Congresso Brasileiro de Microbiologia 2023

Congresso Brasileiro de Microbiologia 2023

Resumo: 839-2

839-2

BACTERIAL SCREENING FOR BIOCONTROL OF THE BEAN DRY ROOT ROT CAUSAL AGENT

Autores:

Mikaely Sousa Marins (UFLA - UNIVERSIDADE FEDERAL DE LAVRAS , EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária - Milho e Sorgo) ; Janaína Martins de Souza (UFLA - UNIVERSIDADE FEDERAL DE LAVRAS ) ; José Edson Fontes Figueiredo (EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária - Milho e Sorgo) ; Ludwig Heinrich Pfenning (UFLA - UNIVERSIDADE FEDERAL DE LAVRAS ) ; Luciano Viana Cota (EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária - Milho e Sorgo) ; Christiane Abreu de Oliveira-paiva (EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária - Milho e Sorgo)

Resumo:

Dry root rot of common bean (Phaseolus vulgaris L.) is a soil-borne disease caused by the Fusarium solani species complex (FFSC). The symptoms are rotting from the main root extending to the hypocotyl, yellowing, and reducing plant growth. Yield losses are frequently attributed to this disease, and fungicides are used in the management. There is a strong effort to reduce both the environmental risks associated with agrochemicals and their costs by adopting sustainable practices in crop production. Biological control offers a viable and complementary alternative to fungicides and managing fungicide resistance. This study tested in vitro the ability of Bacillus velezensis (CNPMS22 and CT02) and Pseudomonas spp. (IPR45) to inhibit the growth of F. solani strain CML4246. Five millimeter-diameter discs of CML4246 were removed from the edge of colonies of 7-day-old PDA cultures, placed on one side of Petri dishes containing PDA and incubated in BOD for two days at 25 °C with constant light. Afterward, the bacterial isolates were streaked 3 cm away from the fungal mycelium. The control was only CML4246 inoculum. The mycelial growth was evaluated after 12 days of incubation in BOD at 25 °C with constant light, and then the percentage of inhibition was estimated. While in the control plates, mycelial growth covered the entire surface area of the plate, B. velezensis (CNPMS22 and CT02) inhibited mycelial growth by 43.7% and 39.6%, respectively. Pseudomonas spp. strain inhibited the CML4246 growth by 53.2%. Moreover, the dual culture of CML4246 and Pseudomonas spp. showed a change in the mycelium color from beige to orange. The results highlight that the evaluated strains exhibit mechanisms of action against CML4246, making them potential biocontrol agents for in-planta tests. The inhibition mechanism includes the action of bacterial secondary metabolites and competition for space and nutrients.

Palavras-chave:

Bacillus, biological control, Fusarium solani, Pseudomonas, root rot

Agência de fomento:

CAPES. CNPq. Embrapa Milho e Sorgo. Finep.