New inoculate associating ciliated protists and plant growth promoting bacteria in crops of economic interest in Brazil

Abstract

The growing concern with the environment has stimulated the companies of agricultural inputs to develop products with biological basis, both for the area of plant health and for the area of nutrition and plant physiology. The latter areas are optimized when the benefits from interspecific relationships of organisms inhabiting the rhizosphere are enhanced. This proposal seeks to assess the technical and scientific feasibility of using ciliated protist and growth promoting bacteria in the rhizosphere (PGPR) to stimulate plant growth. In the near future, it aims to commercialize an inoculum (new product) containing the predator-prey complex (ciliated protists/bacteria), which will act in the rhizosphere environment of commercial plants (corn and soybean), potentiating the microbial link. For this, in phase 1 of PIPE, the research plan is based mainly on (i) the establishment, maintenance of crops, morphological and molecular characterization (18S rDNA) of previously selected ciliated protists (Colpoda spp.); and (ii) evaluation of the agronomic potential of selected species of Colpoda together with the plant growth promoting bacteria, Azospirillum brasiliense, in soybean and corn crops. The synergetic effects of the interaction between the rhizo-bacteria and the ciliated protists promote mutual benefits, mainly for the plants, which increase their survival in terms of nutritional aspect. Ciliated protists optimize the mineralization of nutrients in the rhizosphere environment through predatory activity, releasing 30 to 50% of the immobilized nitrogen in microbial biomass and can contribute to the fertilization of agricultural soil by transporting bacteria resistant to intracellular digestion to the plant roots. In addition to ensuring the survival and efficiency of PGPR in the rhizosphere environment. Therefore, a technology of this impact is expected to increase grain productivity in a collapsed soil environment by 5 to 10% due to yield gap due to environmental stress and impediment to root development. The proposed ciliated protist/bacteria inoculum is unprecedented and has great commercial potential due to the biology of the ciliates and the proposed bacterial species and the importance of agricultural crops in Brazil. (AU)