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Two new records of powdery mildews (Erysiphaceae) from Japan: Erysiphe actinidiicola sp. nov. and Erysiphe sp. on Limonium tetragonum
2021 Volume 62 Issue 3 Pages 198-204
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2021 Volume 62 Issue 3 Pages 198-204
Erysiphe actinidiicola on Actinidia polygama is described based on morphological and molecular data. Erysiphe actinidiicola is distinguished from E. actinidiae var. actinidiae by having irregularly to dichotomously branched chasmothecial appendages, larger chasmothecia sizes and numbers of asci per chasmothecium. Molecular analyses indicated that this species forms a clade separated from E. actinidiae var. actinidiae. An epitype is proposed for E. actinidiae var. actinidiae with ex-epitype sequences. A powdery mildew found on Limonium tetragonum is tentatively described as Erysiphe sp. This species is distinguished from E. limonii, a powdery mildew on Limonium spp., based on the DNA sequence differences in the 28S rDNA and internal transcribed spacer region as well as the morphological differences in the length of the conidiophores. This is the first record of powdery mildew on L. tetragonum in the world.
Powdery mildews (Erysiphaceae, Helotiales) are fungal plant pathogens on a wide range of vascular plants worldwide. Some species cause serious damages on a number of cultivated plants, such as cereals, vegetables, flowers, fruit trees, ornamental plants, etc. (Braun & Cook, 2012). Japan is worldwide one of the most comprehensively explored regions with regard to powdery mildews. However, a number of new powdery mildew species and/or new host plants are still to be found in this country. The diversity of powdery mildews in Japan based on modern taxonomic approaches and additional collections has been explored in recent years (e.g. Meeboon & Takamatsu, 2017; Meeboon, Siahaan, Fujioka, & Takamatsu, 2017; Takamatsu, Katsuyama, & Shinoda, 2017; Meeboon, Takamatsu, & Braun, 2020). During the present study, we found powdery mildew specimens on Actinidia polygama (Siebold et Zucc.) Planch. ex Maxim. (Actinidiaceae) and Limonium tetragonum (Thunb.) A.A.Bullock (Plumbaginaceae) that could not be assigned to any known powdery mildew species. On the basis of detailed morphological and molecular examinations of these collections, we propose to introduce a new Erysiphe species for the fungus on A. polygama.
DNA extraction was conducted according to the procedure described by Meeboon and Takamatsu (2015) based on Hirata and Takamatsu (1996)The 5’-end of the 28S rDNA (including D1 and D2 domains) and internal transcribed spacer (ITS) regions were amplified and sequenced. For the Actinidia powdery mildew, primer sets PM5a (5’-GGCTGGAKCGTGCAYGC-3’)/TW14 and ITS5/PM6a (5’-CGTAGAGTCCACGTCGGG-3’) were used for the amplification of the 28S rDNA and ITS region, respectively. Primer sets PM9/TW14 and ITS5/PM6 were used for the Limonium powdery mildew. The primers PM5a and PM6a were newly designed in this study. DNA sequences retrieved in this study were deposited in NCBI GenBank under the accession numbers MT853059–MT853064. These sequences were combined and aligned with other sequences of Erysiphe species using MUSCLE in MEGA 7 (Edgar, 2004; Kumar, Stecher, & Tamura, 2016). Alignments were refined manually in MEGA 7 and deposited in TreeBASE (http://www.treebase.org/) under the accession number S26749. Phylogenetic trees were obtained from the data using the maximum parsimony (MP) and maximum likelihood (ML) methods. MP analysis was performed in PAUP* 4.0 (Swofford, 2002) with heuristic search option using the tree bisection reconnection (TBR) algorithm with 100 random sequence additions to find the global optimum tree. All sites were treated as unordered and unweighted, with gaps treated as missing data. The strength of internal branches of the resulting trees was tested with bootstrap (BS) analysis using 1000 replications with the step-wise addition option set as "simple" (Felsenstein, 1985). Tree scores, including tree length, consistency index (CI), retention index (RI), and rescaled consistency index (RC), were also calculated. The ML analysis was done using raxmlGUI (Silvestro & Michalak, 2012), under a GTRGAMMA model. The BS supports and trees were obtained by running rapid bootstrap analysis of 1000 pseudo-replicates followed by a search for the tree with the highest likelihood.
