Nitrogen is required for plant growth, and is a significant input in terms of cost and environmental impact. While plants are literally surrounded by nitrogen, it is present in the atmosphere in an unusable form. Some plants (like legumes) have the ability to fix nitrogen, converting it from a gas into a form the plant can use. The idea of somehow moving this important trait from legumes (or microbes) to grain crops has long been considered a holy grail of plant biotechnology. However, the problem is much more complex, and after decades of research it has not been possible. But a land race of maize deep in the heart of corn’s domestication region, selected and cultivated by Indigenous People, may have solved this problem.
Researchers, led by Dr. Alan Bennett at UC-Davis, identified this type of corn that produces aerial roots that exude a clear mucilage. This carbohydrate-dense liquid hosts nitrogen-fixing bacteria that render atmospheric nitrogen usable by the plant. The hope is that the study of the genes that control the plant’s association with the microbes, and study of the microbial communities, may bring about new technologies to help crop plants be less dependent on supplied nitrogen.