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A Phoma sp. was isolated and characterized as endophytic and as a pathogen of Larrea tridentata (creosote bush) growing in the desert region of southern Utah, USA. This fungus produces a unique mixture of volatile organic compounds (VOCs), including a series of sesquiterpenoids, some alcohols and several reduced naphthalene derivatives. Trans-caryophyllene, a product in the fungal VOCs, was also noted in the VOCs of this pungent plant. The gases of Phoma sp. possess antifungal properties and is markedly similar to that of a methanolic extract of the host plant. Some of the test organisms with the greatest sensitivity to the Phoma sp. VOCs were Verticillium, Ceratocystis, Cercospora and Sclerotinia while those being the least sensitive were Trichoderma, Colletotrichum and Aspergillus. We discuss the possible involvement of VOC production by the fungus and its role in the biology/ecology of the fungus/plant/environmental relationship with implications for utilization as an energy source. ; S.K.S. is grateful to the Department of Biotechnology (DBT), the Government of India, New Delhi, for the award of an DBT Overseas Associateship in the Niche Area of Biotechnology (No. BT/IN/BTOA/NICHE/2006 dated 13 February 2008) to study at MSU, USA, and to the Department of Science and Technology (DST), New Delhi, for providing financial support to set up the National Facility for Culture Collection of Fungi (No. SP/SO/PS-55/2005) at MACS' Agharkar Research Institute, Pune, India, and to the Director, MACS' ARI, for granting permission to work at MSU. G.A.S. is grateful to the NSF and DoE for providing research funds. The BOYSCAST program of India granted a 1-year fellowship to S.Y.U.H. to study and work at MSU. We are grateful to Mr Darwin Whitaker who generously supplied plant materials from the Utah desert region on various occasions.

A Nodulisporium species (designated Ti-13) was isolated as an endophyte from Cassia fistula. The fungus produces a spectrum of volatile organic compounds (VOCs) that includes ethanol, acetaldehyde and 1,8-cineole as major components. Initial observations of the fungal isolate suggested that reversible attenuation of the organism via removal from the host and successive transfers in pure culture resulted in a 50 % decrease in cineole production unrelated to an overall alteration in fungal growth. A compound (CPM1) was obtained from Betula pendula (silver birch) that increases the production of 1,8-cineole by an attenuated Ti-13 strain to its original level, as measured by a novel bioassay method employing a 1,8-cineole-sensitive fungus (Sclerotinia sclerotiorum). The host plant produces similar compounds possessing this activity. Bioactivity assays with structurally similar compounds such as ferulic acid and gallic acid suggested that the CPM1 does not act as a simple precursor to the biosynthesis of 1,8-cineole. NMR spectroscopy and HPLC-ES-MS indicated that the CPM1 is a para-substituted benzene with alkyl and carboxyl substituents. The VOCs of Ti-13, especially 1,8-cineole, have potential applications in the industrial, fuel and medical fields. ; We acknowledge the financial support of the NSF via a grant to Dr B. Peyton of the MSU Department of Chemical and Biological Engineering and the DoE to G. S. J. N. recognizes the support of the CBS-SURP, which is funded by the Howard Hughes Medical Institute. S. R-U-L. was supported in a 1 year stay (2010−2011) at MSU on a BOYSCAST fellowship from the Department of Science and Technology, Government of India. The camera lucida drawing was kindly done by Dr Jitra Kokaew of the Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand. Financial support from Endophytics LLC is also acknowledged.