Oral Technical Session: Biology of Pathogens

142-O

Hyphal growth through soil and colonization of organic matter by Fusarium proliferatum.
A. REYES GAIGE (1), J. Stack (1)
(1) Department of Plant Pathology, Kansas State University, Manhattan, KS, U.S.A.

Fusarium proliferatum is a broad host-range pathogen and among the most common corn pathogens globally. It can be endophytic in corn seed, making it a high risk of importing it in corn or other grains. The ability of Fusarium proliferatum to colonize cured, non-viable maize seeds in unsterile Shellabarger sandy loam soil was investigated. A green fluorescent (GFP), hygromycin resistant, F. proliferatum transformant (Fp-G2) was developed to provide markers to track the fungus. Maize seeds were heat-killed in a 75°C water bath for 20 minutes, and re-colonized with Fp-G2 in a 1*106 spores/ml suspension overnight (16 hours). The re-colonized seeds were added to soil at 25°C in constant moisture conditions together with cured, non-viable maize seeds (used as baits), placed at different distances (0cm, 0.5cm, 1cm and 1.5cm). Controls included, non-viable corn seeds that were re-colonized with wild type F. proliferatum. After 14 days, the bait seeds were retrieved from soil and plated on Nash-Snyder medium with 1µl/ml hygromycin. Fp-G2 grew at least 1.5cm through non-sterile soil and colonized the bait seeds at all the distances tested. In addition to pathogenic and endophytic potential, F. proliferatum may have an active soil inhabitant phase in its life history.