Leaf proteomics of sugarcane inoculated with growth-promoting rhizobacterium and fertilized with molybdenum.

Background and Aims: Gene regulation and proteome response can identify how the micronutrient molybdenum (Mo) and plant growth-promoting rhizobacteria (PGPR) alter the physiological mechanisms of nitrogen metabolism in sugarcane. This work aimed to identify differentially accumulated proteins in sugarcane treated with Mo associated with nitrogen (N), and inoculated with PGPR. Methods: The experiment was carried out in the field and the treatments consisted of two sugarcane varieties (RB92579 and RB867515) submitted to doses of nitrogen and molybdenum, and inoculated with Stenotrophomonas sp. Results: In the RB92579 variety, treatments with application of 80 kg N ha−1 and its association with Mo (80 kg N ha−1 + 0.2 kg Mo ha−1) were selected as they had the highest biomass production. For the RB867515 variety, the treatments selected were 80 kg N ha−1, as it presents higher biomass production and its association with bacterial inoculation (80 kg N ha−1 + Stenotrophomonas sp.), as it has lower biomass production. Conclusion: It is concluded that Mo acts in key processes in sugarcane metabolism, such as photosynthesis and control of biotic and abiotic stress, that promote plant growth, and that the rhizobacterium Stenotrophomonas sp. should not be used for inoculation of the sugarcane variety (RB867515) due to a possible imbalance in the photosynthesis/photorespiration ratio, which may have resulted in less development of the aerial part of the plants when fertilized with nitrogen. [ABSTRACT FROM AUTHOR]