DROUGHT STRESS MITIGATION AND SOIL MICROBIOTA IN COMMON BEAN INOCULATED AND COINOCULATED WITH Bacillus aryabhattai AND Rhizobium tropici

• Grant number: 23/15893-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: April 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Juliano Carlos Calonego
• Grantee: Júlia Ribeiro Barbosa Soares
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated scholarship(s): 24/08617-1 - SOIL MICROBIAL COMMUNITY RELATED TO BIOLOGICAL NITROGEN FIXATION IN AN AREA WITH COMMON BEANS UNDER LOW WATER DEFICIT AND INOCULATION WITH Priestia aryabhattai AND Rhizobium tropici., BE.EP.IC

Abstract

In agriculture, the commercial use of beneficial microorganisms has grown in recent years. Some species of microorganisms already have well-known functions and are used on a larger scale, as is the case of microorganisms of the genus Rhizobium and Bradyrhizobium, which are soil bacteria capable of fixing atmospheric N in a symbiosis process with leguminous plants. Other microorganisms, such as some species of the genus Bacillus, are effective as plant growth promoters and biotic and abiotic stress mitigation, as is the case with B. aryabhattai as drought stress mitigation. However, there is little information about the effects of co-inoculation with these microorganisms, both on plant development and on the interaction with soil microbiota. In this context, the cultivation of bean [Phaseolus vulgaris (L.)] needs attention, since, in the winter harvest, its growth is only viable under irrigation. Therefore, this work aims to evaluate the effects of inoculation of B. aryabhattai alone or in association with Rhizobium tropici on the performance of the bean crop and the soil microbial community. The experiment will be conducted in a distroferric Red Latosol soil, during the 2024 winter harvest, in the experimental area of the Lageado Experimental Farm - UNESP, in Botucatu-SP. The experimental design will be randomized blocks, in a 2x4 factorial scheme, with four replications, two irrigation managements, and four bio-input combinations. Irrigation management will consist of (I) full irrigation, which consists of applying 100% of the crop's water needs throughout its growth cycle, and (II) continuous deficit irrigation with the supply of 50% of the crop's water needs during its entire cycle. The bio input factor will consist of the following treatments: (I) inoculation with B. aryabhattai, (II) inoculation with R. tropici, (III) inoculation with B. aryabhattai + R. tropici, and (IV) fertilization with mineral nitrogen (via application of urea at the recommended dose). At the stage of full flowering of the beans (R6), soil will be collected from the rhizospheric region to a depth of 0.10 m to evaluate the microbiological parameters of the soil (carbon and nitrogen of microbial biomass, basal respiration, metabolic and microbial quotient, enzyme activity acid phosphatase, arisulfatase, ²-glucosidase, and dehydrogenase) and for molecular assessment of soil microbial communities. In this phenological phase, the root development of the bean plant will also be evaluated at soil depths of 0.00 - 0.10, 0.10 - 0.20, and 0.20 - 0.40 m. At the end of the crop cycle, production components and grain productivity will be evaluated. The data will be subjected to analysis of variance using the F test and the means compared using the LSD t-test (pd0.05). The results of the molecular analyses will be subjected to multivariate and bioinformatics analysis.