Additions to Rhytidhysteron (Hysteriales, Dothideomycetes) in China

Abstract

In this study, twelve terrestrial hysteriaceous saprobic fungi growing on different pieces of dead wood were collected from Yunnan Province, China. All hysteriaceous strains isolated in this study tallied with the general characteristics associated with Rhytidhysteron. Detailed morphological characteristics and combined multigene phylogeny of LSU, ITS, SSU, and TEF showed that the twelve hysteriaceous fungi strains represent four distinct new species, and seven new host or geographical records of Rhytidhysteron. Based on morphological and phylogenetic evidence, the four new species (Rhytidhysteron bannaense sp. nov., R. coffeae sp. nov., R. mengziense sp. nov., and R. yunnanense sp. nov.) expand the number of species of Rhytidhysteron from thirty-three to thirty-seven, while seven new geographical records expand the records of Rhytidhysteron in China from six to thirteen. In addition, 10 new Rhytidhysteron host records are reported for the first time, thus expanding the known hosts for Rhytidhysteron from 52 to 62. Full descriptions, images of the morphology, and phylogenetic analyses to show the position of the Rhytidhysteron taxa are provided. In addition, the present study summarizes the main morphological characteristics, host associations, and locations of this genus.

Keywords: Ascomycota; Hysteriaceae; four new species; hysteriaceous; saprobes; seven new records.

Figure 1

Phylogenetic tree generated from RAxML analyses based on combined LSU, ITS, SSU, and TEF sequence data for Rhytidhysteron. The tree was rooted with Gloniopsis calami (MFLUCC 15-0739) and G. praelonga (CBS 112415). Bootstrap support values equal to or higher than 60% ML and posterior probability values equal to or higher than 0.90 Bayesian PP are indicated on the nodes. New species are in red, new records are in blue, and ex-type strains are in bold.

Figure 2

Rhytidhysteron bannaense (HKAS 122695, holotype). (a,b) Appearance of hysterothecia on the host; (c,d) Vertical section through hysterothecium; (e–h) Asci; (i) Epithecium mounted in water; (j) Pseudoparaphyses; (k) Exciple; (l–o) Ascospores; (p) A germinating ascospore; (q,r) Colony on PDA medium (after four weeks). Scale bars: (c,d) = 500 μm; (e–h) = 100 μm; (i,j,l–p) = 20 μm; (k) = 50 μm.

Figure 3

Rhytidhysteron coffeae (HKAS 122701, holotype). (a,b) Appearance of hysterothecia on the host; (c,d) Vertical section through hysterothecium; (e–g) Asci; (h) Epithecium mounted in water; (i,j) Pseudoparaphyses; (k) Pedicel of asci; (l) Exciple; (m–r) Ascospores; (s) A germinating ascospore; (t) Colony on PDA medium (after four weeks). Scale bars: (c,d) = 500 μm; (e–g) = 100 μm; (h,l) = 50 μm; (i–k,m–s) = 20 μm.

Figure 4

Rhytidhysteron mengziense(HKAS 122699, holotype). (a,b) Appearance of hysterothecia on the host; (c,d) Vertical section through hysterothecium; (e) Epithecium mounted in water; (f–h) Asci; (i) Exciple; (j) Pseudoparaphyses; (k–m) Ascospores; (n) A germinating ascospore; (o,p) Colony on PDA medium (after one week). Scale bars: (c,d) = 500 μm; (e,k–n) = 20 μm; (f–i) = 100 μm; (j) = 50 μm.

Figure 5

Rhytidhysteron yunnanense (HKAS 122696, holotype). (a–c) Appearance of hysterothecia on the host; (d,e) Vertical section through hysterothecium; (f–j) Asci; (k) Epithecium mounted in water; (l) Pseudoparaphyses; (m) Exciple; (n–q) Ascospores; (r) A germinating ascospore; (s,t) Colony on PDA medium (after one week); Scale bars: (d,e) = 500 μm; (f–j) = 100 μm; (k,l,n–r) = 20 μm; (m) = 50 μm.