Ophiostoma taizhouense G. H. Zheng & Q. Lu, 2022

Zheng, Guiheng, You, Minqi, Li, Xuening, Zhou, Qinzheng, Wang, Zheng, Wang, Huimin & Lu, Quan, 2022, Diversity of fungi associated with Monochamus alternatus larval habitats in Bursaphelenchus xylophilus - infected Pinus massoniana and identification of two new ophiostomatalean species (Ascomycota, Ophiostomatales), MycoKeys 92, pp. 1-25 : 1

Ophiostoma taizhouense G. H. Zheng & Q. Lu sp. nov.

Fig. 10

Etymology.

' taizhou ' (Latin) refers to the type locality.

Type.

China, Zhejiang Province, Taizhou City , from Monochamus alternatus galleries of Pinus massoniana infested by Bursaphelenchus xylophilus , October 2020, collected by G. H. Zheng and Q. Lu, culture ex-holotype CFCC55740 = CXY4001 .

Description.

Sexual morph: not observed.

Asexual form: Hyalorhincladiella -like. Conidiophores abundant, conidiogenous cells single, disposed in a dense rachis (3.08-) (6.6) - (15.63) (-23.07) × (1.11-) (1.44) - (2.23) (-2.9) μm. Conidia hyaline, smooth, lunate, ellipsoid to ovoid, curvulate, aseptate, (3.24-) (4.27) - (7.42) (-10.08) × (1.17-) (1.6) - (2.39) (-2.86) μm.

Culture characteristics.

Colonies on 2% MEA reaching 62.5 mm diameter, after incubation in the dark at 25 °C for 3 d, growth rate up to 22.83 mm/d at the fastest, colony margin smooth, hyphae are superficial on agar. Some white mycelium was produced early during growth and became black after 8-15 d, transitioning from brown to dark brown. The optimal temperature for growth at 30 °C; no growth was observed at 5 °C.

Habitat and distribution.

Larval galleries of Monochamus alternatus in Pinus massoniana , infested by Bursaphelenchus xylophilus , in Zhejiang Province, China.

Additional specimen examined.

China, Zhejiang, Taizhou City, from Monochamus alternatus galleries of Pinus massoniana infested by Bursaphelenchus xylophilus , October 2020, collected by G. H. Zheng and Q. Lu, CFCC55731 = CXY4002, CFCC55733 = CXY4003, CFCC55734 = CXY4004.

Note.

Only the Hyalorhincladiella -like asexual form was observed in Ophiostoma taizhouense . According to ITS and BT phylogenetic analysis, it has a well-supported independent clade with Ophiostoma sp.1 (CFCC52628) and is closely related to O. allantosporum , O. pseudotsugae and O. wuyingensis (Figs 1 , 5 , 6 ). Only one strain of Ophiostoma sp.1 was isolated in our laboratory from P. yunnanensis infested with T. yunnanensis in Yunnan Province, so this strain was not officially named before this study. Although the geographical location and host of O. taizhouense and Ophiostoma sp.1 are different, their culture characteristics and gene sequences (ITS and BT) are identical (Figs 1 , 5 , 6 ) ( Wang et al. 2019). In general, the conidia of O. taizhouense (4.27-7.42 μm) are longer than those of O. minus (2.5-6 μm) ( Upadhyay 1981) and O. pseudotsugae (2.7-5 μm) ( Rumbold 1936). The optimal growth temperature of O. allantosporum and O. pseudotsugae was 25 °C, that of O. wuyingensis was 25-30 °C and that of O. taizhouense was 30 °C ( Gorton and Webber 2000, Chang et al. 2019). Both O. wuyingensis and O. taizhouense showed pigmentation on 2% MEA medium, whereas O. allantosporum has mid-brown hyphae, O. pseudotsugae has white-grey to snuff-brown, both showed no agar pigmentation ( Rumbold 1936; Villarreal et al. 2005). Ophiostoma wuyingensis was first isolated from the gallery of Ips typographus on P. koraiensis in Heilongjiang Province ( Chang et al. 2019). Ophiostoma allantosporum and O. pseudotsugae were isolated from P. resinosa in the USA and P. menziesii were infected with Dendroctonus frontalis in North America ( Gorton and Webber 2000). Strains of O. taizhouense in this study were isolated from P. massoniana infected with PWN and M. alternatus .

Figures

Figure 1. ML tree of the ITS region of Ophiostoma, Sporothrix, Graphilbum, Ceratocystiopsis. Bootstrap values of ML / MP ≥ 70 % are recorded at nodes as ML / MP and bold branches indicate posterior probability values ≥ 0.9. ML and MP, Bootstrap values <70 % are indicated by the symbol *. The tree is drawn to scale (see bar) with branch length measured in the number of substitutions per site. Strains representing ex-type sequences are marked with " T. " ML, Maximum Likelihood; MP, Maximum Parsimony; BI, Bayesian Inference and the final alignment of 734 positions, including gaps.

Figure 5. ML tree of the O. ips complex generated from the combined (ITS + BT) sequence data. Bootstrap values of ML / MP ≥ 70 % are recorded at nodes as ML / MP and bold branches indicate posterior probability values ≥ 0.9. ML and MP, Bootstrap values <70 % are indicated by the symbol *. The tree is drawn to scale (see bar) with branch length measured in the number of substitutions per site. Strains representing ex-type sequences are marked with " T. " Abbreviations: ML, Maximum Likelihood; MP, Maximum Parsimony; BI, Bayesian Inference and the final alignment of 953 positions, including gaps.

Figure 6. ML tree of the ITS region of O. minus complex. Bootstrap values of ML / MP ≥ 70 % are recorded at nodes as ML / MP and bold branches indicate posterior probability values ≥ 0.9. ML and MP, Bootstrap values <70 % are indicated by the symbol *. The tree is drawn to scale (see bar) with branch length measured in the number of substitutions per site. Strains representing ex-type sequences are marked with " T. " Abbreviations: ML, Maximum Likelihood; MP, Maximum Parsimony; BI, Bayesian Inference and the final alignment of 537 positions, including gaps.

Figure 10. Morphological characteristics of Ophiostoma taizhouense sp. nov. (CFCC = 55740, Taxon 4). a, b twenty-day-old cultures on 2 % MEA c-e Hyalorhincladiella - like asexual morph: conidiogenous cells and conidia. Scale bars: 10 μm (c-e).