Phaeobotryon platycladi L. Lin & X.L. Fan, 2023

Lin, Lu, Bai, Yukun, Pan, Meng, Tian, Chengming & Fan, Xinlei, 2023, Morphology and molecular analyses reveal three new species of Botryosphaeriales isolated from diseased plant branches in China, MycoKeys 97, pp. 1-19 : 1

Phaeobotryon platycladi L. Lin & X.L. Fan sp. nov.

Fig. 6

Etymology.

Named after the host genus, Platycladus .

Description.

Conidiomata pycnidial, scattered, subglobose to globose, erumpent, exuding faint yellow translucent conidial droplets from central ostioles, unilocular, 150-250 μm diam. Disc black, 80-200 µm in diam. Ostioles single, central, papillate, 21-35 µm. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, thin-walled, cylindrical, holoblastic, phialidic, proliferating internally with visible periclinal thickening, 5.5-14.0 × 2.5-4.0 μm (av. ± S.D. = 10.2 ± 2.5 × 3.2 ± 0.4 μm). Conidia initially hyaline, oval, both ends broadly rounded, aseptate, rarely becoming 1-septate, 23.0-31.0 × 9.5-12.5 μm (av. ± S.D. = 26.2 ± 2.5 × 10.8 ± 0.8 μm).

Culture characters.

Colonies on PDA spreading, upper white to buff, reverse buff to isabelline covering a 90 mm plate after 14 days at 25 °C. Colonies on MEA spreading, stratiform, with appressed aerial mycelium and crenate edge, upper white to isabelline, reverse buff to hazel, covering a 90 mm plate after 14 days at 25 °C.

Materials examined.

China, Beijing City, Haidian District, National Botanic Gardens , 39°59'42.41"N, 116°12'47.24"E, on dead branches of Platycladus orientalis , 4 August 2022, Yukun Bai & Xinlei Fan (holotype BJFC CF20230110, ex-holotype culture CFCC 58799); 39°59'42.43"N, 116°12'47.46"E, on dead branches of Platycladus orientalis , 4 August 2022, Yukun Bai & Xinlei Fan (paratype BJFC CF20230111, ex-paratype culture CFCC 58800) .

Notes.

Phaeobotryon platycladi is monophyletic with Ph. cupressi in the phylogenetic tree without a significant statistical support. Conidial sizes of the two species overlap, but there are differences in 6/488 in ITS region, 3/556 in LSU region, and 18/293 in tef1 -α gene with gaps.

Figures

Figure 6. Phaeobotryon platycladi (BJFC CF 20230110) A, B habit of conidiomata on twig C transverse section of a conidioma D longitudinal section through a conidioma E-G conidiogenous cells and conidia H colony on PDA at 14 days I colony on MEA at 14 days. Scale bars: 2 mm (A); 200 µm (B-D); 10 µm (E-G).