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Published on: October 28, 2021
Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran
K Chehri1, B Salleh, T Yli-Mattila
1School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
Abstract:
Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20-35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran.
Insights
This study identified five Fusarium species causing significant disease in Iranian cucurbits. Pathogenicity tests confirmed Fusarium oxysporum and Fusarium solani cause damping-off and stem rot, with PCR-ITS-RFLP aiding species differentiation.
Area of Science:
- Plant Pathology
- Mycology
- Molecular Biology
Background:
- Fusarium species are significant phytopathogens causing substantial economic losses in cucurbit crops globally.
- Cucurbits are vital agricultural commodities, and their production is threatened by various fungal diseases, particularly in major cultivation areas like Kermanshah, Iran.
- Accurate identification and pathogenicity assessment of Fusarium species are crucial for effective disease management strategies.
Purpose of the Study:
- To isolate and identify Fusarium species infecting cucurbit plants in Kermanshah province, Iran.
- To evaluate the pathogenicity of the isolated Fusarium species on cucumber and honeydew melon seedlings.
- To determine the phylogenetic relationships among the Fusarium isolates using molecular techniques.
Main Methods:
- Isolation of Fusarium species from infected cucurbit plants.
- Morphological characterization for initial species identification.
- Pathogenicity assays on cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings under greenhouse conditions.
- Molecular identification using Polymerase Chain Reaction-Internal Transcribed Spacer-Restriction Fragment Length Polymorphism (PCR-ITS-RFLP) analysis of ribosomal DNA (rDNA).
Main Results:
- One hundred Fusarium isolates were obtained and identified morphologically as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum, and Fusarium solani.
- Fusarium oxysporum induced damping-off symptoms, while Fusarium solani caused stem rot in both cucumber and honeydew melon seedlings.
- PCR-ITS-RFLP analysis divided the five Fusarium species into two main groups, with the Fusarium solani species complex (FSSC) showing two distinct RFLP types, aligning with morphological classifications.
Conclusions:
- The study successfully identified and confirmed the pathogenicity of five key Fusarium species affecting cucurbits in Iran.
- The PCR-ITS-RFLP method proved to be a rapid and reliable tool for differentiating Fusarium species at the species level.
- This research provides the first report on the identification, pathogenicity, and phylogenetic analysis of major plant pathogenic Fusarium species causing root and stem rot in cucurbits within Iran, laying groundwork for future disease management.
