Theme 16: Advances in Endophyte Research
Description
In temperate zones, endophytic fungi are widely used as biological protection agents for forage and turf grasses. They form nonpathogenic and intercellular associations with grasses and sedges, completing their entire life cycle within the plants’ aerial parts. Our surveys and studies confirmed that various endophytic fungi, including Acremonium spp., also inhabit native savanna grasses and introduced tropical forage grasses. We are now determining the potentially symbiotic relationships between these fungi and C4 tropical forages, specifically between the endophyte A. implicatum and Brachiaria grasses. We treated half of a group of genetically identical clones of Brachiaria with fungicide to generate endophyte-free plants. So far, we have found that, under severe water stress, endophyte-infected plants of B. arrecta CIAT 16845 maintained better leaf expansion and produced significantly more leaf biomass than did clean plants. We also found that the endophyte protects B. brizantha from pathogenic fungi such as Drechslera sp. (causal agent of leaf spot), the grass showing fewer and smaller lesions than did endophyte-free plants. The endophyte also inhibits the growth of Rhizoctonia solani (causal agent of foliar blight in Brachiaria) and Pyricularia oryzae (causal agent of rice blast). It may even protect Brachiaria from pests such as the aphid Rhopalosiphum maidis. However, several years of research has shown that, in infected temperate grasses, endophytes reduce livestock productivity. Whether this is true for tropical forage grasses such as Brachiaria is not yet known, although what little evidence exists suggests that endophytes may cause various health disorders in livestock.
Included in
The Role of Endophytic Fungi in Brachiaria, a Tropical Forage Grass
In temperate zones, endophytic fungi are widely used as biological protection agents for forage and turf grasses. They form nonpathogenic and intercellular associations with grasses and sedges, completing their entire life cycle within the plants’ aerial parts. Our surveys and studies confirmed that various endophytic fungi, including Acremonium spp., also inhabit native savanna grasses and introduced tropical forage grasses. We are now determining the potentially symbiotic relationships between these fungi and C4 tropical forages, specifically between the endophyte A. implicatum and Brachiaria grasses. We treated half of a group of genetically identical clones of Brachiaria with fungicide to generate endophyte-free plants. So far, we have found that, under severe water stress, endophyte-infected plants of B. arrecta CIAT 16845 maintained better leaf expansion and produced significantly more leaf biomass than did clean plants. We also found that the endophyte protects B. brizantha from pathogenic fungi such as Drechslera sp. (causal agent of leaf spot), the grass showing fewer and smaller lesions than did endophyte-free plants. The endophyte also inhibits the growth of Rhizoctonia solani (causal agent of foliar blight in Brachiaria) and Pyricularia oryzae (causal agent of rice blast). It may even protect Brachiaria from pests such as the aphid Rhopalosiphum maidis. However, several years of research has shown that, in infected temperate grasses, endophytes reduce livestock productivity. Whether this is true for tropical forage grasses such as Brachiaria is not yet known, although what little evidence exists suggests that endophytes may cause various health disorders in livestock.
