The Great Five—an artificial bacterial consortium with antagonistic activity towards Pectobacterium spp. and Dickeya spp.: formulation, shelf life, and the ability to prevent soft rot of potato in storage

Abstract

The Great Five" (GF) is an artificial bacterial consortium developed to protect potato tubers from soft rot caused by Pectobacterium spp. and Dickeya spp. To investigate the commercialization potential of the GF, we developed liquid and powder formulations of the consortium and of each of the comprising strains (Serratia plymuthica strain A294, Enterobacter amnigenus strain A167, Rahnella aquatilis strain H145, Serratia rubidaea strain H440, and S. rubidaea strain H469). To form powders, the cells were lyophilized using a newly developed lyoprotectant: Reagent PS. The shelf life of the formulations stored at 8 and 22°C was monitored for a period of 12 months. The longest shelf life was obtained for formulations stored at 8°C; however, the viability of all formulations was negatively affected at 22°C. For the consortium, a 2.5 log 10 cfu (colony forming units) drop in cell number was recorded for the liquid formulation after 6 months, while in case of powders, the drop remained below 1 log 10 cfu following 12 months. The ability of the powder formulations to preserve biocontrol activity of the consortium was tested on potato tubers treated with the formulations and a mixture of the soft rot pathogens. The inoculated tubers were stored for 6 months at 8°C to mimic commercial storage conditions. Soft rot severity and incidence on potato tubers treated with formulations were significantly reduced (62-75% and 48-61%, respectively) in comparison to positive control with pathogens alone. The potential use of the newly developed formulations of "The Great Five" for the biocontrol of soft rot is discussed. Key Points • An innovative reagent to protect bacterial cells during lyophilization was developed. • Powder formulations of "The Great Five" prolonged its shelf life. • The powder-formulated "The Great Five" was active against soft rot bacteria on potato tubers.

Pectobacterium brasiliense: Genomics, Host Range and Disease Management

“…It is commercially and scientifically attractive to develop a control method targeting a broad range of SRP, and most recently, close attention has been given to products with high versatility which could be adapted targeting several bacterial species causing soft rot [ 156 ]. Nanoparticles are also perspective components which could be used as an antibacterial agent such as silver nanostructures (AgNPs) which have been shown to be antiseptic against 650 species of pathogenic bacteria, fungi and viruses and could be combined with other antagonistic bacteria.…”

“…Other lactic acid-producing bacteria also show potential to be used a biocontrol agent for SRP, including Leuconostoc mesenteroides , Leuconostoc citreum , Weisella cibaria , Lactococcus lactis and Enterococcus mudti [ 167 ]. The approach reported by Maciag et al [ 156 ] relay on the use of a cocktail containing antagonistic bacteria species ( Serratia plymuthica strain A294, Enterobacter amnigenus strain A167, Rahnella aquatilis strain H145, Serratia rubidaea strain H440, and S. rubidaea strain H469), targeting a mix of Dickeya and Pectobacterium spp. This broad range biocontrol, significantly reduced soft rot incidences and severity in simulated storage conditions over six months of the experiment [ 156 ].…”

The Endophytic Strain Trichoderma asperellum 6S-2: An Efficient Biocontrol Agent against Apple Replant Disease in China and a Potential Plant-Growth-Promoting Fungus

“…Traditional chemical fumigation and pesticide application are highly effective in preventing and controlling ARD, but their use has harmful effects on the environment [1,8]. At present, Trichoderma, Bacillus, Pseudomonas, and Streptomyces are widely used as biological control agents [9][10][11], in line with the concept of "double reduction" of fertilizers and pesticides. Compared to rhizosphere soil strains, endophytes can more effectively colonize plants and better adapt to environmental changes, making them more effective in disease suppression and growth promotion [12].…”

Impact and Management of Diseases of Solanum tuberosum

“…75% (dry weight) [56]. Treatment with a consortium formulation comprising Enterobacter amnigenus strain A167, Serratia plymuthica strain A294, Serratia rubidaea strain H440, S. rubidaea strain H469 and Rahnella aquatilis strain H145 significantly reduced potato soft rot severity and incidence by 62-75% and 48-61%, respectively, when compared to a positive control with pathogens alone [73]. Also, a combination of rhizobacteria in combination with commercial arbuscular mycorrhiza fungi (AMF) have been reported to effective in abating bacterial wilt of potato [16,17].…”