Tuber longispinosum A. Kinosh., 2018

Kinoshita, Akihiko, Nara, Kazuhide, Sasaki, Hiromi, Feng, Bang, Obase, Keisuke, Yang, Zhu L. & Yamanaka, Takashi, 2018, Using mating-type loci to improve taxonomy of the Tuber indicum complex, and discovery of a new species, T. longispinosum, PLoS ONE (e 0193745) 13 (3), pp. 1-21 : 9-12

Tuber longispinosum A. Kinosh. sp. nov. ( Fig 6A–6F ).

[urn:lsid:mycobank.org:names: MB 821786].

Diagnosis: Differing from T. indicum and T. himalayense in ascospore ornamentation consisting of spines that are unconnected, and narrow at the base; and its significantly long spines.

Holotype: JAPAN, OITA Prefecture, under Quercus acutissima Carruth. , 7 Oct 2006, collected by Hiromi Sasaki, K447 ( TFM: S17009 ).

Ascomata subglobose, brown to dark greyish, 20–70 mm in diam. Peridium warty, two layers, the outer layer pseudoparenchymatous and composed of irregular cells. Gleba whitish

when young, becoming grayish brown to blackish at maturity with yellowish cream to white veins. Asci 1–5(–6)-spored, 59–72 × 50–59 μm, subglobose to broadly ellipsoid. Ascospores ellipsoid to subglobose with spiny ornamentation, brown to dark brown, (15–)21–35(–41) × (12–)15–26(–30) μm in diam excluding ornamentation.

Etymology: longispinosum (Lat.) , referring to “with long spine” from its spore ornamentation (Japanese name “ Iboseiyoshoro ” from ibo = warts, seiyoshoro = Japanese name for the genus Tuber ).

Ascomata: hypogeous, 20–70 mm in diam., subglobose and slightly lobed, firm, brown (10 R 4/8) to dark greyish (7.5YR 8/18), with low polygonal warts, 3–7 ridges, up to 900 μm high. Odor: aromatic, similar to seaweed or laver boiled in soy sauce when mature. Peridium: 400–800 μm thick, variable, pseudoparenchymatous, composed of two layers: outer layer 100– 200 μm thick, composed of irregular or ellipsoidal cells, 7–28 × 5–18 μm, with thick dark brown walls of 1–2 μm; inner layer 200–600 μm thick, composed of hyaline to yellowish, polygonal cells 5–15 × 5–10 μm that merge with glebal tissue of interwoven hyphae. Gleba: solid, whitish when young, becoming greyish brown to blackish at maturity, marbled with distinct, yellowish cream to whitish, meandering veins that merge at many points. Glebal tissue of interwoven hyphae: 3–8 μm broad with scattered cells, gelatinized, inflated up to 10 μm. Asci:

https://doi.org/10.1371/journal.pone.0193745.g005

typically subglobose to broadly ellipsoid, occasionally ellipsoid, variable depending on the number of spores, 59–72 × 50–59 μm (n = 177), rarely stipitate, 1–5(–6)-spored. Ascospore: ellipsoid, whitish or hyaline (glass-like) when young, becoming light brown (5 Y 8/3) to dark brown (5YR 9/4) at maturity, 31–41 × 22–30 μm, Q = 1.3–1.6 (1-spored, n = 18); 21–38 × 16– 29 μm, Q = 1.0–1.8 (2-spored, n = 78); 19–34 × 15–26 μm, Q = 1.1–1.7 (3-spored, n = 70); 15– 33 × 13–22 μm, Q = 1.0–2.1 (4-spored, n = 146); 16–31 × 12–20 μm, Q = 1.1–1.8 (5-spored,

n = 118); 15–26 × 13–18 μm, Q = 1.0–1.8 (6-spored, n = 24), excluding ornamentation, typically free spines, 3–7 (–12) μm (n = 430) in height with 1–4-μm bases.

Habitat and distribution: The fruiting period is from July to January. Woodland or forest edges under Abies ( Pinaceae ), Carpinus ( Betulaceae ), and Castanopsis and Quercus ( Fagaceae ).

Additional specimens examined (paratypes): JAPAN, KANAGAWA Prefecture, Atsugi City, under Carpinus tschonoskii Maxim. and Quercus serrata Murray , 9 Dec 2007, collected by Hiromi Sasaki, K 230 ( TFM: S 17001); Hayama-cho, under Castanopsis sieboldii (Makino) Hatsushima ex Yamazaki et Masiba and Quercus glauca Thunb. , 30 Dec 2002, collected by Hiromi Sasaki, K 70 ( TFM: S 17002); Ibid., 25 Oct 2004, collected by Kazuhide Nara, N 52 ( TFM: S 17004); Ibid., 23 Dec 2005, collected by Hiromi Sasaki, K 466 ( TFM: S 17003); SHIZUOKA Prefecture, Izu City, under Abies firma Sieb. Et Zucc. , Quercus salicina Blume , and Q. serrata , 31 Jan 2003, collected by Hiromi Sasaki, K 395 ( TFM: S 17005); KOCHI Prefecture, Umaji Village, under Q. glauca and Q. serrata , 3 Feb 2017, S 71 ( TFM: S 17006); EHIME Prefecture, Matsuyama City, 14 Oct 2006, collected by Fumitaka Nagao, K 209 ( TFM: S 17007); OITA Prefecture, Saiki City, under Quercus spp. , 17 Oct 2003, collected by Yoichi Sunada, K 401 ( TFM: S 17008); Yufuin-cho, 29 Sep 2007, collected by Atsuko Hadano and Hiromi Sasaki, K 225 ( TFM: S 17010).

Additional comments: T. longispinosum have more five-spored asci than the other species, but the frequency of five-spored asci varies depending on specimens; observations of two or more specimens are needed. Sakae Takayama and Shoichi Yoshimi first found a black truffle in Japan and identified it as T. indicum (Japanese name “ Iboseiyoshoro ”) [ 42]. The ascospores exhibit surface ornamentation with conspicuously long spines that were 4–8 (–10) μm high with 4 μm bases, which correspond to the T. longispinosum characters. Therefore, we assigned the Japanese “ Iboseiyoushoro ” to T. longispinosum .

Figures

Fig 6. Tuber longispinosum photographs (holotype, TFM: S17009). A. Dried ascomata (bar = 1 cm). B. Fruit bodies photographed in the field.C. Peridial warts, (bar = 3 mm). D. Asci and ascospores (bar = 30 μm). E. Ascospore (bar = 10 μm). F. Peridium in cross section (bar = 50 μm). https://doi.org/10.1371/journal.pone.0193745.g006