Interactions of arbuscular mycorrhizal fungi with pathogens:

The role of glomeromycetes in plant-mirobe interaction has gained increased attention in recent years. In particular, their interactions of with plant-pathogenes. It is well documented in many studies that glomeromycetes play a role in controlling soilborn pathgens and  several mechanisms have been proposed to explain their biocontrol activites (Filion et al., 1999; St-Arnaud and Vujanovic, 2007; Pozo et al., 2009; Wehner et al., 2009, Ismal. et al. 2011, Ismail and Hijri 2012, Ismail et al. 2013). These mechanisms have been summarized by Wehner et al. (2009) as; i) Improved nutrient status of the host plant; ii) Competitive interactions with pathogenic fungi; iii) Anatomical or architectural changes in the root system; iv) Microbial community changes in the rhizosphere; and v) Induction of plant defense mechanisms.

The objective of this project is to understand the interactions of the arbuscular mycorrhizal fungus G. irregulare with mycotoxin-producing fungi. Youssef Ismail during his PhD studies, isolated and characterized 16 fungal strains belonging to the genus Fusarium from naturally infected potato plants in Montreal region and confirmed that nine isolates produced trichothecenes (trichothecenes are a large group of sesquiterpenes that are inhibitors of eukaryotic protein synthesis. They cause health problems for humans and animals that consume fungus-infected agricultural products as well as for plants). One particular isolate, F. sambucinum strain T5 was extremely aggressive for potato plants by inducing a rapid wilting and yellowing that resulted in plant death. This strain was therefore selected for further studies as a model.

 

References:

• Filion M, St-Arnaud M,  Fortin JA. 1999 New Phytologist 141: 525-533.

• Ismail Y, McCormick S, Hijri M. 2011 PloS one 6: e17990.

• Ismail Y and Hijri M 2012. Functional Plant Biology 39 (3):236-245.

• Ismail Y, McCormick S, Hijri M. 2013 FEMS Microbioly Letters, In press.

• Pozo, M.J., et al. 2009. Priming Plant Defence Against Pathogens by Arbuscular Mycorrhizal Fungi. In: Azcon-Aguilar, C., Barea, J.M., Gianinazzi, S., Gianinazzi-Pearson, V. (Eds.), Mycorrhizas – Functional Processes and Ecological Impact. Springer Verlag, Berlin, pp. 123–136.

• St-Arnaud and Vujanovic, 2007 Effect of the arbuscular mycorrhizal symbiosis on plant diseases and pests. pp. 67-122 In: Hamel, C. & Plenchette, C. (eds). Mycorrhizae in crop production. Haworth Food & Agricultural Products Press, Binghampton, NY.

• Wehner J, Antunes PM, Powell JR, Mazukatow J, Rillig MC, 2009 Pedobiologia (2009), doi:10.1016/j.pedobi.2009.10.002