Undifilum, a new genus for endophyticEmbellisia oxytropisand parasiticHelminthosporium bornmuellerion legumes

Abstract

Fungal endophytes of Oxytropis kansuensis Bunge from China, previously described as Embellisia oxytropis Q. Wang, Nagao & Kakish, and endophytes of Oxytropis sericea Nutt. and Oxytropis lambertii Pursh from the United States were compared and are reported here as conspecific members of a new genus in the Pleosporaceae, Undifilum, based on morphological and molecular analyses. Morphological comparisons revealed characters that are similar to those of the genus Embellisia including conidia ovate to obclavate to long ellipsoid, straight or slightly to decidedly inequilateral with occasionally one or two cells distinctly swollen, and transepta occasionally thickened, dark, and rigid in comparison with the exterior conidium wall. However, upon germination, conidia produced unique and diagnostic germ tubes that were wavy or undulating in their growth until branching. Moreover, all isolates were found to produce the toxic alkaloid swainsonine. Parsimony analysis of sequences from ITS1–5.8S–ITS2, glyceraldehyde-3-phosphate dehydrogenase gene, and mitochondrial small subunit rDNA data sets revealed that the Oxytropis endophytes formed a clade distinct from other Embellisia species and species in the genera Alternaria , Ulocladium , Nimbya , and Crivellia . A second taxon, Helminthosporium bornmuelleri P. Magnus, was reexamined and found to possess similar morphological features to those of the Oxytropis isolates, but lacked swainsonine production. Sequence analysis placed this second taxon in the same clade with high bootstrap support. The distinct morphology and genetics of these taxa demonstrates that these fungi, both recovered from legumes, represent a new genus, hereinafter described as Undifilum . The two species now placed in this genus are redescribed as Undifilium oxytropis and Undifilium bornmuelleri .

Plant Bioactive Metabolites and Drugs Produced by Endophytic Fungi of Spermatophyta

“…The latter are forage plants whose consumption by livestock is associated to the syndrome of locoism. It has been observed that a fungal endophytic species occurring in locoweeds, the vertically-transmitted Undifilum oxytropis [324,325], previously described as Embellisia sp. [326,327], is capable to produce swainsonine in vitro.…”

Solutions to Locoweed Poisoning in New Mexico and the Western United States: Collaborative research between New Mexico State University and the USDA–Agricultural Research Service Poisonous Plant Lab

“…Swainsonine-producing endophytes isolated from Oxytropis in China were essentially identical to those collected in the United States, and both were given the name Undifilum oxytropis. 3 Endophytes isolated from Astragalus species will likely be classified into several additional species of the fungal genus.…”

Endogenous fungi isolated from three locoweed species from rangeland in western China

“…that produces the swainsonine (Braun et al, 2003;Wang et al, 2006;Pryor et al, 2009;Yu et al, 2010;Lu et al, 2012a;Creamer and Baucom, 2013;Grum et al, 2013;Woudenberg et al, 2013). Although not every plant in a population is toxic or contains the endophyte, all toxic plants that contain swainsonine have been shown to contain a swainsonine-producing fungal endophyte (Cook et al, 2011Achata et al, 2012).…”

“…The diversity of fungal endophytes includes species diversity in colonization of host plants and diversity in the distribution of fungal endophytes within different tissues of host plants. This diversity could be due to differences in the host plants and natural factors, such as geographical location and climate, in addition to presence of other organisms (Tiina et al, 2013 (Pryor et al, 2009;Baucom et al, 2012). Alternaria sect.…”

“…can readily be cultured from dried plant tissue and most produce conidia in culture. The cultures are very slow growing, expanding less than an average of 0.2 mm/day (Pryor et al, 2009). They can be readily isolated from leaves, petioles, stems, flowers and seed (Braun et al, 2003).…”