Pestalotiopsis mangifericola X. X. Luo & Jian Ma 2024, sp. nov.

Pestalotiopsis mangifericola X. X. Luo & Jian Ma sp. nov. Fig. 9 Type. China • Yunnan Province, Xishuangbanna Dai Autonomous Prefecture, Mengla County, Menglun Town, Tropical Botanical Garden, on diseased leaves of Mangifera indica, 23 June 2022, X. X. Luo (holotype HJAUP M 1639.221; ex-type living culture HJAUP C 1639.221). Etymology. Referring to the host genus, Mangifera from which it was collected. Description. Regular leaf spots, initially brown with a yellowish halo around the edges, later yellowish-white center with black edges. Asexual morph on PDA: Conidiomata acervular, subglobular, 426–786 μm diam, solitary or aggregated in clusters, black. Conidiophores indistinct and reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, cylindrical to ampulliform. Conidia fusiform, straight or slightly curved, 13.5–18 × 4.7–6 μm (x ̄ = 15.2 × 5.4 μm, n = 50), 4 - septate, slightly constricted at the septa; basal cell conical, 2.9–4.4 μm (x ̄ = 3.6 μm), hyaline or sometimes pale brown, smooth, thin-walled, with a single filiform appendage, unbranched, 3.1–5.5 μm (x ̄ = 4.2 μm) long; three median cells doliiform to cylindrical, smooth, 10.8–12.3 μm (x ̄ = 11.5 μm), concolorous or sometimes darker at the central cell or the two upper cells, somewhat constricted at the septa, second cell from the base pale brown, 3.3–4.6 µm (x ̄ = 3.9 μm) long, third cell pale brown to brown, 3.6–4.5 µm (x ̄ = 3.9 μm) long, fourth cell pale to medium brown, 3.5–5.1 µm (x ̄ = 4.2 μm) long; apical cell conical to acute, hyaline, smooth, thin-walled, 2.5–4 µm (x ̄ = 3.1 μm) long, with 2–3 filiform appendages, arising from the apical crest, unbranched, 7.2–11.6 µm (x ̄ = 9.8 μm) long. Sexual morph not observed. Culture characteristics. Colonies on PDA grow fast, filamentous to circular, growing all over the Petri dish (d = 8.5 cm) after 2 weeks at 25 ° C in darkness, white, with flocculent aerial mycelium and entire edge, forming black conidiomata, and reverse pale orange. Additional specimen examined. China • Yunnan Province, Xishuangbanna Dai Autonomous Prefecture, Mengla County, Menglun Town, Tropical Botanical Garden, 23 June 2022, X. X. Luo. On diseased leaves of Mangifera indica, paratype HJAUP M 1639.222, living culture HJAUP C 1639.222. Note. Two strains (HJAUP C 1639.221 and HJAUP C 1639.222) of Pestalotiopsis mangifericola isolated from leaf spots of Mangifera indica formed a distinct clade sister to P. adusta (MFLUCC 10–146 and ICMP 6088) with 100 % ML / 0.90 BI bootstrap support (Fig. 1). The ex-type strain HJAUP C 1639.221 is closely related to P. adusta (ICMP 6088) and comparisons of their nucleotides showed 4 bp differences (1 %, including one gap) nucleotide differences in three loci. Moreover, P. mangifericola is morphologically distinguished from P. adusta (Ellis & Everh.) Steyaert in its smaller conidia (13.5–18 × 4.7–6 μm vs. 16–22 × 5–7 μm) with shorter three median cells (10.8–12.3 μm vs. 12–15 μm) (Steyaert 1953; Maharachchikumbura et al. 2012).