Targeted introduction of point mutations in Epichloe festucae

Abstract

AgResearch is a world leader in the commercial utilisation of endophytes in forage grasses. These fungal endophytes have a symbiotic relationship with their host grass and and have traditionally been an agricultural double edged sword. On one hand, they increase plant yield, provide resistance to abiotic stress, and produce insecticidal secondary metabolites. However, they also produce toxic mammalian alkaloids that seriously affect the health of the grazing livestock. AgResearch has identified and commercialised endophyte strains (AR1, AR37 and MaxQ/ MaxP) that lack the capacity to produce two of the main classes of toxic mammalian alkaloids. In addition to the successful commercial strains, AgResearch has characterised a number of strains with potentially beneficial traits that were not placed into a commercial development pipeline because they would lead to negative effects on livestock (e.g. lolitremB producers). As part of our strategy for developing the next generation of endophytes, we are looking for strains with novel activities against some of the insect pests that are not deterred by the current commercial strains. It is likely that some of these strains will be lolitrem B or ergovaline producers and therefore some means of eliminating these pathways is desirable.