To fuel and feed the planet for the future, we need new approaches. Biofuels derived from plants are an attractive alternative energy source, but many biofuel feedstock crops are in direct competition with food crops for agricultural resources such as land, water, and fertilizers. Present research is looking for ways to improve the growth of biofuel feedstock plants on land that cannot be economically used for food production. Poplar is a model species for biofuel production, in part because of its ability to grow on marginal soils unsuitable for food crops. Previous studies have shown that the bacterium Enterobacter increases poplar growth by as much as 40 percent. The scientists have identified an extended set of genes that help Enterobacter establish itself in this niche. The studies also revealed remarkable interactions between the microbe and its host that help the plant survive and thrive. One of the most remarkable things about this association is that the production of these plant-growth-promoting phytohormones is directly dependent on the presence of plant-synthesized sugars, such as sucrose, in the growth medium. So the plant makes sugar that helps the bacteria grow and make phytohormones and other compounds that help the plants grow better and healthier. This approach can be applied to improve plant productivity for sustainable agriculture, bioenergy feedstock production on marginal lands, or to fight desertification of arid areas.