Kevinia lignicola Rajeshk., Verma R., Wijayaw., Karun. & Tibpromma, sp. nov.
Index Fungorum number: IF 559657; MycoBank number: MB 559657; Facesoffungi number: FoF 10830; Figs. 1, 2, and 3
Etymology – based on the lignicolous nature of the fungus.
Saprobic. Sexual morph: Undetermined. Asexual morph: hyphomyceteous. Conidiophores reduce to conidiogenous cells. Conidiogenous cells (–38) 50–99×(–15.5) 21–30.5 μm, macronematous, mononematous, ampulliform, wider base, smooth, erect, unbranched or rarely branched. Conidia 46–74 (–93)×20–48 μm, holoblastic, monoblastic, dictyosporous, dark at base, digitate and branched towards paler apex, smooth base, brown to dark-brown, smooth to slightly roughened, euseptate, base truncate.
Culture characteristics – Colonies on MEA, reaching 30 to 40 mm diam. after 20 days at 25 °C, initially aerial mycelium greyish to brownish grey (4D2), velutinous, in old cultures brownish grey (4D2) to dark brownish grey, colonies reverse dark grey (4F1). Soluble pigments and exudates are absent.
Material examined – India, Maharashtra, Thane, (19° 13′ 13″ N 72° 57′ 17″ E), decaying branches of unidentified plant, July 2020, K. C. Rajeshkumar, (AMH 10455, holotype), ex-type cultures NFCCI 5058, NFCCI 5059.
GenBank numbers – ITS: OK255497, OK255498; LSU: OK255501, OK255500; tef1α: OK236374, OK236375.
Notes – The proposed new genus Kevinia does not have any morphological resemblance to any of the known genera and species of Parabambusicolaceae. The morphological characteristics of our collection such as apically branched, digitate, dictyosporous conidia and mononematous conidiogenous cells distinguish this taxon as unique and different from all the species in this family. An indefinite morphological comparison is probable with the allied genera Paratrimmatostroma Jayasiri, Phookamsak, D.J. Bhat & K.D. Hyde. However, the sporodochial conidiomata, black powdery, superficial mass on host substrates, helicoid, sigmoid, or reniform conidia that are tapering near apex and base are absent in our collection. The combined ITS, LSU and tef1-α sequence analysis showed that our collection is allied to Neoaquastroma species well within Parabambusicolaceae. Morphological comparison between our collection, Neoaquastroma and Pseudomultiseptospora is improbable due to the absence of anamorph in these genera. Hence, we introduce our collection as Kevinia lignicola sp. Nov (Fig. 4).
Figure 1 – Kevinia lignicola (AMH 10455, holotype). a–c SEM of conidiophores and developing conidia. d Conidiophore and mature conidia. e, f Conidiophore with apical conidia. Scale bars: a–f=2 µm
Figure 2 – Kevinia lignicola (AMH 10455, holotype). a–c Conidiophores with apical branched dictyosporous digitate conidia (front view). d–f Conidiophore with conidia (side view). g, h Developing conidia. i, j Conidiophores. k–n Mature conidia. Scale bars: a–n=10 µm
Figure 3 – Kevinia lignicola (AMH 10455, holotype) a, b Colonies on the decaying wood. c Colonies of NFCCI 5058 (ex-type) on MEA obverse and reverse view. d Colonies of NFCCI 5059 obverse and reverse view
Figure 4 – The best scoring RAxML tree for the combined ITS, LSU and tef1-α sequence data of Parabambusicolaceae and allied families is shown. The topology and clade stability of the combined gene analyses were not significantly different from the single gene analyses. The matrix had 1036 distinct alignment patterns with 19.45% undetermined characters and gaps. Estimated base frequencies were as follows; A=0.211898, C=0.289868, G=0.265372, T=0.232861; substitution rates AC=1.185503, AG=2.613342, AT=1.743890, CG=0.861391, CT=5.838493, GT=1.0; gamma distribution shape parameter α=0.648723. Bootstrap support for ML equal to or greater than 70%, Bayesian posterior probabilities (PP) equal to or greater than 0.88 are shown as ML/PP at the nodes. The tree is rooted to Melanomma pulivis-pyrius CBS 124080. The newly generated sequences are indicated in blue bold