Diatrypasimilis australiensis, a novel xylarialean fungus from mangrove

Abstract

A marine xylarialean fungus, isolated from roots of Rhizophora (mangrove) in Australia, displays morphology of eight ellipsoidal dark brown ascospores in a cylindrical ascus having a refractive apical apparatus. Each ascospore has a longitudinal germ slit. The fungus grew very slowly and produced dark brown water-soluble pigment(s) on various media. It developed unique, column-shaped, indeterminate synnemata on which needle-shaped conidia were produced. The sexual stage of this fungus was not observed under the laboratory conditions tested. Molecular phylogenetic analyses of the combined sequences of nuclear ribosomal RNA genes and their internal transcribed spacers placed it at a basal position in the clade of Diatrypaceae of the Xylariales with comparatively high statistical support. However the morphological features and phylogenetic position of this organism do not closely resemble any known fungal taxa. Therefore this fungus is proposed to be a representative of a novel taxon and described as Diatrypasimilis australiensis gen. et sp. nov.

• acicular conidia
• eight-spored ascus
• germ-slit ascospore
• indeterminate synnema
• spiral hyphae

We thank ATCC MR4 lab for use of microscopy and photography equipment, ATCC Stem Cell Center for imaging editing software, and Drs Marian McKee and Brian Beck for their support and critical reading of the manuscript. This work was financially supported in part by the National Science Foundation, Grant DBI-0548684, to JZ.