Natures wonders: legume bacteria symbiosis (Introduction)

by David Turell , Thursday, July 09, 2015, 15:39 (3423 days ago) @ David Turell

Legumes allow bacterial infection of their roots to fix nitrogen from the air into the soil:-http://www.sciencedaily.com/releases/2015/07/150709092733.htm-"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.-"Now the researchers at the Centre for Carbohydrate Recognition and Signalling (CARB) from Denmark and New Zealand and their collaborators from the Centre for Complex Carbohydrate Research in Georgia, USA, have determined how legumes perceive and distinguish compatible bacteria based on the exopolysaccharides featuring on the invading cells' surfaces.-"Using an interdisciplinary approach involving plant and microbial genetics, biochemistry and carbohydrate chemistry, 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.-***-"Microbiome studies in plants, animals and humans are some of the areas that will benefit from the new discovery. The mechanism governing microbiota colonisation of hosts is poorly understood and the identification of an exopolysaccharide receptor is likely to inspire new approaches to understand the interaction between multicellular organisms and microbes."