Mechanisms of beneficial colonisation of barley by fungal root endophytes

Pathogenic fungal infections of barley can lead to costly crop losses. However, not all
fungal infections are detrimental, and some are even beneficial. Beneficial root infections
often involve symbiotic endophytic fungi. Benefits to barley and other plants infected
with endophytic root fungi include an increase in seed yield, enhanced resistance to
pathogens and improved stress tolerance. Here, we examine the mechanisms and
outcomes of fungal endophyte colonisation of barley roots and briefly discuss reported
benefits for the host. The most important factors that determine the nature of the
relationship are the specific combination of partner genotypes and developmental stage,
and the ecological and environmental setting. The full potential of these organisms is still
to be determined and further studies are urgently required to develop specific beneficial
root-endophyte associations, or combination of them, that are tailored to barley cultivars
for maximum impact in agriculture.