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- Title
Antibacterial And Growth Promoting Activity Of Bacillus Thuringiensis F14 Isolated From Rice Varieties.
- Authors
Barbosa-Garcias, Adrian; Pérez-Cordero, Alexander; Montes-Vergara, Donicer E.
- Abstract
The aim of this work was to isolate endophytic bacteria associated with roots, stems, leaves and panicles of rice varieties 2000, Tana, 473, 67 and to determine in vitro antimicrobial activity on Burkholderia glumae. The population density of endophytic bacteria was estimated by direct count on R2A medium. The antimicrobial activity of endophytic bacteria on B. glumae was determined by disc diffusion technique in King B culture media. Growth promoting capacity was determined by biological nitrogen fixation, phosphate solubilization, siderophore production. Extraction of microbial secondary metabolites was evaluated in vitro on B.glumae. Molecular identification of endophytic bacteria with antimicrobial activity was performed by sequencing technique from PCR products amplified with specific primers of eubacterial groups, bacteria with equal or higher percentage of inhibition were selected for DNA extraction and phylogenetic analysis. Differences between the population density (CFU/g tissue) of endophytic bacteria according to variety and tissue type were analyses by multifactorial ANOVA in the InfoStat programme. The multiple range test (Tukey) was also used to establish separate differences between communities of endophytic bacteria in relation to variety and type of colonized tissue. The multiple range test (Duncan) was also used to establish differences in inhibition percentages. A total of 107 isolates in the different rice varieties with the highest population density in variety 2000 and the lowest density in variety 67, the tissue with the highest colonization was the root. Of the isolates, 4 showed equal or higher in vitro antibacterial activity on B. glumae compared to the control, these also showed the ability to fix nitrogen, solubilize phosphate and produce siderophores. The sequencing results proved the identity of Bacillus thuringensis. It can be concluded that the population density of endophytic bacteria depends on the degree of susceptibility of the plant. In addition to this, the isolates showed an antagonistic effect on B.glumae which, in turn, have the ability to promote plant growth through phosphate solubilization, nitrogen fixation and siderophore production. Finally, the extraction of microbial secondary metabolites was not adequate, which was confirmed by in vitro evaluation giving a negative result.
- Subjects
ANTANANARIVO (Madagascar); RICE; BACILLUS thuringiensis; NITROGEN fixation; ENDOPHYTIC bacteria; MICROBIAL metabolites; METABOLITES
- Publication
Webology, 2022, Vol 19, Issue 6, p423
- ISSN
1735-188X
- Publication type
Article