Castanediella brevis s C.G. Lin & K.D. Hyde

Lin, Chuan-Gen, J. Bhat, Darbhe, Liu, Jian-Kui, D. Hyde, Kevin & Yong Wang,, 2019, The genus Castanediella, MycoKeys 51, pp. 1-14 : 4-5

Castanediella brevis s C.G. Lin & K.D. Hyde sp. nov. Figure 2

Holotype.

THAILAND. Lampang: Amphoe Mueang Pan, Tambon Chae Son, on decaying leaves, 24 September 2016, Chuangen Lin, LCG 10-1 (MFLU 18-1695, holotype; HKAS 102198, isotype), ex-type living cultures KUMCC 18-0132.

GenBank number.

ITS: MH806361, LSU:MH806358

Etymology.

In reference to the short conidiophores.

Saprobic on plant host. Asexual morph: Colonies on substrate effuse, white. Mycelium partly superficial, composed of septate, branched, smooth, hyaline to subhyaline hyphae. Conidiophores macronematous, mononematous, solitary, erect, unbranched, straight or flexuous, short, 0-1-septate, hyaline, subcylindrical, ampulliform, smooth, often reduced to conidiogenous cells. Conidiogenous cells holoblastic, polyblastic, sympodial, integrated, terminal, subcylindrical, ampulliform, hyaline, denticulate, with 2-4 tiny protuberant denticles, 3-14 × 1.5-5.5 μm. Conidia solitary, dry, acropleurogenous, smooth, fusiform, curved, aseptate, hyaline, 12.5-21.7 × 1.2-3 μm (av. 16.95 × 2.2 μm, n = 60). Sexual morph: Undetermined.

Culture characteristics: Conidia germinating on PDA within 24 h. Colonies on PDA effuse, greyish white to dark from above and below, reaching a diam. of 5-7 cm in 30 days at 25 °C.

Notes.

Based on a megablast search of the NCBI nucleotide database using the ITS sequence of the ex-type culture, the highest similarities found were with Castanediella malaysiana (GenBank NR_154810; identities = 526/537(98%), gaps = 1/537(0%)) and C. couratarii (GenBank KX960789; identities = 521/538(97%), gaps = 3/538(0%)). Castanediella brevis differs from these two species by its conidiophore morphology. Castanediella couratarii has pale brown conidiophores and longer conidiogenous cells (10.5-37 × 2-3.5 μm) whereas C. malysiana has pale brown and longer conidiophores (76-157 × 2.5-3 μm).

Among the species that produce more or less falcate and aseptate conidia, Castanediella communis , C. eucalypti , C. eucalypticola and C. eucalyptigena are most similar to C. brevis . However, Castanediella brevis differs from these species by its short, unbranched and 0-1-septate conidiophores.