Revision of the genus Aciculosporium (Clavicipitaceae) with a description of a new species on wavyleaf basketgrass, and proline-containing cyclic dipeptide production by A. take

Abstract

The genus Aciculosporium (Clavicipitaceae, Hypocreales, Ascomycota)was established in 1908 for A. take , which is the causal fungus of witches' broom of bamboo. Although the original description was valid at that time, a type specimen for A. take has not been designated. To standardize the use of this genus and species name, a neotypification and reference specimen of A. take are proposed. Multilocus phylogenetic analyses based on DNA sequences from 28S rDNA, TEF, Tub2, Mcm7, and RPB2 revealed that A.sasicola is from a different lineage to A. take, and other specimens from wavyleaf basket grass (Oplismenus undulatifolius) represent a distinct species proposed here as Aciculosporium oplismeni sp. nov. Chemical analysis using mass spectrometry and nuclear magnetic resonance spectroscopy showed that A. take produces four proline-containing cyclic dipeptides, which are moieties of ergot alkaloids. However, ergot alkaloids, lolines, peramine, indole-diterpenes, and lolitrem were not detected in the culture solvent. This study offers clarification of the lineage and morphology of this genus.

Keywords: Aciculosporium oplismeni; Claviceps; Ergot alkaloids; Hypocreales; Witches' broom.

Fig. 1 -. Aciculosporium take. A: Witches' broom symptom on Phyllostachys bambusoides. B: Witches' broom symptom (arrows) on Phyllostachys pubescens (TNS-F-60468). C: Ascostroma on shoot apex of P. bambusoides. D–F: Asci. D: Intact ascus. E: Eight filiform ascospores emerged from an ascus. F: Apical hemispherical thickened tip of asci. G: Colony (MAFF 241224) on PDA at 25˚C for 1 mo. H: Apical appendagedconidia. D–F, H: These spores were stained with lactophenol cotton blue. Bars: C, G 1 cm; D, E, H, 50 µm; F10 µm.

Fig. 2 -. Aciculosporium sasicola. A: Witches’ broom symptom on Sasa palmata (TNS-F-91306). B: Conidiostroma on shoot apex of S. palmata (TNS-F-91306). C: Colony (MAFF 246967) on PDA at 25˚C for 1 mo. D: Apical appendagedconidia stained with lactophenol cotton blue. Bars: B,C 1 cm; D 50 µm.

Fig. 3 -. Aciculosporium oplismeni. A, B: Ascostroma on shoot apex of Oplismenus undulatifolius (TNS-F-87159). C: Cross section of ascostroma stained by periodic acid-Schiff reaction. D–F: Asci. D: Unmatured ascus. E: Apical hemispherical thickened tip of ascus. F: Matured ascus with germinated ascospores. G: Colony (MAFF 246966) on PDA at 25˚C for 1 mo. H: Apical appendaged conidia stained with lactophenol cotton blue. C, D, F: Multiple images were combined into a single image using GraphicConverter (Remke Software, Peine, Germany). Bars: A, G 1 cm; B 5 mm; C 100 µm; D, F, H 50 µm; E 10 µm.

Fig. 4 -. A maximum-likelihood phylogenetic tree of a concatenated data set of five loci (28S rDNA, Mcm7, TEF, Tub2, and RPB2). Sequence data obtained in this study are shown in bold face. Bootstrap support values (ML/MP) are given at nodes and based on 1000 replicates. The scale represents the number of nucleotide substitutions per site. ^T ex-type isolates.