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Chemical ecology of Hobsonia christiansenii , a lichenicolous hyphomycete
Author(s) -
Lawrey James D.
Publication year - 1993
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1993.tb15341.x
Subject(s) - lichen , biology , generalist and specialist species , botany , acetone , pathogen , herbivore , chemical ecology , ecology , microbiology and biotechnology , habitat , biochemistry
Hobsonia christiansenii B. L. Brady & D. Hawksw. is a helicosporous hyphomycete reported to parasitize a number of lichen species. Quantitative study of a lichen community in Montgomery County, Maryland, revealed that H. christiansenii colonized one lichen species, Flavoparmelia baltimorensis , almost exclusively. This pattern of attack was unexpected because F. baltimorensis produces an array of phenolic secondary metabolites known to inhibit generalist herbivores and microorganisms. The chemical ecology of the pathogen was investigated further in a series of experiments designed to determine if acetone‐soluble compounds from various lichens (including F. baltimorensis ) inhibited growth of H. christiansenii under controlled laboratory conditions. Results demonstrated that acetone extracts of lichens other than F. baltimorensis were frequently quite inhibitory to the growth of H. christiansenii in culture, but that those of F. baltimorensis had no significant effect on the growth of the pathogen. Indeed, acetone extracts of F. baltimorensis stimulated the growth of Hobsonia on artificial media. These observations suggest H. christiansenii is a relatively specialized lichen pathogen that has been able to overcome the chemical defenses of F. baltimorensis .