Submitted to: FEMS Microbiology Letters
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/19/2013
Publication Date: 9/10/2013
Citation: Ismail, Y., McCormick, S.P., Hijri, M. 2013. The arbuscular mycorrhizal fungus, Glomus irregulare, controls the mycotoxin production of Fusarium sambucinum in the pathogenesis of potato. FEMS Microbiology Letters. 348(1):46-51. Interpretive Summary: In this research, we determined that a mycorrhizal fungus, Glomus irregulare, can limit the production of a trichothecene mycotoxin by Fusarium sambucinum-infected potato tubers. Mycorrhizal fungi form symbioses with plant roots that improve mineral uptake and protect the plants from soil-borne pathogens. F. sambucinum is the major cause worldwide of dry rot of potato tubers both in the field and in storage. The present research found that G. irregulare limited toxin accumulation in the roots and tubers of F. sambucinum-infected plants. This research shows the potential of using mycorrhizal fungi to reduce mycotoxin contamination of potato crops.
Technical Abstract: Trichothecenes are an important family of mycotoxins produced by several species of the genus Fusarium. These fungi cause serious disease on infected plants and postharvest storage of crops and the toxins can cause health problems for humans and animals. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens and most rely on chemicals therefore creating subsequent problems of chemical resistance. We tested the impact of the symbiotic arbuscular mycorrhizal fungus (AMF) Glomus irregulare on a trichothecene-producing strain of Fusarium sambucinum isolated from naturally infected potato plants. Using dual in vitro cultures, we showed that G. irregulare inhibited the growth of F. sambucinum and, significantly reduced the production of the trichothecene 4, 15-diacetoxyscirpenol (DAS). Furthermore, using AMF-colonized potato plants infected with F. sambucinum, we found that the AMF treatment inhibited the production of DAS in roots and tubers. Thus, in addition to the known beneficial effect of mycorrhizal symbiosis on plant growth, we found that AMF controlled the growth of a virulent fungal pathogen and reduced production of a mycotoxin. This previously undescribed, biological control of Fusarium mycotoxin production by G. irregulare, has potential implications for improved potato crop production and food safety.