METHOD FOR IMPROVING THE YIELD AND TOLERANCE TO ABIOTIC STRESS IN LEGUMINOUS AND GRASS INOCULATED WITH BACTERIA HAVING AND INCREASED TREHALOSE CONTENT.

摘要

Some of the most important goals in agriculture are improving the tolerance to abiotic stress (drought, salinity, cold, heat) and the crop yield. Described are novel methods for increasing the tolerance to drought and the yield in leguminous and grass crops by the inoculation with plant-growth promoting bacteria (PGPB) having an increased trehalose content, i.e., by means of the overexpression of a gene encoding for a trehalose-6-phosphate synthase (TPS) in said PGPB. As a demonstration, Phaseolus vulgaris plants (common bean) were cultivated and inoculated with rhizobia for overexpressing the TPS, thus showing that said plants have more nodules with an increased biomass and a higher nitrogenase activity. Plants subjected to drought totally recovered while plants inoculated with wild-type bacteria withered and died. Furthermore, bean plants inoculated with rhizobia overexpressing the OtsA gene, and growth under constant irrigation had an increase of more than 50% in the grain yield an d plant biomass. Therefore, the genetic manipulation of the trehalose metabolism in PGPB, particularly the rhizobia, has a great impact on crops since it is the solution to increase the growth and biomass in plants, as well as the tolerance to abiotic stress thereof.