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

Fig. 5

Type.

China, Yunnan Province, Lincang City Triangle Plum Garden , on diseased leaves of Oenothera biennis , 26 April 2022, S.J. Li, holotype BJFC-S1919, ex-type living cultures CFCC 58972, LS 395 .

Etymology.

Named after the host from which it was isolated.

Description.

Asexual morph: Hyphae hyaline, branched, septate, 1.2-4.8 µm in diam. (n = 20). Conidiophores reduced to conidiogenous cells. Conidiogenous cells smooth, ampulliform to doliiform, 2.0-14.2 × 1.1-4.9 µm, mean ( ± SD): 5.4 ( ± 2.9) × 3.1 ( ± 1.1) µm (n = 50). Conidia globose, subglobose to lenticular, with a longitudinal germ slit, occasionally elongated to ellipsoidal, colourless to dark brown, smooth to finely roughened, 6.6-13.9 × 5.5-10.1 µm, mean ( ± SD): 8.9 ( ± 1.2) × 7.8 ( ± 1.1) µm, L/W = 1.0-1.5 (n = 50). Sexual morph: Undetermined.

Culture characteristics.

On PDA, colonies thick, concentrically spreading with aerial mycelium, circular, margin irregular, yellow to pale green pigment diffused into medium, surface with aerial mycelia, the reverse lightly pigmented with a few dark yellow patches, mycelia white to grey, sporulation occurs after 10 days, reaching 9 cm in 7 days at 25 °C.

Notes.

Apiospora oenotherae belongs to the large clade, where it shows a relationship with A. gaoyouense , A. hispanicum , A. locuta-pollinis , A. longistroma , A. marii , A. mediterranei , A. piptatheri and A. pseudomarii (Fig. 1 ), but differs in distinct morphological characters (Table 3 ) and nucleotide differences (Table 5 ). A. oenotherae differs from A. gaoyouense by its production of significantly conidiogenous cells (2.0-14.2 × 1.1-4.9 µm vs. 1-2 × 2-3 μm) (from Phragmites australis ; collected in China; Jiang et al. (2018)) and the presence of 30 distinct nucleotide positions (9/583 in ITS, 12/413 in tef1, 9/784 in tub2). A. oenotherae is distinct from A. hispanicum in producing larger conidial cells (6.6-13.9 × 5.5-10.1 µm vs. 7.5-8.5 × 6.2-7.6 µm) (from maritime sand; collected in Spain; Larrondo and Calvo (1992)) and in 30 nucleotides differences (1/539 in ITS, 1/320 in LSU, 28/796 in tub2). A. oenotherae differs from A. locuta-pollinis by its production of significantly conidiogenous cells (2.0-14.2 × 1.1-4.9 µm vs. 3-7.5 × 3-6 μm) (from hive-stored pollen; collected in China; Zhao et al. (2018)) and by the presence of 19 distinct nucleotide positions (1/539 in ITS, 7/416 in tef1, 11/485 in tub2). A. longistroma can be distinguished by growth rate, growing slowly on PDA, reaching 60 mm in 4 weeks (from bamboo; collected in Thailand; Dai et al. (2017)) and by the presence of 8 distinct nucleotide positions (6/572 in ITS, 2/840 in LSU). Moreover, A. mari produces elongated cells intermingled amongst conidia (from beach sand; collected in Spain; Crous and Groenewald (2013)), but A. oenotherae does not and can be distinguished by the presence of 23 distinct nucleotide positions (1/539 in ITS, 10/414 in tef1, 12/787 in tub2). Strains of A. mediterranei were isolated from pharmaceutical excipient, air-borne and on grass in Spain, while those of A. oenotherae collected from Oenothera biennis in China. There are no discernible morphological characters distinguishing these species, but the elongated stem branches and the presence of 30 distinct nucleotide positions (1/539 in ITS, 1/320 in LSU, 28/796 in tub2) serve as clear indicators of their distinct and phylogenetically well-separated taxa. A. oenotherae differs from A. piptatheri because of its wider conidial cells (6.6-13.9 × 5.5-10.1 µm vs. 6-8 × 3-5 μm) (from Piptatherum miliaceum ; collected in Spain; Pintos et al. (2019)) and the presence of 14 distinct nucleotide positions (10/528 in ITS, 4/827 in LSU). It also differentiates from A. pseudomarii through the production of notably wider conidial cells (6.6-13.9 × 5.5-10.1 µm vs. 6-9 × 4.5-6 µm) and through 12 unique nucleotide positions (5/556 in tef1, 7/416 in tub2) (from Aristolochia debilis ; collected in China; Chen et al. (2021)).

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 5. Apiospora oenotherae (CFCC 58972, ex-holotype culture) A leaf of host plant B colony on PDA C conidiomata formed in culture D, E conidiogenous cells giving rise to conidia F conidia. Scale bars: 1000 µm (C); 10 µm (D-F).