Hysteriales » Roussoellaceae » Roussoella

Roussoella elaeicola

Roussoella elaeicola Konta. & K.D. Hyde [as 'elaeicola'], in Phookamsak et al., Fungal Diversity Notes: 10.1007/s13225-019-00421-w, [69] (2019)

Index Fungorum number: IF555291         Facesoffungi number: FoF04834


Sexual morph: Ascomata 315–410 μm high, 325–350 μm diam., solitary, immersed in host tissue, erumpent through the host surface with minute papilla, globose to subglobose, uni-loculate, ostiole central with papilla, lacking periphyses. Peridium 25–70 μm wide, thin-walled, composed of several layers of small, compressed, hyaline to light brown pseudoparenchymatous cells of textura angularis, outer layers fusing with the host. Hamathecium composed of dense, 0.9–2.8 μm broad, filamentous, septate, trabeculate pseudoparaphyses, embedded in mucilage. Asci 70–140 × 6–9 μm ( = 100 × 8 lm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical, pedicellate, rounded apex with an indistinct ocular chamber. Ascospores 10–15 × 3–6 μm ( = 12 × 4 μm, n = 30), slightly overlapping 1-seriate, hyaline to light brown when immature, ellipsoid with obtuse ends, becoming dark brown at maturity, 1-septate, with large guttules in each cell, constricted at the septum, rough-walled with poroid ornamentation, surrounded by mucilaginous sheath. Asexual morph: Undetermined.


Culture characteristics: Ascospores germinated on MEA within 24 h with germ tube was produced from both cells. Colony on MEA, at first whitish, felty, azonate, with fluffy margin, after incubation for 3–4 weeks appear circular, with fluffy, dense, pale brown mycelium in the middle and dense mycelium in the outer ring on the surface with smooth margin; from below, brown to dark brown in the middle and pale brown to yellow at the margin hyphae, septate, branched, and smooth.


Material examined: THAILAND, Chiang Rai Province, on dead petiole of Elaeis guineensis (Arecaceae), 25 November 2014, S. Konta, HR02d (MFLU 15-0022, holotype), ex-type living culture, MFLUCC 15-0276.


GenBank Accession No: ITS: MH742329, LSU: MH742326 (MFLUCC 15-0276a); ITS: MH742330,

LSU: MH742327 (MFLUCC 15-0276b); LSU: MH742328, SSU: MH742331 (MFLUCC 15-0276c).


Notes: Roussoella elaeicola (MFLU 15-0022) is introduced as a novel species and it was collected from oil palm (Elaeis guineensis) in Chiang Rai, Thailand for the first time. Multigene phylogenetic analyses show that R. elaeicola has a close relationship with R. euonymi Crous & Akulov and Pseudoneoconiothyrium rosae Phukhams et al. (Fig. 39) which were collected from Euonymus europaeus L. (Celastraceae) in Ukraine and on dead aerial spines of Rosa canina L. (Rosaceae) in Italy, respectively (Crous et al. 2018; Wanasinghe et al. 2018). However, we could not compare the morphological characteristics of our new species with these two species as Roussoella euonymi and Pseudoneoconiothyrium rosae are only known as asexual morph species, while our new taxon is represented by the sexual morph. One of the distinctive characters of Roussoella elaeicola is the distinctive trabeculate pseudoparaphyses (sensu Liew et al. 2000). A comparison of ITS nucleotide base pairs indicates that Roussoella elaeicola differs from R. euonymi and Pseudoneoconiothyrium rosae in 37/513 bp (7.2%) and 38/514 bp (7.4%). Roussoella elaeicola can be distinguished from other Roussoella species by its ascospores having poroid ornamentation, similar to R. scabrispora (Liu et al. 2014). However, R. elaeicola and R. scabrispora form a distinct lineage in Roussoellaceae.

Figure X. Roussoella elaeicola (MFLU 15-0022, holotype). a, b Asco-c mata on host substrate. c Section of ascoma. d Peridium. e Pseudoparaphyses. f–h Asci. i–l Immature ascospores. m, n Mature ascospores. o, p Ascospores with poroid ornamentation. q Germinated ascospore. r Culture characteristic on MEA from above and below. Scale bars a, b = 1000 μm, c = 100 μm, d = 50 μm, e–h, q = 20 μm, i–p = 5 μm


Phookamsak R, Hyde KD, Jeewon R, Bhat DJ, et al. (2019) Fungal diversity notes 929–1035: taxonomic and phylogenetic contributions on genera and species of fungi. Fungal Diversity (2019) 95:1–273


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