Antagonistic and Competitive Dynamics Detected in vitro Between Sagebrush-Associated Microbes
Additional Funding Sources
The Bridges to Baccalaureate program is supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award No. R25GM123927.
Presentation Date
7-2022
Abstract
Plant leaf surfaces host abundant and diverse communities of microbial organisms that influence plant health and function. The interactions between species of a plant’s microbiome, often via antimicrobial metabolites, impact community structure and host-microbe dynamics. These metabolites can be isolated and harnessed for biocontrol or medicinal applications. To date, no studies have investigated interactions between microbes isolated from the leaves of sagebrush (Artemisia tridentate). In this study, we selected three previously isolated microbes from sagebrush leaves to determine their interactive properties when co-cultured in vitro: Aureobasidium pullulans, Bacillus amyloliquefaciens, and Cladosporium herbarum. These microbes were chosen based on known antimicrobial or phytopathogenic properties. In order to examine microbial interactions, we plated six replicates of cultures containing all three species, six replicates each of three pairwise cultures, and monocultures as controls. We photographed cultures for ten days and observed morphology, growth patterns, and signs of antagonism for all microbes. Total growth in surface area of the microbial colonies was measured in ImageJ. Statistical analysis conducted in R revealed significantly inhibited growth of C. herbarum in all co-cultures when compared to the control, while A. pullulans growth was only inhibited in co-cultures with B. amyloliquefaciens, and no significant reduction in growth was found for B. amyloliquefaciens in any co-culture. We observed visible zones of inhibition in co-cultures of B. amyloliquefaciens with C. herbarum and A. pullulans with C. herbarum. Co-cultured microbes also exhibited altered morphology when compared to controls. These results support the presence of competitive and antagonistic dynamics between these sagebrush-associated microbes. Future work examining metabolites produced in monocultures vs. co-cultures will isolate the mechanism driving growth inhibition. From enhanced crop performance to potential novel antibiotic therapies, increasing our understanding of microbial interactions opens the door for myriad real-world applications in agriculture, ecosystem management, and medicine.
Antagonistic and Competitive Dynamics Detected in vitro Between Sagebrush-Associated Microbes
Plant leaf surfaces host abundant and diverse communities of microbial organisms that influence plant health and function. The interactions between species of a plant’s microbiome, often via antimicrobial metabolites, impact community structure and host-microbe dynamics. These metabolites can be isolated and harnessed for biocontrol or medicinal applications. To date, no studies have investigated interactions between microbes isolated from the leaves of sagebrush (Artemisia tridentate). In this study, we selected three previously isolated microbes from sagebrush leaves to determine their interactive properties when co-cultured in vitro: Aureobasidium pullulans, Bacillus amyloliquefaciens, and Cladosporium herbarum. These microbes were chosen based on known antimicrobial or phytopathogenic properties. In order to examine microbial interactions, we plated six replicates of cultures containing all three species, six replicates each of three pairwise cultures, and monocultures as controls. We photographed cultures for ten days and observed morphology, growth patterns, and signs of antagonism for all microbes. Total growth in surface area of the microbial colonies was measured in ImageJ. Statistical analysis conducted in R revealed significantly inhibited growth of C. herbarum in all co-cultures when compared to the control, while A. pullulans growth was only inhibited in co-cultures with B. amyloliquefaciens, and no significant reduction in growth was found for B. amyloliquefaciens in any co-culture. We observed visible zones of inhibition in co-cultures of B. amyloliquefaciens with C. herbarum and A. pullulans with C. herbarum. Co-cultured microbes also exhibited altered morphology when compared to controls. These results support the presence of competitive and antagonistic dynamics between these sagebrush-associated microbes. Future work examining metabolites produced in monocultures vs. co-cultures will isolate the mechanism driving growth inhibition. From enhanced crop performance to potential novel antibiotic therapies, increasing our understanding of microbial interactions opens the door for myriad real-world applications in agriculture, ecosystem management, and medicine.