2.2. Morphological examinationTo examine the asexual morphs of fresh materials, hyphae, conidiophores, and conidia of fresh collections were stripped off from the leaf surfaces with clear adhesive tape, mounted on a microscope slide with the fungal mycelium upper most, and examined in water. For dried materials, examinations were done following the lactic acid protocol (Shin & La, 1993). To examine the sexual morphs, chasmothecia were picked up from the leaf surface with a sterile needle, mounted in 3% NaOH solution and examined by optical microscopy. Thirty measurements for each structure were made where possible. Herbarium samples used in this study were deposited in the herbarium of National Museum of Nature and Science (TNS, Tsukuba, Japan) and Mycological Herbarium of Mie University (TSU-MUMH, Tsu, Japan).
The nucleotide sequences of the rDNA ITS region and 5`-end of the 28S rDNA (including D1 and D2 domains) was determined for four specimens on Actinidia arguta (Siebold et Zucc.) Planch. ex Miq. and A. polygama. We tried to align these ITS sequences with other sequences of powdery mildews belonging to the Uncinula-lineage (Takamatsu, Ito, Shiroya, Kiss, & Heluta, 2015b). But the alignment was almost ambiguous because of too much sequence variation. BLAST search using the ITS sequence (MT853059) of MUMH3409 (host: A. arguta) as a query showed that the maximum similarity was 99.4% with E. actinidiae (Miyabe ex Jacz.) U. Braun & S. Takam. on A. arguta (LC028963) and only 85% with "E. actinidiae" on A. polygama (LC028965) with only 77% query coverage. The next hit was Phyllactinia sp. (LC371301), but only with 24% query coverage (only 5.8S rDNA region alignable). Thus, the variation of ITS sequences is higher than 15% between E. actinidiae on A. arguta and A. polygama. BLAST search using the 5’-end of 28S rDNA sequence (MT853059) of MUMH3409 (host: A. arguta) as a query indicated a maximum similarity of 99.6% with E. actinidiae on A. arguta (LC028963), but only 95.3% with "E. actinidiae" on A. polygama (LC028965), followed by 91.6% with E. erlangshanensis (Y. N. Yu) U. Braun & S. Takam. (LC010053) and E. epigena S. Takam. & U. Braun (AB292722–AB292724). These results suggest that E. actinidiae is a powdery mildew species having a large intraspecific variation and being only distantly related to other powdery mildew species in its molecular characteristics. We thus decided to use only 28S rDNA sequences for the phylogenetic analysis.
The four 28S rDNA sequences of E. actinidiae determined in this study were aligned with the sequences of powdery mildews on Actinidia (E. actinidiae), Fraxinus [E. salmonii (Syd.) U. Braun & S. Takam. and E. fraxinicola U. Braun & S. Takam.], Salix (E. caprea DC. ex Duby), Liquidambar [E. liquidambaris (R. Y. Zheng & G. Q. Chen) U. Braun & S. Takam.], and Lagerstroemia [E. australiana (McAlp.) U. Braun & S. Takam.] retrieved from DNA databases. These taxa were chosen because they are situated at the base of the Uncinula-lineage together with E. actinidiae (Takamatsu et al., 2015b). Four sequences from Phyllactinia moricola (Henn.) Homma, Leveillula taurica (Lév.) G. Arnaud, Golovinomyces ambrosiae (Schwein.) U. Braun & R. T. A. Cook, and G. tabaci (Sawada) H. D. Shin, S. Takam. & L. Kiss were used as outgroup taxa based on Mori, Sato, and Takamatsu (2000). The alignment data matrix consisted of 23 sequences and total 849 characters, of which 166 (19.6%) were variable and 140 (16.5%) were parsimony informative. A total of 66 equally parsimonious trees with 308 steps were constructed by the MP analysis. The best tree with the highest likelihood value is given in Fig. 1. Because the ML tree was almost identical to the MP tree, only BS values were shown on the MP tree. All the 19 ingroup sequences formed distinct clades in line with the host families with BS supports higher than 90%, suggesting that these Uncinula-lineage species co-evolved together with their host plants. The four sequences from Actinidia powdery mildews also grouped into a distinct clade with strong BS supports (MP = 100%; ML =100%). This clade was further divided into two subclades per host species [A. arguta and A. polygama] with BS supports higher than 90%. The powdery mildews on Fraxinus were sister to the Actinidia powdery mildews, but this was not supported by BS analysis.. The alignment data matrix consisted of 23 sequences and total 849 characters, of which 166 (19.6%) were variable and 140 (16.5%) were parsimony informative. A total of 66 equally parsimonious trees with 308 steps were constructed by the MP analysis. The best tree with the highest likelihood value is given in Fig. 1. Because the ML tree was almost identical to the MP tree, only BS values were shown on the MP tree. All the 19 ingroup sequences formed distinct clades in line with the host families with BS supports higher than 90%, suggesting that these Uncinula-lineage species co-evolved together with their host plants. The four sequences from Actinidia powdery mildews also grouped into a distinct clade with strong BS supports (MP = 100%; ML =100%). This clade was further divided into two subclades per host species [A. arguta and A. polygama] with BS supports higher than 90%. The powdery mildews on Fraxinus were sister to the Actinidia powdery mildews, but this was not supported by BS analysis.
