Pseudorepetophragma Phookamsak, Bhat & Hongsanan, in Hongsanan, Phookamsak, Bhat, Wanasinghe, Promputtha, Suwannarach, Sandamali, Lumyong, Xu & Xie, Frontiers in Cellular and Infection Microbiology 13(no. 1252387) (2023)
Index Fungorum Number: IF 900624, MycoBank Number: MB 900624, Facesoffungi Number: FoF 15862
Etymology – The generic epithet “Pseudorepetophragma” refers to the genus that is morphologically resembling Repetophragma.
Fungus associated with a sooty blotch on living leaves of Zygopetalum mackayi (Orchidaceae). Sexual morph: Undetermined. Asexual morph: Colonies effuse, black, forming a dark mycelial mat. Mycelium superficial, composed of septate, branched, dark brown hyphae. Conidiophores macronematous, mononematous, simple, erect, septate, straight, or slightly narrow toward the apex, percurrently proliferating, septate, dark brown to brown. Conidiogenous cells monoblastic, enteroblastic, integrated, terminal, conspicuously percurrent, with apices remaining wavy or uneven after each conidial secession. Conidia acrogenous, solitary, brown, dark brown, cylindrical to obclavate, with truncate base, septate, thick, and smooth-walled. Conidial secession schizolytic (adapted from Buyck et al., 2017).
Type species –Pseudorepetophragma zygopetali(O.L. Pereira, Meir. Silva and R.F. Castañeda) Phookamsak, Bhat and Hongsanan
Notes – Subramanian (1992) established the genus Repetophragma and accommodated some species previously described as Sporidesmium. The genus is characterized by macronematous, brown, solitary, septate conidiophores, with monoblastic, enteroblastic, integrated, terminal, percurrently proliferating, and distinctly annellidic conidiogenous cells and acrogenous, solitary, dry, euseptate, conidia with a truncate base (Subramanian, 1992; Castañeda-Ruiz et al., 2011). Castañeda-Ruiz et al. (2011) re-illustrated the genus by providing the synopsis table of morphological features and key to the species of Repetophragma. Based on this comprehensive study, Castañeda-Ruiz et al. (2011) introduced a novel species, R. paracambrense, and 12 new combinations in the genus. Of these, most species were previously known in Endophragmiella and Sporidesmium. Considering the species of Repetophragma, most of the accepted species have annellidic, percurrent proliferations of the conidiogenous cells bearing euseptate conidia with apically rounded, well-defined, and without rostrate or appendiculate apical cell (Iturriaga et al., 2008; Silvera-Simón et al., 2009). This led to the inclusion of morphologically diverse species in Repetophragma. The phylogenetic analyses inferred by Shenoy et al. (2006) and Hernández-Restrepo et al. (2017) also revealed the status of some Repetophragma to be polyphyletic. Unfortunately, the phylogenetic affinity of Repetophragma is uncertain due to the lack of molecular data for the type species of Repetophragma. Furthermore, R. zygopetali formed an independent lineage within the Phaeothecoidiellaceae. Morphologically, R. zygopetali is similar to R. biseptatum in having monoblastic, enteroblastic, conspicuously percurrent conidiogenous cells. However, R. zygopetali can be distinguished from the rest of Repetophragma in having integrated, monoblastic, conspicuously percurrent but irregularly distanced conidiogenous cells with wavy or uneven apices after each conidial secession [Figure 29a in Buyck et al. (2017)] rather than equidistantly laid annellidic conidiogenous cells with even apices after each conidial secession (Subramanian, 1992; Seifert et al., 2011). Based on the morphological differences in the conidiogenous cells and phylogenetic analyses, we introduce the new genus Pseudorepetophragma to accommodate R. zygopetali as P. zygopetali comb. nov.
Figure 1 – Phylogram of the best-scoring maximum likelihood (ML) consensus tree based on a combined dataset (ITS and LSU) of Pseudostomiopeltis. The new species is indicated in blue, and the new combination species are indicated in green. Isolates from type materials are in bold. The ML ultrafast bootstrap and Bayesian PP values greater than 70% and 0.95 are shown at the nodes. The tree is rooted with Botryosphaeria fusispora (MFLUCC 10-0098) and Lasiodiplodia gonubiensis (CBS 115812).
Species