Grass growth promotion by dark septate endophytic fungi is host specific

Non-Peer ReviewedIsolates of dark septate endophytic fungi (DSE) were obtained from healthy looking roots of two early season grasses [crested wheatgrass (Agropyron cristatum L), Russian wildrye (Elymus junceus Fisch)] and one late season grass [blue gramma (Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] growing in southwest Saskatchewan. The capacity of some fungal isolates to colonize the roots or to promote the growth of these grasses was tested under controlled conditions. A first study revealed that DSE isolates AC 1 and EJ 5 colonize with more intensity the roots of the grass species from which they were isolated. A second study showed that the ability of each fungal isolate to promote plant growth depended on the plant species inoculated. Inoculation with four out of five isolates reduced B. gracilis growth, but increased the growth of one of the early season grasses. The results indicate that DSE fungal isolates are not species specific colonizers but have a strong preference for certain plant species, and some isolates can promote or depress plant growth depending on specific DSE isolate-grass combinations