| Congresso Brasileiro de Microbiologia 2023 | Resumo: 279-1 | ||||
Resumo:Eucalyptus genus comprises over 700 species that are mostly relevant for the wood industry, especially to produce firewood, charcoal, cellulose and fiber-based materials. However, bacterial wilt disease, caused by the phytopathogenic bacterium Ralstonia solanacearum, has significantly impacted eucalyptus forestry and there is still no efficient method of controlling it. A promising alternative against bacterial wilt is the usage of endophytic bacteriafound in the eucalyptus roots for the biocontrol of this disease. In order to explore this approach this work aims to 1) perform in vitro antagonism tests with previously isolated endophytes from the eucalyptus roots against R. solanacearum; 2) identify molecularly the endophytes that present antagonistic activity against R. solanacearum in vitro through 16S rRNA sequencing; 3) perform in vivo experiments to evaluate the biocontrol potential of the endophytes against R. solanacearum in eucalyptus seedlings; and 4) analyze the impact of the microbial inoculation on the roots’ microbiome of eucalyptus through 16S rRNA gene metabarcoding. A total of sixtynine endophytes were tested against R. solanacearum by the spot-on-lawn assay on the CPG medium, incubated for 48 hours at 28°C. Thirty endophytes showed positive results, as they produced a halo of inhibition against R. solanacearum and were molecularly identified through 16S rRNA gene sequencing using the primers 907R, 785F and 351F to obtain ~1500bp fragments. Three strains were the most efficient against the phytopathogen's growth, as they produced halo diameters of inhibition of 38.8, 33.8 and 31.7 mm, and were identified as belonging to the genera Enterobacter, Streptomyces and Bacillus, respectively. Next, those endophytes will be tested on eucalyptus seedlings in a germination chamber in vivo experiment. The impact of inoculation on the bacterial community of the seedlings will be assessed by the evaluation of the occurrence and severity of the wilt disease, and also using 16S rRNA gene metabarcoding to understand microbial community dynamics. Hopefully, this study will contribute to a sustainable management of a healthy eucalyptus forest, enabling it to continue
to serve as a home to endangered species and as a resource for the industries. Palavras-chave: Antagonismo, Biocontrole, Eucalyptus, Ralstonia solanacearum, Murcha Agência de fomento:Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) | |||||