Neopestalotiopsis alpapicalis Vin. Kumar, Gentekaki & K.D. Hyde, 2019

Kumar, Vinit, Cheewangkoon, Ratchadawan, Gentekaki, Eleni, Maharachchikumbura, Sajeewa S. N., Brahmanage, Rashika S. & Hyde, Kevin D., 2019, Neopestalotiopsis alpapicalis sp. nov. a new endophyte from tropical mangrove trees in Krabi Province (Thailand), Phytotaxa 393 (3), pp. 251-262 : 253-259

Neopestalotiopsis alpapicalis Vin. Kumar, Gentekaki & K.D. Hyde , sp. nov. ( FIG. 2 )

Index Fungorum number: IF556161, Facesoffungi number: FoF 05753

Etymology:— Refers to small size of the apical cell, ‘alpa’ = small (Sanskrit), apicalis = apical (Latin).

Holotype:— MFLU 19-0405

Endophyte isolated from healthy leaves of Rhizophora mucronata and symptomatic leaves of R. apiculata . Asexual morph: Conidiomata (on PDA) pycnidial, globose to clavate, solitary or confluent, embedded or semi-immersed to erumpent, dark brown, 200–450 μm diam., exuding globose, dark brown to black conidial masses. Conidiophores indistinct often reduced to conidiogenous cells. Conidiogenous cells discrete, subcylindrical to ampulliform, hyaline, 8–15 × 1.5–2.5 μm. Conidia fusoid, ellipsoid, straight to slightly curved, 4-septate, 14–22.3 × 5–6.8 μm (x = 18.5 × 6.0 μm, n = 20); basal cell conic with a truncate base, hyaline, rugose and thin-walled, 2.7–6.5 μm long; three median cells doliiform, 12–15 μm long (x = 12.50 μm), wall smooth, versicoloured, septa darker than the rest of the cell (second cell from the base pale brown, 3.5–5.5 μm long; third cell honey brown, 3.4–5.6 μm long; fourth cell brown, 3.2–6.0 μm long); apical cell 0.75–2.3 (x = 1.25 μm) μm long, hyaline, subcylindrical, rugose, thin- and smooth-walled; with 1–4 tubular apical appendages (mostly 1 and 2, seldom 3 and 4), arising from the apical crest, unbranched, filiform, 5.6–15 μm (x = 9.3 μm); basal appendage single, tubular, unbranched, centric, 3.1–6.4 μm (x = 4.7 μm) long. Sexual morph: Undetermined.

Culture characteristics: Colonies on PDA attaining 25–30 mm diameter after 7 days at 26 ± 1 ° C, with undulate edge, white, sparse aerial mycelium on the surface with black, gregarious conidiomata; reverse pale yellow.

Habitat: Endophytic on leaves of Rhizophora mucronata and R. apiculata .

Material examined: THAILAND, Krabi Province, fresh asymptomatic leaves of Rhizophora mucronata ( Rhizophoraceae ), 22 Sept. 2017, Vinit Kumar, RM 5 ( MFLU 19-0405), holotype, ex-type culture MFLUCC 17-2544), ibid. BBH isotype.

Notes:— Neopestalotiopsis alpapicalis ( MFLUCC 17-2544) falls within Neopestalotiopsis and forms a separate branch with a sister strain, MFLUCC 17-2545 ( FIG. 1 ). N. alpapicalis is morphologically similar to N. samarangensis . However, N. samarangensis has 3 tubular apical appendages, which are long and thin, while N. alpapicalis has 1–4 short and thick apical appendages ( Maharachchikumbura et al. 2013a). Along with this, N. alpapicalis has smaller apical cell as compared to other species within Neopestalotiopsis (Maharach. et al. 2014) . When comparing the 472 TEF 1 nucleotides of N. alpapicalis with other N. rosicola in the clade, there are only 6 bp differences, 5 bp differences in ITS, and 2 bp difference in β- tub. Morphological characters of the two strains of N. alpapicalis ( MFLUCC 17-2544 and MFLUCC 17-2545), such as, the size of conidia, are often overlapping, but differ based on the size of apical cells, 0.75–2.3 (x = 1.25 μm) in MFLUCC 17-2544 and 2.0–4.0 (x = 2.75 μm). The sister taxon, N. rosicola ( CFCC 51992, CFCC 51993), is different from N. alpapicalis in terms of conidial size and in the number and size of apical appendages (1–4 in N. alpapicalis and 2–4 in N. rosicola ), while the size of apical appendages varies from 17−22.8 μm (x = 20.5 μm) in N. rosicola and 5.6–15 μm (x = 9.3 μm) in N. alpapicalis ( Crous et al. 2012, Maharach. et al. 2014, Jiang et al. 2018).

Figures

FIGURE 1. Maximum-likelihood phylogenetic tree inferred from combined ITS, β-tub and TEF1 gene sequences of 65 taxa. The GTR+ Γ model of nucleotide evolution was used. Strains of the newly described species are depicted in bold lettering.Values at tree nodes indicate bootstrap support and posterior probabilities in that order. Only bootstrap values above 60 and posterior probabilities above 0.9 are shown. Dashes indicate BP/BI with less than 50/0.9. The tree is artificially rooted to Pestalotiopsis humus (CBS 336.97), P. anacardiacearum (IFRDCC 2397), P. adusta (ICMP 6088), P. linearis (MFLUCC 12-0271) and P. inflexa (MFLUCC 12-0270).

FIGURE 2. Neopestalotiopsis alpapicalis (holotype MFLU 19-0405) on healthy leaf of Rhizophora mucronata. and symptomatic leaf of R. apiculata b, c Colony on PDA (above and below). d Conidiomata on PDA. e, f Conidia germinating from mycelia. g Conidiogenous cell. h–l Conidia. Scale bars: e–h = 10 μm, i–l = 5 μm.