Bioprospecting Fluorescent Pseudomonas from the Brazilian Amazon for the Biocontrol of Signal Grass Foliar Blight

Author(s)

Vicentini, Samara Nunes Campos ; de Carvalho, Giselle ; Krug, Loane Dantas ; Nunes, Tiago Calves ; da Silva, Abimael Gomes ; Moreira, Silvino Intra ; Goncalves, Lucas Matheus de Deus Paes ; Silva, Tatiane Carla ; Ceresini, Paulo Cezar

• Document type: Journal article
• Source: AGRONOMY-BASEL; v. 12, n. 6, p. 15-pg., 2022-06-01.

Abstract

Biological control is considered the only viable integrated disease management practice for controlling the widely distributed and destructive foliar blight and sudden death disease caused by the fungus Rhizoctonia solani AG-1 IA on signal grass (Urochloa brizantha) pastures. Since major signal grass varieties are highly susceptible and fungicide sprays are not labeled for grass pasture cropping systems, biological control is sought as an alternative for managing this fungal disease. In this study, 24 fluorescent Pseudomonas isolates obtained from naturally suppressive soils from the Amazon biome were bio-prospected for their role as biocontrol agents against R. solani AG-1 IA. Based on in vitro antagonism, three isolates (Amana, Poti, and Yara) were selected for further in vivo assays. Multilocus phylogenetic analysis indicated that Amana and Yara were grouped into the Pseudomonas putida group while Poti was grouped into the Pseudomonas asplenii group, and could well constitute a new Pseudomonas species. For in vivo biocontrol assays, the biocontrol agents were applied either via seed-treatment or via foliar spray. All three isolates produced siderophores and solubilized phosphate, while Amana and Poti showed protease and chitinase in vitro activity. Foliar application of P. putida Amana from Amazonian suppressive soils resulted in a significant reduction of the foliar blight disease severity on signal grass. We discuss further steps for the development and labeling of Pseudomonas-based biofungicides for managing the foliar blight disease on signal grass pastures in Brazil. (AU)

• FAPESP's process: 17/03403-0 - Bioprospecting of fluorescent bacteria of the genus Pseudomonas in the biocontrol of the foliar blight of signal grass (Urochloa brizantha)
• Grantee: Samara Nunes Campos Vicentini
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 11/50150-3 - The origin of the emerging populations of the Brachiaria collar rot pathogen (Rhizoctonia solani AG-1 IA) in the Amazon and its potential for adaptation to another Brazilian agroecosystem
• Grantee: Paulo Cezar Ceresini
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 11/23050-8 - The origin of the emerging populations of the Brachiaria collar rot pathogen (Rhizoctonia solani AG-1 IA) in the Amazon and its potential for adaptation to another Brazilian agroecosystem
• Grantee: Edisson Chavarro Mesa
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/11944-0 - Population genetic structure of Rhizoctonia oryzae-sativae from rice in the Paraíba Valley, SP, and adaptive potential of the pathogen to Brachiaria.
• Grantee: Danilo Augusto dos Santos Pereira
• Support Opportunities: Scholarships in Brazil - Master