Two distinctEpichloëspecies symbiotic withAchnatherum inebrians, drunken horse grass

Abstract

Achnatherum inebrians, colloquially known as drunken horse grass, is associated with livestock toxicity in northern China. Epichloë gansuensis (Eg) was described from endophyte isolates from A. inebrians in Sunan County, Gansu Province, whereas a morphologically distinct variety, E. gansuensis var. inebrians (Ei), was described based on two isolates from A. inebrians seeds collected in Urumqi County, Xinjiang Province. Genome sequencing and alkaloid analyses also distinguish these taxa; the Ei isolates produce neurotropic lysergic acid amides (ergot alkaloids), and an Eg isolate produces paxilline (an indole-diterpene alkaloid). To better elucidate the taxonomic diversity of Epichloë spp. symbiotic with A. inebrians, we surveyed eight populations in Xinjiang, Gansu and Inner Mongolia provinces of China and analyzed their genotypes by multiplex PCR for alkaloid biosynthesis genes and mating-type genes. Genotypes consistent with Ei were present in all eight populations, of which they dominated seven. The Ei isolates were all mating type A and tested positive for the ergot alkaloid gene, dmaW. In contrast Eg isolates were all mating type B and had the indole-diterpene gene, idtG. The genome was sequenced from an Ei isolate from seeds collected in Xiahe County, Gansu, and compared to that of the varietal ex type isolate from Urumqi. Alkaloid genes and four different housekeeping genes were nearly identical between the two sequenced Ei isolates and were distinct from a sequenced Eg isolate. Phylogenetic analysis placed Ei, Eg and Epichloë sibirica into respective subclades of a clade that emanated from the base of the Epichloë phylogeny. Given its chemotypic, genotypic, morphological and phylogenetic distinctiveness, its widespread occurrence in rangelands of northern China, and its importance in livestock toxicity, we propose raising Ei to species rank as Epichloë inebrians.

Caenorhabditis monodelphis sp. n.: defining the stem morphology and genomics of the genus Caenorhabditis

“…In Eukaryota, this practice is just gaining traction, with the recent publication of the description of a fungal taxon with genome data (Epichloë inebrians, an ergot fungus [62]). Additionally, novel arthropod taxa used in phylogenomic analyses have had species descriptions published independently, but near-concurrently, with their genome data (Mengenilla moldrzyki, a strepsipteran insect [63,64] or transcriptome data (the centipede Eupolybothrus cavernicolus [65]).…”

Ergot Alkaloids of the Family Clavicipitaceae

“…Epichloë species, which grow endobiotically and are often seed-transmitted in cool-season grasses (Poaceae, subfamily Poöideae), can be a source of various ergot alkaloids that cause important toxic syndromes in livestock (Chen et al 2015; Klotz 2015; Shymanovich et al 2015; Thompson and Stuedemann 1993). Periglandula species, which are epibiotic symbionts on buds and leaf surfaces of morning glories (Convolvulaceae, tribe Ipomoeae), produce diverse ergot alkaloids (Beaulieu et al 2015).…”

“…The latter also produce ergot alkaloids, and little consideration has been given to the possibility that they may contribute to the toxicity of endophyte-infected perennial ryegrass. Other examples of ergot-alkaloid toxicoses are reported in animals that consume drunken horse grass ( Achnatherum inebrians with Epichloë inebrians ) in western China (Chen et al 2015) or sleepy grass ( Achnatherum robustum with Epichloë sp.) in the southwestern United States, especially near Cloudcroft, New Mexico (Petroski et al 1992).…”

“…This seems to contradict the common paradigm that systems evolve toward greater complexity, but these simpler lysergic acid amides may have been selectively favored in some systems because they are less costly for the fungus to produce. Although there is overlap of symptoms associated with simpler and complex lysergic acid amides, mammalian grazers that ingest ergopeptines can exhibit acute toxicoses, whereas those ingesting the simpler lysergic acid amides present in sleepy grass ( Achnatherum robustum ) and drunken horse grass ( Achnatherum inebrians ) exhibit inebriation and are deterred from future grazing of these plants (Chen et al 2015; Shymanovich et al 2015). …”

Epichloë hybrida, sp. nov., an emerging model system for investigating fungal allopolyploidy

“…Approximate likelihood-ratio tests were computed as branch supports, and the tree was formatted on the interactive Tree Of Life (iTOL) Web site Bork 2007, 2016; https://itol.embl.de; accessed September 2017). The trees were rooted on the E. inebrians branch, as suggested by Chen et al (2015). All sequences have been deposited in GenBank:…”