First Report of Wilt of European Hornbeam (Carpinus betulus) Caused by Fusarium oxysporum in China
Abstract: European hornbeam (Carpinus betulus L.) has been used as an important ornamental species for urban landscaping since the Italian Renaissance (Rocchi et al. 2010). In May 2019, 15% of 3000 C. betulus trees with wilted leaves and root rot were observed in a field (about 26 ha) in Pizhou, Jiangsu Province, China. Internal discoloration of the stem began with brown to black discoloration of the vascular system and gradually spread to inward areas. Roots and stems from symptomatic plants were washed free of soil, s… Show more
Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Cited by 3 publications
References 10 publications
Chamaedorea elegans, native to Mexico and Guatemala, is a commonly planted indoor and small-scale garden ornamental due to its stately appearance, tolerance of low light levels, and its ability to improve air quality (El-Khateeb et al. 2010). In December 2021, an unknow leaf-spot disease was observed on C. elegans in Ganzhou City of Jiangxi Province, China (25.83 °N, 114.93 °E). The symptoms were small brown spots on the leaves, gradually expanded into irregular dark brown spots with necrotic tissue forming in the center of the lesions (Figure 2 A-1 and A-2). To isolate the pathogen, the diseased leaves were surface sterilized in 75% ethanol for 30 s. Small pieces of tissue (5 × 5 mm) were taken from the margin between diseased and healthy tissue, disinfected 1% NaClO for 45 s, washed three times in sterile water, and then placed on PDA at 25 ± 1°C for 5 days. Later, five isolates were purified from single spores and each of the five isolates has the same properties as described below. The isolates had abundant pale purple flocculent hyphae with purple pigmentation (Figure 2 C-1 and C-2). Macroconidia were falciform, straight or slightly curved, 1-2 septate, 11.75 to 22.99 × 3.06 to 4.44 μm (μ=16.08 μm × 3.37 μm, n=50) (Figure 2 D-1). Microconidia were oval or elliptical, a septate, 4.03 to 9.19 × 1.92 to 3.73 μm (μ=5.88 μm × 2.66 μm, n=50) (Figure 2 D-2). Chlamydospores formed singly or in pairs, and were terminal or intercalary in hyphae (Figure 2 D-3). Based on morphological characteristics, the fungus was preliminarily identified as a Fusarium sp. (Leslie et al. 2006). To confirm the identification, primers ITS1/ITS4 (White et al. 1990), RPB2-5f2/RPB2-7cr (O'Donnell et al. 2010; Liu et al. 1999) and TEF 1-αF/TEF 1-αR (O'Donnell et al. 2000) were used to amplify and sequence apportion of the ITS, RPB2 and TEF (Table 1). The sequences (Genebank accession number: OM780148, OM782679, OM782680) shared 100% idnetity with Fusarium oxysporum (Genebank accession number: MH866024.1, MH484930.1, MH485021.1). The maximum likelihood (ML) phylogenetic analysis of the concantenated ITS, RPB2 and TEF sequences was performed in MEGA7.0. (Sudhir et al. 2016), assigning the isoaltes to the F. oxysporum species complex (Figure 1). To confirm the pathogenicity, nine pots of healthy 3-year-old C. elegans plants were inoculated in the greenhouse (12 h light/12 h dark cycle, RH 90 %, three for wounded inoculation, three for nonwounded inoculation and three for control). Fifty disinfected leaves were wounded with sterile needles and fifty remained unwounded. The wounded (Figure 2 B-1 and B-2) and unwounded leaves were inoculated with a 10 μL spore suspension (1.0 × 106 conidia/ml) which was taken from each of the five isolates cultured for 7 days. Fifty leaves were mock-inoculated with sterile water (Figure 2 B-3 and B-4). After incubation for 7 days, the wounded leaves inoculated with the spore suspension had similar symptoms to the original diseased leaves, while the unwounded leaves and the control leaves did not develop symptoms. The experiment was repeated three times and the pathogens was reisolated from wound-inoculated leaves with the same morphological characteristics to the original pathogens, and identified as F. oxysporum by morphological and molecular analysis, completing Koch’s postulates. F. oxysporum, a pathogen with a broad spectrum of hosts, ranks 5th among the top 10 fungal plant pathogens (Amjad et al. 2018.) and has been reported to Carpinus betulus, Citrullus lanatus, Pinus pinea (Mao et al. 2021; Muhammad et al. 2021; Monther et al. 2021). To our knowledge, this is the first report of leaf spot disease on C. elegans caused by F. oxysporum in China. C. elegans is an important ornamental plant in China with high economic value, so the disease has the potential to be a threat to its cultivation industry.
