Pseudocryphonectria elaeocarpicola Huayi Huang, 2022

Huang, Hua-Yi, Huang, Huan-Hua, Zhao, Dan-Yang, Shan, Ti-Jiang & Hu, Li-Li, 2022, Pseudocryphonectria elaeocarpicola gen. et sp. nov. (Cryphonectriaceae, Diaporthales) causing stem blight of Elaeocarpus spp. in China, MycoKeys 91, pp. 67-84 : 67

Pseudocryphonectria elaeocarpicola Huayi Huang sp. nov.

Figs 4 , 5

Etymology.

Named after the host genus, Elaeocarpus .

Description.

Sexual morph: Unknown. Asexual morph: Conidiomata pycnidial, aggregated or solitary, immersed under the host bark, subglobose to pulvinate, yellow to orange, 500-1200 μm wide, 150-450 μm high, multilocular, single ostiolate, forming long orange tendrils. Conidiophores cylindrical, aseptate, hyaline, sometimes reduced to conidiogenous cells. Conidiogenous cells lining inner cavity of conidiomata, phialidic, ampulliform, with attenuated or truncate apices, hyaline, smooth, 12.8-25.7 × 1.7-3.2 μm (n = 50). Conidia dimorphic. Microconidia minute, aseptate, hyaline, smooth, cylindrical, straight, (3.1-)3.3-4(-4.4) × (1.5-)1.6-2(-2.1) μm (n = 50), L/W = 1.6-2.7. Macroconidia aseptate, hyaline, smooth, obclavate, straight or slightly curved, (4.6-)5.1-6.1(-6.6) × (1.4-)1.6-2(-2.2) μm (n = 50), L/W = 2.5-3.9.

Culture characters.

Colonies on PDA flat, spreading, with aerial mycelium and entire margin, white to mouse grey, forming abundant orange conidiomata with orange conidial masses.

Specimens examined.

China, Guangdong Province, Guangzhou City, Meihua middle school, 23°8'37.94"N, 113°14'18.12"E, 24 m asl, on stems and branches of Elaeocarpus hainanensis , 7 March 2022, Huayi Huang (CAF 800051 holotype; ex-type living culture, CFCC 57515). Guangdong Province, Guangzhou City, Luhu Park, 23°9'11.15"N, 113°16'46.01"E, 92 m asl, on stems and branches of E. apiculatus , Huayi Huang, 15 March 2022 (CAF 800055 paratype; ex-paratype living culture, CFCC 57516). Guangdong Province, Guangzhou City , Longdong straight street, 23°11'41.02"N, 113°22'8.33"E, 46 m asl, on stems and branches of E. apiculatus , Huayi Huang, 1 April 2022 (DY03, culture, CFCC 57517). Guangdong Province, Guangzhou City, South China botanical garden, 23°11'3.5"N, 113°21'41.53"E, 39 m asl, on stems and branches of E. apiculatus , Huayi Huang , 11 April 2022 (DY24, culture, DY24-2). Guangdong Province, Guangzhou City, Linke 1st street, 23°11'35.81"N, 113°22'46.69"E, 74 m asl, on stems and branches of E. apiculatus , Huayi Huang, 15 April 2022 (DY32; culture, DY32-1). Guangdong Province, Guangzhou City, Nonglin middle street, 23°11'23.84"N, 113°22'43.08"E, 46 m asl, on stems and branches of E. apiculatus , Huayi Huang, 15 April 2022 (DY42, culture, DY42-1) .

Notes.

Pseudocryphonectria elaeocarpicola is the sole species within the new genus, which causes serious stem blight of Elaeocarpus trees. Another notorious pathogen in Cryphonectriaceae , Cryphonectria parasitica , causes serious chestnut worldwide. Morphologically, P. elaeocarpicola is similar to C. parasitica in the appearance of conidiomata with orange conidial tendrils formed on the host bark. However, P. elaeocarpicola can be distinguished from C. parasitica by its obvious dimorphic conidia ( Jiang et al. 2019a). Phylogenetically, isolates of P. elaeocarpicola clustered into a distinct clade in the phylograms of Cryphonectriaceae (Figs 2 , 3 ).

Figures

Figure 2. Phylogram of Cryphonectriaceae resulting from a maximum likelihood analysis based on combined ITS and LSU loci. Numbers above the branches indicate ML bootstrap values (left, ML-BS ≥ 50 %) and Bayesian Posterior Probabilities (right, BPP ≥ 0.9). The tree is rooted with Diaporthe eres (LC 3198). Isolates from the present study are marked in blue, and ex-type strains are marked with *.

Figure 3. Phylogram of Cryphonectriaceae resulting from a maximum likelihood analysis based on combined ITS, LSU, tef 1 and rpb 2 loci. Numbers above the branches indicate ML bootstrap values (left, ML-BS ≥ 50 %) and Bayesian Posterior Probabilities (right, BPP ≥ 0.9). The tree is rooted with Diaporthe eres (LC 3198). Isolates from the present study are marked in blue, and ex-type strains are marked with *.

Figure 4. Morphology of Pseudocryphonectria elaeocarpicola from Elaeocarpus hainanensis A, B habit of conidiomata on the host stem C transverse section through the conidioma D longitudinal section through the conidioma E conidiogenous cells giving rise to conidia F macroconidia and microconidia. Scale bars: 300 μm (C, D); 10 μm (E, F).

Figure 5. Morphology of Pseudocryphonectria elaeocarpicola from PDA A, B colonies C, D orange conidiomata.