The Fusarium oxysporum Species Complex (FOSC) comprises a wide diversity of plant pathogenic fungi, causing severe disease in a wide range of economically important crops including banana, cotton, melon, tomato and over 100 others. The group also contains nonpathogenic isolates, some of which have been studied as biological control agents against pathogenic F. oxysporum (Fo).
by Chyanna McGee
Previous research showed that asymptomatic tomato plants and soil from two Pennsylvania tomato fields harbored a highly diverse set of Fo genotypes. Two genotypes types were particularly frequent, representing 65% of all isolates. This raises the questions of whether genotype abundance is the result of the plant host influence on Fo soil populations, whether such genotypes represent clones, and whether they are seed transmitted.
I will approach these questions using a population perspective to provide insight into nonpathogenic FOSC dynamics that will add to the knowledge of FOSC biocontrol-pathogen interactions. A further goal is to better characterize the diversity of soil and endophytic populations in agroecosystems that will aid further studies of how these fungi interact with their host from the soil, to the seed, and into mature plants.
To address the plant host influence on soil Fo populations, I will monitor the abundance of nonpathogenic Fo in soil before and after cultivation of tomato. To address whether these common nonpathogenic Fo are potentially seedborne, Fo will be sampled from tomato seeds and typed using the Fusarium barcoding locus translation elongation factor 1-α (TEF) to determine the genotypic diversity of Fo in each sample population. Isolates that are found in high abundance will be sequenced at multiple loci to assess their clonality. The results of this work will contribute key insights regarding the adaptive nature of nonpathogenic Fo in the agroecology of tomato.
Source: Penn State