The Potential for Bacteriophage to Control Soft Rot Development in Store DR ALISON BLACKWELL, APS BIOCONTROL LTD.

Transcription

1 The Potential for Bacteriophage to Control Soft Rot Development in Store DR ALISON BLACKWELL, APS BIOCONTROL LTD. AHDB Potato Storage Forum 1 st March 2016

2 WHAT ARE BACTERIOPHAGE? The most abundant organisms in the world (10 31 on Earth) Naturally abundant in soil, water, sewage, animals Act as natural antimicrobial agents, with different bacteriophage being specific to different hosts Completely harmless to the surrounding environment Key benefits: their specificity, safety, biodegradability and rapid mode of action

3 BACTERIOPHAGE LYTIC LIFECYCLE

4 HOW DO WE ISOLATE BACTERIOPHAGE? Bacterial Isolation Enrichment Isolate Lytic bacteriophage Screened for broad range activity and accepted or rejected Scale up

5 ADVANTAGES OF BACTERIOPHAGE Safe: naturally-occurring (food, water soil etc) Highly specific: will not infect beneficial bacteria or other organisms Zero non-target risks and environmental residues Applicable to both mainstream & organic agriculture The right mix of bacteriophage is highly effective, continuing to work long after chemicals have lost their potency

6 OPTIONS FOR BACTERIOPHAGE APPLICATION The challenge: developing an innovative, sustainable and environmentallysound bactericide treatment that is applicable across the potato industry

7 A first bacteriophage-based processing aid for fresh produce, targeting only the harmful, rot-causing Pectobacterium & Dickeya bacteria & and providing significantly greater control than existing chemical products A bacteriophage mixture covering up to 90% of rot-causing bacteria isolated, with regular monitoring of the mix efficacy

8 BIOLYSE DEVELOPMENT: POTATO SOFT ROTS Washer barrel tubers Biolyse treated tubers Washer barrel Water spray post washer barrel Biolyse mist prepacking (5 nozzle spray bar L/min)

9 BIOLYSE DEVELOPMENT: POTATO SOFT ROTS Untreated Water rinsed Reduced shelf-life failures, depot rejections & customer complaints

10 INDUSTRY SHELF-LIFE DATA Logan Estima (Phage+7 days)

11 INDUSTRY SHELF-LIFE DATA Crombie Desiree (Phage +2 days)

12 INDUSTRY SHELF-LIFE DATA % Shelf life failures due to rots 40% 35% 30% 25% 20% 15% 10% Site A: four-year shelf-life failure data, comparing untreated & Biolyse -treated tubers at day 6 after packing Customer complaints due to off / rotten / mouldy have halved since the introduction of Biolyse Untreated shelf life failures at day 6 Biolyse treated shelf life failures at day 6 5% 0% 2012 (n = 346) 2013 (n = 1334) 2014 (n = 497) 2015 (n = 339)

13 OPTIONS FOR BACTERIOPHAGE APPLICATION

14 TREATMENT AT PLANTING: PILOT DATA Method: Desiree seed (low natural inoculum) was damaged & inoculated with water or Pba (10 7 cfu/ml) & left to dry Treated with phage (10 6, 10 7 &10 8 pfu/ml) or water spray Planted as normal Assessment: Emergence (no diff.) Blackleg levels (12% to 3%, 1%, 0%) Percentage blackleg per plot 14% 12% 10% 8% 6% 4% % blackleg per plot * Stem number (no diff.) Yield (no diff.) 2% 0% * * Rots (no diff.) This work is ongoing as part of an Innovate UK Agri-Tech Catalyst project

15 OPTIONS FOR BACTERIOPHAGE APPLICATION

16 STORAGE TREATMENT: QUICK LOOK Variety: Lanorma, with much of the stock rotting in store (4 x 10 8 cfu/ml Pectobacterium spp.) Pba from rotting tubers showed 70% susceptibility to a phage mix Following grading, 'cleaner' tuber samples were phage treated, bagged in groups of & placed in cold store (n = 20 per treatment) % Average Percentage rots per storage bag 12.00% 10.00% 8.00% 6.00% 4.00% 2.00% Week 24 Week 18 Week 12 Week % T1 (Phage) This work is ongoing as part of an Innovate UK Agri-Tech Catalyst project T2 (Water)

17 SUMMARY Bacteriophage have significant potential for the specific control of spoilage pathogens of fresh produce The variability of plant pathogens complicates issues and requires a mixture of bacteriophage to provide sufficient pathogen control For soft rots in potatoes, a bacteriophage mix (Biolyse ) is in routine use by the packing industry and microbiological evidence of lower bacterial counts following Biolyse treatment is backed up by both industry and retail customer data Soft rot control at other points in the growing cycle are actively being investigated, including treatments aimed at reducing the overall pathogen loading of seed Storage applications are potentially very interesting; work is required on application method/timing

18 CONTACT Dr Alison Blackwell APS Biocontrol Ltd. Prospect Business Centre Gemini Crescent Dundee DD2 1TY Tel