Pseudomonas fluorescens NK4 siderophore promotes plant growth and biocontrol in cucumber

Abstract

Aims:To test the effect of zinc oxide nanoparticle (ZnO-NP) supplementation for enhancing the efficacy of Pseudomonas fluorescens NK4 siderophore as a biocontrol agent against P. viridiflava NK2 and a plant growth promoter.Methods and Results: Cucumber seedlings were treated with a suspension of P. fluorescens NK4 and its siderophore generated in siderophore-inducing medium (SIM), SIM supplemented with ZnO-NP (<100 nm) and SIM supplemented with Zn 2+ ions from Zn(NO 3 ) 2 . Supplementing SIM with ZnO-NP increased siderophore secretion in P. fluorescens NK4, and irrigation of cucumber seedlings with a filtrate containing the ZnO-NP-supplemented siderophore increased survival, improved vegetative and root growth, and thus increased yield similar to the effects of dipping seedlings in a P. fluorescens NK4 suspension. Both P. fluorescens NK4 and its ZnO-NP-supplemented siderophore inhibited P. viridiflava NK2 population growth in planta. Conclusions:The siderophore of P. fluorescens NK4 produced by ZnO-NP supplementation can be employed as a biocontrol agent and biofertilizer.Significance and Impact of the Study: ZnO-NPs can boost the synthesis of siderophores, which can then be employed as biofertilizers to boost iron bioavailability in iron-deficient soils.

Purification and Characterization of Desferrioxamine B of Pseudomonas fluorescens and Its Application to Improve Oil Content, Nutrient Uptake, and Plant Growth in Peanuts

“…The Arachis hypogaea pot experiment was also conducted to evaluate the siderophore-producing LNPF1 isolate’s bioinoculant efficacy on plant growth and other physico-chemical parameters. Previous studies have shown that siderophores during the germination and emergence phases [ 47 ] increase the germination rate and seedling activity of popular crops such as tomatoes [ 48 ], cucumbers [ 49 ], and wheat [ 50 ], etc.…”

The role of the type VI secretion system in the stress resistance of plant-associated bacteria

“…Recent studies have found that many plant-beneficial bacteria, as biocontrol agents, possess the T6SS (Marchi et al 2013 ), and most of these beneficial plant bacteria belong to the genus Pseudomonas. These bacteria can inhibit plant diseases and are considered an important source of biocontrol agents (Abo-Elyousr et al 2021 ; Al-Karablieh et al 2022 ; Gu et al 2022 ).…”

Microbial Consortia for Plant Protection against Diseases: More than the Sum of Its Parts

“…These microorganisms have been extensively studied for their application in biocontrol [90]. Multiple fluorescent Pseudomonas species utilize this mechanism in biocontrol applications [91][92][93]. However, several studies have reported the direct antimicrobial action of siderophores toward bacteria and fungi [90][91][92][93], suggesting their activity in antibiosis, not competition "sensu stricto".…”

“…Multiple fluorescent Pseudomonas species utilize this mechanism in biocontrol applications [91][92][93]. However, several studies have reported the direct antimicrobial action of siderophores toward bacteria and fungi [90][91][92][93], suggesting their activity in antibiosis, not competition "sensu stricto". For example, Pseudomonas donghuensis produces two alternative iron chelators, pyoverdine and 7-hydroxytropolon [94].…”