Fuente: WIPO "tomato" Herbaspirillum bacterial strains are engineered to express or overexpress one or more proteins and/or attenuate expression of or delete one or more genes involved in nitrogen fixation and its regulation. This enables the diazotrophic bacteria to secrete more ammonia. The engineered bacteria arc introduced to agricultural plants, or seeds for growing such, forming a symbiotic relationship that results in increased nitrogen availability to the plant and improved plant agronomic traits.