Chamaedorea elegans, native to Mexico and Guatemala, is a commonly planted indoor and small-scale garden ornamental due to its stately appearance, tolerance of low light levels, and its ability to improve air quality (El-Khateeb et al. 2010). In December 2021, an unknow leaf-spot disease was observed on C. elegans in Ganzhou City of Jiangxi Province, China (25.83 °N, 114.93 °E). The symptoms were small brown spots on the leaves, gradually expanded into irregular dark brown spots with necrotic tissue forming in the center of the lesions (Figure 2 A-1 and A-2). To isolate the pathogen, the diseased leaves were surface sterilized in 75% ethanol for 30 s. Small pieces of tissue (5 × 5 mm) were taken from the margin between diseased and healthy tissue, disinfected 1% NaClO for 45 s, washed three times in sterile water, and then placed on PDA at 25 ± 1°C for 5 days. Later, five isolates were purified from single spores and each of the five isolates has the same properties as described below. The isolates had abundant pale purple flocculent hyphae with purple pigmentation (Figure 2 C-1 and C-2). Macroconidia were falciform, straight or slightly curved, 1-2 septate, 11.75 to 22.99 × 3.06 to 4.44 μm (μ=16.08 μm × 3.37 μm, n=50) (Figure 2 D-1). Microconidia were oval or elliptical, a septate, 4.03 to 9.19 × 1.92 to 3.73 μm (μ=5.88 μm × 2.66 μm, n=50) (Figure 2 D-2). Chlamydospores formed singly or in pairs, and were terminal or intercalary in hyphae (Figure 2 D-3). Based on morphological characteristics, the fungus was preliminarily identified as a Fusarium sp. (Leslie et al. 2006). To confirm the identification, primers ITS1/ITS4 (White et al. 1990), RPB2-5f2/RPB2-7cr (O'Donnell et al. 2010; Liu et al. 1999) and TEF 1-αF/TEF 1-αR (O'Donnell et al. 2000) were used to amplify and sequence apportion of the ITS, RPB2 and TEF (Table 1). The sequences (Genebank accession number: OM780148, OM782679, OM782680) shared 100% idnetity with Fusarium oxysporum (Genebank accession number: MH866024.1, MH484930.1, MH485021.1). The maximum likelihood (ML) phylogenetic analysis of the concantenated ITS, RPB2 and TEF sequences was performed in MEGA7.0. (Sudhir et al. 2016), assigning the isoaltes to the F. oxysporum species complex (Figure 1). To confirm the pathogenicity, nine pots of healthy 3-year-old C. elegans plants were inoculated in the greenhouse (12 h light/12 h dark cycle, RH 90 %, three for wounded inoculation, three for nonwounded inoculation and three for control). Fifty disinfected leaves were wounded with sterile needles and fifty remained unwounded. The wounded (Figure 2 B-1 and B-2) and unwounded leaves were inoculated with a 10 μL spore suspension (1.0 × 106 conidia/ml) which was taken from each of the five isolates cultured for 7 days. Fifty leaves were mock-inoculated with sterile water (Figure 2 B-3 and B-4). After incubation for 7 days, the wounded leaves inoculated with the spore suspension had similar symptoms to the original diseased leaves, while the unwounded leaves and the control leaves did not develop symptoms. The experiment was repeated three times and the pathogens was reisolated from wound-inoculated leaves with the same morphological characteristics to the original pathogens, and identified as F. oxysporum by morphological and molecular analysis, completing Koch’s postulates. F. oxysporum, a pathogen with a broad spectrum of hosts, ranks 5th among the top 10 fungal plant pathogens (Amjad et al. 2018.) and has been reported to Carpinus betulus, Citrullus lanatus, Pinus pinea (Mao et al. 2021; Muhammad et al. 2021; Monther et al. 2021). To our knowledge, this is the first report of leaf spot disease on C. elegans caused by F. oxysporum in China. C. elegans is an important ornamental plant in China with high economic value, so the disease has the potential to be a threat to its cultivation industry.
