Phylogenetic lineages in the Botryosphaeriaceae

Abstract

Botryosphaeria is a species-rich genus with a cosmopolitan distribution, commonly associated with dieback and cankers of woody plants. As many as 18 anamorph genera have been associated with Botryosphaeria, most of which have been reduced to synonymy under Diplodia (conidia mostly ovoid, pigmented, thick-walled), or Fusicoccum (conidia mostly fusoid, hyaline, thin-walled). However, there are numerous conidial anamorphs having morphological characteristics intermediate between Diplodia and Fusicoccum, and there are several records of species outside the Botryosphaeriaceae that have anamorphs apparently typical of Botryosphaeria s.str. Recent studies have also linked Botryosphaeria to species with pigmented, septate ascospores, and Dothiorella anamorphs, or Fusicoccum anamorphs with Dichomera synanamorphs. The aim of this study was to employ DNA sequence data of the 28S rDNA to resolve apparent lineages within the Botryosphaeriaceae. From these data, 12 clades are recognised. Two of these lineages clustered outside the Botryosphaeriaceae, namely Diplodia-like anamorphs occurring on maize, which are best accommodated in Stenocarpella (Diaporthales), as well as an unresolved clade including species of Camarosporium/Microdiplodia. We recognise 10 lineages within the Botryosphaeriaceae, including an unresolved clade (Diplodia/Lasiodiplodia/Tiarosporella), Botryosphaeria s.str. (Fusicoccum anamorphs), Macrophomina, Neoscytalidium gen. nov., Dothidotthia (Dothiorella anamorphs), Neofusicoccum gen. nov. (Botryosphaeria-like teleomorphs, Dichomera-like synanamorphs), Pseudofusicoccum gen. nov., Saccharata (Fusicoccum- and Diplodia-like synanamorphs), "Botryosphaeria" quercuum (Diplodia-like anamorph), and Guignardia (Phyllosticta anamorphs). Separate teleomorph and anamorph names are not provided for newly introduced genera, even where both morphs are known. The taxonomy of some clades and isolates (e.g. B. mamane) remains unresolved due to the absence of ex-type cultures.

Fig. 1.

Distance tree obtained using the HKY85 substitution model on the LSU sequence alignment. The scale bar shows 0.01 substitutions per site and bootstrap support values from 1000 replicates are shown at the nodes. Clades are numbered from 1 to 12 next to the brackets. The tree was rooted to Gaeumannomyces graminis var. avenae (AF362556) and Magnaporthe grisea (AF362554).

Fig. 1.

Distance tree obtained using the HKY85 substitution model on the LSU sequence alignment. The scale bar shows 0.01 substitutions per site and bootstrap support values from 1000 replicates are shown at the nodes. Clades are numbered from 1 to 12 next to the brackets. The tree was rooted to Gaeumannomyces graminis var. avenae (AF362556) and Magnaporthe grisea (AF362554).

Fig. 2.

Consensus phylogram of 950 trees resulting from a Bayesian analysis of 115 LSU sequences. Bayesian posterior probabilities are given at the nodes. Clades are numbered from 1–12 next to the brackets, following the number-to-clade assignment presented in Fig. 1. The tree was rooted to Gaeumannomyces graminis var. avenae (AF362556) and Magnaporthe grisea (AF362554) (Diaporthales, Magnaporthaceae).

Fig. 2.

Consensus phylogram of 950 trees resulting from a Bayesian analysis of 115 LSU sequences. Bayesian posterior probabilities are given at the nodes. Clades are numbered from 1–12 next to the brackets, following the number-to-clade assignment presented in Fig. 1. The tree was rooted to Gaeumannomyces graminis var. avenae (AF362556) and Magnaporthe grisea (AF362554) (Diaporthales, Magnaporthaceae).

Fig. 3.

“Botryosphaeria” subglobosa (CBS 448.91). A. Pycnidia on pine needles. B–C. Conidiogenous cells. D. Young conidia. E–H. Mature conidia with striations. Scale bars: A = 150 μm, B = 9 μm.

Fig. 4.

Botryosphaeria mamane (CBS 117444). A–B. Conidia in culture. Scale bar = 7 μm.

Fig. 5.

Macrophomina phaseolina (CPC 11052). Conidiogenous cells, young conidia with apical mucoid appendages, and mature, brown conidia devoid of appendages. Scale bar = 10 μm.

Fig. 6.

Macrophomina phaseolina (CPC 11052). A. Conidia and sclerotia formed on pine needles. B. Conidiogenous cells. C–H. Hyaline conidia with apical, mucoid appendages. I–M. Brown, mature conidia with verrucose walls. Scale bars = 8 μm.

Fig. 7.

Tiarosporella graminis var. karoo (CBS 118718). A. Pycnidium on a pine needle. B–C. Conidiogenous cells. D–G. Conidia (arrows denote apical, mucoid appendages). H. Conidia. Scale bars: A = 200 μm, B–D = 7 μm.

Fig. 8.

Tiarosporella tritici (CBS 118719). A. Pycnidia on a pine needle. B–D. Conidiogenous cells. E–F. Conidia (arrows denote apical, mucoid appendages). Scale bars: A = 300 μm, B–F = 10 μm.

Fig. 9.

Neoscytalidium dimidiatum (CBS 312.90). A–B. Neoscytalidium conidia. C. Conidiogenous cells of coelomycete synanamorph. D–F. Conidia of coelomycete synanamorph (arrows denote sheath). Scale bars = 4 μm.

Fig. 10.

Dothiorella pyrenophora (K 54912). A–B. Pycnidia on stems. B. Spermatia and spematogenous cells. D–H. Conidia. Scale bars = 10 μm.

Fig. 11.

Pseudofusicoccum stromaticum (CBS 117448). A. Pycnidia on pine needles. B–C. Conidiogenous cells. D–H. Conidia (arrows denote mucoid sheaths). Scale bars = A = 90 μm, B = 6 μm.

Fig. 12.

Camarosporium quaternatum (CBS 134.97). A. Pycnidia in agar. B–C Conidiogenous cells. D–E. Conidia. Scale bars: A = 100 μm, B = 6 μm.

Fig. 13.

Stenocarpella maydis on Zea mays. A. Pycnidium on upper leaf surface. B–C. Conidial cirrhi. D. Conidiogenous cells giving rise to conidia. E–H. Conidia. Scale bars = 10 μm.