found that a membrane-bound receptor kinase encoded by the Epr3 gene binds directly with exopolysaccharides and regulates beneficial bacteria's passage through the plant's epidermal cell layer.