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

Etymology.

The specific epithet “ decaspermi ” refers to the host plant Decaspermum montanum .

Type.

CHINA • Hainan Province, Hainan Diaoluoshan National Forest Park , on diseased leaves of Decaspermum montanum Ridl. , 27 March 2023, M. Y. Zhang ( holotype HSAUP 6466–1 ), ex-type living culture CGMCC 3.28667 .

Description.

Leaf endogenic and associated with leaves of Decaspermum montanum Ridl. Asexual morph: Conidiomata pycnidial, mostly aggregated in clusters, black, erumpent. In PDA culture exuding colourless to opaque conidial masses within 12 days or longer. Conidiophores indistinct, often reduced to conidiogenous cells. Conidiogenous cells 6.5–15.5 × 2–4 μm, subcylindrical, ampulliform, hyaline, smooth. Conidia 10–13.5 × 5.5–7 μm, hyaline, aseptate, thin and smooth walled, coarsely guttulate, ovoid, ampulliform, ellipsoidal to subglobose, enclosed in a thin mucoid sheath. Sheath 1–2.5 μm thick and bearing a hyaline, apical mucoid appendage. Appendages 3–7 × 0.5–1 μm, flexible, unbranched, tapering towards an acutely rounded tip. Sexual morph not observed, see Fig. 4 .

Culture characteristics.

Colonies on PDA 12–16 mm in diameter after 7 d at 25 ° C in darkness, with a growth rate of 1.7–2.3 mm / day, white and undulate at edge, grey-green in center in obverse and reverse.

Additional specimen examined.

CHINA • Hainan Province, Hainan Diaoluoshan National Forest Park , on dead leaves, 27 March 2023, M. Y. Zhang ( HSAUP 6512–2 ), living culture SAUCC 6512–2 .

Notes.

Two isolates from leaf spots of Decaspermum montanum phylogenetically clustered into a well-supported clade (1.00 / 100), which is closely related to Phyllosticta guangdongensis ( CFCC 58144 ), P. mangiferae ( IMI 260.576 ) and P. morellae ( CGMCC 3.28669 ). However, P. decaspermi differs from P. guangdongensis by 68 nucleotides (10 / 480 in ITS, 5 / 740 in LSU, 38 / 199 in tef 1, 6 / 195 in act, and 9 / 594 in gpdh), from P. mangiferae by 75 nucleotides (8 / 518 in ITS, 4 / 740 in LSU, 36 / 198 in tef 1, 6 / 195 in act, and 21 / 615 in gpdh) and from P. morellae 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). In morphology, they are distinguished by different hosts ( Decaspermum montanum vs. Viburnum odoratissimum vs. Mangifera indica vs. Morella rubra ) and narrower conidia in P. decaspermi than P. guangdongensis , P. mangiferae and P. morellae (10–13.5 × 5.5–7 μm vs. 10–14 × 6–8 μm vs. 10.0–12.0 × 6.0–7.0 μm vs. 8.4–13.7 × 5.7–9.2 μm) ( Jeewon and Hyde 2016; Wang et al. 2023). Therefore, based on morphology and phylogenetic evidence, we establish this fungus as Phyllosticta decaspermi sp. nov.

Figures

Figure 4. Phyllosticta decaspermi (CGMCC 3.28667) a diseased leaf of Decaspermum montanum b, c colonies (left-above, right-reverse) after 7 d on PDA d conidiomata e, f conidiogenous cells with conidia g, h conidia. Scale bars: 10 μm (e – h).