Biodiversity Data Journal :
Taxonomy & Inventories
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Corresponding author: Xiang-Yu Zeng (xyzeng3@gzu.edu.cn)
Academic editor: Ning Jiang
Received: 28 Jun 2022 | Accepted: 29 Jul 2022 | Published: 19 Aug 2022
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Liu Y-W, Zeng X-Y (2022) Acrocalymma chuxiongense sp. nov., a new species of Acrocalymmaceae (Pleosporales) on leaves of Quercus. Biodiversity Data Journal 10: e89635. https://doi.org/10.3897/BDJ.10.e89635
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In Huafo Mountain, Mouding, Yunnan Province, China, we found black protrusions on the leaf surface of Quercus plants. The collection which we identified as Acrocalymma chuxiongense sp. nov., a new species of Acrocalymmaceae (Pleosporales) is characterised by dome-shaped ascomata, bitunicate asci with pedicel furcate and an ocular chamber and hyaline, obovoid to ellipsoid, 1-septate ascospores.
Morphologically, this species is typical with obovoid to ellipsoid, larger ascospores than other known species in Acrocalymma. Phylogenetic analysis also showed that it represents a distinct clade, distant to any other species of Acrocalymma. Therefore, we introduce it as Acrocalymma chuxiongense, a new species of Acrocalymmaceae. This study is adding to the current situation where there are very few species and lack of teleomorph characteristics.
morphology, new taxa, pathogen, phylogeny
The genus Acrocalymma was introduced by
At present, Acrocalymma includes 11 species viz. A. ampeli, A. aquaticum, A. bipolare, A. cycadis, A. fici, A. hongheense, A. medicaginis, A. pterocarpi, A. vagum, A. walkeri and A. yuxiense. The major species are reported from terrestrial habitats (
This study introduces a new species in Acrocalymma collected from Chuxiong, Yunnan, China, based on morphological description and phylogenetic analysis.
Fresh fungal materials were collected from leaves of Quercus sp. in Huafo Mountain of Mouding County (Yunnan Province, China). The Mountain is located at 24˚09’–25˚40’N, 101˚18’–101˚51’E at an elevation of 1900–2588 m above sea level. The mountain ranges from north to south and is located on the windward side of the southeast airstream, which is warm, humid and rainy and the air humidity is high. This area also has an annual average rainfall of 1029 mm and an annual average temperature of 12.1˚C–13.5˚C (
Photographs of the ascomata were taken using a stereomicroscope (Keyence VHX-7000 digital microscope). Observations and photomicrographs were made from material mounted in lactic acid (60%) using a compound light microscope (Zeiss Scope 5) equipped with an AxioCam 208 colour camera with interference contrast optics. All measurements were made with ZEN2 (blue edition) and images used for figures were processed with Adobe Photoshop version 2022 software.
Fungal isolates were grown on PDA for 20 days at 25°C in the dark. DNA was extracted from the pure culture with a Biospin Fungus Genomic DNA Extraction Kit (BioFlux, China) according to the manufacturer’s instructions (Hangzhou, P.R. China). The internal transcribed spacer (ITS), along with the 5.8S ribosomal rDNA, was amplified with the primer pair ITS1 and ITS4 (
Taxa used in the phylogenetic analysis of Acrocalymmaceae and their corresponding GenBank numbers. The newly generated sequences are indicated in bold. NA: Sequence data not available in GenBank. T = ex-type strain.
