Epichloë − a lifeline for temperate grasses under combined drought and insect pressure

Fungal Epichloëendophytes form symbiotic associations with many temperate grasses,such as Lolium and Festuca,giving their host grasses an ecological advantage.The importance of specific Epichloëendophytes in providing varying levels of protection against invertebrate pests has been well documented.Similarly,but with fewer studies,the benefits of Epichloëto host grasses in drought events has been shown.Endophyte-infected grasses show an improved persistence against herbivore insect attack as well as resilience under drought.However,there are relatively few studies that investigate the interaction between drought and insect pressure,and yet it is these combined pressures that can prove detrimental for a ryegrass or fescue crop.This review examines the current state of knowledge on the effects of Epichloëon the interactions of insects and drought in temperate grasses.

The exploitation of epichloae endophytes for agricultural benefit

Epichloae endophytes of family Clavicipitaceae(comprising genera Epichloëand Neotyphodium)are fungal symbionts of Pooideae grasses.The associations formed,range from mutually beneficial to antagonistic and the nature of this relationship is dependent upon the importance of vertical(via host seeds)versus horizontal(ascospore mediated)transmission of the fungus.These endophytes can enhance their hosts’survival through protection from abiotic and biotic stresses and can thus be utilized in an agricultural context.Animal-safe grass-endophyte associations that confer bio-protective properties for increased pasture persistence and productivity have been developed and commercialized.One of the crucial drivers underpinning the selection of epichloae strains for commercial development is endophyte derived bioactivity.The potential of next generation endophytes is determined by testing a number of attributes such as agronomic fitness,animal and food safety as well as compatibility with host plants of interest.Strategic research supports these activities by focusing on elucidating mechanisms of compatibility between host and fungal symbiont,as well as investigating other molecular drivers of symbiosis such as siderophore mediated iron-uptake,fungal signalling,fungal growth in host plants and fungal secondary metabolism.This review weaves together the different strands of multidisciplinary research aimed at ultimately exploiting epichloae endophytes for increased pasture performance.