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Citation for Study 648

About Citation title: "The evolutionary origins of EpichloŽ endophytes from annual ryegrasses.".
About This study was previously identified under the legacy study ID S482 (Status: Published).

Citation

Moon C., Scott B., Schardl C.L., & Christensen M. 2000. The evolutionary origins of EpichloŽ endophytes from annual ryegrasses. Mycologia, 92(6): 1103-1118.

Authors

  • Moon C.
  • Scott B.
  • Schardl C.L. Phone 859-218-0730
  • Christensen M.

Abstract

The annual Lolium (ryegrass) species were surveyed for seedborne, asexual EpichloŽ endophytes (ie. Neotyphodium spp.). Extremely slow growing endophytes were isolated from all seven annual ryegrass spp. Sequences of ?-tubulin gene (tub2) introns and the internal transcribed spacers of the nuclear ribosomal RNA (rDNA-ITS) were determined, as were fingerprints based on five microsatellite loci. Two taxonomic groups of annual ryegrass endophytes were distinguishable by morphology, culturability and genotypes. One group, for which the name Neotyphodium occultans is proposed, was comprised solely of isolates that could not by subcultured on potato dextrose agar medium. These isolates contained multiple tub2 genes and multiple alleles at microsatellite loci, suggestive of an interspecific hybrid origin. The results of phylogenetic analysis implied that the ancestors of N. occultans included EpichloŽ baconii and EpichloŽ bromicola, or close relatives. The second taxonomic group of annual ryegrass endophytes, exemplified by isolate Lc4, was found only in L. canariense. This taxon had a single tub2 sequence and microsatellite genotype that was nearly identical to those of extant EpichloŽ typhina isolates that infect Poa nemoralis. Therefore, it is proposed that Lc4 is an asexual derivative of an E. typhina genotype closely related to extant strains from P. nemoralis. We propose the name Neotyphodium typhinum var. canariense for this form. These two new endophyte taxa from the annual ryegrasses are further examples of asexual Neotyphodium species that have arisen from sexual EpichloŽ spp. either directly by loss of the sexual state, or by interspecific hybridization events.

Keywords

Ŗ-tubulin gene; interspecific hybridization; Lolium; molecular systematics; Neotyphodium endophytes; rDNA-ITS; symbiosis

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  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S648
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