Endophytic fungi, characteristics and their potential for genetic manipulation

Abstract Unique benign endophytes from Ascomycets have wide distribution among grass species. The symbiotic fungi enhance plant characters including performance, insect and mammalian deterrence, nematode resistance and tolerance to drought, salt and other biotic and abiotic stresses. Endophytes from genus Neotyphodium (Acremonium) are of the major focus than their ancestors, and Epichloe species, because the formers have lost their sexual reproduction. Therefore they should be genetically stable, and most importantly, they cannot disassociate from host tissues, and are transferred vertically. They are maternally inherited and are therefore attractive for genetic transformation without the concern about gene escape. Some marker genes have been successfully transferred to endophyte Neotyphodium coenophialum and Neotyphodium lolii existing in Festuca arundinacea Schreb. and Lolium perenne L., respectively. Furthermore, gene silencing has been proved to be feasible for eliminating traits, which are economically harmful. Methods of direct DNA uptake using polyethylene glycol (PEG) and electroporation have been found to be useful in transformation of these fungi. Transgenic fungi can be reinserted into the host without need to tissue culture. The endophytic genes responsible for a specific trait can be isolated and transferred to grass species or other microorganisms for direct exploitation of secondary metabolites and endophytic enzymes. Considering advancements in this filed, endophytes can open new horizons faced to scientists and biotechnologist to use them as a surrogate target of transformation.