ITS and 28S rDNA sequences were determined for two powdery mildew collections on Limonium tetragonum and aligned with closely related sequences from the Microsphaera-lineage of the genus Erysiphe (Takamatsu, Ito, Shiroya, Kiss, & Heluta, 2015a). Erysiphe glycines F. L. Tai, E. monascogera Shiroya, C. Naksh. & S. Takam., and E. hypophylla (Nevod.) U. Braun & Cunningt. were used as outgroup taxa based on Takamatsu et al. (2015a). This data set consisted of 25 sequences and 1366 characters, of which 119 (8.7%) were variable and 77 (5.6%) were parsimony informative. MP analysis generated 12 equally parsimonious trees with 163 steps. The best tree with the highest likelihood value is given in Fig. 2. BS values with ML analysis are shown on the MP tree. The 10 sequences from powdery mildews on Limonium and Acantholimon (both belonging to Plumbaginaceae) formed a clade with strong BS supports (MP = 97%; ML = 100%). This clade was a sister to the clade consisting of E. malvae V. P. Heluta, E. heraclei DC., E. betae (Vaňha) Weltzien, and E. buhrii U. Braun, but this was not supported by BS analyses. The former clade was further divided into three subclades, viz., a clade consisting of six sequences from specimens on other Limonium species, including material of European origin (referred to as E. limonii L. Junell), a clade of two sequences from specimens on A. hedinii Ostenf. reported from China (E. acantholimonis J. G. Song, B. Xu & H. D. Shin), and a clade of two sequences from specimens on L. tetragonum.
Erysiphe actinidiae(Miyabe ex Jacz.) U. Braun & S. Takam. Schlechtendalia 4: 15, 2000, var. actinidiae Fig. 3.
≡Uncinula actinidiae Miyabe ex Jacz., Karmanny opredelitel’ gribov. Vyp.2. Muchnisto-rosyanye griby: 369, Leningrad 1927.
= U. necator var. actinidiae Hara, J. Forest Ass. Japan 395: 63, 1915.
= U. necator auct. p.p. (sensu Salmon 1900).
= U. actinidiae Miyabe, in herb.
Lectotype (designated by Braun, 1987): On Actinidia arguta Miq., JAPAN, Sapporo, Sep 1890, leg. Miyabe (K(M) 168937).
Epitype (designated here, MycoBank MBT396026): On Actinidia arguta, JAPAN, Hokkaido, Sapporo-shi, Nopporo Forest Park, 23 Sep 2004, leg. S. Takamatsu (TNS-F91389), GenBank (ex-epitype): MT853059 (ITS+28S). isoepitype: TSU-MUMH3409
Descriptions: Mycelium amphigenous, persistent or almost persistent, white, effuse or in dense white patches. Hyphae substraight to somewhat wavy, 5–7 μm in width, branching at right or narrow angle. Appressoria simply lobed or nipple-shape, single. Conidia oblong to ovate, 23–33 × 9–14 μm (l/w ratio = 2.1–3.0). Conidiophores not observed. Chasmothecia scattered to ± gregarious, 90–109(–120) μm diam. Peridium cells irregularly polygonal, 10–20 μm diam. Appendages 6–28, equatorial, stiff, rarely flexuous, 1.5–2 times as long as the chasmothecial diam, 150–294 × 7–10 μm, enlarged at the very base, almost equal throughout, either slightly increasing or occasionally somewhat decreasing towards the tip, 0–1-septate, brown in the lower part, paler or hyaline above, walls smooth, thin, but thick towards the base, apices uncinate-circinate, mostly tight, not enlarged, often even narrowed towards the tip. Asci 3–5, broad ellipsoid-obovoid, saccate, 44–60 × 37–58 μm, sessile or short-stalked, 5–8-spored. Ascospores ellipsoid-ovoid, 16–22 × 9–12 μm, colorless.
