For 31 years, the North American Symbiotic Nitrogen Fixation Conference (for- merly Rhizobium Conference) has been a forum for scientists and graduate students to discuss their research advances, extending from basic aspects to agricultural appli- cations, and dealing with topics ranging from bacterial genetics and metabolism to plant genetics and physiology. Nitrogen fixation, being a major life-supporting process on this planet, has attracted the interest of researchers for more than one century. Nitrogen fixation is responsible for the conversion of "inert" dinitrogen (N ) gas from the...