Phyllosticta morellae M. Y. Zhang, Z. X. Zhang & X. G. Zhang, 2025

Zhang, Meng-Yuan, Zhang, Zhao-Xue, Wang, Ya-Ling, Zhang, Xiu-Guo & Li, Zhuang, 2025, Molecular and morphological characterization of four new Phyllosticta species (Botryosphaeriales, Phyllostictaceae): Genomic insights into evolutionary dynamics and metabolic adaptation, IMA Fungus 16, pp. e 168055-e 168055 : e168055-

Phyllosticta morellae M. Y. Zhang, Z. X. Zhang & X. G. Zhang sp. nov.

Etymology.

The specific epithet “ morellae ” refers to the host plant Morella rubra .

Type.

CHINA • Hainan Province, Ledong Li Autonomous County, Jianfengling National Forest Park , on diseased leaves of Morella rubra Lour. , 14 October 2023, M. Y. Zhang ( holotype HSAUP 7509–5 ), ex-type living culture CGMCC 3.28669 .

Description.

Leaf endogenic and associated with leaves of Morella rubra Lour. Asexual morph: Conidiomata pycnidial, mostly aggregated in clusters, black, erumpent, globose to clavate or elongated with necks, in PDA culture exuding colourless to opaque conidial masses within 12 days or longer. Conidiophores indistinct, often reduced to conidiogenous cells. Conidiogenous cells 9.5–19 × 2–3 μm, subcylindrical, hyaline, smooth, proliferating several times percurrently near apex. Conidia 8.5–13.5 × 6–9 μm, solitary, hyaline, aseptate, thin and smooth walled, coarsely guttulate, or with a single large central guttule, ovoid to irregularly ellipsoid, surrounded by a mucilaginous sheath. Sheath 1–1.5 μm thick, and bearing a hyaline apical mucoid appendage. Appendages 2.5–5.5 × 1 μm, flexible, unbranched, tapering towards an acutely rounded tip. Sexual morph not observed, see Fig. 5 .

Culture characteristics.

Colonies on PDA 26–32 mm in diameter after 7 d at 25 ° C in darkness, with a growth rate of 3.7–4.7 mm / day, white and undulate at edge, grey-green in center in obverse and reverse.

Additional specimen examined.

CHINA • Hainan Province, Ledong Li Autonomous County, Jianfengling National Forest Park , on diseased leaves of Morella rubra Lour. , 14 October 2023, M. Y. Zhang ( HSAUP 7515–2 ), living culture SAUCC 7515–2 .

Notes.

Two isolates from leaf spots of Morella rubra phylogeneticallyclustered into a well-supported clade (1.00 / 100), which is closely related to P. decaspermi ( CGMCC 3.28667 ), Phyllosticta guangdongensis ( CFCC 58144 ) and P. mangiferae ( IMI 260.576 ). However, P. morellae differs from P. decaspermi by 114 nucleotides (6 / 559 in ITS, 7 / 743 in LSU, 84 / 324 in tef 1, 5 / 196 in act, and 12 / 715 in gpdh), from P. guangdongensis by 36 nucleotides (11 / 480 in ITS, 6 / 743 in LSU, 13 / 219 in tef 1, 3 / 212 in act, and 3 / 594 in gpdh), and from P. mangiferae by 40 nucleotides (5 / 518 in ITS, 5 / 743 in LSU, 7 / 219 in tef 1, 3 / 212 in act, and 20 / 621 in gpdh). In morphology, they are distinguished by different hosts ( Morella rubra vs. Decaspermum montanum vs. Viburnum odoratissimum vs. Mangifera indica ) and narrower conidia in Phyllosticta decaspermi than P. guangdongensis , P. mangiferae and P. morellae (8.5–13.5 × 6–9 μm vs. 10.2–13.4 × 5.6–6.8 μm vs. 10–14 × 6–8 μm vs. 10.0–12.0 × 6.0–7.0 μm) ( Jeewon and Hyde 2016; Wang et al. 2023). Therefore, based on morphology and phylogenetic evidence, we establish this fungus as Phyllosticta morellae sp. nov.

Figures

Figure 5. Phyllosticta morellae (CGMCC 3.28669) a diseased leaf of Morella rubra b, c colonies (left-above, right-reverse) after 7 d on PDA d conidiomata e, f conidiogenous cells with conidia g – j conidia. Scale bars: 10 μm (e – j).