Beyond genes: Protein atlas scores nitrogen fixing duet

Of the many elusive grails of agricultural biotechnology, the ability to confer nitrogen fixation into non-leguminous plants such as cereals ranks near the very top.

Doing so is a huge challenge because legumes partner with bacteria called rhizobia in a symbiotic waltz that enables plants to draw sustenance from the air and transcend the need for environmentally harmful chemical fertilizers. The natural process is central to the practice of crop rotation, widely used to prevent exhaustion of soil from crops such as corn, which depend on the application of synthetic fertilizers.

The fact that two distinct and very distantly related organisms — a plant and a bacterium — can partner to perform the feat of drawing life-sustaining nitrogen from the atmosphere is just one of the challenges plant engineers face as they seek to confer this quality on other important crops.

The answer to the challenge, however, may be one big step closer with the publication Monday (Oct. 17, 2016) of a massive atlas of plant and bacterial proteins at play as the symbiotic process plays out between plant and microbe.

Writing in the current Nature Biotechnology, a group from the University of Wisconsin–Madison details more than 23,000 plant and bacterial proteins and the molecular controls by which they execute the beneficial relationship. The atlas, possibly the most exhaustive proteomic inventory of any kind to date, shows in minute detail the interplay of proteins as rhizobia colonize root nodules on the model legume Medicago truncatula.

“We can see deeper into the proteome than ever before,” explains Joshua Coon, a UW–Madison professor of biomolecular chemistry and chemistry, and a corresponding author of the new atlas. “We’re able to use technology to provide an unprecedented view of these proteins.”

To read more about this research, see the press release here.

Photo of Josh Coon