Advances in research on Hordeum brevisubulatum–Epichloë bromicola symbionts

Grass and Epichloë endophyte symbionts are an important direction in the study of plant–microbe and agro–microbe systems. Over the past thirty years, research on wild barley (Hordeum brevisubulatum) endophytic symbionts has revealed outstanding findings. This article summarizes advances in research from two aspects: wild barley H. brevisubulatum and its endophytic symbiont E. bromicola. The distribution of E. bromicola in host tissue and its infection rate, detection and removal methods, biophysiological properties, morphology, and alkaloid production are described. The resistance of the symbiont E. bromicola to abiotic (salinity, drought, water logging, cold, and seed aging) and biotic (pathogens and pests) stresses as well as the effects of exogenous substances on the symbiont are discussed. The article prospects the extraction of literature on wild barley endophytes and the mechanisms for improving resistance (at the gene and protein level) using a novel endophyte to breed new varieties of grasses and cereals. Given the advantage of resistance to various stresses, these new symbionts and host varieties can be used to improve saline soils and restore ecological balance, among others.