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Mushrooms: Identification, detection and control of Pseudomonas species causing different types of bacterial blotch symptoms

Research

M 063 - Mushrooms: Identification, detection and control of Pseudomonas species causing different types of bacterial blotch symptoms

Start Date: 
01/05/2017
Completion Date: 
30/04/2018
Project Leader: 
John Elphinstone, Fera Science Limited
Code: 
M 063
AHDB Horticulture Cost:  £48,607
 
SummaryThe proposed project aims to provide tools that will assist evaluation and development of potential control methods for bacterial blotch disease (caused by different Pseudomonas species), which is considered to be the most important disease problem currently faced by the mushroom industry in the UK and elsewhere in Europe
 
Aim: 
1. Ensure that the full diversity of Pseudomonas species currently causing significant losses to the UK mushroom industry is known and can be detected early in the supply chain and production processes so as to avoid potential losses and maximise yield of high quality mushrooms.
2. To develop and evaluate potential control measures which could have practical application in commercial mushroom production, and to demonstrate their efficacy against the known diversity of blotch-causing Pseudomonas species.
 
Objective:
1. Review the phylogenetic and ecological relationships between the various fluorescent Pseudomonas species causing bacterial blotch disease and those which are beneficial for mushroom production and may contribute to disease suppression.  
2. Compare blotch pathogenicity obtained from small-scale culture test and cap tissue bioassay.
3. Generate whole genome sequences of blotch-causing isolates of P. tolaasii, P. gingeri and other Pseudomonas sp. and perform bioinformatic analysis to compare these with other sequenced isolates. 
4. Select DNA sequences that (i) are unique to pathogenic isolates and not found in non-pathogenic Pseudomonas species (ii) distinguish isolates causing typical bacterial blotch, ginger blotch or mild blotch symptoms.  
5. Develop improved diagnostic tests (e.g. real-time PCR or LAMP assays) which detect and differentiate Pseudomonas species pathogenic to mushrooms in both casing and mushroom samples, and evaluate performance of new tests using reference isolates, casing and Phase III compost samples and symptomatic mushrooms from commercial sources.
6. Investigate control of different types of bacterial blotch by manipulation of the casing bacterial population through use of casing additives and casing inoculum and addition of calcium chloride to irrigation water
 
Benefits to Industry:
Currently considered the most important mushroom disease affecting the UK industry, losses can exceed 30% of production due to bacterial blotch.  Since conditions that favour high yield are also favourable for disease development and transmission, there is a constant trade-off between maximising yield and maintaining health and quality of production.  It is suspected that mushroom casing and compost may be sources of the bacteria.  Association of any supplier with bacterial blotch can have an immediate detrimental effect on business.