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HHMI Gilliam Seminar Series: Assessment of viral influence on plant root colonization by plant growth promoting rhizobacteria

Dr. Jonelle Basso
Lawrence Berkeley National Laboratory | Postdoctoral Scholar, DOE Joint Genome Institute
Seminar date:
Monday, May 9, 2022 - 12:00 to 13:00
HCK 132

Beneficial members of the plant microbiome can increase nutrient availability for their hosts, protect their hosts against pathogens, and enhance host resilience against abiotic stress. While previous and ongoing studies of the rhizosphere microbiome have been critical for assessing the impact of specific plant-microbe interactions, their focus has overwhelmingly targeted bacterial and fungal members of the microbiome. Viruses are ubiquitous, outnumbering all other biological entities on the planet, yet they are remarkably understudied in the rhizosphere. Prior work from our group identified functional roles for hundreds of genes in a plant growth promoting rhizobacterium Pseudomonas simiae that are important for its colonization of the rhizosphere. Two of these genes that cause reduced fitness in the rhizosphere when mutated are components of a latent bacteriophage, and are present among three phage loci ranging in size from 15-65kbp. We observed significant differences in bacterial cell lysis and fluorescently stained populations upon mitomycin c induction and flow cytometry respectively, between induced and control cultures over a 24-hour period. Taken together, these findings suggest the possibility that bacteriophages are involved in modulating the ability of bacteria to colonize plants. The quantitative impact of these phage genes on root colonization and the molecular underpinnings of this presumptive plant-bacterial-phage interaction are currently being investigated.

Fields of interest: