Chaetothyrina Theiss., Annls mycol. 11(6):495 (1913)

The genus Chaetothyrina was established by Theissen (1913), with C. musarum (Speg.) Theiss. as the type species. Chaetothyrina was placed in Micropeltidaceae based on its superficial, flattened base, poorly developed thyriothecium and irregular meandering arrangement of compact hyphae of walled cells. Singtripop et al. (2016) provided molecular data of one reference specimen and one new species. Hongsanan et al. (2017) established a new species of Chaetothyrina and introduced a new family Phaeothecoidiellaceae to accommodate species of Chaetothyrina, Houjia, and Phaeothecoidiella in Capnodiales. Based on its placement in phylogenetic trees and the morphological uniqueness, Micropeltidaceae was excluded from Microthyriales and treated as family incertae sedis in Lecanoromycetes (Hongsanan et al. 2017; Zeng et al. 2019).

ClassificationDothideomycetes, incertae sedis, Capnodiales, Phaeothecoidiellaceae

Type speciesChaetothyrina musarum (Speg.) Theiss., Annls mycol. 11(6):495 (1913)

Distribution – Known from Brazil, Cook Islands, Dominican Republic, India, Mexico, Pakistan, Panama, Thailand, US

Disease symptoms – Sooty blotch and flyspeck

Species in this genus cause flyspeck disease on various plants, such as C. musarum on Musa sp. and C. panamensis (F. Stevens & Dorman) Arx on Oncoba laurina. Sooty blotch and flyspeck (SBFS) is a disease complex caused by nearly 80 fungal species (Singtripop et al. 2016) that are epiphytes which blemish the epicuticular wax layer of several fruit crops, such as apple, pear, orange, persimmon, banana and grape worldwide (Gleason et al. 2011; Gao et al. 2014), cutting sale price and limiting the growth rate of fruit production (Williamson et al. 2000; Gao et al. 2014). ‘Sooty blotch’ is characterized by colonies produced on host tissues from superficial, spreading, dark irregular blotches of mycelium with or without sclerotium-like structures or fruiting bodies. On the other hand, ‘flyspeck’ defines clusters of shiny, small, black sclerotium-like structures or fruiting bodies, lacking visible intercalary mycelium (Gleason et al. 2011; Mayfield et al. 2013; Singtripop et al. 2016).

Hosts – Species of Anacardium, Anodendron, Anogeissus, Carallia, Cassia, Chonemorpha, Dalbergia, Dianella, Euonymus, Hevea, Iiana, Magnifera, Magnolia, Mammea, Maytenus, Memecylon, Mitragyna, Musa, Myrcia, Ochrocarpos, Olea, Oncoba, Phoebe, Similax, Streblus and Vochysia.

Fig.  Disease symptoms caused by Chaetothyrina spp. a on mango. b, d appearance of thyriothecia on hosts. c on a banana. e on mango leaves.


Morphological based identification and diversity

Chaetothyrina is characterized by superficial, flattened thyriothecia, with base poorly developed, with thyriothecial setae and 1-septate ascospores (Reynolds and Gilbert 2005; Singtripop et al. 2016; Hongsanan et al. 2017). Chaetothyrina can be distinguished from other species in Micropeltidaceae on the basis of thyriothecial setae appearance, shape, and septation of the ascospores (Singtripop et al. 2016; Hongsanan et al. 2017). Twenty-three species of Chaetothyrina epithets are listed in Index Fungorum (2019), but sequence data are available for only two species (4/7/2019). Chaetothyrina is a poorly studied genus. Fresh collections and sequence data are needed for this genus. The disease cycle of this genus is yet to be established.

Fig. Chaetothyrina guttulata a Thyriothecium when viewed in squash mount. b Surface of thyriothecium. c Section through thyriothecium. d Ascus when immature. e Asci at maturity. f Ascospores. Scale bars: a=50 µm, b, d, e=10 µm, c=100 µm, f=5 µm.


Molecular based identification and diversity

Singtripop et al. (2016) provided a reference type specimen of C. musarum with sequence data. Using combined LSU, SSU and ITS sequence data, Chaetothyrina clustered as a sister genus to Houjia and Phaeothecoidiella within Capnodiales (Hongsanan et al. 2017; Fig. 6).


