Pleosporales » Melanommataceae » Camposporium

Camposporium dulciaquae

Camposporium dulciaquae M.S. Calabon & K.D. Hyde

Index Fungorum number: IF 838551; Facesoffungi number: FoF 09156

Etymology: of freshwater

Holotype: MFLU 21–0015

 

Saprobic on submerged decaying wood in freshwater. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate, effuse, golden brown, velvety. Mycelium mostly immersed, composed of white, septate, branched and guttulate hyphae. Conidiophores 16–95 × 5–9 μm ( = 54.4 × 6.7 μm, n = 20) macronematous, mononematous, often procumbent on substrate, light brown to brown, unbranched, irregularly cylindrical, flexuous, septate, thick-walled. Conidiogenous cells 9–41 × 3–5 μm (= 22.2 × 4.4 μm, n = 20) monoblastic, terminal, integrated, subcylindrical, pale brown. Conidia 100–130 μm ( = 115 μm, n = 30) long, 8.5–13 μm ( = 10.7 μm, n = 30) wide at middle, 4–9 μm (= 6.1 μm, n = 30) wide at base, solitary, dry, cylindrical, elongate, median brown, paler at base, finely verrucose, 8–11-septate, not constricted or slightly constricted at septa, apex rounded, basal cell truncate, apical cell gives rise to (2–)3 simple appendages; appendage hyaline, aseptate, smooth, tapering from base to apex. Chlamydospores 8–18 × 5–13 μm (= 12.4–9.1 μm, n = 30) diameter, numerous, mostly in chains, intercalary or solitary, globose to subglobose, hyaline. (Description from Calabon et al. 2021)

 

Culture characteristics: Conidia germinating on malt extract agar (MEA) within 24 h. Germ tubes produced from the basal and apical cell of conidia. Colonies growing on MEA, reaching 20 mm in 2 weeks at 25 °C. Mycelia superficial, circular, with entire edge, flat, rugose, from above mossy gray in the center and pale yellow at the edge, from below brown at the center then becoming yellow orange at the edge. Chlamydospores produced in culture and induced with plant tissues within 60 days. Formation of crystals in the culture was observed.

 

Material examined: THAILAND, Chiang Mai Province, Mushroom Research Center, on decaying wood submerged in a freshwater stream, 29 January 2019, S. Boonmee, SB14-7 (MFLU 21–0015, holotype), ex-type living culture, MFLUCC 21–0009.

 

GenBank accession numbers: LSU = MT860430, SSU = MW485612, ITS = MT864352, TEF1-α = MW537104

 

Notes: Camposporium dulciaquae closely resembles Camposporium septatum based on conidial morphology with 2–3 appendages and number of septa, but the former has larger conidia (100–130 μm long, 8.5–13 μm wide at middle, 4–9 μm wide at base versus 98–125 μm long, 7–11.5 μm wide at middle, 3.5–6 μm wide at base). BLAST results of ITS and TEF1-α sequence data were C. cambrense CBS 132,486 (95% similarity) and C. septatum MFLUCC 19–0483 MFLUCC 16–0274 (97% similarity), respectively. Phylogenetic analyses of the combined LSU, SSU, ITS, and TEF1-α sequence dataset showed that C. dulciaquae clustered with C. septatum (MFLUCC 19–0483), Fusiconidium aquaticum (MFLUCC 16–0991 and F. mackenziei (HKAS 95019; MFLUCC 14-0434) (Hyde et al. 2020). In addition, an unknown species of Camposporium (MHR 1565) isolated from a dead wood in Nan Province, Thailand grouped as a sister taxon to C. dulciaquae with high bootstrap support (95% ML, 1.00 BYPP) (Hernández-Restrepo et al. 2017). The former did not have morphological data, but since comparison of its LSU sequence with the latter revealed 2 base pair differences (0.25%, 794 bp), we considered this as another strain of Camposporium dulciaquae. A comparison of ITS and TEF1-α sequence data of C. dulciaquae differed by 19 (3.81%, 499 bp) and 33 (3.48%, 947 bp) base pairs with C. septatum, respectively. Camposporium dulciaquae had 33 (914 bp, 3.61%) and 32 (838 bp, 3.82%) base pair differences with F. aquaticum and F. mackenziei in TEF1-α region, respectively. Camposporium dulciaquae differed from Fusiconidium in conidiogenesis (monoblastic versus enteroblastic), conidial shape (cylindrical versus fusiform to ellipsoidal), and presence of apical appendage. Furthermore, C. dulciaquae fit to the description of the genus, so in this paper, we introduced a new species under Camposporium. (Description from Calabon et al. 2021)

 

A key to freshwater Camposporium is provided below:

 

1 Appendage absent............................................................................................. C. ontariense

1 Appendage present............................................................................................................. 2

2 Appendage branched......................................................................................... C. japonicum

2 Appendage simple............................................................................................................... 3

3 Conidial septation ≤10.......................................................................................................... 4

3 Conidial septation >10......................................................................................................... 5

4 Conidia 20–75 × 3–5 μm....................................................................................... C. hyalinum

4 Conidia 28–45 × 3.5–4.5 μm................................................................................ C. quercicola

5 Conidial length ≤50 μm.................................................................................. C. marylandicum

5 Conidial length >50 μm......................................................................................................... 6

6 Appendage aseptate............................................................................................................ 7

6 Appendage septate............................................................................................................ 10

7 Conidial length up to <100 μm........................................................................... C. antennatum

7 Conidial length up to >100 μm.............................................................................................. 8

8 Conidial width ≥13............................................................................................................... 9

8 Conidial width <13.............................................................................................. C. septatum

9 Conidia 100–130 × 8.5–13 μm............................................................................. C. dulciaquae

9 Conidia 86–115 × 13.5–19 μm........................................................................... C. fusisporum

10 Conidial septation ≤13..................................................................................................... 11

10 Conidial septation >13...................................................................................................... 12

11 Conidia 107–119 × 9.5–11.5 μm................................................................. C. appendiculatum

11 Conidia 97–111 × 9–11 μm.......................................................................... C. multiseptatum

12 Conidia 62–115 × 8–10 μm.............................................................................. C. cambrense

12 Conidia 78–140 × 7.5–12 μm............................................................................ C. pellucidum