First Report of Gliocephalotrichum simplex Causing Fruit Rot of Choerospondias axillaris in China

Abstract

HomePlant DiseaseAhead of PrintFirst Report of Gliocephalotrichum simplex Causing Fruit Rot of Choerospondias axillaris in China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Gliocephalotrichum simplex Causing Fruit Rot of Choerospondias axillaris in ChinaKexin Zhu, Huanhuan Liu, Chaozhi Li, Zhengyue Zhu, Jiahui Peng, Fei Ding, Fenggang Luan, and Dong LiKexin ZhuKey Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, Huanhuan LiuKey Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, Chaozhi LiKey Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, Zhengyue ZhuKey Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, Jiahui PengKey Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, Fei DingSchool of Vocational and Teachers Education, Jiangxi Agricultural University, Nanchang 330045, ChinaSearch for more papers by this author, Fenggang Luanhttps://orcid.org/0000-0001-7604-4091Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this author, and Dong Li†Corresponding author: D. Li; E-mail Address: [email protected]Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations Kexin Zhu1 Huanhuan Liu1 Chaozhi Li1 Zhengyue Zhu1 Jiahui Peng1 Fei Ding2 Fenggang Luan1 Dong Li1 † 1Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed (JXAU), Nanchang 330045, China 2School of Vocational and Teachers Education, Jiangxi Agricultural University, Nanchang 330045, China Published Online:5 Apr 2023https://doi.org/10.1094/PDIS-04-22-0876-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleNepali hog plum, Choerospondias axillaris (Roxb.) B. L. Burtt & A. W. Hill, is mainly found in Nepal, Bhutan, and China, and is an economically important plant in China for its nutritious fruit (Zheng and Min 1980). Rot of C. axillaris fruit was observed in orchards in Nanchang city, Jiangxi Province, China (28.69°N and 115.87°E), with approximately 40% of the fruits (1 ha in total) affected. Initially, the fruit appeared soft, and water-soaked lesions appeared. Then, the spots enlarged and became dark brown, and most of the diseased fruit abscised prematurely. Ten fruits with typical symptoms were collected from different C. axillaris plants. Tissue between healthy and necrotic areas (approximately 0.5 × 0.5 cm) was cut with a sterile scalpel, surface sterilized with 75% ethanol for 30 s and 2.5% NaClO for 2 min, and washed three times with sterile distilled water. Then, the samples were transferred to potato dextrose agar (PDA) and incubated at 25 ± 1°C for 3 to 5 days. Hyphal tips were further transferred onto PDA medium. A total of 60 fungal isolates, including 42 isolates of Gliocephalotrichum spp. according to the morphological characters, were obtained. Colonies were regular with white sparse aerial mycelium, the reverse side was sienna to umber, and it grew rapidly (87.5 mm in 7 days on PDA). The sexual stage was not observed on PDA. Chlamydospores formed singly, terminal, and intercalary on the mycelium, and were brown and spherical with diameter about 18.91 to 37.92 μm (average 28.13 μm, n = 30). Conidiophores developed erect from mycelium compact, aseptate, cylindrical, hyaline, and with penicillus phialides at the apex. Conidia were cylindrical to ellipsoidal, smooth, hyaline, 4.71 to 6.95 (average 6.16) × 2.03 to 2.51 (average 2.11) μm (n = 30). To confirm the identity of the fungus, genomic DNA of two representative isolates (JXAU20210713.1 and JXAU20210713.2) was extracted. Four genes (ITS, tub2, tef1, and his3) were amplified and sequenced as previous described (Lombard et al. 2010). The sequences of ITS, tub2, tef1, and his3 were ON024766 to ON024767 and ON035618 to ON035623, respectively. Phylogenetic analysis based on concatenated sequences of ITS, tub2, tef1, and his3 showed that the isolates JXAU20210713.1 and JXAU20210713.2 formed a single clade with the reference strains of Gliocephalotrichum simplex. Pathogenicity tests for two isolates were performed by inoculating surface-sterilized wounded or nonwounded fruits using colonized plugs (6 mm) and placed in a humid box (RH 90 ± 3%, 25 ± 1°C, 12 h light) for 5 days. The controls on healthy fruits were treated with sterile PDA plugs. All the wounded fruits showed similar symptoms to those observed in the field, while the nonwounded fruits and controls remained symptomless. To fulfill Koch’s postulates, 20 fungal isolates were reisolated from symptomatic fruits and identified by morphological characters, and the isolate HML2-8-A was randomly selected, sequenced, and had its phylogenetic relationship inferred. G. simplex has been reported causing fruit rot of Nephelium lappaceum (Nishijima et al. 2002), Terminalia chebula (Singh et al. 2010), Cyrtostachys renda, Dypsis madagascariensis, Syzygium cumini, and S. purpurea (Silva et al. 2020), and so on. To our knowledge, this is the first report of G. simplex causing fruit rot of C. axillaris in China, and our findings will provide important information on its management in the future.The author(s) declare no conflict of interest.