Recommended genetic markers (genus level) – LSU and SSU

Recommended genetic markers (species level) – ITS and RPB2

The accepted number of species: There are 23 epithets in Index Fungorum (2019). However, only two species have molecular data.

References: Reynolds and Gilbert 2005; Singtripop et al. 2016; Hongsanan et al. 2017 (morphology, phylogeny)


Table Details of Chaetothyrina isolates used in the phylogenetic analyses. Ex-type (or ex-epitype) strains are in bold and marked with an asterisk* and voucher strains are in bold.

Species Isolate/Voucher no LSU SSU ITS
Austroafricana associata CBS 120732 KF901829 KF901512
Capnobotryella renispora CBS 215.90 GU214399 AY220613 AY220613
Capnodium coffeae CBS 147.52 GU214400 DQ247808 AJ244239
Chaetothyrina guttulata MFLUCC15-1080 KU358917 KU358916 KX372277
C. guttulata MFLUCC15-1081* KU358914 KU358915 KX372276
C. musarum MFLUCC15-0383 KU710171 KU710174 KX372275
C. musarum MFLUCC15-0383 KU710171 KU710174 KX372275
Devriesia strelitziae CBS 122379 GU301810 GU296146 EU436763
Dissoconium aciculare CBS 204.89 GU214419 GU214523 AY725520
D. dekkeri CBS 342.86 JN232431
Dothistroma septosporum CBS:112498 GQ852597 JX901744 JX901744
Hortaea werneckii 4263 JX141471 JX141470 DQ336709
Houjia yanglingensis YHLB20 GQ433630 GQ433629
H. yanglingensis YHJN13* GQ433631 GQ433628
Leptoxyphium cacuminum MFLUCC10-0049* JN832602 JN832587  
Mycosphaerella ellipsoidea CBS:110843* GQ852602 AY725545 AY725545
M. endophytica CBS:114662* GQ852603 DQ302953 DQ302953
M. keniensis CBS:111001* GQ852610
Myriangium duriaei CBS 260.36 NG027579 AF242266
M. hispanicum CBS 247.33 GU301854 GU296180
Phaeothecoidiella illinoisensis CBS:125223 GU117901 GU117897
P. missouriensis CBS:118959 GU117903 GU117899
Phragmocapnias asiticus MFLUCC10-0062 JN832612 JN832597
P. betle MFLUCC10-0053 JN832606 JN832591
P. betle MFLUCC10-0050 JN832605 JN832590
Pseudoveronaea ellipsoidea MI3 34F1a* JQ622103 FJ425205
P. obclavata UIF3 AY598916 AY598877
Ramichloridium apiculatum CBS 400.76 EU041851 EU041794 EU041794
Rasutoria pseudotsugae rapssd EF114704 EF114729 EF114687
R. tsugae ratstk EF114705 EF114730 EF114688
Schizothyrium pomi CUA1a AY598895 EF164898
S. pomi Flyspeck1924-Zj001 AY598894 AY598848
Scorias spongiosa MFLUCC10-0084 JN832586 JN832601
S. spongiosa AFTOL-ID 1594 DQ678075 DQ678024
Stomiopeltis versicolor GA3 23C2b FJ147163 FJ438375
Zygophiala cryptogama KY1 1.2A1c* EF164902 EF164900
Z. tardicrescens MWA1a* EF164901 AY598856
Z. wisconsinensis MSTA8a* AY598897 AY598853

Fig. Phylogenetic tree generated by maximum parsimony analysis of combined LSU, SSU and ITS sequence data. Thirty-nine strains are included in the analyses, which comprised 2225 characters including gaps. The tree was rooted with Myriangium duriaei (CBS 260.36) and M. hispanicum (CBS 247.33). The maximum parsimonious dataset consisted of 1645 constant, 461 parsimony-informative and 119 parsimony-uninformative characters. The parsimony analysis of the data matrix resulted in the maximum of ten equally most parsimonious trees with a length of 1637 steps (CI = 0.549, RI 0.736, RC = 0.404, HI = 0.451) in the first tree. MP and ML bootstrap values ≥50% and Bayesian posterior probabilities ≥0.90 (BYPP) are shown respectively near the nodes. Ex-type strains are in bold.

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