First Report of Walnut Anthracnose Caused by <i>Colletotrichum fioriniae</i> on English (Persian) Walnut Fruits in Hungary

Persian walnut (Juglans regia L.) fruit with preharvest anthracnose symptoms, necrotic fruit stalks, and twigs with necrotic buds, and peaks were collected in a Hungarian orchard next to Nágocs, in September 2018. Disease incidence was approximately 15% on a Hungarian bred walnut cultivar ‘Milotai 10’. Similar symptoms were found on Persian walnut in other locations (eg. Milota, Érd, Sarród, and Kocs). Acervuli were observed on necrotic lesions on fruit, and twigs with pale orange conidial masses. Conidia were hyaline, unicellular, and fusiform. Morphometric measurements of conidia showed mean length ± SD × width ± SD = 15.9 ± 1.7 × 4.5 ± 0.4 μm, length/width ratio 1:0.3 (n=100). The fungus was isolaed from conidial masses on potato dextrose agar (PDA) medium amended with Chlorampenicol (25 mg/L). A total of 12 isolates were obtained as pure cultures by single-spore isolations and incubated at 23°C in dark for 10 days. The colonies were white to gray or grayish-orange on the upper side and with black spots on the reverse side. The isolates showed morphological characteristics of Colletotrichum acutatum in sensu lato (Jayawardena et al. 2016). Molecular analyses were conducted to identify the exact species. Internal transcribed spacer (ITS) region, actin (ACT), and calmodulin (CAL) partial genes were amplified by ITS1F/ITS4R, ACT512F/ACT783R and CAL1/CAL2 primers (White at al. 1990, Carbone and Kohn 1999, O’Donnell et al. 2000). The sequences of ITS region (GenBank Accession Nos: MK367398-99, MK367401-02) showed 100% identity with C. godetiae sequence. Based on ACT gene (GenBank Accession Nos: MK415991-92, MK415994-95) were 100% identity with the deposited C. godetiae type strains from walnut. The obtained sequences of CAL gene (GenBank Accession Nos: MK415998-99, MK416001-02) were same and showed 100% with other C. godetiae sequences from other host plants. The fungus was identified as Colletotrichum godetiae Neerg. Pathogenicity tests were accomplished in the field and under laboratory conditions (25°C on thermostat) on 10 green ‘Milotai 10’ walnut fruit, and 10 walnut twigs each. Tests were conducted on living trees, collected fruit, and two-year-old twigs by inserting mycelial agar plugs (5 mm in diameter) onto wounded pericarp tissues, which were then wrapped with wet cotton and parafilm. Wounded tissues on 5 fruit and 5 two-year-old twigs were treated with non-colonized PDA plugs as noninoculated controls. After 14 d necrotic lesions 9 to 17 mm in diameter developed on fruit on living trees. Lengths of 12 to 17 mm and width of 7 to 12 mm necrosis was measured on phloem of walnut twigs, and almost two times larger in cambium. No necrosis developed around control wounds. Koch's postulates were fulfilled with the reisolation of the pathogen from symptomatic tissues, isolates were identical morphologically and by sequence analysis of ITS region, ACT, and CAL partial genes to the original isolates. Damm et al. (2012) described two C. godetiae strains associated with walnut, one isolated in Austria and another one of unknown origin. An epidemic event of walnut anthracnose caused by Colletotrichum species mainly C. godetiae was reported in France (Da Lio et al. 2018). The pathogen was isolated from nuts, buds, insects, and stems. To our knowledge, this is the first report of anthracnose of walnut fruit caused by C. godetiae in Hungary. Anthracnose caused by C. godetiae, and previously reported C. fioriniae (Varjas et al. 2019) is becoming an increasing preharvest problem on Persian walnut in Hungary.

