Distribution of Neotyphodium endophytes in naturalised ryegrasses (Lolium spp.) in Japan

Abstract

Introduced Lolium grasses are utilised in Japan for forage, turf and soil conservation. Many of these grasses have become naturalised in disturbed ecosystems. Neotyphodium endophytes in the tissues of grasses can increase host fitness by increasing tolerance to both biotic and abiotic stresses. Consequently, endophyte infection may be a factor enhancing invasion success of exotic grasses in the Japanese islands. We detected infection by Neotyphodium endophytes in 162 of 173 naturalised ryegrass populations in Japan. Italian ryegrass (L. multiflorum) had a higher infection rate than perennial ryegrass (L. perenne). Italian ryegrass also exhibited geographic variation in infection rate. It is unlikely that the infected Italian ryegrasses found in this study have come from cultivars used in meadows, since the use of forage ryegrass cultivars infected with Neotyphodium endophytes has been restricted in Japan to prevent toxicity problems. Possible sources of the ryegrasses may be turf seeds, soil conservation materials and/or contaminants in imported plant materials. Keywords:ô€€ alien species,ô€€ invasive plants, Italian ryegrass, Lolium multiflorum, Neotyphodium endophyte, perennial ryegrass, Lolium perenne