Monitoring Fusarium complex mycelia replacement by mycopathogenic Sphaerodes using alcohol percentage test, qRT-PCR and HPLC

Abstract

The biotrophic mycoparasite-host interface and replacement remain poorly described, yet their understanding is important for effective biocontrol of Fusarium plant pathogens. Alcohol percentage test (APT) and real-time PCR quantification of DNA were employed to evaluate the efficiency of mycopathogenic Sphaerodes mycoparasitica mycelia to replace an array of pathogenic/toxigenic Fusaria in co-cultures. Shifts in Fusarium mycelial growth and hydrophobicity measured (APT) at the interaction zone with S. mycoparasitica indicated the degree of Fusarium mycelia replacement by the mycoparasite (P < 0.05); while qRT-PCR accurately detected DNA quantity changes in mycotoxigenic Fusarium graminearum 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) chemotypes challenged with S. mycoparasitica. Results from the HPLC experiments also demonstrated a considerable decrease in mycotoxin (DON, 3-ADON, 15-ADON, and ZEA) concentrations at the contact zone. Estimated shifts in the DNA quantity and mycotoxin production, assessed using qRT-PCR and HPLC respectively, correlated with an alteration in APT values, demonstrating the effectiveness of the mycoparasite in vivo. © 2012 Elsevier Ltd.