Abstract:
Wheat covers more land area than any other crop, therefore is responsible for a large amount of synthetic chemical usage in agriculture. The beneficial microorganisms that associate with wheat plants are a safer alternative to these chemicals. Some bacteria and fungi, including the Metarhizium genus, can protect plants from pests and disease while simultaneously positively influencing plant growth. However, the beneficial microbes associated with wheat and its wild relatives are under-studied, and the effects of Metarhizium on wheat growth are largely unknown. The growth-promotion effects of a range of Metarhizium isolates were analysed in wheat plants. Differences were observed in the ability of isolates to benefit wheat growth, which was affected by the conditions in which the plants were grown. Three strains in particular, identified as isolates of M. robertsii and M. flavoviride, were found to persist in the rhizosphere of wheat grown in natural conditions while positively influencing plant growth. The culturable microorganisms of wild Triticum and Aegilops species seeds were isolated and identified, and further studied. In total, 121 bacterial endophytes, predominantly belonging to the Bradyrhizobiaceae, Paenibacillaceae and Sphingomonadaceae families, were isolated. Four fungal endophytes were obtained that are not common endophytic fungi. This thesis reports for the first time the isolation of Neurospora crassa, Penicillium chrysogenum, Sistotrema, Burgella, Chitinophagaceae and Rhodocyclaceae isolates as endophytes of Triticum and Aegilops species. Slight differences were observed in the culturable endophytic communities between species of seed, and seed collection locations. Various isolates were found to have growth-promoting effects in wheat, and inhibitory activity towards several microorganisms. This research suggests that isolates of Metarhizium and the seedborne endophytes of wild Triticum and Aegilops species are able to benefit wheat growth and inhibit other microorganisms, therefore have the potential to be used in place of the currently used synthetic chemicals in wheat production.