Protection Induction of Cucumber and Squash By Plant Growth Promoting Rhizobacteria Against Cucumber Mosaic Virus
Cucumber mosaic virus (CMV) is one of the most virulent plant viruses with a wide host-range.CMV-16 is a strain of the CMV virus that causes severe stunting, chlorosis and malformation of the fruits in both cucumber (Cucumis sativus) and squash (Cucurbita pepo). Based on the previous study and their success with tomatoes, Green house investigations were conducted on the possibility of using a naturally-occurring satellite RNA associated with a benign strain of cucumber mosaic virus (CMV-KU1) in combination with mixtures of plant growth promoting rhizobacteria (PGPR) to enhance the natural resistance of cucumber and squash plants against CMV-16. Observations were made based on the symptoms. PGPRs have the ability to induce systemic defenses in plants even in sites far away from their plane of action. A mixture of two known PGPR strains, Pseudomonas aeruginosa and Stenotrophomonas rhizophilia were used in this investigative study. Two different methods of PGPR application to the plants were also compared. One method was to apply PGPRs directly into the soil in the ratio 1:3 before sowing the seeds and the other was to coat the seeds directly with the PGPRs before application to the soil. The results of the study reveal that although protective treatment plays some role in alleviating the CMV-16 symptoms in both squash and cucumber, they are not as effective as compared to the healthy controls. Of the two methods of applying PGPR to plants, coating PGPRs onto the seeds proved to be more effective compared to applying PGPRs directly into the soil.
Keywords- PGPR, CMV, CMV- KU1, Plant growth promoting rhizobacteria.