Podonectriaceae H.T. Dao & MycoBank number: MB 304079Rossman, Mycological Progress 15(5): 47 (2016) amended.2021
MycoBank number: MB 304079
Type genus: Podonectria Petch, Trans. Br. mycol. Soc. 7(3): 146 (1921)
Morphological description:
Sexual morph: Stromata byssoid, brown, well-developed, and covered the scale insects. Ascomata solitary, rarely aggregated, superficial on the byssoid stroma, concomitant with sporodochia, light yellow, covered with long hairs, 150–415 µm high (x = 240 µm, n = 20), 100–350 µm wide (without hairs) (x = 192 µm, n = 30). Hairs 60–280 µm long, multiseptate, 3–6.5 µm wide, straight, or curved, abundant, hyaline, slightly narrowed toward the apex, 1–2.5 µm thick-walled (n = 30). Peridium 60–100 µm thick, usually wider at the base, composed of hyaline suborbicular cells forming textura angularis, the cells measuring 5.5–12 × 4.5–10 µm (x = 8.9 × 7.0 µm, n = 20). Hamathecium 1.5–3 µm diameter (x = 2.3 µm, n = 30), 1 µm diameter at the apex, longer than the asci, numerous, filiform, curved, septate, branched pseudoparaphyses. Asci 220–340 × 18–26 µm (x = 267 × 21 µm, n = 20), 8-spored, bitunicate, cylindrical, straight, or curved, rounded at apex. Ascospores 100–160 × 7–10 µm (x = 138 × 9 µm, n = 30), fasciculate, parallel, long-clavate, rounded at ends, multiseptate, 10–22 septa with slight constriction, curved, hyaline, smooth.
Asexual morph: Stromata hard, white to grey-brown, cushion-shaped, formed directly on host scales with 1–4 sporodochia. Sporodochia erupted, white, yellowish to grey-brown, scattered or aggregated. Conidiophores inconspicuous, short, 1–2 celled, the cells 3–7 × 4–10 µm (x = 5.0 × 7.5 µm, n = 30), usually globose, subglobose, or shortly cylindrical, attached with 1–2 conidiogenous cells. Conidiogenous cells 3–7 × 4–11 µm (x = 7.3 × 6.5 µm, n = 30), globose or ellipsoidal. Conidia usually with two and three “arms”, occasionally one and four “arms”, each “arm” varies in length and slightly divergent, 85–163 µm long (x = 117 µm, n = 70), 7–11 µm wide (x = 9 µm, n = 70) with 11–25 septa, mature conidium tapering toward the acute apex. All “arms” of single conidium joined at a basal oval or irregular cell, measuring 4–7 × 5–10 µm (x = 5.3 × 7.1 µm, n = 40).
Culture characters: Conidia germinate on PDA within 12 h, and the cultures grow slowly on PDA. Colonies reach 2 cm in diameter after 25 days. Colonies from single conidia are flocculent and hard, with irregular margins. The mycelium is creamy white to light lemon yellow starting at the center but gradually becoming brown to dark brown after 20 days. Aerial hyphae cluster and raise straightly, measuring 2–3 µm diam. Conidia develop on small, sparsely distributed mycelial clumps after two months. Conidiophores moniliform, branched, multi-celled, and longer than those in nature. Conidia commonly have three “arms”, occasionally two and four “arms”, rarely one and five “arms”, each “arm” with 17–22 septa, measuring 115–145 µm long, 6.5–10 µm wide (x = 128 × 7.9 µm, n = 30). Ascospores germinate on PDA within 12 h, and the cultures grow slowly on PDA. Colonies reach 1 cm in diameter after 20 days. Colonies from single ascospores are cottony, with regular margin; the mycelium is creamy white to yellow; and the back of colonies is brown, with concentric rings.
Habitat ), on scale insect Kuwanaspis howardi
Distribution: CHINA, Sichuan Province, Ya’an City, Lushan County (102◦55058.1300 E, 30◦15024.0700 N, Alt. 1116 m)
GenBank Accession: XXL202006006 (SICAU 21-0005), living culture SICAUCC 21-0005; ibid. XXL202006005 (SICAU 21-0004), living culture SICAUCC 21-000
Notes: Here, we follow the recommendation of Rossman et al. [62] by adopting Podonectria over Tetracrium. The asexual morph of P. novae-zelandiae was reported by Dao et al. [5], and was supported with morphology and molecular data. Our observations agree with the descriptions provided by Rossman [4] and Dao et al. [5]. Nucleotide comparison of ITS and LSU (SICAUCC 21-0005) reveals high similarity to P. novae-zelandiae (isolate PUcS13, similarities = 473/476 (99%), 0 gaps (0%); similarities = 517/518 (99%), 0 gaps (0%), respectively) in Dao et al. [5]; however, the latter lack SSU, tef1-α, and rpb2 sequences for further comparisons. The conidia produced here in culture were similar to those on scale insects in the field.
Reference:[1] Humber, R. A. . (2008). Evolution of entomopathogenicity in fungi. Journal of Invertebrate Pathology, 98(3), 262-266.
Podonectria novae-zelandiae (SICAU 21-0005). (a,b) Ascomata and sporodochia on host
substrate. (c) Section through ascoma. (d) Peridium. (e,f) Hairs covering on ascoma. (g) Pseudoparaphyses. (h) Ocular chamber. (i–k) Asci. (l–p) Ascospores. (q) Germinated ascospores. (r,s) Colonies
on PDA after 18 days. Scale bars: (a,b) 200 µm, (c) 100 µm, (d) 50 µm, (e–g) 20 µm, (h) 10 µm,
(i–q) 20 µm
Podonectria novae-zelandiae (SICAU 21-0004). (a–c) Sporodochia and ascomata on host
substrate. (d–f) Immature conidia. (g–j) Mature conidia. (k,l) Conidiophores. (m,n) Colonies on
PDA after 20 days and 60 days. (o) Germinated conidium. Scale bars: (a–c) 500 µm, (d–k) 20 µm,
(l,o) 10 µm.