Additional specimen examined: On Actinidia arguta, JAPAN, Gumma Pref., Katashina-mura, Oh-Shimizu, 23 Sep 2006, leg. S. Takamatsu (TSU-MUMH4335), GenBank: MT853060 (ITS+28S).
Host range and distribution: on Actinidia (arguta, kolomikta), Actinidiaceae; Asia (China, Japan, Korea, Far East of Russia).
Note: Braun (1987) designated K(M) 168937 collected in 1890 from Japan as lectotype. This specimen is too old to extract DNA. We thus designate TNS-F91389 collected in 2004 from Japan as an epitype here and MT853059 as an ex-epitype sequence.
Erysiphe actinidiicola Meeboon & S. Takam., sp. nov. Fig. 4
MycoBank no.: MB 838788.
Diagnosis: Differs from Erysiphe actinidiae var. actinidiae in having irregularly shaped geniculate-sinuous chasmothecial appendages, which are sometimes irregularly to dichotomously branched, larger (94–142 μm) chasmothecia and a higher number (4–9) of asci per chasmothecium; supported as a separate species by genetic differences in the ITS and 28S rDNA sequences.
Type: On Actinidia polygama (Siebold & Zucc.) Planch. ex Maxim., JAPAN, Nara-Pref., Uda-shi, Mt. Kaigahira, 4 Oct 2009, S. Takamatsu (TNS-F91390). Isotype: TSU-MUMH5011.
Gene sequences (ex-holotype): MT853061 (ITS+28S)
Etymology: The epithet of the new species is composed of Actinidia, the name of the host genus, and -icola (dweller).
Description: Mycelium amphigenous, persistent or almost persistent, white, effuse or in dense white patches. Hyphae substraight to somewhat wavy, 3.5–6 μm in width, branching at right or narrow angle. Appressoria lobed, opposite in pairs. Conidia oblong to ovate, 24–34 × 12–15 μm (l/w ratio = 1.8–2.5). Conidiophores not observed. Chasmothecia scattered to ± gregarious, 94–142 μm diam. Peridium cells irregularly polygonal, 10–25 μm diam. Appendages 7–13, equatorial, stiff to flexuous, rather irregularly shaped, geniculate-sinuous, sometimes irregularly to dichotomously branched below the apex, occasionally forked in the lower half, (1–)1.5–3 times as long as the chasmothecial diam, 172–335 × 6–8 μm, enlarged at the very base, otherwise almost equal throughout, either slightly increasing or occasionally somewhat decreasing towards the tip, 0–3-septate, brown in the lower part, paler or hyaline above, walls smooth, thin, but thick towards the base, apices uncinate-circinate, mostly tight, not enlarged, often evenly narrowed towards the tip. Asci 4–9, broad ellipsoid-obovoid, saccate, 43–63 × 31–48 μm, sessile or short-stalked, 5–8-spored. Ascospores ellipsoid-ovoid, 17–22 × 8.5–11 μm, colorless.
Additional specimens examined: On Actinidia polygama, JAPAN, Niigata, Gosen-shi, Mt. Sugana, 24 Oct 1997, leg. S. Takamatsu (TSU-MUMH457), GenBank: LC028965 (ITS+28S); Iwate Pref., Ninohe-shi, Tendaiji Temple, 11 Oct 2009, leg. S. Takamatsu (TSU-MUMH5043), GenBank: MT853062 (ITS+28S).
Host range and distribution: on Actinidia polygama, Actinidiaceae; Asia (Japan, Korea).
Erysiphe sp. on Limonium tetragonum Fig. 5.
Specimens examined: On Limonium tetragonum (Thunb.) A. A. Bullock (Plumbaginaceae), JAPAN, Oita Pref., Oita-shi, Aosaki, 8 Oct 2017, leg. J. Okamoto (TSU-MUMH7086), GanBank: MT853063 (ITS+28S); 9 Dec 2017, leg. J. Okamoto (TSU-MUMH7147), GenBank: MT853064 (ITS+28S).
