Dothiorella viticola A.J.L. Phillips & J. Luque, Mycologia

Pereira, Diana S. & Phillips, Alan J. L., 2023, Botryosphaeriaceae on palms-a new species of Neodeightonia, N. chamaeropicola, and new records from diseased foliage of ornamental palms in Portugal, Phytotaxa 627 (1), pp. 1921-1935 : 1921-1935

Dothiorella viticola A.J.L. Phillips & J. Luque, Mycologia 97: 1118 (2005), MycoBank MB357425

( Figure 9 )

Type: SPAIN, Catalonia, Vim-bodí, near the Monastery of Poblet, on pruned canes of Vitis vinifera cv. Garnatxa Negra ( Vitaceae ), Aug 2004, J. Luque & S. Martos, (holotype LISE 95177, culture ex-type CBS 117009).

Sexual morph and asexual morph reported. See Phillips et al. (2013) for illustrations and descriptions.

Isolate CDP 1010. Sexual morph: Undetermined. Asexual morph: Conidiomata on palm leaf pieces in culture pycnidial, spherical, globose to subglobose, few slightly papillate, non-stromatic to stromatic, uniloculate, rarely multiloculate, black, solitary, occasionally aggregated, semi-immersed to superficial, immersed when produced on culture medium, glabrous, covered with few mycelial hairs towards the ostiolar region, thick-walled. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the pycnidial cavity, hyaline, smooth- and thin-walled, simple, discrete, determinate, cylindrical to broadly lageniform, straight, aseptate, enteroblastic, proliferating at the same level giving rise to periclinal thickenings, occasionally proliferating percurrently giving rise to 1–2 annelations, 6.65–13.68 × 2.97–7.75 μm, 95 % confidence limits = 8.24–9.37 × 3.90–4.72 μm (mean ± SD = 8.80 ± 1.60 × 4.31 ± 1.17 μm, n = 30). Conidia broadly ellipsoid or oblong, often broadly obovoid, rounded ends, often with truncated base, dark brown and 1-septate, finely rough- and moderately thick-walled, eguttulate, 17.85–21.86 × 8.12–10.79 μm, 95 % confidence limits = 19.70–20.43 × 9.20–9.72 μm (mean ± SD = 20.06 ± 1.02 × 9.46 ± 0.74 μm), mean ± SD conidium length/width ratio = 2.13 ± 0.20 (n = 30).

Culture characteristics: Colonies on 1/2 PDA, reaching 85 mm diam. after 7 d at 20 ℃ in darkness. Surface slightly raised, with fluffy, cottony aerial mycelium, with entire margin, circular shape, whitish to olivaceous towards the centre, opaque. Reverse pale to dark brown to blackish towards the centre. Turning entirely smokey grey (surface) and dark brown to blackish (reverse) after about 2 w. No diffusible pigment.

Material examined: PORTUGAL, Lisbon, Areeiro, Robalo Gouveia Street, on foliar lesions of segments of Trachycarpus fortunei ( Arecaceae ), 26 October 2018, Diana S. Pereira (specimen HDP 069, new host and geographical record), living culture CDP 1010 (ITS sequence OQ996228, tef1 sequence OR233683); Parque das Nações, on foliar lesions of leaflets of Phoenix roebelenii ( Arecaceae ), 8 May 2021, Diana S. Pereira (specimen HDP 088, new host record), living culture CDP 1381 (ITS sequence OQ996230, tef1 sequence OR233684); Parque das Nações, on foliar lesions of segments of Chamaerops humilis ( Arecaceae ), 8 May 2021, Diana S. Pereira (specimen HDP 090, new host record), living culture CDP 1513 (ITS sequence OQ996234, tef1 sequence OR233685); Parque das Nações, on foliar lesions of segments of Washingtonia filifera ( Arecaceae ), 8 May 2021, Diana S. Pereira (specimen HDP 095, new host record), living cultures CDP 1813 (ITS sequence OQ996240, tef1 sequence OR233686), CDP 1815 (ITS sequence OQ996241, tef1 sequence OR233687).

Hosts: Chamaerops humilis ( Arecaceae ), Citrus sinensis , Citrus sp. ( Rutaceae ), Juglans regia ( Juglandaceae ), Phoenix roebelenii ( Arecaceae ), Podocarpus henkelii ( Podocarpaceae ), Populus cathayana ( Salicaceae ), Prunus domestica , P. dulcis , P. pérsica , P. salicina ( Rosaceae ), Trachycarpus fortunei ( Arecaceae ), Vachellia karroo ( Fabaceae ), Vitis vinifera ( Vitaceae ) and Washingtonia filifera ( Arecaceae ) ( Farr & Rossman 2023, present study).

Distribution: Australia, China, Iran, Portugal, South Africa, Spain, Tunisia and USA (California) ( Farr & Rossman 2023, present study).

Notes: Based on the phylogenetic analyses of the combined ITS- tef1 dataset, strains CDP 1010, CDP 1381, CDP 1513, CDP 1813 and CDP 1815 clustered with the ex-type strain and other strains of Dothiorella viticola with high ML-BS/PP values ( Figure 3 ). Sequence comparisons with the ex-type of D. viticola (CBS 117009) for ITS and tef1 showed 99.78–100 % and 99.15–99.78 %, respectively, sequence similarity and differences are represented by gaps or single nucleotide changes in ITS2, and single nucleotide changes in tef1 partial sequences. Morphologically, the strains isolated in this study are similar to the holotype of D. viticola from Vitis vinifera in Spain ( Luque et al. 2005) ( Figure 9 ). Considering the strain characterized here (CDP 1010) and the ex-type strain of D. viticola (CBS 117009), both produce spherical, globose, black pycnidial conidiomata with oblong, dark-brown, moderately thick-walled and 1-septate conidia, which display very similar dimensions (mean = 20.06 × 9.46 μm for CDP 1010 versus 20.4 × 9.3 μm for CBS 117009) ( Luque et al. 2005) ( Figure 9 ). Dothiorella viticola has not previously been reported from Portugal, representing a new geographical record. Moreover, this is the first time this species is recorded on palms and thus four new host records are reported, namely Trachycarpus fortunei , Phoenix roebelenii , Chamaerops humilis and Washingtonia filifera ( Table 5). The isolates of D. viticola studied here were recorded from foliar lesions of palms but pathogenicity has not been tested.

Figures

FIGURE 3. Phylogenetic tree of Dothiorella generated from BA inference based on combined ITS and tef1 sequences. ML bootstrap support values (ML-BS ≥ 50 %) and Bayesian posterior probabilities (PP ≥ 0.85) are shown at the nodes. Strains with type status are indicated in bold font, the isolates from this study are presented in brown typeface and species are delimited with coloured blocks. The scale bar represents the expected number of nucleotide changes per site. The tree was rooted to Neofusicoccum australe (CMW 6837) and N. luteum (CBS 562.92).

FIGURE 9. Dothiorella viticola (CDP 1010). A–F. Conidiogenous layer (A,B and E,F represent different optical sections of the conidiogenous layer). G–I. Conidiogenous cells. J. Conidia. Scale bars:A–F, J = 5 μm, G–I = 2.5 μm.