Comparison of Fusarium spp. composition between stressed and healthy Spartina spp. in Atlantic marshes in North and South America

ELMER, W.; DALEO, P.; ALBERTI, J.; IRIBARNE, O.

San Diego

Conferencia; 22nd biennial conference of the Coastal & Estuarine Research Federation; 2013

We sampled Spartina alterniflora in Connecticut, US and S. alterniflora and S. densiflora in Argentina to determine the incidence of Fusarium, an endophytic/pathogenic fungus associated with stressed plants.  Plants including roots were removed and washed free of soil.  Surface-disinfested pieces were placed on selective agar.  Colonies originating from single spores were sub-cultured and identified to morphological species.  In North American marshes, two species of Fusarium predominated on S. alterniflora, F. palustre and F. incarnatum-like species.  The incidence of these species was much higher on plants from sites where dieback occurred, but both species were found in similar proportion on healthy plants.  In Argentinian, the incidence of Fusarium did not differ between any of the six sites or between the two Spartina species or whether they were stressed or not.  In addition, the incidence of F. palustre was between 6-23% and F. incarnatum-like species were not found. Four unfamiliar species were observed on these plants in Argentina and may represent new species of Fusarium.  The incidence of Fusarium on S. densiflora did not differ from S. alterniflora except that F. palustre was not found on S. densiflora which is consistent with a current hypothesis that F. palustre has a strong association with S. alterniflora.