Species |
Strain no. |
GenBank accession no. |
Reference |
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ITS |
LSU |
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Acrocalymma ampeli |
MFLU 19-2734 |
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Acrocalymma ampeli |
NCYU19-0008 |
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Acrocalymma aquaticum |
MFLUCC 11-0208 T |
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Acrocalymma bipolare |
MD1321 T |
NA |
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Acrocalymma cycadis |
CBS 137972 T |
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Acrocalymma chuxiongense |
IFRDCC3104 |
This study |
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Acrocalymma fici |
CBS 317.76 T |
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Acrocalymma hongheense |
HKAS 111909 T |
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Acrocalymma medicaginis |
CPC 24340 T |
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Acrocalymma medicaginis |
MFLUCC 17-1423 |
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Acrocalymma pterocarpi |
MFLUCC 17-0926 T |
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Acrocalymma pterocarpi |
NC 13-171 |
Unpublished |
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Acrocalymma vagum |
CPC 24226 |
NA |
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Acrocalymma vagum |
CPC 24225 |
NA |
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Acrocalymma walkeri |
CBS 257.93 |
[1] |
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Acrocalymma yuxiense |
HKAS 111910 T |
NA |
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Sequences of each gene generated from forward and reverse primers were assembled with BioEdit version 7.2.5 (
Habitat terrestrial, epiphytic with dome-shaped black protrusions on living leaves of Quercus sp. Teleomorph: Ascomata 50–80 µm high, 270–320 µm in diam. (average = 70 × 280 µm, n = 10), dark brown, gregarious, erumpent to nearly superficial, visible as numerous, raised, dome-shaped areas on host surface, globose, uni-loculate, glabrous with rough walls, coriaceous. Peridium 10–30 µm wide, of unequal thickness, composed of dark brown to black cells, arranged in textura angularis. Asci 130–170 × 40–45 µm, (average = 150 × 40 µm, n = 20), 8-spored, bitunicate, pedicel furcate, apically rounded with an ocular chamber. Ascospores 35–45 × 18–20 µm, (average = 40 × 20 µm, n = 40), overlapping, bi-seriate, hyaline, obovoid to ellipsoid, 1-septate, constricted at the septum, with conically rounded ends, upper cell larger than lower cell, smooth-walled (Fig.
Bayesian Inference (BI) phylogenetic tree, based on a combined dataset of partial LSU and ITS sequence data. Bootstrap support values for ML equal to or greater than 50%, Bayesian posterior probabilities equal to or greater than 0.9 are shown as ML/BI above the nodes. The new isolates are in red. The scale bar represents the expected number of nucleotide substitutions per site. The tree was rooted with Acrocalymma aquaticum (MFLUCC 11-0208).
Culture Characteristics: Colonies grew on PDA at 250C in the dark and reached 4 cm in diam., within 14 days, dense, circular, slightly raised in the middle, entire margin off-white to grey in surface view.
The specific epithet reflects Chuxiong, from where the specimen was collected.
The teleomorph of Acrocalymma chuxiongense was similar to A. pterocarpi, but can be distinguished by the shape and size of ascospores. Our new collection has a larger ascospore (35–45 × 18–20 µm) than Acrocalymma pterocarpi (17–21 × 3–5 µm) (
The alignment comprised 16 strains with 1322 total characters including gaps. The best nucleotide substitution model for LSU and ITS is K80+I and TIM2ef+G, respectively. The RAxML analysis of the combined dataset yielded a best scoring tree with a final ML optimisation likelihood value of -2834.090234. Estimated base frequencies are as follows: A = 0.240753, C = 0.220941, G = 0.279900, T = 0.258406; substitution rates AC = 3.347637, AG = 2.128594, AT = 3.236536, CG = 0.316367, CT = 10.359429, GT = 1.000000; proportion of invariable sites I = 0.752805; gamma distribution shape parameter α = 0.633740. The Bayesian analysis ran (92000) generations before the average standard deviation for split frequencies reached (0.008966). The analysis generated (1842) trees, from which 1382 were sampled after 46 of the trees were discarded as burn-in. Our new collection forms a distinct clade, distant to any other species in Acrocalymma (Fig.
In this study, we introduced a new species, Acrocalymma chuxiongense, from living leaves of Quercus, based on phylogenetic analysis and morphological comparisons.
