Sporothrix cryptarchum R. Jankowiak & A. Ostafinska, 2021

Ostafinska, Agnieszka, Jankowiak, Robert, Bilanski, Piotr, Solheim, Halvor & Wingfield, Michael J., 2021, Six new species of Sporothrix from hardwood trees in Poland, MycoKeys 82, pp. 1-32 : 1

Sporothrix cryptarchum R. Jankowiak & A. Ostafinska sp. nov.

Fig. 9

Etymology.

Referring to the genus name of the beetle, Cryptarcha sp. ( Coleoptera : Nitidulidae ), with which this fungus is associated.

Type.

Poland, Małopolskie Province, Wierzchosławice, from Cryptarcha undata on Quercus robur , June 2016, R. Jankowiak, (O-F- 258633 holotype, culture ex-type CBS 147934) .

Description.

Sexual and asexual structures produced on the sterilised oak twigs and on the surface of malt agar in Petri dishes. Ascomata abundant, superficially or partly embedded in the agar, single or in groups; ascomatal bases black, globose, (55-)115-172(-210) μm diam., with brown hyphal hairs, 15 to 141 μm long and 0.9 to 3.8 μm wide at the base; ascomatal necks black, straight or curved, (126-)198-412(-544) μm long, diameter (10.9-)13-19(-23.8) μm at the apex and (17.6-)29.3-47.6(-59.6) μm at the base. Ostiolar hyphae present, pale brown, with small granules, septate, straight or curved, simple or dichotomous branching, tips tapering or sometimes thickened, (9-)13-24(-31) in number, (15.8-)30.5-51.8(-60.9) μm long, (0.2-)0.3-0.5(-0.7) μm at the apex and (0.9-)1.6-2.4-(3) μm at the base. Asci subglobose to ovoid, (5.5-)6.7-9(-11) × (4-)4.9-6.2(-7.2) μm. Ascospores one-celled, kidney-shaped to almost triangular in side view in side view (3.2-)3.8-4.7(-5.8) × (0.8-)1-1.3(-1.5) μm, elliptical in front view (3.1-)3.6-4.4(-5) × (1-)1.2-1.6(-1.8) μm, sometimes with residual sheath up to 0.6 μm thick, accumulated in white-colored mass at the tip of the neck. Conidiophores hyaline, micronematous, simple or occasionally branched and bearing several conidiogenous cells, either borne on vegetative hyphae or on upright hyphae. Conidiogenous cells blastic, cylindrical, terminal, lateral or intercalary, straight or curved, tapering towards the apex, swollen apical part forming conidia by sympodial proliferation on narrow denticles, (2.2-)13.9-51.2(-102.8) μm long, (0.7-)1.2-1.8(-2.2) μm wide at the base. Apical part (0.6-)1.4-3.1(-5.3) μm long and (1-)1.7-3(-3.8) μm wide, single denticles often below. Conidia of two types: 1) abundant in cultures, often produced, hyaline, unicellular, smooth, obovate to ellipsoid, pointed at the base, (3.3-)4.6-8.1(-10.3) × (1-)1.3-1.9(-2.2) μm, formed directly on denticles; 2) sparse in cultures, subhyaline to lightly pigmented, unicellular, smooth, subglobose to globose, (2.3-)3.1-4.1(-4.5) μm diam, formed singly, either directly on the side of vegetative hyphae or on short lateral branches. Culture characteristics: Cultures showing optimum growth at 25 °C (1.3 mm/d) followed by at 30 °C (1.1 mm/d), mostly pigmented or white or pig, flat, growing in a circular pattern with smooth margins.

Host tree.

Alnus glutinosa , Quercus robur .

Insect vector.

Cryptarcha undata , C. strigata .

Distribution.

Poland.

Additional specimen examined.

Poland, Małopolskie Province, Wierzchosławice, from Cryptarcha undata on Quercus robur , June 2016, R. Jankowiak, (O-F-258634, cultures CBS 147933).

Notes.

This species is phylogenetically distinct from the other Sporothrix species based on the ITS, βT, CAL and TEF1-α sequences. Sporothrix cryptarchum is phylogenetically closely related to S. undulata ( Sporothrix sp. 12) described in the present study. This species also shares morphological similarities such as kidney-shaped ascospores and two morphological forms of conidia with S. undulata . However, S. cryptarchum has narrow ascospores (0.8-1.5 µm) compared to S. undulata (1.1-2 µm). It also has distinct ostiolar hyphae, with those in S. cryptarchum often dichotomously branching while in S. undulata these hyphae occur only sporadically and do not have dichotomous branching. Both species produce hyaline and pigmented conidia. However, S. cryptarchum cultures are predominantly hyaline whereas those in pure cultures of S. undulata are mostly pigmented. Their conidial shapes in these two species are similar but their dimensions are distinct. Sporothrix cryptarchum has conidia that are smaller than those of S. undulata . In addition, cultures of S. cryptarchum are white and grow in a circular pattern with smooth margins while those of S. undulata grow in a circular pattern with undulate margins and some have grey pigmentation.

Sporothrix cryptarchum was represented by four isolates collected from Poland. It corresponds to Sporothrix sp. 11 in the study of Jankowiak et al. (2019b). Sporothrix cryptarchum was isolated from wounds on hardwood trees and nitidulid beetles ( Coleoptera : Nitidulidae ), which visited fresh wounds on Quercus robur .

Figures

Figure 9. Sporothrix cryptarchum sp. nov. (CBS 147934) a ascoma b ascomatal base c, d ostiolar hyphae e ascospores f asci g conidiogenous cell with an inflated cluster of denticles at the apex h conidia i globose conidia arising on long conidiophore j globose conidia arising directly from hyphae k fourteen-day-old culture on MEA. Scale bars: 100 μm (a), 25 μm (b-d), 10 μm (e), 25 μm (f, g), 10 μm (h, i), 5 μm (j).