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Hybrids hybrids everywhere: The role of hybridization in the evolution of Neotyphodium grass endophytes.
K. D. CRAVEN (1), S. R. Ghimire (2), C. Young (1), N. D. Charlton (1), G. Swoboda (1), B. Hall (1), M. Afkhami (3). (1) The Samuel Roberts Noble Foundation, Ardmore, OK, U.S.A.; (2) RTI International, Research Triangle Park, NC, U.S.A.; (3) University of California-Davis, Davis, CA, U.S.A.

Interspecific somatic hybridization has played a prominent role in the evolution of seed-transmissible, mutualistic fungal endophytes collectively known as the epichloae. Current theory suggests that hybridization events may provide increased herbivore protection for the host plant through pyramiding of bioactive alkaloid genes. Additionally, these endophytes typically lack a sexual cycle and thus, hybridization may alleviate the destabilizing effects of deleterious mutations that accumulate in the fungal genome. Here, we analyzed the genetic diversity of epichloid endophytes infecting populations of a single host grass species endemic to California, <i>Bromus laevipes</i>. In total, 58 isolates representing samples from 12 populations were analyzed and grouped based on intron sequences of translation-elongation factor 1-alpha (<i>tefA</i>) and beta-tubulin (<i>tubB</i>). We also grouped the isolates based on both morphological characters and alkaloid chemotypes to evaluate congruency between classification schemes. Preliminary data suggest that some of these hybrids were formed from different progenitor species while others share the same progenitor species, but may have involved distinct genotypes with differing alkaloid profiles. These findings suggest that the diversity of hybrid endophytes within single host species can reflect that observed more broadly within the grass subfamily Pooideae.<p><p>Keywords:

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