Dark septate endophytic pleosporalean genera from semiarid areas

Abstract

Dark septate endophytes (DSE) are distributed worldwide as root-colonising fungi, and frequent in environments with strong abiotic stress. DSE is not a taxon, but constitutes numerous fungal taxa belonging to several orders of Ascomycota. In this study we investigate three unidentified DSE lineages belonging to Pleosporales that were found previously in semiarid sandy grasslands. For molecular phylogenetic studies seven loci (ITS, partial 18S nrRNA, 28S nrRNA, actin, calmodulin, transcription-elongation factor 1- α and ß -tubulin genes) were amplified and sequenced. Based on morphology and the resulting molecular phylogeny these isolates were found to represent three novel genera within the Pleosporales, namely Aquilomyces, Flavomyces and Darksidea, with eight novel species. Molecular data revealed that monotypic Aquilomyces belongs to Morosphaeriaceae, monotypic Flavomyces represents an incertae sedis lineage related to Massarinaceae, and Darksidea, with six new species, is allied to the Lentitheciaceae. During this study we tested numerous conditions to induce sporulation, and managed for the first time to induce several DSE to form their sexual morphs.

Communities of Cultivable Root Mycobionts of the Seagrass Posidonia oceanica in the Northwest Mediterranean Sea Are Dominated by a Hitherto Undescribed Pleosporalean Dark Septate Endophyte

“…Since the pleosporalean mycobiont also produced thick, septate, a melanized hyphae, it can be ranked among DSE, a miscellaneous group of ubiquitous endophytes colonizing roots of most terrestrial plants [51][52][53]. Pleosporalean fungi are often reported as DSE in roots of plants from arid and semi-arid regions [54,55]. On the other hand, although the Pleosporales comprise many freshwater and marine, mostly saprobic, genera [56], to our knowledge, they have not yet been reported as DSE in roots of seagrasses.…”

Sexual and asexual states of some endophytic Phialocephala species of Picea

“…Cultural studies of endophytes frequently yield sterile isolates that may be unidentifiable using morphological characters or DNA barcodes or conversely can produce novel teleomorphs. For instance Knapp et al (2015) isolated three novel pleosporalean DSE genera from grass roots and attempted to induce in vitro sporulation with various methods, including culturing on different media or sterilized plant material, mechanically damaging mycelia, exposure to near-UV light and slowly drying out cultures. Isolates of Darksidea produced ascomata on the surface of stinging nettle stems on synthetic nutrient-poor agar 3-4 wk after inoculation at room temperature.…”

Lentithecium cangshanense sp. nov. (Lentitheciaceae) from freshwater habitats in Yunnan Province, China

“…Sequences generated from this study were analyzed with reference sequences from GenBank and those derived from Knapp et al (2015), Phookamsak et al (2015), and Luo et al (2016). The consensus sequences were initially aligned using MAFFTv.7 (http://mafft.cbrc.jp/alignment/server/) (Katoh & Standley 2013) and further improved using Bioedit v.5.0.6 (Hall 2001) and ClustalX v. 1.83 (Thompson et al 1997) to allow maximum alignment and maximum sequence similarity.…”

“…Presently, there are eight genera included in Lentitheciaceae viz. Darksidea, Katumotoa, Keissleriella, Lentithecium, Murilentithecium, Poaceascoma, Setoseptoria (Hyde et al 2013, Knapp et al 2015. Members of Lentitheciaceae were reported as being saprobes on herbaceous and woody plants and produce coelomycetous asexual morphs.…”