EFFECTS OF BENEFICIAL MICROBES ON PLANT-VIRUS-VECTOR INTERACTIONS INVOLVING SOYBEAN
Open Access
- Author:
- Pulido Barrios, Hannier
- Graduate Program:
- Biology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 04, 2016
- Committee Members:
- Mark Mescher, Dissertation Advisor/Co-Advisor
Andrew Stephenson, Committee Chair/Co-Chair
Consuelo de Moraes, Committee Member
John Frazier Tooker, Committee Member
Cristina Rosa, Outside Member
Naomi S Altman, Committee Member - Keywords:
- Beneficial rhizobacteria
multi-trophic interactions
parasitoid wasps
metabolomics
transcriptomics
VOCs
plant volatiles
herbivory - Abstract:
- Soil-borne microorganisms can have significant effects on aboveground interactions between plants and other organisms. For example, association with some non-pathogenic soil microbes stimulates plants and modify volatile emissions, defense capability, nutritional quality and host gene expression. Likewise, detrimental microorganisms like some plant viruses, can also change plant phenotype in ways that influence transmission. As a result, microbe-plant associations may indirectly modify the interactions among plants, herbivorous insects and parasitoids. While the relevance of microorganisms on the ecology of plant mediated interactions has been widely studied, research that integrates ecological and molecular approaches involved in these multi-trophic interactions are still limited. The general goal of this research is to understand how microbial associations influences plant-pathogen and plant-insect interactions in soybean. To achieve this goal, I use a combination of chemical analysis, gene transcriptomics and insect behavior linked with state-of-the-art data mining techniques. We examined how two species of beneficial rhizobacteria—the plant growth promoter rhizobacteria (PGPR) species Delftia acidovorans, which lives in the rhizosphere in close association with root surfaces, and the nitrogen-fixing Bradyrhizobium japonicum—influence the interactions of soybean plants (Glycine max cultivar Williams 82) with the herbivorous beetle Epilachna varivestis, which vectors an economically important pathogen of cultivated soybean, Bean pod mottle virus (BPMV) and with the parasitoid wasp Pediobius foveolatus. In a multi-factorial experiment, we characterized the volatile organic compounds (VOC), the primary and secondary leaf metabolites and the transcriptome produced by soybean plants in the presence/absence of the two rhizobacteria and with or without infection by BPMV. Our results indicate that BPMV infection and inoculation with beneficial rhizobacteria cause dramatic changes in metabolites and genes related with plant nutrition and defense, with significant consequences for soybean interactions with an important herbivore and virus vector.