Description: Mycelium amphigenous, also on stems and flowers, dense, white, persistent. Hyphae 4–8 µm wide. Hyphal appressoria lobed, solitary or in opposite pairs. Conidiophores erect, arising from top of mother cells, which are 37.5–41 × 6.5–8 µm, or slightly laterally, 50–127 µm long, foot-cells cylindrical, straight or somewhat curved at the very base, 25–44 × 5–8.5 µm, followed by 1–2 mostly shorter cells or by a cell of about the same length or slightly longer, with a basal septum at (0–)5.5–11.5(–16) μm away from the branching point of the external mycelium, forming conidia singly. Conidia ± cylindrical to doliiform, 28–42 × 10.5–15 µm (l/w ratio = 2.6–3.0). Sexual morph (chasmothecia) not found.
The genus Actinidia comprises 54 species and 21 varieties found mainly in East and South Asia (Tang, Xu, Shen, & Yao, 2019). Of these 54 species, powdery mildews of the genus Erysiphe have only been reported on three species, viz. A. arguta, A. kolomikta (Maxim. et Rupr.) Maxim., and A. polygama, all of which belong to Actinidia sect. Leiocarpae among the currently recognized four sections of this genus. Molecular phylogenetic analyses of Actinidia revealed that species belonging to sect. Leiocarpae form a basal grade in Actinidia (Li, Huang, & Sang, 2002; Jáuregui, Petit, & Nadot, 2004; Li, Kang, Huang, & Testolin, 2007; Tang et al., 2019).Braun and Cook (2012) listed A. hemsleyana Dunn (sect. Strigosae) as a host of E. actinidiae, but we did not use this record here because we found this record neither in Amano (1986) nor in Farr and Rossman (2020).
Takamatsu et al. (2015b) published each one sequence (ITS + 28S rDNA) of powdery mildews on A. arguta and A. polygama to show that these two sequences distinctly differ each other. However, they did not draw taxonomic consequences because this result was just based on a single sequence per host. We retrieved additional four sequences (each with two from the respective hosts) in the present study to confirm the previous result. Morphological examinations of these specimens revealed that the powdery mildews on the two Actinidia species resemble each other, but the fungus on A. polygama is distinguishable from the fungus on A. arguta in having rather irregularly shaped geniculate-sinuous chasmothecial appendages, which are sometimes irregularly to dichotomously branched, below or apically. Based on the morphological characteristics and A. arguta as type host of E. actinidiae var. actinidiae, it is feasible to confine E. actinidiae var. actinidiae to the fungus of A. arguta and to propose a new species, E. actinidiicola, for the fungus on A. polygama.
Nomura (1997) described Uncinula actinidiae Miyabe ex Jacz. var. argutae Y. Nomura [now E. actinidiae var. argutae (Y. Nomura) U. Braun & S. Takam.] as a new variety of E. actinidiae. This variety is morphologically distinguishable from var. actinidiae and E. actinidiicola by the long appendages [up to 550(–750) µm]. We tried to locate the holotype specimen of this variety, YNMH7832 [YNMH3768 in Braun & Cook (2012)], for comparison, but failed. This variety was said to be distinguishable from var. actinidiae by having long, irregular chasmothecial appendages. Because DNA sequence data for this variety are not yet available, we prefer to keep this variety, at least tentatively.
The ITS sequence similarity between E. actinidiae and E. actinidiicola was lower than 85%. The similarity of 5’-end of 28S rDNA was 95.3% between E. actinidiae and E. actinidiicola, and 91.6% to the other closest Erysiphe species (both based on BLAST search). These genetic distances are beyond interspecific variation of fungi (Bruns, White, & Taylor, 1991; Kõljalg et al., 2013). In the phylogenetic tree based on 28S rDNA sequences (Fig. 1), the branch leading to the fungi on Actinidia was 2–3 times longer than those leading to fungi on other host families. The possibilities of contamination and other technical problems as well as the possibility of chimeras or pseudogenes can be excluded. The two sequences retrieved from GenBank were obtained by using procedure (PCR primers, sequence primers, equipment, etc.) different from the four sequences determined in this study and conducted by another person at another time, but all the sequences obtained were almost identical. Possible interpretations of this result may be as follows: 1) the split of the fungi on Actinidia from fungi on other host families occurred in a very early stage of evolution, that is, the fungi on Actinidia have an old origin in Erysiphe, 2) the molecular evolution rate accelerated two to three times in the branch leading to the fungi on Actinidia. Taking the close relationship between A. arguta and A. polygama in consideration, the latter possibility may be more likely than the former one. However, because there is no evidence to support this hypothesis, further studies are required.
