Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Fenstermacher, Kristi [1].

Fusarium oxysporum f.sp. lycopersici and tomato: small chromosomes usually define friend vs. foe.

Fusarium oxysporum f.sp. lycopersici is a tomato wilt pathogen that is notoriously difficult to get rid of once it has infested soil, and it is capable of causing disease on all cultivars of tomato (L. esculentum) that have not been bred for resistance. Like several other filamentous fungi, Fusarium has been shown to contain small, conditionally dispensable chromosomes harboring clusters of pathogenicity genes that can be horizontally transferred—converting a closely-relatedly non-pathogen into a pathogen. This study sampled a variety of tomato growing sites, both with Fusarium wilt symptoms and without to get a better picture of Fusarium communities in various systems. Multiple soil and plant tissue (if available) samples were collected from each site and screened for Fusarium species in an attempt to get a better picture of isolate diversity within, between, and across sites. Results confirm previous reports of higher diversity at non-diseased sites, but reveal two genotypes (based on elongation factor sequences) of pathogen at multiple disease sites infested with pathogenic races 2 and 3. The pathogenic isolates present at each site still appear to be clonal isolates that humans have dispersed far and wide with the host, but 3 highly diseased sites sampled have two distinct genotypes present with the same pathogenicity genes, and most sites contained non-pathogenic isolates of the same genotype. Further work is underway to determine the presence of small chromosomes, the implications of having two pathogen genotypes, and the potential for transfer to non-pathogenic relatives.

1 - The Pennsylvania State University, Plant Pathology and Environmental Microbiology, 120 Buckhout Lab, University Park, Pa, 16802, United States

Keywords:
Fusarium.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PPA027
Abstract ID:1309
Candidate for Awards:MSA Best Poster Presentation Award by a Graduate Student