Alternaria kunyuensis Lin Huang, Jiao He & D.W. Li, 2024

He, Jiao, Li, De-Wei, Cui, Wen-Li & Huang, Lin, 2024, Seven new species of Alternaria (Pleosporales, Pleosporaceae) associated with Chinese fir, based on morphological and molecular evidence, MycoKeys 101, pp. 1-44 : 1

Alternaria kunyuensis Lin Huang, Jiao He & D.W. Li sp. nov.

Fig. 6

Holotype.

China, Shandong Province, Yantai City, Kunyu Mountain, 37°15'22"N, 121°46'05"E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, (holotype: CFCC 59355). Holotype specimen is a living specimen being maintained via lyophilisation at the China Forestry Culture Collection Center (CFCC). Ex-type (XXG21) is maintained at the Forest Pathology Laboratory, Nanjing Forestry University.

Etymology.

Epithet is after Kunyu Mountain, Yantai City, Shandong Province where the type specimen was collected.

Host/distribution.

From C. lanceolata in Kunyu Mountain, Yantai City, Shandong Province, China.

Description.

Mycelium superficial on the PCA medium, composed of septate, branched, smooth, thin-walled, colourless to pale brown hyphae. Conidiophores short to long, straight or geniculate, simple or branched, pale brown, 1-5 septate, with one or several apical conidiogenous loci, (17.0-)21.4-53.5(-79.2) × (3.0-)3.3-4.0(-4.6) μm, (mean ± SD = 37.4 ± 16.0 × 3.6 ± 0.4 μm, n = 33). Each conidiogenous locus bears a primary chain of 3-8 conidia; each chain usually has one secondary chain of 2-4 conidia. Conidiogenous cells apical or subapical, cylindrical, light brown, smooth, (3.6-)5.2-11.1(-14.7) × (2.5-)3.2-4.2(-4.7) μm, (mean ± SD = 8.1 ± 2.9 × 3.7 ± 0.5 μm, n = 37), mono- or polytretic. Conidia ovoid to ellipsoid, pyriform, pale brown to brown, usually smooth; conidial bodies (16.1-)20.5-29.8(-36.3) × (7.7-)9.4-13.5(-15.8) μm, (mean ± SD = 25.1 ± 4.6 × 11.5 ± 2.0 μm, n = 43), 1-5 transverse and 0-3 longitudinal septate, slightly constricted at the median. Some septa darkened. Secondary conidia commonly produced via a short apical or lateral secondary conidiophore, but rarely by conidia through an inconspicuous apical conidiogenous locus. Secondary conidiophores (false beaks) at the apical end and median of conidium, short or long, multicellular or single cell, (2.9-)2.9-20.0(-37.3) × (2.3-)2.8-3.9(-4.6) μm, (mean ± SD = 11.5 ± 8.5 × 3.3 ± 0.6 μm, n = 33). Conidial beakless mostly with a conical cell at the apex. Chlamydospores not observed.

Culture characteristics.

Colonies on PCA incubated at 25 °C in the dark growing at 7.5 ± 0.2 mm/d; aerial hypha sparse, olive green to dark green; reverse centre grey; sporulation abundant; diffusible pigment absent.

Additional materials examined.

China, Shandong Province, Yantai City, Kunyu Mountain , 37°15'22"N, 121°46'05"E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, XXG12-2, XXG22, XXG26-2, XXG30, XXG31 .

Notes.

The isolates of A. kunyuensis were phylogenetically close to A. hunanensis (this study, HN43-10-2), A. longqiaoensis (this study, HN43-14), A. vaccinii (ex-type, CBS 118818), A. platycodonis (ex-type, CBS 121348), A. rhadina (ex-type, CBS 595.93), A. citriarbusti (ex-type, CBS 102598) and A. tomaticola (ex-type, CBS 118814) (Fig. 2 ). Between A. kunyuensis isolates and A. hunanensis HN43-10-2, there were 2/453 differences in Alt a1, 1/510 in ITS, 1/664 in OPA10-2, 5/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. longqiaoensis HN43-14, there were 3/453 differences in Alt a1, 2/510 in ITS, 1/664 in OPA10-2, 3/401 in endoPG, 6/757 in RPB2, 19/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. vaccinii CBS 118818 (ex-type), there were 5/453 differences in Alt a1, 2/499 in GAPDH, 3/510 in ITS, 1/664 in OPA10-2, 4/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. platycodonis CBS 121348 (ex-type), there were 2/453 differences in Alt a1, 2/499 in GAPDH, 3/510 in ITS, 1/664 in OPA10-2, 3/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. rhadina CBS 595.93 (ex-type), there were 2/453 differences in Alt a1, 2/499 in GAPDH, 3/510 in ITS, 1/664 in OPA10-2, 3/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. citriarbusti CBS 102598 (ex-type), there were 2/453 differences in Alt a1, 3/510 in ITS, 1/664 in OPA10-2, 3/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. kunyuensis isolates and A. tomaticola CBS 118814 (ex-type), there were 4/453 differences in Alt a1, 3/510 in ITS, 1/664 in OPA10-2, 3/401 in endoPG, 4/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. The PHI analysis showed that there was no significant recombination between A. kunyuensis isolates and its related species (Φw = 0.3502) (Fig. 2B ). Distinguishing characteristics of this new species and other related species of Alternaria spp. are shown in Table 2 . Morphologically, sporulation patterns of the A. kunyuensis isolates were different from those of A. hunanensis HN43-10-2 (one secondary chain of 2-4 conidia vs. one secondary chain of 1-2 conidia.) and A. longqiaoensis HN43-14 (one secondary chain of 2-4 conidia vs. 1-3 branching chains of 3-4 conidia). Conidia in chains of the A. kunyuensis isolates were less than those of A. vaccinii CBS 118818 (ex-type) (3-8 conidia vs. 8-10 conidia) ( Simmons 2007), A. platycodonis CBS 121348 (ex-type) (3-8 conidia vs. 8-10 conidia) ( Zhang 2003) A. rhadina CBS 595.93 (ex-type) (3-8 conidia vs. 9-15 conidia) ( Simmons 1993) and A. tomaticola CBS 118814 (ex-type) (3-8 conidia vs. 10-15 conidia) ( Simmons 2007). Transverse septa of conidia of the A. kunyuensis isolates were less than those of A. citriarbusti CBS 102598 (ex-type) (1-5 transverse septa vs. 6-11 transverse septa) ( Simmons 1999). Thus, the phylogenetic and morphological evidence supports this fungus being as a new species within the Alternaria alternata species complex.

Figures

Figure 2. Splitgraphs showing the results of the pairwise homoplasy index (PHI) test of newly described taxa and closely-related species using both LogDet transformation and splits decomposition A the PHI of Alternaria xinyangensis sp. nov. and A. dongshanqiaoensis sp. nov. with their phylogenetically related isolates or species B the PHI of A. shandongensis sp. nov., A. kunyuensis sp. nov., A. hunanensis sp. nov. and A. longqiaoensis sp. nov. with their phylogenetically related isolates or species C the PHI of A. cunninghamiicola sp. nov. with their phylogenetically-related isolates or species. PHI test value (Φw) <0.05 indicate significant recombination within a dataset. * indicates strains of this study. T indicates the ex-type strains, ET indicates the ex-epitype strains, HT indicates the ex-holotype strains.

Figure 6. Alternaria kunyuensis (XXG 21) A colony on PCA after 6 days at 25 ° C in the dark B, C sporulation patterns D conidiophores bear conidiogenous cells E secondary conidiophores, conidiogenous cells and conidia F conidium. Scale bars: 50 μm (B); 10 μm (C-F).