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Charles Sturt University (2012)

Biochemical consequences of endophytic fungi—grass mutualism

Qawasmeh, Abdel Qader A.

Titre : Biochemical consequences of endophytic fungi—grass mutualism

Auteur : Qawasmeh, Abdel Qader A.

Université de soutenance : Charles Sturt University

Grade : Doctor of Philosphy (PhD) 2012

Résumé
"Lolium perenne L. (perennial ryegrass) and Festuca arundinacea Schreb. (syn. Lolium arundinaceum Schreb., Schedonorus phoenix Holub.) are sown in pastures in south-eastern parts of Australia. ... Extreme variations in climate in Australia such as extended periods of drought, and an abundance of invasive weeds and pestiferous organisms in pastures represent some of the major stress factors affecting the persistence of these pasture grasses. Consequently, researchers and farmers have become increasingly interested in finding techniques to enhance L. perenne and F. arundinacea persistence, performance and tolerance to extreme climatic conditions and the invasive organisms. Over the past three decades, a group of fungi known as ’endophytes’ has been the focus of much research. This group of fungi includes the species of Neotyphodium (Ascomycetes : Clavicipitaceae). These fungi have been shown to enhance the host grass’s persistence and productivity, particularly in areas infested with herbivorous insects ... This enhancement is attributed to a number of secondary compounds mainly alkaloids produced during the endophyte-grass association. ... Other major groups of the secondary compounds which enhance the grass’s persistence, include phenolic and volatile compounds. ... Both phenolic and volatile compounds can directly influence the host-insect relationship, but little is known about how the fungal endophyte alters their profiles to achieve optimal symbiosis. The present thesis reports the findings pertaining to the underpinning chemical factors, i.e., alkaloids, phenolics and volatiles involved in the interactions beteen the endophytic fungi N. lolli and N. coenophialum and their grass hosts, L. perenne and F. arundinacea, respectively, and the pestiferous beetle, H. arator that feeds on both grasses

Mots Clés : Beetles — Biological control. — Endophytic fungi — Australia. — Lolium perenne. — Neotyphodium. — Pasture ecology — Australia. — Pasture plants — Chemical defenses. — Pasture plants — Diseases and pests — Australia. — Plant-fungus relationships — Australia. — Tall fescue.

Présentation (TROVE National Library of Australia)

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Page publiée le 29 novembre 2012, mise à jour le 3 juillet 2017