Acrocalymma species are able to produce pycnidia in culture easily (
Species |
Ascomata |
Asci |
Ascospores |
Locality |
Reference |
Acrocalymma chuxiongense |
50–80 µm high, 270–320 µm in diam., gregarious, dark brown. |
130–170 × 40–45 µm |
35–45 × 18–20 µm, hyaline, obovoid to ellipsoid, 1-septate, upper cell larger than lower cell. |
Yunnan |
This study |
Acrocalymma hongheense |
180–220 µm high, 160–200 µm diam., gregarious, dark brown, ostiolate. |
100–140 × 15–22 µm |
25–35 × 9.5–11 µm, hyaline, 1-septate, fusiform, with a sheath, the expansion near the septate. |
Yunnan |
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Acrocalymma pterocarpi |
140–150 µm high, 130–145 µm diam., scattered, black, without ostiole. |
65–75 × 7–12 µm |
17–21 × 3–5 µm, hyaline, fusiform, 1-3 septate, guttulate, sheath present in immature stage. |
Thailand |
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Acrocalymma walkeri |
160–180(225) µm wide, 160–180(225) µm high, covered with light grey hairs. |
50–80 × 8–11µm |
19–22 × 4.5–5.5 µm, pale reddish-brown, 3-septate, fusiform, with a sheath. |
Australia |
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Species |
Conidia |
Locality |
Reference |
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Size |
Color |
Shape |
Apex and base |
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Acrocalymma hongheense |
20–35 × 7–9 µm |
hyaline |
subcylindrical |
obtusely rounded and with mucoid ooze at the apex, protuberant and with a rounded hilum at base. |
Yunnan |
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Acrocalymma yuxiense |
15–21 × 4–5 µm |
hyaline |
subcylindrical |
obtusely rounded at apex and base, guttulate. |
Yunnan |
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Acrocalymma fici |
(12–)13–15(–16) × 2.5(–3) µm |
hyaline |
cylindrical |
cylindrical with subobtuse apex, acutely tapered at base to a small flattened central scar, with flaring mucoid apical appendage, visible in water mounts. |
India |
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Acrocalymma medicaginis |
(11–)13–15(–16) × (3.5–)4 µm |
hyaline |
subcylindrical |
apex obtuse, tapering at base to truncate hilum, ends with mucoid caps. |
Australia |
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Acrocalymma vagum |
(16–)18–25(–28)×(4.0–)4.5–6.0(–6.9) µm |
hyaline to brown |
cylindrical to fusiform |
apex rounded, base obtuse or tapering abruptly to a truncate base, guttulate. |
Spain, USA |
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Acrocalymma ampeli |
17–19 × 5.5–6.5 µm |
hyaline |
cylindrical to fusoid |
apex obtuse, unicellular, with flaring mucoid apical appendage at lower end, visible in water mounts. |
Taiwan |
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Acrocalymma aquatica |
12–17 × 3–4 µm |
hyaline |
cylindrical to fusoid |
truncate at the base and becoming a little narrower at apex with a mucilaginous helmet-shaped appendage. |
Thailand |
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Acrocalymma bipolare |
9–12 × 3–5 µm |
hyaline |
cylindrical to fusiform |
with rounded apex and slightly narrow, truncate base, with mucoid polar appendages that are filled with oil droplets, appendages elongate in water to form filaments. |
Egypt |
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Acrocalymma cycadis |
(25–)28–32(–35) × (4–)5 µm |
hyaline |
subcylindrical |
apex obtusely rounded, hilum truncate, guttulate. |
Australia |
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All species of Acrocalymma have sequence data in GenBank, but most have only ITS and LSU sequences and lack SSU and TEF sequences. On the other hand, sequence data of TEF were not used in the phylogenetic analyses due to lack of relevant data. Enriching the sequence data will provide more comprehensive phylogenetic relationships of the genus.
So far, only 11 species of Acrocalymma have been reported, indicating that Acrocalymma has great research potential. The future investigations of Acrocalymma will reveal more undiscovered species.
This study was funded by the Natural Science Special Research Fund of Guizhou University, Special Post 2021(25).