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Molecular and Morphological Identification and Pathogenicity of Fusarium Species Causing Melon Wilt in Russia
Irina Engalycheva1, Elena Kozar1, Alina Kameneva1
1Federal State Budgetary Scientific Institution "Federal Scientific Vegetable Center" (FSBSI FSVC), 143072 Moscow, Russia.
Abstract:
Fusarium wilt of melon, caused by Fusarium fungi, results in sizeable economic losses worldwide. In Russia, data on the species composition of the causative pathogens of this disease on melon are lacking. From 2022 to 2025, 19 Fusarium isolates from the Volgograd and Rostov regions were included in a study that included species identification using molecular phylogenetic analysis of the tef1 and rpb2 loci, morphological description, and pathogenicity assessment against the host plant and other members of the Cucurbitaceae family. Four Fusarium species were found to be involved in the pathogenesis of Fusarium wilt of melon in Russia: F. clavus (37% of the total number of isolates), F. annulatum (21%), F. cf. inflexum (21%), and F. brachygibbosum (21%). All identified species were isolated in the Volgograd Region, while only F. cf. inflexum and F. brachygibbosum were isolated in the Rostov Region. This study reports for the first time the high pathogenicity of F. cf. inflexum and F. brachygibbosum species associated with melon wilt. Morphological variability and different aggressiveness of isolates of the species F. brachygibbosum and F. clavus, isolated in the Volgograd (-V) and Rostov (-R) regions in different years, were observed. The isolate F. brachygibbosum-V showed high aggressiveness both at the sprout and seedling stages, while the isolate F. brachygibbosum-R was characterized by moderate aggressiveness only at the sprout stage. High pathogenicity of the species isolated from melons was established for other cucurbit crops. F. cf. inflexum was also pathogenic for watermelon and pumpkin, and F. brachygibbosum was pathogenic for pumpkin. The obtained data will have practical value for the development of biological control measures against Fusarium fungi and will be used in a melon breeding program for resistance to Fusarium wilt.
Insights
Fusarium wilt in melons is caused by four key Fusarium species in Russia, with F. clavus being most common. This study identifies new pathogenic species and their impact on cucurbits, aiding disease management.
Area of Science:
- Plant Pathology
- Mycology
- Agricultural Science
Background:
- Fusarium wilt causes significant global economic losses in melon production.
- Limited data exists on the specific Fusarium species causing melon wilt in Russia.
- Understanding pathogen diversity is crucial for effective disease management strategies.
Purpose of the Study:
- To identify the species composition of Fusarium pathogens causing melon wilt in Russia.
- To assess the pathogenicity and aggressiveness of identified Fusarium species on melon and other cucurbits.
- To provide data for developing biological control and breeding programs for Fusarium wilt resistance.
Main Methods:
- Isolation and identification of 19 Fusarium fungal isolates from infected melons in Volgograd and Rostov regions (2022-2025).
- Molecular phylogenetic analysis using tef1 and rpb2 gene loci for species identification.
- Morphological characterization and pathogenicity tests on melon and other Cucurbitaceae family members.
Main Results:
- Four Fusarium species identified: F. clavus (37%), F. annulatum (21%), F. cf. inflexum (21%), and F. brachygibbosum (21%).
- F. cf. inflexum and F. brachygibbosum demonstrated high pathogenicity, reported for the first time in association with melon wilt.
- Variability in aggressiveness observed among F. brachygibbosum and F. clavus isolates; F. cf. inflexum and F. brachygibbosum also pathogenic to watermelon and pumpkin.
Conclusions:
- The study establishes the species diversity and pathogenicity of Fusarium causing melon wilt in Russia.
- Newly identified pathogenic species, F. cf. inflexum and F. brachygibbosum, require specific management considerations.
- Findings support the development of targeted biological control agents and resistant melon cultivars.
