Cladosporium maltirimosum Wonjun Lee & Y.W. Lim, 2023

Lee, Wonjun, Kim, Ji Seon, Seo, Chang Wan, Lee, Jun Won, Kim, Sung Hyun, Cho, Yoonhee & Lim, Young Woon, 2023, Diversity of Cladosporium (Cladosporiales, Cladosporiaceae) species in marine environments and report on five new species, MycoKeys 98, pp. 87-111 : 87

Cladosporium maltirimosum Wonjun Lee & Y.W. Lim sp. nov.

Figs 2B , 3B

Typification.

Republic of Korea. Jeollanam-do, Muan-gun, 35°03′44″N, 126°20′13″E, sea sand, Jul 2021, M.S. Park & Y.W. Lim (holotype SFC20230103-M51, stored in a metabolically inactive state).

Etymology.

The epithet ' maltirimosum ' refers to the cracked colony that appears on the MEA medium derived from Latin rimosus (cracked).

Description.

Asexual morphology: Mycelium immersed, composed of septate, branched, hyaline to subhyaline, verruculose hyphae, nodulose, 2-5.5 μm wide. Conidiophores macronematous and micronematous, arising laterally from hyphae, septate, erect to slightly flexuous, non-nodulose, unbranched, up to 278 μm long, 1.9-4.3 μm wide, pale brown, verruculose. Conidiogenous cells integrated, terminal and intercalary, cylindrical to subcylindrical, 16-45.7 × 2.7- 4.1 μm, bearing up to three protuberant, slightly darkened, and refractive conidiogenous loci. Ramoconidia 0(-1)-septate, subcylindrical to ellipsoidal, 8.4-23 × 2.2-5.2 μm [av. ( ± SD)15.3 ( ± 4.5) × 3.6 ( ± 0.77)], pale brown, verruculose. Conidia solitary or forming branched chains, with up to seven conidia in the terminal unbranched part, aseptate, pale green, smooth to verruculose, with protuberant, slightly darkened, and refractive hila. Small terminal conidia aseptate, ellipsoidal, 4.2-6.7 × 2.2-3.3 μm [av. ( ± SD) 5.4 ( ± 0.61) × 2.8 ( ± 0.29)]. Intercalary conidia aseptate, ellipsoidal to limoniform, rarely fusiform, 4.6-6.7 × 1.8-3.5 μm [av. ( ± SD) 5.5 ( ± 0.5) × 2.7 ( ± 0.35)]. Secondary ramoconidia 0(-1)-septate, subcylindrical to ellipsoidal, 8.9-22.5 × 2.7-5.6 μm [av. ( ± SD) 15.6 ( ± 3.34) × 3.6 ( ± 0.67)].

Cultural characters: Colonies on PDA 44-63 mm diam after 14 d at 25 °C, olive yellow (2D8) to olive (3E8), reverse dark gray (1F1), powdery, floccose, sometimes slightly fluffy, radially furrowed, wrinkled; margin white edge, slightly undulated or lobate, sometimes regular; aerial mycelia formed, moderate, without prominent exudates, sporulation profuse. Colonies on MEA 34-36 mm diam after 14 d at 25 °C, gray (1B1 to 1E1), reverse concolorous to dark gray (1F1), slightly crateriform due to cracked medium, floccose, woolly, radially furrowed, wrinkled; margin white, undulate; aerial mycelia abundantly formed, without prominent exudates, sporulation profuse. Colonies on OA 52-63 mm diam after 14 d at 25 °C, grayish green (1D3) to olive (1E5), reverse concolorous, powdery, floccose, fluffy, sometimes woolly, radially furrowed, wrinkled, flat; margin yellowish white (1A2), regular; aerial mycelia formed in spots, sometimes without prominent exudates, sporulation profuse. Colonies on SNA 37-39 mm diam after 14 d at 25 °C, grayish green (1D4) to olive (1E4), reverse concolorous to olive (3F8), powdery, flat; margin whitish, undulate; aerial mycelia absent, without prominent exudates, sporulation profuse.

Habitat and distribution.

Isolated from mudflats, sea sands, and seaweeds; Eastern, Southern, and Western Korean seaside in Republic of Korea.

Additional cultures examined.

