Knowing how plants and microbes work together can boost crop yields

INTERACTIONS WITHAAAS microbes in the soil are crucial to the health of plants. Some bacteria turn nitrogen from the air into ammonia, and thence into nitrates, thus “fixing” that element in a form which plants can absorb and turn into proteins. Others, by secreting antibiotics, protect plants from pathogens. Others still, through the formation of colonies called biofilms on the surfaces of soil particles, help trap water in the soil. And fungi, which consist of long networks of hyphae that often penetrate plant roots, facilitate the uptake by those roots of nutrients from the soilAlso this means that soil microbes affect crop yields. Indeed, they are one of the most important influences on crop growth that has yet to be exploited systematically to raise those yields. But that will soon change, if researchers who study the rhizosphere, (as the zone of interaction between plants’ roots and microbes is known) have anything to do with it. This study is hard, for the rhizosphere is a habitat as complex, in its way, as a rainforest or a coral reef. It just operates at a smaller scale. As a group of researchers told the meeting in Seattle, the first step to understanding the rhizosphere is therefore to simplify it.