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United States Department of Agriculture

Agricultural Research Service

Research Project: FORAGE SYSTEMS FOR SUSTAINABLE ANIMAL PRODUCTION IN THE MID-SOUTH

Location: Forage-Animal Production Research

Title: Chemotypic diversity of epichloae, fungal symbionts of grasses

Authors
item Schardl, Christopher -
item Young, Carolyn -
item Faulkner, Jerome -
item Florea, Simona -
item Pan, Juan -

Submitted to: Fungal Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2011
Publication Date: June 24, 2011
Citation: Schardl, C.L., Young, C.A., Faulkner, J.R., Florea, S., Pan, J. 2011. Chemotypic diversity of epichloae, fungal symbionts of grasses. Fungal Ecology. 5:331-344.

Interpretive Summary: The epichloid fungi - comprising sexual Epichlo€e species and asexual Neotyphodium species - are symbionts of cool-season grasses (subfamily Po€oideae), mostly vertically transmissible (seedborne), and well known for production of anti-herbivore alkaloids. Four classes of alkaloids are known to be produced by epichloae: lolines (saturated aminopyrrolizidines), indole editerpenes, ergot alkaloids, and peramine. There is a wide range of chemotypic diversity among and even within epichloid species. At the molecular level, this diversity may in part reflect the telomeric association of two of the four alkaloid biosynthesis gene clusters. Ecologically, the chemotypic diversity within species may reflect frequency-dependent selection for the alkaloids, which provide defences against insects and, in some cases, vertebrates, but can be expensive to produce. Interspecific hybridization, common among asexual epichloae, can pyramid the alkaloid biosynthesis genes. Compared to sexual epichloae, many asexual epichloae produce high levels of alkaloids - articularly lolines - suggesting that strict vertical transmission selects for enhanced capability of host protection.

Technical Abstract: The epichloid fungi - comprising sexual Epichlo€e species and asexual Neotyphodium species - are symbionts of cool-season grasses (subfamily Po€oideae), mostly vertically transmissible (seedborne), and well known for production of anti-herbivore alkaloids. Four classes of alkaloids are known to be produced by epichloae: lolines (saturated aminopyrrolizidines), indole editerpenes, ergot alkaloids, and peramine. There is a wide range of chemotypic diversity among and even within epichloid species. At the molecular level, this diversity may in part reflect the telomeric association of two of the four alkaloid biosynthesis gene clusters. Ecologically, the chemotypic diversity within species may reflect frequency-dependent selection for the alkaloids, which provide defences against insects and, in some cases, vertebrates, but can be expensive to produce. Interspecific hybridization, common among asexual epichloae, can pyramid the alkaloid biosynthesis genes. Compared to sexual epichloae, many asexual epichloae produce high levels of alkaloids - articularly lolines - suggesting that strict vertical transmission selects for enhanced capability of host protection.

Last Modified: 8/29/2014
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