Apricot (Prunus armeniaca) is one of the most important economic fruit species in China, which is highly prized for its excellent quality and high nutritional value. In June 2020, fruit rot was observed on 10 to 15% of apricot fruit at the full fruit stage in an orchard of Yiyang County (34.54° N, 112.28° E), Luoyang City, Henan Province, China. Initially, the symptoms appeared as brown lesions. With the aggravation of the disease, the lesions enlarged and appeared white hyphae on the fruit surface, which eventually turned soft and brown rots. To identify the pathogen, the surface of symptomatic fruit was sterilized with 2% sodium hypochlorite for 2 min followed by 70% ethanol for 30 s and rinsed 3 times with sterilized water. Tissues (5 × 5 mm) from the margin of the necrotic lesion were cut and cultured on potato dextrose agar (PDA) and incubated for 7 days at 28±1°C for morphological identification. Five pure isolates were obtained from single spores. The isolates had abundant white aerial mycelia initially and turned light violet on the third day. Macroconidia were falciform, 2-5 septate, straight or slightly curved, 15.27 to 37.18 × 1.97 to 3.99 µm (n = 50). Microconidia predominated and were elliptical or oval, hyaline, 0-1 septate, 5.08 to 14.42 × 1.65 to 4.10 µm (n = 50). Chlamydospores were spherical, intercalary or terminal. According to these morphological characteristics, the fungus was initially identified as Fusarium species (Leslie and Summerell 2006). To confirm the identification, The ITS, cal, RPB2, EF and ACT genes were amplified and sequenced with the primers ITS1/ITS4 (White et al. 1990), CL1C/CL2C (O’Donnell et al. 2000), fRPB2-5F/fRPB2-7cR (Liu et al. 1999), EF-1Ha/EF-2Tb and ACT-512F/ACT-783R (Carbone and Kohn 1999), respectively. Compared with the sequence in GenBank, it showed 99-100% homology to F. oxysporum (GenBank accessions No. MT560381, LS423442, AB986568, MN417202, MK001023), and the results of sequences were deposited into GenBank with accession No. MW812394, MW849863, OK067318, MW792498, MW849864. A maximum likelihood (ML) phylogenetic analysis based on ITS, EF and RPB2 sequences using MEGA7.0. (Mao et al. 2021), revealed that the isolates were placed in the F. oxysporum species complex. To confirm pathogenicity, a spore suspension was prepared from the cultures grown on PDA for 7 days at 28±1°C. Twenty healthy P. armeniaca fruit were disinfected with 75% ethanol. Half of the disinfected fruit was wounded using a sterile needle and the other half remained non-wounded. These wounded and non-wounded fruit were inoculated with spore suspension (1.0 × 106 conidia/ml). Fruit inoculated with sterilized water served as the controls. After 5 days of incubation at 28±1°C and 90% relative humidity (12 h light/dark), all the inoculated fruit developed typical symptoms similar to the original diseased fruit, whereas the control fruit remained healthy. The pathogenicity test was repeated two times and F. oxysporum was re-isolated from the inoculated fruit, fulfilling Koch’s postulates. Although the pathogenicity of F. oxysporum has been previously studied in apricot fruit in vivo (Seyed and Raeisi 2018), this is the first report of F. oxysporum causing fruit rot on P. armeniaca in nature. This finding will help develop effective disease management strategies.
European hornbeam (Carpinus betulus L.) is widely planted in landscaping. In October 2021 and August 2022, leaf spot was observed on C. betulus in Xuzhou, Jiangsu Province, China. To identify the causal agent of anthracnose disease on C. betulus, 23 isolates were obtained from the symptomatic leaves. Based on ITS sequences and colony morphology, these isolates were divided into four Colletotrichum groups. Koch’s postulates of four Colletotrichum species showed similar symptoms observed in the field. Combining the morphological characteristics and multi-gene phylogenetic analysis of the concatenated sequences of the internal transcribed spacer (ITS) gene, Apn2-Mat1-2 intergenic spacer (ApMat) gene, the calmodulin (CAL) gene, glyceraldehyde3-phosphate dehydrogenase (GAPDH) gene, Glutamine synthetase (GS) gene, and beta-tubulin 2 (TUB2) genes, the four Colletotrichum groups were identified as C. gloeosporioides, C. fructicola, C. aenigma, and C. siamense. This study is the first report of four Colletotrichum species causing leaf spot on European hornbeam in China, and it provides clear pathogen information for the further evaluation of the disease control strategies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
Contact Info
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Product
Resources
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.
