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| Author(s): |
Ana Gabriele Barbosa Casteliani
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2016-12-01 |
| Examining board members: |
Itamar Soares de Melo;
Gisele Abigail Montan Torres
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| Advisor: | Itamar Soares de Melo |
| Abstract | |
Wheat (Triticum aestivum) is the second largest crop in the world and Brazil is in the second position in the ranking of production in South America. However, its productivity can be limited due to the occurrence of diseases like wheat blast, caused by the fungus Pyricularia grisea and the disease called Fusarium head blight (FHB), caused by the fungus Fusarium graminearum. Bacterial populations associated to wheat rhizosphere may have potential to act as biological control agents of different plant pathogens. In this context, this research aimed to look at wheat rhizosphere bacterial community and the pursuit of microorganisms with potential for the biological control of wheat blast and FHB. Given this, in order to study wheat bacterial communities, data collection was carried out in two different regions in Brazil, returning 606 bacterial and actinomycetes isolates from wheat rhizosphere and bulk soil. Among these,, 16 strains revealed antagonistic potential against both plant pathogens Pyricularia grisea and Fusarium graminearum, with different percentages of inhibition. Ten strains were selected out of the 16 and showed similarity with the family Streptomycetaceae, whereas four of them displayed a low similarity, requiring a deeper analysis and might indicate new species. Four isolates showed similarity with the family Bacillaceae and two with the family Paenibacillaceae. On the assessment of production of secondary metabolites with inhibitory effects, only ten strains were positive, but more detailed studies are necessary to confirm this mechanism. The analysis of bacterial diversity revealed a larger abundance of the phylum Actinobacteria, followed by the phylum Proteobacteria and Acidobacteria in both areas, however, the phylum Acidobacteria revealed more variation among its classes when both araes were compared, indicating a selection of the community according to the cultivar and the developmental stage. Wheat bacterial community presents microorganism with inhibition potential against fungi responsible for wheat blast and FHB, yet the effect of such strains should be investigated closely under field conditions. The understanding of bacterial communities associated to wheat may be seen as an important tool to help in the search for antagonists. (AU) | |
| FAPESP's process: | 14/07382-9 - Study of rhizosphere bacterial communities of Triticum aestivum L. with antagonist potential against wheat blast caused by Magnaporthe grisea |
| Grantee: | Ana Gabriele Barbosa Casteliani |
| Support Opportunities: | Scholarships in Brazil - Master |