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

Fig. 8

Holotype.

China, Shandong Province, Yantai City, Penglai District, Hougou village, 37°27'32"N, 120°46'48"E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, (holotype: CFCC 59354). Holotype specimen is a living specimen being maintained via lyophilisation at the China Forestry Culture Collection Center (CFCC). Ex-type (SDHG12) is maintained at the Forest Pathology Laboratory, Nanjing Forestry University.

Etymology.

Epithet is after Shandong Province where the type specimen was collected.

Host/distribution.

From C. lanceolata in Hougou village, Penglai District, Yantai City, Shandong Province, China.

Description.

Mycelium superficial on the PCA medium, composed of septate, branched, smooth, thin-walled, pale brown hyphae. Conidiophores solitary, emerging from aerial or creeping hyphae, straight or geniculate, simple or branched, with one or several apical conidiogenous loci, 1-5 septate, variable in length, (16.8-)23.6-51.1(-68.8) × (3.0-)3.4-4.3(-5.0) μm, (mean ± SD = 37.3 ± 13.8 × 3.8 ± 0.4 μm, n = 35). Each conidiogenous locus bears a primary chain of 9-13 conidia; each primary chain usually has 1-3 lateral branches (secondary chains) of 1-2 conidia. Conidiogenous cells apical or subapical, cylindrical, light brown, smooth, (3.9-)4.8-9.6(-17.3) × (2.5-)3.2-4.3(-4.8) μm, (mean ± SD = 7.2 ± 2.4 × 3.7 ± 0.6 μm, n = 46), mono- or polytretic. Conidial bodies ovoid to ellipsoid, brown to dark brown, (14.8-)20.1-31.2(-51.5) × (7.5-)9.3-14.1(-17.0) μm, (mean ± SD = 25.6 ± 5.6 × 11.7 ± 2.4 μm, n = 66), with 2-7 transverse and 0-3 longitudinal septa, mostly smooth to occasionally roughened. Secondary conidia commonly produced via a short lateral secondary conidiophore. Secondary conidiophores (false beaks) at the apical end and median of conidium, short, mostly single-celled, (2.9-)2.7-10.3(-23.5) μm × (2.0-)2.3-3.1(-3.7) μm, (mean ± SD = 6.5 ± 3.9 μm × 2.7 ± 0.4 μm, n = 34). 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 7.6 ± 0.7 mm/d; aerial hypha sparse, dark green to black; reverse centre grey, sporulation abundant; diffusible pigment absent.

Additional materials examined.

China, Shandong Province, Yantai City, Penglai District, Hougou village , 37°27'32"N, 120°46'48"E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, SDHG12-1, SDHG12-2, SDHG12-3, SDHG12-4 ; China, Fujian Province, Longyan City, Lianfeng Town , 25°09'27"N, 117°01'50"E, isolated from leaf spots of C. lanceolata , May 2017, Wen-Li Cui, LY 15 .

Notes.

The isolates of A. shandongensis were phylogenetically close to A. kunyuensis (this study, XXG21), 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. shandongensis isolates and A. kunyuensis XXG21, there were 1/453 differences in Alt a1, 2/499 in GAPDH, 1/664 in OPA10-2, 5/757 in RPB2, 1/996 in SSU and 3/293 in TEF1. Between A. shandongensis isolates and A. hunanensis HN43-10-2, there were 1/453 differences in Alt a1, 2/499 in GAPDH, 1/510 in ITS, 5/401 in endoPG and 1/757 in RPB2. Between A. shandongensis isolates and A. longqiaoensis HN43-14, there were 3/453 differences in Alt a1, 2/499 in GAPDH, 2/510 in ITS, 3/401 in endoPG, 1/757 in RPB2 and 18/996 in SSU. Between A. shandongensis isolates and A. vaccinii CBS 118818 (ex-type), there were 5/453 differences in Alt a1, 4/499 in GAPDH, 3/510 in ITS, 4/401 in endoPG and 1/757 in RPB2. Between A. shandongensis isolates and A. platycodonis CBS 121348 (ex-type), there were 2/453 differences in Alt a1, 4/499 in GAPDH, 3/510 in ITS, 3/401 in endoPG and 1/757 in RPB2. Between A. shandongensis isolates and A. rhadina CBS 595.93 (ex-type), there were 2/453 differences in Alt a1, 4/499 in GAPDH, 3/510 in ITS, 3/401 in endoPG and 1/757 in RPB2. Between A. shandongensis isolates and A. citriarbusti CBS 102598 (ex-type), there were 2/453 differences in Alt a1, 2/499 in GAPDH, 3/510 in ITS, 3/401 in endoPG and 1/757 in RPB2. Between A. shandongensis isolates and A. tomaticola CBS 118814 (ex-type), there were 4/453 differences in Alt a1, 2/499 in GAPDH, 3/510 in ITS, 3/401 in endoPG and 1/757 in RPB2. The PHI analysis showed that there was no significant recombination between A. shandongensis isolates and its related species (Φw = 0.3502) (Fig. 2B ). Distinguishing characteristics of this new species and their related species of Alternaria are shown in Table 2 . Morphologically, conidia in chains of the A. shandongensis isolates were more than those of A. kunyuensis XXG21 (9-13 conidia vs. 6-8 conidia), A. hunanensis HN43-10-2 (9-13 conidia vs. 3-7 conidia), A. longqiaoensis HN43-14 (9-13 conidia vs. 4-8 conidia), A. citriarbusti CBS 102598 (ex-type) (9-13 conidia vs. 5-8 conidia) ( Simmons 1999) and A. platycodonis CBS 121348 (ex-type) (9-13 conidia vs. 8-10 conidia) ( Zhang 2003). Conidiophores of the A. shandongensis isolates were significantly shorter than those of A. vaccinii CBS 118818 (ex-type) (23.6-51.1 × 3.4-4.3 μm vs. 100-200 × 3-4 μm) ( Simmons 2007), A. rhadina CBS 595.93 (ex-type) (23.6-51.1 × 3.4-4.3 μm vs. 60-110 × 3-4 μm) ( Simmons 1993), A. citriarbusti CBS 102598 (ex-type) (23.6-51.1 × 3.4-4.3 μm vs. 200 × 5 μm) ( Simmons 1999) and A. tomaticola CBS 118814 (ex-type) (23.6-51.1 × 3.4-4.3 μm vs. 50-80 × 3-5 μm) ( Simmons 2007). In conclusion, the phylogenetic and morphological evidence supports this fungus as being 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 8. Alternaria shandongensis (SDHG 12) A colony on PCA after 6 days at 25 ° C in the dark B-D sporulation patterns E, F conidiophores and conidiogenous cells G conidia. Scale bars: 50 μm (B, C); 10 μm (D-G).