Researcher(s)
- Meyer Scholl, Plant Science, University of Delaware
Faculty Mentor(s)
- Harsh Bais, Plant and Soil Sciences, University of Delaware
Abstract
Other than natural disasters and climatological stressors, fungal phytopathogens are a major cause of crop losses worldwide. There has been a growing interest in finding alternatives to conventional chemical pesticides due to their downstream environmental impacts, and the ecological and biological functions of bacteria make them rich in potential as biocontrol agents. Streptomyces coelicolor is an actinobacteria known for the amount and diversity of its secondary metabolites – it is this production variety that inspires this project: investigating the antifungal potential of S. coelicolor, primarily through direct assays against Magnaporthe oryzae, Rhizoctonia solani, and Clarireedia jacksonii. Streptomyces and one of the three fungi were grown together on agar plates and observed daily to compare growth between treated and untreated plates. This is an ongoing project now entering the third round of plate assays, but so far there have been three main patterns: Rhizoctonia has not been inhibited by Streptomyces growth, nor has Clarireedia. Magnaporthe has consistently been displaying some kind of interactive effect with plated Streptomyces: the fungus hasn’t been growing over bacterial colonies, Streptomyces releases blue metabolites into the agar following fungal contact, and co-inoculated plates allowed to develop longer (considering both organisms grow slowly individually) have had rings of altered fungi around sites of bacterial-fungal contact. However, these Magnaporthe x Streptomyces plates, as well as any of the plates with bacteria given more time to grow, have exhibited strange growth at the bacterial colonies’ edges. The going theory is some kind of bacterial contamination (Bacillus suspected), but there is still Streptomyces present as indicated by color and colony formation. This probable-contamination makes it difficult to attribute fungal effects to coelicolor alone – a point for further troubleshooting – but it has also inspired a branching project where I run the assays with UD1022 (a B. subtilis strain).