Taxonomy and Pathology of Togninia (Diaporthales) and its Phaeoacremonium Anamorphs

Abstract

The genus Togninia (Diaporthales, Togniniaceae) is here monographed along with its Phaeoacremonium (Pm.) anamorphs. Ten species of Togninia and 22 species of Phaeoacremonium are treated. Several new species of Togninia (T.) are described, namely T. argentinensis (anamorph Pm. argentinense), T. austroafricana (anamorph Pm. austroafricanum), T. krajdenii, T. parasitica, T. rubrigena and T. viticola. New species of Phaeoacremonium include Pm. novae-zealandiae (teleomorph T. novae-zealandiae), Pm. iranianum, Pm. sphinctrophorum and Pm. theobromatis. Species can be identified based on their cultural and morphological characters, supported by DNA data derived from partial sequences of the actin and β-tubulin genes. Phylogenies of the SSU and LSU rRNA genes were used to determine whether Togninia has more affinity with the Calosphaeriales or the Diaporthales. The results confirmed that Togninia had a higher affinity to the Diaporthales than the Calosphaeriales. Examination of type specimens revealed that T. cornicola, T. vasculosa, T. rhododendri, T. minima var. timidula and T. villosa, were not members of Togninia. The new combinations Calosphaeria cornicola, Calosphaeria rhododendri, Calosphaeria transversa, Calosphaeria tumidula, Calosphaeria vasculosa and Jattaea villosa are proposed.Species of Phaeoacremonium are known vascular plant pathogens causing wilting and dieback of woody plants. The most prominent diseases in which they are involved are Petri disease and esca, which occur on grapevines and are caused by a complex of fungi, often including multiple species of Phaeoacremonium. Various Phaeoacremonium species are opportunistic fungi on humans and cause phaeohyphomycosis. The correct and rapid identification of Phaeoacremonium species is important to facilitate the understanding of their involvement in plant as well as human disease. A rapid identification method was developed for the 22 species of Phaeacremonium. It involved the use of 23 species-specific primers, including 20 primers targeting the β-tubulin gene and three targeting the actin gene. These primers can be used in 14 multiplex reactions. Additionally, a multiple-entry electronic key based on morphological, cultural and β-tubulin sequence data was developed to facilitate phenotypic and sequence-based species identification of the different Phaeoacremonium species. Separate dichotomous keys are provided for the identification of the Togninia and Phaeoacremonium species. Keys for the identification of Phaeoacremonium-like fungi and the genera related to Togninia are also provided. The mating strategy of several Togninia species was investigated with ascospores obtained from fertile perithecia produced in vitro. Togninia argentinensis and T. novae-zealandiae have homothallic mating systems, whereas T. austroafricana, T. krajdenii, T. minima, T. parasitica, T. rubrigena and T. viticola were heterothallic

Evaluation of Substrates for Mass Culture of <i>Phaeoacremonium parasiticum</i>, the Fungus Responsible for Artificial Oleoresin Deposition in Agarwood Plant

“…The other study suggested that discrepant optimal growth temperatures have been obtained for P. parasiticum, ranging from 25˚C -30˚C and the optimum was closer to 30˚ than to 25˚C [15]. Akhila et al [12], after trying incubating P. parasiticum at temperature viz., 25˚C ± 1˚C, 27˚C ± 1˚C, 30˚C ± 1˚C and 32˚C ± 1˚C in PDA media, concluded that optimal growth temperature of P. parasiticum was 30˚C ± 1˚C.…”

Phaeoacremonium species associated with olive wilt and decline in southern Italy

“…Moreover, of the 43 Phaeoacremonium species known throughout the world, of which 29 have been associated with decline and dieback diseases or with esca of grapevine, and have been isolated from grapevine necrotic wood (Crous et al 1996;Essakhi et al 2008;Graham et al 2009;Gramaje et al 2009;Larignon and Dubos 1997;Mohammadi and Banihashemi 2012;Morton 1995;Mostert et al 2006;Raimondo et al 2014;Sidoti et al 2000). This indicates that olive and grapevine hosts represent inoculum sources for each other, especially when olive orchards and vineyards are very close, as is frequently the case in Italy.…”

“…The morphological and culture characteristics were initially used to distinguish all fungal genera and species isolated from symptomatic tissues (De Hoog et al 2000;Ivic et al 2010;Phillips et al 2013;Rumbos 1988). Regarding Phaeoacremonium spp., a detailed morphological study was carried out based on structure and size, phialide type, extent of wart formation, and conidial shape and size (Essakhi et al 2008;Gams et al 2007;Mostert et al 2006;Raimondo et al 2014). A total of 378 strains of Phaeoacremonium spp.…”

Molecular Tools for Detection of Plant Pathogenic Fungi and Fungicide Resistance

“…Other housekeeping genes with higher variability are being more extensively used to develop diagnostics for fungi, including nuclear genes such as -tubulin (Aroca et al, 2008;Fraaije et al, 2001;Mostert et al, 2006), translation elongation factor 1 alpha (TEF 1 (Geiser et al, 2004;Knutsen et al, 2004, Kristensen et al, 2005, calmodulin (Mulè et al, 2004), avirulence genes (Lievens et al, 2009), and mitochondrial genes such as the multicopy cox I and cox II and their intergenic region (Martin & Tooley, 2003;Nguyen & Seifert, 2008;Seifert et al, 2007). Mating type genes also show high diversity and fast evolutionary rate and could be used for inter-and intra-species differentiation, e.g.…”