Neodeightonia phoenicum A.J.L. Phillips & Crous

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

Neodeightonia phoenicum A.J.L. Phillips & Crous , Persoonia 21: 43 (2008), MycoBank MB511708

( Figure 11 )

Type: SPAIN, Catalonia, Tarragona, Salou, on Phoenix sp. ( Arecaceae ), date unknown, F. Garcia (holotype CBS H-20108, culture ex-type CBS 122528).

Sexual morph not reported. See Phillips et al. (2013) for illustrations and descriptions of asexual morph.

Isolate CDP 0281. Sexual morph: Undetermined. Asexual morph: Conidiomata on palm leaf pieces in culture pycnidial, globose to subglobose, slightly papillate, non-stromatic, uniloculate, dark brown to black, solitary or aggregated, scattered, immersed to semi-immersed, covered with greyish to blackish mycelial hairs, exuding a creamy, whitish mucoid mass or cirrus of conidia, immersed in the host becoming erumpent when mature. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the pycnidial cavity, hyaline, smooth- and thin-walled, simple, indeterminate, cylindrical, often swollen at the base, few lageniform to ampulliform, straight or curved, aseptate, enteroblastic, proliferating at the same level giving rise to inconspicuous periclinal thickenings, or proliferating percurrently to form 1–2 annellations, variable in size, 8.32–18.06 × 3.21–11.02 μm, 95 % confidence limits = 12.11– 14.23 × 4.65–5.95 μm (mean ± SD = 13.17 ± 2.96 × 5.30 ± 1.82 μm, n = 30). Conidia broadly ellipsoid to obovoid, apex and base broadly rounded, widest in the middle to upper third, thick-walled, initially hyaline and aseptate, becoming pale to dark brown and 1-septate, with melanin deposits on the inner surface of the wall arranged longitudinally giving a striate appearance to the conidia, mostly eguttulate, 13.37–19.49 × 7.75–10.33 μm, 95 % confidence limits = 16.35–17.45 × 8.80–9.28 μm (mean ± SD = 16.90 ± 1.54 × 9.04 ± 0.67 μm), mean ± SD conidium length/width ratio = 1.88 ± 0.23 (n = 30).

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

Material examined: PORTUGAL, Lisbon, Parque das Nações, Jardim das Palmeiras, on foliar lesions of segments of Phoenix dactylifera ( Arecaceae ), 16 October 2018, Diana S. Pereira (specimen HDP 046, new geographical record), living cultures CDP 0281 (ITS sequence OQ996220), CDP 0284 (ITS sequence OQ996221), CDP 0290 (ITS sequence OQ996222); Parque das Nações, Cais dos Argonautas, on foliar lesions of segments of Phoenix reclinata ( Arecaceae ), 24 October 2018, Diana S. Pereira (specimen HDP 055), living culture CDP 0593 (ITS sequence OQ996224); Parque das Nações, Cais dos Argonautas, on foliar lesions of segments of Phoenix reclinata ( Arecaceae ), 24 October 2018, Diana S. Pereira (specimen HDP 060), living cultures CDP 0745 (ITS sequence OQ996225), CDP 0771 (ITS sequence OQ996226, tef1 sequence OR233667), CDP 0774 (ITS sequence OQ996227, tef1 sequence OR233668).

Hosts: Phoenix spp. , including P. canariensis ( Phillips et al. 2008) , P. dactylifera ( Phillips et al. 2008, Elliot et al. 2018, Nishad & Ahmed 2020, present study), P. reclinata ( Rathnayaka et al. 2022b, present study), P. roebelenii ( Zhang & Song 2022) and unidentified Phoenix species ( Phillips et al. 2008, Ligoxigakis et al. 2013) ( Arecaceae ).

Distribution: China ( Zhang & Song 2022), Greece ( Ligoxigakis et al. 2013), Portugal (Lisbon) (present study), Quatar ( Nishad & Ahmed 2020), Spain ( Phillips et al. 2008), Thailand ( Rathnayaka et al. 2022b), USA (California) ( Phillips et al. 2008, Elliot et al. 2018).

Notes: Based on the phylogenetic analysis of the combined ITS- tef1 dataset, strains CDP 0281, CDP 0284, CDP 0290, CDP 0593, CDP 0745, CDP 0771 and CDP 0774 clustered with the ex-type strain and other strains of Neodeightonia phoenicum with high ML-BS/PP values ( Figure 4 ). Sequence comparisons with the ex-type of N. phoenicum (CBS 122528) for ITS and tef1 showed 99.61–100 % and 98.14 %, respectively, sequence similarity and differences are represented by gaps or single nucleotide changes in ITS1 and tef1 partial sequences. Morphologically, the strains isolated in this study are similar to the holotype of N. phoenicum from Phoenix sp. in Spain ( Phillips et al. 2008) ( Figure 11 ). Considering the strain characterized here (CDP 0281) and the ex-type strain of N. phoenicum (CBS 122528), both produce dark brown to black pycnidial conidiomata with ellipsoid, hyaline and aseptate conidia that become pigmented, 1-septate and striate after discharge from the conidiomata ( Phillips et al. 2008) ( Figure 11 ). Nevertheless, the mean size of the conidia observed here (CDP 0281) is smaller than that reported for the ex-type strain (CBS 122528) (16.90 × 9.04 μm and 19.1 × 11.5 μm, respectively), though a similar mean conidium length/width ratio was observed (1.88 and 1.7, respectively) ( Phillips et al. 2008). Thus, based on these morpho-molecular analyses, strains CDP 0281, CDP 0284, CDP 0290, CDP 0593, CDP 0745, CDP 0771 and CDP 0774 are here reported as representing intraspecific variation of N. phoenicum . This intraspecific variation on the morphology of N. phoenicum has also been reported from other collections ( Rathnayaka et al. 2022b). Neodeightonia phoenicum has only been reported from Phoenix spp. ( Arecaceae ), including P. canariensis , P. dactylifera , P. reclinata and P. roebelenii , and thus it is apparently restricted to palms. Nonetheless, it has not previously been reported from Portugal, representing a new geographical record ( Table 5). The isolates of N. phoenicum studied here were recorded from foliar lesions of P. dactylifera and P. reclinata , but pathogenicity has not been tested. Nonetheless, N. phoenicum is an important pathogen of Phoenix hosts worldwide and has already been reported has a palm rot disease pathogen of Phoenix spp. in Greece and Quatar, as well as a leaf spotting agent of P. roebelenii in China ( Ligoxigakis et al. 2013, Nishad & Ahmed 2020, Zhang & Song 2022).

Figures

FIGURE 4. Phylogenetic tree of Neodeightonia 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 last accepted species names are noted after the strain number in quotation marks where species were synonymised in this study. The scale bar represents the expected number of nucleotide changes per site. The tree was rooted to Botryosphaeria corticis (CBS 119047) and B. dothidea (CBS 115476).

FIGURE 11. Neodeightonia phoenicum (CDP 0281). A. Conidiomata formed on palm leaf piece. B. Conidiogenous layer. C–H. Conidiogenous cells. I. Hyaline, aseptate conidia. J, K. Pigmented, 1-septate conidium with longitudinal striations observed through optical sectioning. Scale bars:A = 1 mm, B, I = 10 μm, C–H, J, K = 5 μm.