Screening de bactérias com potencial para promoção de crescimento e antagonismo aos patógenos do arroz

Abstract

Beneficial microorganisms have been gaining prominence in the current agricultural scenario for increasing productivity and protecting crops against pathogens and pests. This study selected bacteria with potential for growth promotion. Bacteria from upland rice leaf isolates from the state of Pará were selected through antagonisms between rice pathogens (Magnaporthe oryzae, Bipolaris oryzae and Rhizoctonia solani), totaling 48 bacterial isolates. Two tests were performed: 1st Antagonism and subculture and maintenance of bacteria and 2nd Biochemical Tests. After mass selection of the isolates, 13 isolates (188F, 25F1, 43FB2, 250Fa, 25F, 11F, 19Fa, 240F, 34F, 36F1, 200Fa, 181Fa2 and 7Fa) were selected for biochemical characterization of phosphorus, potassium and zinc solubilization, hydrocyanic acid (HCN) production and nitrogen fixation. The collected data were subjected to analysis of variance and the means were compared by Tukey's test at 5% probability using SPSS software version 21.0. The results of this test led to 5 isolates of the 13 (240F, 34F, 36F1, 7Fa, 43Fb2) being selected, since they responded well to the biochemical tests. It was concluded that these isolates are capable of solubilizing phosphorus, potassium and zinc, and fixing nitrogen, thus improving root growth, regulating osmosis, hormonal development and increasing rice productivity.