Interaction between Pseudomonas fluorescens, Arbuscular mycorrhizae and iron chelates and their potential for controlling Rhizoctonia solani on potato

In the current experiment, the impact of two strains of Pseudomonas fluorescens (VUPf5, and F140) along with two species of Arbuscular mycorrhizae, Funneliformis mosseae (Glomusmosseae) and Rhizophagus intraradices (Glomus intraradices) as well as two types of chemical iron chelators (EDTA and EDDHA) were tested individually and in combination against Rhizoctonia solani AG3, causing black scurf and canker of potato, under in vivo conditions. This research revealed the positive effect of all treatments in reducing pathogenic effects of R. solani compared to untreated inoculated plants. In this vein, the highest reduction in disease severity (100%) was found in plants treated with VUPf5 alone and in multifarious combinations, F140 + F.m + EDTA, and F140 + R.in + EDDHA. Furthermore, all treatments had a positive effect in decreasing the harmful effects of R. solani in all growth parameters (e.g., fresh and dry weights of shoots, length, and diameter of the stem). The evaluation of these treatments on the rate of chlorophyll and carotenoid showed that VUPf5 + F.m + EDDHA significantly increased the amount of chlorophyll and carotenoids compared to control. Moreover, R. solani AG3 in the presence of most biocontrol agents has little effect on zinc and iron concentration. The Maximum concentration of iron and zinc was observed in plants treated with F140 + R.in and VUPf5 + F.m + EDTA, respectively. Therefore, by using a combination of bio-agent factors, this study highlights the remarkably increased biological control's efficacy in comparison to using each of them individually.

Automated summary

The experiment demonstrated the positive effects of different treatments in reducing the pathogenic effects of R. solani, with VUPf5 showing the most significant impact. The treatments also had positive effects on plant growth parameters and chlorophyll/carotenoid levels.