Leptographium yunnanense X.D. Zhou, K. Jacobs, M.J. Wingf. & M. Morelet, Mycoscience 41(6): 576. 2000.

Min Wang, Hui, Wang, Zheng, Liu, Fu, Xu Wu, Cheng, Fang Zhang, Su, Kong, Xiang Bo, Decock, Cony, Lu, Quan & Zhang, Zhen, 2019, Differential patterns of ophiostomatoid fungal communities associated with three sympatric Tomicus species infesting pines in south-western China, with a description of four new species, MycoKeys 50, pp. 93-133 : 107-108

Leptographium yunnanense X.D. Zhou, K. Jacobs, M.J. Wingf. & M. Morelet, Mycoscience 41(6): 576. 2000. Fig. 12

Description.

Sexual form: unknown.

Asexual form: Leptographium -like. Conidiophores occurring singly or in groups of up to three, arising from the superficial mycelium, erect, macronematous, mononematous, (93.5-) 159-412 (-544) μm long, without rhizoid-like structures; stipes simple, cylindrical, not constricted at septa, 1-6-septate, pale olivaceous at the base, (12-) 19.0-128 (-245) × (3.3-) 4.1-6.1 (-7.3) μm; conidiogenous apparatus (33.0-) 65.5-119.5 (-168.0) μm long (high), with 2 to 3 series of cylindrical branches; primary branches hyaline to pale olivaceous, smooth, cylindrical, 2-3 septate, (11.5-) 18.2-37.7 (-56.0) μm long and (3.0-) 3.7-5.9 (-7.7) μm wide; secondary branches hyaline, 0-2 septate, (10.3-) 14.5-30.0 (-50.1) μm long, (2.8-) 3.4-5.5 (-7.3) μm wide; conidiogenous cells discrete, 2-3 per branch, cylindrical, (10.2-) 13.2-29.6 (-57.4) × (2.2-) 2.9-3.9 (-4.4) μm; conidia 1-celled, oblong to obovoid with truncate bases, hyaline, (5.8-) 7.0-10.4 (-13.0) × (2.9-) 3.6-5.3 (-6.4) μm.

Culture characteristics.

Colonies on 2% MEA medium fast growing in the dark, reaching 76 mm in diam. in 8 days at 25 °C, growth rate up to 20 mm/day at the fastest; colony margin smooth. Hyphae submerged in agar with aerial mycelium, greenish-olivaceous to olivaceous, smooth, straight; reverse hyphae umber-brown to dark olivaceous. Optimal growth temperature 25 °C, slow growth at 5 °C and 30 °C.

Known substrate and hosts.

Tomicus yunnanensis and its galleries in Pinus yunnanensis , galleries of T. brevipilosus in P. kesiya .

Known insect vectors.

Tomicus brevipilosus , T. yunnanensis .

Known distribution.

Yunnan Province, China.

Specimens examined.

CHINA, Yunnan, adults of Tomicus yunnanensis and their galleries in Pinus yunnanensis , Tomicus brevipilosus galleries in P. kesiya . Apr. 2017, HM Wang, CFCC 52619 = CXY 1897, CFCC 52620 = CXY 1900, CFCC 52621 = CXY 1904, CFCC 52622 = CXY 1908, CFCC 52623 = CXY 1917, CFCC 52624 = CXY 1925.

Note.

The sole reproductive structure formed on MEA in L. yunnanense is a Leptographium -like state. Our strains were identified as L. yunnanense , based on phylogenetic evidence and secondarily, on morphological features. However, our strains slightly deviated from L. yunnanense in having longer conidiophores, mainly 159-412 μm vs mostly 74-227 (-233) μm ( Zhou et al. 2000) or 80-240 μm ( Yamaoka et al. 2008). Furthermore, our strains grew faster than reported for the species, 76 mm vs 44 mm in 8 days at 25 °C ( Zhou et al. 2000).

Although our strains were slightly genetically and morphologically divergent, we are of the opinion that they enter into the current L. yunnanense species concept (e.g. sensu Zhou et al. 2000). Yamaoka et al. (2008) showed the genetic diversity of L. yunnanense in Yunnan to be higher than in other places, that which is confirmed by the present study.

Leptographium yunnanense was originally described from Yunnan Province with only an asexual state ( Zhou et al. 2000). Subsequently, mating of strains from different origins (Thailand, China and Japan) yielded the sexual state, which is formed by neckless ascocarps and cucullate ascospores ( Yamaoka et al. 2008).

Leptographium yunnanense was the third most abundant species associated with T. yunnanensis in our study. A few strains also were isolated from T. brevipilosus infesting P. kesiya and none from T. minor .