Screening fungal endophytes from a wild grass for growth promotion in tritordeum, an agricultural cereal

Celtica gigantea(= Stipa gigantea) is a large perennial grass which grows in nutrient-poor sandy soils in semiarid zones of the western Iberian Peninsula. The purpose of this work was to find out if culturable fungal symbionts isolated from roots of this wild grass could have growth promoting activity in tritordeum, a hybrid cereal for human consumption. A survey of fungi from the root endosphere of C. gigantea produced an isolate collection consisting of 60 different taxa, mostly ascomycetes. Fungal strains were inoculated into tritordeum plants in order to evaluate their effect in leaf and root biomass, nutrient content, and total antioxidant capacity. Two consecutive screening processes were made to test endophyte effects in plants. In the first screening, 66 strains were inoculated into seedlings by dipping roots in a liquid suspension of inoculum. In the second screening, 13 strains selected from the first screening were inoculated by sowing seeds in a substrate containing inoculum. The inoculation method used in the second screening involved less labor and plant manipulation and improved the quantity and quality of the inoculum, making it more appropriate for big scale experimental inoculation procedures. Several fungal strains promoted leaf or root growth. In particular, a strain belonging to the genus Diaporthe caused an increase in leaf and root biomass in both screening processes, suggesting that this endophyte might have a good potential for field application in tritordeum.