Scientists from the University of Kentucky led by Professor Hongyan Zhu have discovered a more efficient way for legumes to fix nitrogen. Zhu and his team found two antimicrobial peptides in the legume Medicago truncatula that kill certain rhizobial bacteria as nitrogen fixation begins. M. truncatula is closely related to alfalfa, a forage legume.
Zhu believes that the antimicrobial proteins originally functioned to kill bacteria as they entered the plant, but have evolved to manipulate certain bacteria to start the nitrogen fixation process. Bacteria that do not tolerate the peptides die almost immediately. “This finding offers scientists a strategy to improve nitrogen fixation in legumes by selecting or manipulating these genes to accept more bacteria. This could potentially allow legumes to fix more nitrogen,” Zhu said. Read more