In a growing population, producing enough food has become a challenge in the face of the increase in climate changes. Plants, as sessile organisms, developed countless mechanisms to better adapt to the environment and its fluctuations. One important way is through modulation of their body and their forms, by perceiving environmental stimulus, followed by activation of signaling cascades and gene expression responses, that end in an accurate control of plant growth. One of the best-reported outcomes of plant symbiosis with endophytic and associative beneficial bacteria is the promotion of plant growth by direct and indirect mechanisms, as well as increase in tolerance against biotic and abiotic stresses.
By using genomic approaches, our group has been studying sugarcane and maize genes involved in the establishment of a beneficial type of association with nitrogen-fixing bacteria. Integrated differential transcriptomes were generated, providing an overview of sugarcane and maize expression profiles during plant-bacteria association. Functional analyses of plant genes are being performed. The data suggest that an important control of the efficiency of the association is already set in the early stages of plant-bacterium recognition, when specific plant genotypes sense the environment and regulate several plant signaling pathways involved in microorganism recognition, plant defense, nitrogen metabolism and cell division controls. Several of the genetic controls and expression profiles might possibly be used as tools for optimization of plant growth and response to bioinoculants, presenting a sustainable alternative to the use of chemical fertilizers, with positive economical and environmental impacts on agriculture.