Republic of Korea, Jeju-do, Hallim-eup, 33°23′53″N, 126°14′24″E, seaweed, Jul 2021, M.S. Park & Y.W. Lim (SFC20230103-M41, stored in a metabolically inactive state); Jeju-do, Chuja-myeon, 33°57′10″N, 126°20′18″E, seaweed, 31 Aug 2021, M.S. Park & Y.W. Lim (SFC20230103-M42, stored in a metabolically inactive state); Jeju-do, Chuja-myeon, 33°57′11.88″N, 126°18′07.56″E, seaweed, 31 Aug 2021, M.S. Park & Y.W. Lim (SFC20230103-M43, stored in a metabolically inactive state); Jeju-do, Hallim-eup, 33°23′53″N, 126°14′24″E, seaweed, 15 Aug 2021, M.S. Park & Y.W. Lim (SFC20230103-M44, stored in a metabolically inactive state); Jeollanam-do, Muan-gun, 35°01′40″N, 126°25′16″E, mudflat, Jan 2020, M.S. Park & Y.W. Lim (SFC20230103-M45, stored in a metabolically inactive state); Gangwon-do, Goseong-gun, 38°28′39″N, 128°26′22″E, Sea sand, 31 Oct 2016, M.S. Park & Y.W. Lim (SFC20170718-M12, stored in a metabolically inactive state); Ulsan, Ulju-gun, 35°23′00″N, 129°20′46″E, sea sand, Apr 2017, M.S. Park & Y.W. Lim (SFC20230103-M47, stored in a metabolically inactive state); Jeollanam-do, Suncheon-si, 34°50′29″N, 127°29′09″E, Sea sand, Jan 2020, M.S. Park & Y.W. Lim (SFC20230103-M48, stored in a metabolically inactive state); Gangwon-do, Goseong-gun, 38°28′39″N, 128°26′22″E, sea sand, Jan 2020, M.S. Park & Y.W. Lim (SFC20230103-M49, stored in a metabolically inactive state); Jeollanam-do, Suncheon-si, 34°50′29″N, 127°29′09″E, sea sand, Jul 2020, M.S. Park & Y.W. Lim (SFC20230103-M50, stored in a metabolically inactive state); Jeollanam-do, Suncheon-si, 34°50′29″N, 127°29′09″E, sea sand, Jul 2021, M.S. Park & Y.W. Lim (SFC20230103-M52, stored in a metabolically inactive state).

Notes.

Cladosporium maltirimosum sp. nov. is closely related to C. anthropophilum and C. devikae and formed a well-supported clade (Fig. 1 ). The colonies of C. maltirimosum grow faster than those of C. anthropophilum associated with human (17-39 mm, 27-32 mm, and 23-26 mm, respectively) on PDA, MEA, and OA ( Sandoval-Denis et al. 2016). However, whereas the growth rate of C. maltirimosum on PDA and OA falls within the range of the indoor C. anthropophilum colonies (17-80 mm and 27-74 mm, respectively), the colonies on MEA grow slower than the indoor C. anthropophilum (50-72 mm) ( Bensch et al. 2018). Cladosporium maltirimosum has wider hyphae (2-3 μm) and fewer maximum numbers of conidiogenous loci [3-8(-10)] than in C. anthropophilum ( Sandoval-Denis et al. 2016). In addition, the ramoconidia of C. maltirimosum are significantly shorter than those of C. anthropophilum (20-42 × 2-5 μm; Sandoval-Denis et al. 2016). Cladosporium maltirimosum produces up to six conidia, whereas C. anthropophilum produces up to four in an unbranched chain ( Sandoval-Denis et al. 2016). The colonies of C. maltirimosum grow slower than those of C. devikae (70 mm diam) on PDA ( Prasannath et al. 2021). Also, secondary ramoconidia of C. maltirimosum is longer than those of C. devikae (5-11 × 2-4 μm) ( Prasannath et al. 2021), but the conidiophores are shorter than those of C. devikae (200-700 μm) ( Prasannath et al. 2021). Cladosporium maltirimosum showed a genetic identity of about 96% with C. anthropophilum (CBS 140685) (96.89% in act and 96.585% in tef1) but showed a high level of identity with C. devikae (BRIP 72278a) (100% in act and 97.56% in tef1). Despite having considerable genetic similarities with C. devikae , C. maltirimosum had distinct clades, different from C. devikae , in the phylogenetic tree. Furthermore, the two species can be distinguished by morphological differences such as growth rate on PDA and length of conidiophore and secondary ramoconidia. Aside from that, as C. devikae employs a single strain, there is not much information on the species, and the species’ phylogenetic placement within Cladosporium is unclear. Hence, additional study on C. devikae appears to be required.

Figures

Figure 1. Maximum likelihood (ML) tree of Cladosporium, inferred based on ITS, act, and tef 1 sequences. The values at each node indicate the bootstrap of ML (≥ 70) and the posterior probability (PP; ≥ 0.90) of Bayesian inference (BI) analyses. Thick lines on branches indicate 100 bootstrap and 1.00 PP support. The tree is rooted to Cercospora beticola (CBS 116456). The small tree on the upper left represents the topology of species complexes of the genus. The filled triangles correspond to the species complex (es) shown. The colored circles symbolize habitats where the species were isolated. Previously described species are grouped in gray boxes, and blue boxes indicate new species. Strains with newly generated sequences are in red, with the holotypes in bold. The holotype and epitype for the reference strains are represented with " * " and " ** ", respectively.

Figure 2. Morphological characteristics of the new and unrecorded species on PDA, MEA, OA, and SNA media A Cladosporium lagenariiforme sp. nov. B Cladosporium maltirimosum sp. nov. C Cladosporium marinisedimentum sp. nov. D Cladosporium marinum sp. nov. E Cladosporium proteacearum F Cladosporium snafimbriatum sp. nov. " F " and " R " represent the front and the reverse sides of the culture plate, respectively. PDA: potato dextrose agar; MEA: malt extract agar; OA: oatmeal agar; SNA: synthetic nutrient-poor agar.

Figure 3. Morphological characteristics of conidial structures on SNA A Cladosporium lagenariiforme sp. nov. B Cladosporium maltirimosum sp. nov. C Cladosporium marinisedimentum sp. nov. D Cladosporium marinum sp. nov. E Cladosporium proteacearum F Cladosporium snafimbriatum sp. nov. Scale bars: 10 μm (A-F).