Combined application of antagonist Bacillus amyloliquefaciens and essential oils for the control of peach postharvest diseases

Abstract

a b s t r a c tBacillus amyloliquefaciens PPCB004 was selected as a potential antagonist to control Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer on peach fruit. The HPLC data of PPCB004 indicated the lipopeptides iturin A, fengycin and surfactin as secondary metabolites. The GC/MS analysis of PPCB004 showed 3-hydroxy-2-butanone as the dominant compound (97.52% of relative peak area). Thyme (TO) and lemongrass (LO) oils showed over 50% and 25% inhibition of radial mycelial growth respectively with 8 ml oil per plate for all pathogens. Combination treatment with both oils failed to increase the percentage inhibition of radial mycelial growth of the pathogens. Combined application of PPCB004 with TO or LO was tested to assess the effectiveness in the control of these pathogens during postharvest storage. The biofilm formation of PPCB004 was significantly higher in LO than TO. LO (6 ml plate À1 ) and PPCB004 completely inhibited the mycelial growth of the pathogens. Fruit inoculation trials with PPCB004 þ LO in NatureFlexÔ modified atmosphere packaging (MAP), showed lower disease incidence and severity at 25 C for 5 d than treatments with PPCB004 þ MAP, PPCB004 þ TO þ MAP, LO þ MAP, TO þ MAP or stand-alone MAP. On naturally infected fruit, PPCB004 þ LO þ MAP and LO þ MAP treatments retained the total soluble solids/titratable acidity ratio and flesh firmness but failed to stimulate the levels of total phenolic content, phenylalanine ammonia-lyase, b-1,3-glucanase and chitinase activities. Combination of PPCB004 (spray treatment) þ LO (in pad delivery system) in NatureFlexÔ MAP showed absence of disease and off-flavour development, retained the overall appearance and increased the overall acceptance at market shelf conditions (20 C for 2 d) after cold storage at 4 C for 14 d.

Effect of biocontrol agent Bacillus amyloliquefaciens and 1-methyl cyclopropene on the control of postharvest diseases and maintenance of fruit quality

“…A similar increase in antagonist Metschnikowia Pulcherrima strain ST1-D9 on 1-MCP treated apples was reported in comparison with the 1-MCP untreated fruits (Leverentz et al, 2003). The PPCB004 B. amyloliquefaciens showed multiple modes of action by producing iturin A, fengycin and surfactin (Arrebola et al, 2010a) and 3-hydroxy-2-butanone (Acetoin) as dominant volatile compound (Arrebola et al, 2010b). Therefore, PPCB004 can be applied as a protectant for 1-MCP treated fruit.…”

“…The background microflora was obtained from control fruits. Identity of B. amyloliquefaciens PPCB004 was confirmed by molecular identification according to Arrebola et al (2010a).…”

“…amyloliquefaciens PPCB004 isolated from the surface of citrus 'Valencia' was used in this study. Molecular identification of B. amyloliquefaciens PPCB004 was confirmed according to Arrebola et al (2010a). The biocontrol PPCB004 formulation of PPCB004 was prepared for this trial by Stimuplant cc., Pretoria, South Africa.…”

“…The biocontrol agent, Bacillus amyloliquefaciens PPCB004 was selected as a potential antagonist to control Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer on peach fruit (Arrebola et al, 2010a). The HPLC data of PPCB004 indicated the lipopeptides iturin A, fengycin and surfactin as secondary metabolites (Arrebola et al, 2010a).…”

“…The HPLC data of PPCB004 indicated the lipopeptides iturin A, fengycin and surfactin as secondary metabolites (Arrebola et al, 2010a). The GC/MS analysis of PPCB004 showed 3-hydroxy-2-butanone as dominant compound (Arrebola et al, 2010b).…”