Isolation and molecular identification of Rhizoctonia solani and Fusarium solani isolated from cucumber (Cucumis sativus L.) and their control feasibility by Pseudomonas fluorescens and Bacillus subtilis

Fadhal A Al-Fadhal,Aqeel N Al-Abedy,Duaa A Alkhafije

doi:10.1186/s41938-019-0145-5

Fadhal A Al-Fadhal, Aqeel N Al-Abedy + Show 1 more

Open Access

https://doi.org/10.1186/s41938-019-0145-5

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Abstract

This study was conducted to isolate and molecularly identify two pathogenic fungi namely Rhizoctonia solani and Fusarium solani implicated in root rot and seedling damping-off disease of cucumber, Cucumis sativus. Besides, the efficacy of Pseudomonas fluorescens and Bacillus subtilis as bacterial agents in controlling these two pathogens was also evaluated in vitro and in a greenhouse pot experiment.Results of polymerase chain reaction (PCR) amplification and nucleotide sequence analysis using BLAST demonstrated that R. solani isolate was genetically different from the R. solani isolates in the National Centre for Biotechnology Information (NCBI). Therefore, it was recorded in GenBank under the accession number MK105921. P. fluorescens and B. subtilis showed a complete inhibition of the mycelial growths of R. solani and F. solani in vitro. In the pot experiments, soil treatment with a suspension of P. fluorescens and B. subtilis before planting significantly reduced the damping off of cucumber seedlings caused by R. solani and F. solani. This study suggests that these bacterial antagonists could have a good potential as biological control agents to protect cucumber plants from the infection with R. solani and F. solani.

Highlights

Cucumber, Cucumis sativus L., is one of the most important vegetable crops worldwide but, is affected by many pathogens in the field causing serious yield losses (Mohammed and Hasan 2018)
Isolation and identification of F. solani and R. solani Results of the cultural and morphological characteristics showed that R. solani, isolated from diseased cucumber plants, showed slightly melanized hyphae and irregularly shaped and brownish sclerotia
Similar results concerning morphological characters of R. solani were reported by several researchers (Moni et al, 2016; Desvani et al, 2018)

Summary

Introduction

Cucumis sativus L., is one of the most important vegetable crops worldwide but, is affected by many pathogens in the field causing serious yield losses (Mohammed and Hasan 2018). Are devastating pathogens that cause damping-off diseases of cucumber plants either in the greenhouses or in the fields (De Curtis et al 2010). Both R. solani and F. solani have a wide host range and are capable to resist the extreme environmental conditions. The accurate diagnosis of plant pathogenic fungi is one of the urgent needs due to its importance in reaching rapid and efficient disease management systems to reduce or prevent damages caused by the fungal infections (Balodi et al 2017). In addition to its need for time and effort, morphological methods are sometimes inaccurate

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