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“…godetiae, and previously reported C. fioriniae (Varjas et al 2019) is becoming an increasing preharvest problem on Persian walnut in Hungary.…”

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confidence: 71%

First Report of Colletotrichum godetiae Causing Anthracnose and Twig Blight on Persian Walnut in Hungary

et al. 2021

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“…belonging to kingdom-Fungi, division-Ascomycota, class-Sordariomycetes, order Diaporthales and family Gnomoniaceae (Kirk et al, 2008). Although most of the scientific reports including those from India mention M. juglandis as the incitant of walnut anthracnose (Hassan et al 2017;Sanjeev et al 2022), Colletotrichum gloeosporiodes, C. aenigma, C. fioriniae, C. siamense, C. fruticola, C. nymphaeae and C. godetiae have been also reported from countries like China, Hungary, France and Italy as cause of walnut anthracnose in the recent past (Laura et al 2021;Varjas et al 2019Varjas et al , 2021Wang et al 2017Wang et al , 2018Wang et al , 2020Wang et al , 2021. As in many other parts of the world, M.juglandis was reported to overwinter in the form of dormant mycelium and conidia in diseased fallen leaves/ leaf stalks in Kashmir (Hassan et al, 2017).…”

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confidence: 99%

First report of the teleomorph of Marssonia juglandis ( Gnomonia leptostyla) in Kashmir

Mushtaq,

Bhat,

Rather

et al. 2024

JMycR

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Anthracnose is the only important foliar fungal disease that affects walnut in Kashmir valley. Contrary to earlier reports, this investigation revealed existence of Gnomonia leptostyla (teleomorph of Marssonina juglandis) in Kashmir and the ascospore maturity in the spring coincided with primary infection event and thus can be seen as a possible inoculum for primary infection besides conidia. The fungus formed hypophyllous, globose to sub-globose and blackish-brown perithecia having a long beak and containing ellipsoid to fusiform asci. Ascospores were hyaline and bicelled with a median to supramedian septum and were fusiform having small appendages.

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“…The pathogen Colletotrichum causes anthracnose blight in a broad range of plant species, including walnut (Wang et al, 2017; Zhu et al, 2014). Several species of Colletotrichum have been reported on Juglans regia : C. siamense , C. fioriniae , and C. gloeosporioides in China; C. fioriniae in Hungary; C. acutatum in Australia; and C. godetiae , C. fioriniae , C. nymphaeae , and C. gloeosporioides in France (Da Lio et al, 2018; Savian et al, 2019; Varjas et al, 2019; Wang et al, 2017, 2020; Zhu et al, 2014, 2015). Accurate species identification is essential to understand the pathogenesis and to breed pathogen‐resistant cultivars.…”

Section: Introductionmentioning

confidence: 99%

Identification of the anthracnose fungus of walnut (Juglans spp.) and resistance evaluation through physiological responses of resistant vs. susceptible hosts

et al. 2021

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Walnut anthracnose is one of the most serious diseases of walnut globally. In this study, the pathogen was identified as Colletotrichum gloeosporioides by morphological and molecular approaches. Then, the resistance of 18 walnut genotypes was evaluated by field investigation as well as field and detached leaflet inoculation. A field inoculation assay was used as a benchmark for comparing field evaluation and the detached leaflet inoculation assay. Seven genotypes, Panhe1 and clones 71 and 200 of Juglans sigillata, Yanyuanzao and Qingxiang of J. regia, and Shujiang1 and Chuanzao1 of J. regia × J. sigillata, displayed high resistance in all assays, suggesting that they may be good candidates for further evaluation. Subsequently, two genotypes (Panhe1 with high resistance, and clone 199 with high susceptibility) were selected to analyse the different physiological responses between highly resistant and susceptible genotypes after inoculation. C. gloeosporioides infection induced the activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), and chitinase; they were all significantly increased in both Panhe1 and clone 199. However, the POD activity and its change rate in Panhe1 were significantly higher than those in clone 199. The change rates of PPO activity, and total phenol and proline content in Panhe1 were significantly higher than those in clone 199. Moreover, the change rates of SOD activity, malondialdehyde, and soluble sugar content in clone 199 were significantly higher than those in Panhe1. These findings not only enhance our understanding of the resistance of walnut to anthracnose, but also lay the foundation for breeding anthracnose‐resistant walnuts in the future.

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First Report of Walnut Anthracnose Caused by Colletotrichum fioriniae on English (Persian) Walnut Fruits in Hungary

Cited by 9 publications

References 6 publications

First Report of Colletotrichum godetiae Causing Anthracnose and Twig Blight on Persian Walnut in Hungary

First Report of Colletotrichum godetiae Causing Anthracnose and Twig Blight on Persian Walnut in Hungary

First report of the teleomorph of Marssonia juglandis ( Gnomonia leptostyla) in Kashmir

Identification of the anthracnose fungus of walnut (Juglans spp.) and resistance evaluation through physiological responses of resistant vs. susceptible hosts

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