NOVELTY - Isolated fungal endophyte comprising any one of ribosomal DNA (rDNA) sequence of SEQ ID NOs: 1-555 (comprising fully defined sequences of 283-1042 nucleobases as given in the specification), is new.    USE - The isolated fungal endophyte is useful: in a commodity product including a biofuel feedstock or an animal feed; to produce biofuel which is ethanol; increasing the biomass of the grass plant; and for cultivating a grass plant which has enhanced root growth, more tillers, enhanced total biomass or enhanced seed yield relative to a host grass plant of the same genotype that lacks the endophyte, and displays tolerance to stress as relative to a host grass plant of the same genotype that lacks the endophyte, when grown under the same conditions, where the stress is a biotic stress, pest stress, insect stress, abiotic stress and a water deficit stress, where the biotic stress caused by at least one organism including a mammalian herbivore, microbial pathogen or an insect, and the abiotic stress is water deficiency, nutrient deficiency, heat stress, salt toxicity, aluminum toxicity, heavy metal toxicity or freezing temperatures (all claimed). No biological data given.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a synthetic combination of a grass plant and the fungal endophyte;    (2) a commodity product comprising the synthetic combination of a harvested grass plant or its part, and the fungal endophyte;    (3) a seed comprising the synthetic combination of the fungal endophyte and a grass plant embryo;    (4) a grass seed comprising a seed-coat comprising the fungal endophyte;    (5) propagating a grass plant-fungal endophyte combination, comprising: obtaining a synthetic combination of a grass plant and the fungal endophyte; and vegetatively reproducing the grass plant tissue colonized by the fungal endophyte;    (6) cultivating a grass plant comprising contacting the host grass plant with the fungal endophyte, so that the endophyte colonizes the plant; and    (7) producing a biofuel comprising: obtaining grass plant comprising the fungal endophyte; and producing biofuel from it.