Scytalidium assmuthi G Mane, R Avchar, R Morey, R Sharma, sp. nov.
Index Fungorum number: IF 901341; Mycobank number: MB 901341; Facesoffungi number: FoF 15056; Fig. 1
Etymology – refers to the host termite species Odontotermes assmuthi from which this novel species was isolated.
Holotype – MCC 10102
Scytalidium assmuthi was reported from the gut of the termite Odontotermes assmuthi feeding on wood logs from northern western ghat (India). Sexual morph: Not observed. Asexual morph: Mycelia consists of hyaline to sub-hyaline light brown, smooth-walled, branched, andseptate hyphae (3.04–6.39 µm in width) without conidiophores were observed after 7 days on potato dextrose agar (PDA). Few light brownshort septate intercalary chlamydospores were observed after 14 days of growth on PDA. Intercalary or terminal thick-walled smooth chlamydospores are globose to subglobose, or in chains of different sizes (7.3–13.22 µm diameter).
Culture characteristics – After 10 days colony size was 68 mm diameter at 25 °C on a PDA plate, circular, flat, creamish white, spreading with an entire margin with abundant aerial mycelium. However, after two weeks the colony color changes from creamish white to pinkish white and reverse cream white. This newly isolated fungi is positive for a few hydrolytic enzymes like amylase, cellulase, pectinase, and xylanase and negative for laccase.
Material examined – India, Maharashtra, Kolhapur district, 17.1324519° N, 73.8561159° E, from the gut of an Odontotermes assmuthi termite, 5 February 2021, collected by G Mane, (holotype MCC 10102 preserved in a metabolically inactive state at the National Centre for Microbial Resource (NCMR), formerly known as a Microbial Culture Collection (MCC), National Centre for Cell Science, Pune, India, PYCC 9837 ex-type, MycoBank MB 850092.
GenBank numbers – OR415885 (LSU); OR415883 (ITS)
Notes – Phylogenetic analysis based on the sequences of ITS rDNA and D1/D2 domain of the 28S rRNA gene supported the recognition of a new species in the genus Scytalidium and placed S. assmuthi close to S. circinatum. Additionally, newly isolated species are also distinct based on colony morphology, size, and shape of chlamydospores. The colonies of S. assmuthi on PDA are creamish white (6 D) to pinkish white (14 D), whereas S. circinatum colonies are pale to dark grey (6 D) or dark brown. New species also differentiated from closed-related species (S. circinatum) as it forms light brown globose to sub-globose intercalary or terminal chlamydospores whereas, S. circinatum produces irregularly shaped dematiaceous chlamydospores (Sigler and Wang 1990).
Figure 1 – Scytalidium assmuthi (MCC 10102, holotype) a, b Tree bark with termite colony in Kolhapur, Maharashtra, India. c Host Odontotermes assmuthi sp.; d–h mycelium with melanized chlamydospores; dark brown hyphae with intercalary chlamydospores. i Long hyphae. j colony on PDA agar, Scale bars=20 μm (hyphae and chlamydospores)