Sirococcus fujianensis Ning Jiang

Sirococcus fujianensis (Zhao X. Zhang & X. G. Zhang) Ning Jiang, in Jiang, Wijayawardene, Xue & Li, IMA Fungus 17: 13 (2026) Fig. 3 Ecology. Isolated from diseased leaf tissues of Camellia sinensis (Theaceae). New host-record. Description. Sexual morph not observed. Asexual morph: Pycnidial conidiomata, solitary to aggregated, globose to pulvinate, reddish-brown, exuding creamy pale-pink conidial masses after 10 d of incubation at 25 ° C in darkness. Conidiophores hyaline, smooth, indistinct, often reduced to conidiogenous cells. Conidiogenous cells phialidic, hyaline, smooth, cylindrical to ampulliform, attenuate towards the apex, 15.7–22.7 × 1.5–2.0 μm. Conidia hyaline, smooth, multi-guttulate, obovoid to oval-fusoid, straight or slightly curved, base truncate, (4.9 –) 5.7–7.4 (– 8.1) × (1.7 –) 1.8–2.3 (– 2.7) μm, mean ± SD = 6.54 ± 0.81 × 2.09 ± 0.25 μm, n = 33. Culture characteristics. Colonies on PDA attaining 54–55 mm diam. after 7 d at 25 ° C in darkness, spreading, petaloid, greyish-white, with moderate aerial mycelium; margin undulate; reverse concolorous. Additional materials examined. China. • Fujian Province: Wuyishan City, Rare and Precious Botanical Garden, 27°07'47"N, 117°07'17"E; ca. 724 m a. s. l., on leaves of Camellia sinensis, 19 October 2024, coll. Y. L. Wang, culture: SAUCC 10881. Notes. Multilocus phylogenetic analysis based on the combined ITS, tef 1, and tub 2 dataset shows that the strain obtained in this study (SAUCC 10881) clusters with Sirococcus fujianensis with high statistical support (MLBS = 100 %, BIPP = 1.00) (Fig. 1). Pairwise sequence comparisons reveal only negligible intraspecific nucleotide differences: 0 % divergence in the ITS region, 0.64 % (4 / 621) in tef 1, and 0.23 % (1 / 441) in tub 2, which are far below the commonly accepted interspecific divergence thresholds for Sirococcus (≥ 1 % for ITS, ≥ 3 % for tef 1, ≥ 1 % for tub 2). Morphologically, the conidial dimensions of the strain in this study (SAUCC 10881; (4.9 –) 5.7–7.4 (– 8.1) × (1.7 –) 1.8–2.3 (– 2.7) μm) completely overlap with those of the ex-type strain CGMCC 3.28229 (4.8–7.5 × 1.7–2.5 μm), and no distinct morphological differences were observed in colony characteristics or conidiogenous cell morphology. Sirococcus fujianensis was originally described as an endophytic fungus isolated from leaves of Castanopsis chinensis in Fujian Province, China (Zhang et al. 2025). Prior to this study, it was known only from its type host Castanopsis chinensis (Fagaceae, Castanopsis). This study presents the first record of S. fujianensis on Camellia sinensis (Theaceae), extending its known host range to Theaceae. This finding indicates that S. fujianensis has broader host adaptability than previously documented. Based on congruent results of morphological observations and multi-locus phylogenetic analysis, we report Sirococcus fujianensis as a new host record on Camellia sinensis in Fujian Province, China.