Specimens on A. kolomikta, another host of E. actinidiae, were not available and could not be included in our analyses. Because A. kolomikta is phylogenetically closely related to A. arguta (Tang et al., 2019), we prefer to keep it as a host of E. actinidiae pending molecular data retrieved from powdery mildew on A. kolomikta.
4.2. Erysiphe sp.The genus Limonium (Plumbaginaceae) encompasses about 600 species distributed worldwide (Koutroumpa et al., 2018). They are mostly perennial herbs and shrubs growing in coastal areas as well as lagoons, meadows, steppes, and deserts of the continental interior. Several species are popular garden flowers generally known as statices. Two Erysiphe species, viz. E. aurea R. Y. Zheng & G. Q. Chen and E. limonii, have so far been known to occur on Limonium (Braun et al., 2012). Erysiphe limonii is commonly distributed in wide area of Asia and Europe and occurs on many Limonium species as well as Acantholimon and Goniolimon, while E. aurea, so far only known from China, is reported only on L. suffruticosum (L.) Kuntze, a Limonium species distributed in Asia [Afghanistan, China (North Xinjiang), Iran, Kazakhstan, Kyrgyzstan, SW Mongolia, Russia, Uzbekistan] and Europe. In 2017, Jun Okamoto, one of the authors, found an asexual morph of a powdery mildew on L. tetragonum in a coastal area of Oita Prefecture, Japan. The sexual morph has not yet been found. Molecular phylogenetic analyses of these specimens revealed that this fungus forms a clade of its own that clearly differs from the clade of E. limonii. The morphology of the asexual morph of this fungus differs from E. limonii in having longer conidiophores, 50–127 µm vs. up to 95 µm long in E. limonii. The asexual morph of E. aurea is poorly known and DNA sequences of this fungus are not yet available. This species is only known from China on L. suffruticosum, although this host species is widespread in Asia and Europe. The status of E. aurea as a species of its own, distinct from E. limonii, is currently quite unclear and in need of additional collections and morphological re-examinations as well as phylogenetic analyses. Thus, we decided to tentatively identify this fungus as Erysiphe sp. and wait further study of E. aurea.
Limonium tetragonum is a wild biennial herb distributed in coastal areas of East Asia, and a near-threatened species in Japan. Six ITS sequences of Limonium powdery mildews have been deposited in DNA databases from specimens collected worldwide including East Asia. All of these sequences, including sequences retrieved from European samples, form a single clade that can be referred to as E. limonii, although the latter species was described from powdery mildew on L. vulgare Mill. in Germany [sequences retrieved from type material or other German or central European specimens on the latter host are not yet available but urgently necessary]. The sequences retrieved from L. tetragonum belong to a separate clade, distant from the former ones. Powdery mildew on L. tetragonum was for the first time detected in this study. Details of the speciation of Erysiphe sp. on this wild plant in Japan and whether this fungus may occur on other Limonium species or in other countries are still unknown. Further examinations of Limonium powdery mildews, including DNA sequence analysis, are urgently required.
4.3. Key to the species of Erysiphe on Actinidia spp.1a. Chasmothecial appendages long [up to 550(–750) µm], irregularly shaped geniculate-sinuous .................................................................. E. actinidiae var. argutae
1b. Chasmothecial appendages short (up to 350 µm) ................................................. 2
2a. Chasmothecia 90–109(–120) μm in diam, appendages stiff, rarely flexuous, asci 3–5 per chamothecium. On Actinidia arguta.......................................................................... E. actinidiae var. actinidiae
2b. Chasmothecia 94–142 μm in diam, appendages rather irregularly shaped, geniculate-sinuous, sometimes irregularly to dichotomously branched below the apex, asci 4–9 per chamothecium. On Actinidia polygama................................................................................................ E. actinidiicola
The authors declare no conflicts of interest. All the experiments undertaken in this study comply with the current laws of the country where they were performed.
This work was financially supported in part by a Grant-in-Aid for Scientific Research (No.16 K07613 and 16F16097) from the Japan Society for the Promotion of Science to Susumu Takamatsu and the Japan Society for the Promotion of Science postdoctoral fellowship (PD16097) to Jamjan Meeboon. The authors thank Makoto Shinohara for his many-sided supports, Uwe Braun for critical reading the previous version of this manuscript, and handling editor and anonymous reviewers for helpful comments.
