P-372 - Putative transcription factors modulate growth in Dickeya spp.

Tuesday, August 5, 2025

10:15 AM - 11:00 AM HST

Location: Exhibit Hall 3

Presenting Author(s)

LR

Lindsey E. Reid (she/her/hers)

Plant Pathology and Plant-Microbe Biology, SIPS, Cornell University
Ithaca, New York, United States

Author(s)

TH

Tyler Helmann

United States Department of Agriculture - Agricultural Research Service
Ithaca, New York, United States
PS

Paul Stodghill

United States Department of Agriculture - Agricultural Research Service; Plant Pathology and Plant-Microbe Biology, SIPS, Cornell University
Ithaca, New York, United States
MF

Melanie Filiatrault

United States Department of Agriculture - Agricultural Research Service; Plant Pathology and Plant-Microbe Biology, SIPS, Cornell University
Ithaca, New York, United States

Abstract Text: Dickeya spp. are adaptable bacterial plant pathogens and infect diverse tissue types across a broad range of host plants. Dickeya spp. habituate to a range of nutrient, chemical, and osmotic gradients. Growth rates of Dickeya in potato alone vary as cells adapt to diverse conditions throughout potato seeding, vegetative growth, and storage. However, the mechanisms Dickeya use to modulate growth are predominantly unexplored. Here, a high throughput transposon insertion sequencing (Tn-Seq) experiment in three strains of Dickeya (encompassing two species) identified an ortholog group of putative transcription factors (TFs) important for growth in planta. To characterize the TFs, targeted knockout mutants were constructed. We hypothesized that TF loss would produce a consistent phenotype across the ortholog group. However, in vitro and in planta growth assays revealed differences between mutant and wild-type in some strains, but not others. Phenotypes differed between species, which may be expected, and between strains, which is noteworthy, as intraspecies variation in transcriptional regulation is understudied. To determine the specific regions of DNA that the putative TFs bind, fusion proteins were constructed and constitutively expressed in strains lacking TFs. Chromatin immunoprecipitation of the FLAG-tagged proteins was performed. Our results begin to define new mechanisms of growth modulation in Dickeya. By illuminating variation within a species, our findings imply functional diversity of conserved genes and regulatory system modification due to strain history and niche.