Apiospora lophatheri S.J. Li & C.M. Tian, 2023

Li, Shuji, Peng, Cheng, Yuan, Rong & Tian, Chengming, 2023, Morphological and phylogenetic analyses reveal three new species of Apiospora in China, MycoKeys 99, pp. 297-317 : 297

Apiospora lophatheri S.J. Li & C.M. Tian sp. nov.

Fig. 4

Type.

China, Yunnan Province, Xishuangbanna Primeval Forest Park, on diseased leaves of Lophatherum gracile , 4 June 2022, S.J. Li, holotype BJFC-S1917; ex-type living cultures CFCC 58975, CFCC 58976 .

Etymology.

Named after the host from which it was isolated.

Description.

Asexual morph: Sporulated on PDA, mycelium consisting of hyaline, smooth, branched, septate hyphae 1.0-5.2 µm in diam. (n = 20). Conidiophores reduced to conidiogenous cells. Conidiogenous cells aggregated in clusters on hyphae, hyaline to pale brown, smooth, doliiform, clavate to ampulliform, 2.2-11.9 × 2.2-4.9 µm, mean ( ± SD): 6.4 ( ± 2.5) × 3.4 ( ± 0.6) µm (n = 50). Conidia globose, subglobose to lenticular, with a longitudinal germ slit, olive to dark brown, smooth to finely roughened and two or more conidia are produced on each conidiogenous cell, 5.1-8.9 × 4.6-7.7 µm, mean ( ± SD): 6.5 ( ± 0.8) × 5.9 ( ± 0.7) µm, L/W = 1.0-1.4 (n = 50). Sexual morph: Undetermined.

Culture characteristics.

On PDA, colonies flat, spreading, margin circular, thick, concentrically spreading with aerial mycelium, surface light greyish-brown, reverse tawny pigment diffused in media, mycelia white to grey and pale brown, sporulation on hyphae, reaching 9 cm in 7 days at 25 °C.

Notes.

Phylogenetic analysis indicated that Apiospora lophatheri is closely related to a clade comprising A. chromolaenae , A. euphorbiae , A. italicum , A. malaysiana , A. phyllostachydis , A. thailandica and A. vietnamense (Fig. 1 ). We compared the new species with phylogenetically similar taxa, based on morphological differences (Table 3 ) and base pair differences (Table 4 ). A. lophatheri can be differentiated from A. chromolaenae by its wider conidiogenous cells (2.2-11.9 × 2.2-4.9 µm vs. 6.5-12 × 1-2 µm) (from Euphorbia sp.; collected in Zambia; Ellis (1965)) and by 18 gene base pair differences (17/529 in ITS, 1/838 in LSU). A. lophatheri differs from A. euphorbiae by its larger olive to dark brown conidia (5.1-8.9 × 4.6-7.7 µm vs. 4-5.5 × 3-4 µm) (from Euphorbia sp.; collected in Zambia; Ellis (1965)), with nucleotide differences in ITS as 3/529, in LSU as 2/318, in tub2 as 22/801. A. italicum has smaller conidia (4-6 × 3-4 µm) (from Arundo donax ; collected in Italy; Pintos et al. (2019)) and has 125 nucleotides differences (41/552 in ITS, 2/828 in LSU, 27/432 in tef1, 55/838 in tub2). Additionally, A. lophatheri is distinguished from A. malaysiana by having larger globose or subglobose conidia (5.1-8.9 × 4.6-7.7 µm vs. 5-6 × 3-4 µm) (from Macaranga hullettii ; collected in Malaysia; Crous and Groenewald (2013)), with 43 nucleotide differences (3/529 in ITS, 1/838 in LSU, 18/424 in tef1, 21/801 in tub2). A. lophatheri differs from A. phyllostachydis by its relatively shorter conidiogenous cells (2.2-11.9 × 2.2-4.9 µm vs. 20-55 × 1.5-2.5 µm) (from Phyllostachys heteroclada ; collected in China; Yang et al. (2019)) and by 48 nucleotides differences (7/529 in ITS, 3/838 in LSU, 12/424 in tef1, 26/795 in tub2). A. lophatheri can be differentiated from A. thailandica by having shorter conidiogenous cells (2.2-11.9 × 2.2-4.9 µm vs. 11.5-39 × 2-3.5 µm) (from bamboo; collected in Thailand; Dai et al. (2017)) and by 12 nucleotides differences (9/529 in ITS, 3/828 in LSU). The conidia of A. lophatheri are significantly wider and paler-coloured than those of A. vietnamense (5.1-8.9 × 4.6-7.7 µm vs. 5-6 × 3-4 µm) (from Citrus sinensis ; collected in Vietnam; Wang et al. (2018)) and there are 7 nucleotides differences between the two species (2/526 in ITS, 2/803 in LSU, 3/315 in tub2). Therefore, A. lophatheri is described as a new species, based on phylogeny and morphological comparison.

Figures

Figure 1. Phylogram of Apiospora, based on combined ITS, LSU, tef 1 and tub 2 genes. ML bootstrap support values (≥ 50 %) and Bayesian posterior probability (≥ 0.90) are shown as first and second position above nodes, respectively. Strains from this study are shown in blue boxes, ex-type or ex-epitype cultures are indicated in bold face. Some branches were shortened according to the indicated mulipliers.

Figure 4. Apiospora lophatheri (CFCC 58975, ex-holotype culture) A leaf of host plant B colony on PDA C conidiomata formed in culture D conidiogenous cells giving rise to conidia E, F conidia. Scale bars: 1000 µm (C); 10 µm (D-F).