Fungal diseases cause over 30% yield losses in plants and widespread fungicide use has environmental and health impacts. Biological control using living organisms or natural products offers an alternative, but current products have low efficacy. The presentation describes a project that uses high-throughput screening of natural extracts on model plants to identify compounds that stimulate plant immune responses. The goal is to discover new active ingredients and improve formulations to develop more effective biological control products with less environmental impact than synthetic fungicides.

1. Screening and identification of new natural
compounds for plant protection against
biotic stresses
Dr Bernard DUMAS
Research Director CNRS
Plant-Microbe Interactions team
UMR 5546 CNRS-Université Paul Sabatier
Toulouse III , France

2. Plant diseases: strong economical and environmental impacts
Fungal diseases:
major cause of yield losses (>30%)
Massive use of fongicides
 Toxic compounds targeted to pathogens
 Environmental and health concerns
 Development of resistant strains
Biological control as an alternative strategy to control plant diseases
Biological control:
The use of living organisms, or products derived from living organisms, for pest control

3. Plant diseases: strong economical and environmental impacts
 World market of pesticides (fungicides, insecticides, herbicides) : 44 billions $
 Strong increase of the biopesticide market
Source: IUPP

4. Commercial products against fungal diseases
 Microorganisms (~15) (antagonisms)
Rhizobacteria : Bacillus sp., Pseudomonas fluorescens…
Fungi: Trichoderma sp., Coniothyrium minitans, Ampelomyces quisqualis…..
Natural products (active compounds known):
β-1,3-glucan (Iodus2)….
 Inducers of plant defense (5)
Natural extracts (active compounds unkown):
Giant knotweed (Milsana), Fenugrec seeds (Stifenia)…
In France, about 20 active compounds are registrated
Problem: Low and variable efficacy
Solution: Identification of new active compounds, improvement of the formulation

5. Phase I : Molecular characterization of active compounds
 Identification, mode of action, first toxicity evaluation…
Phase II : Product development
 Industrial production, formulation, field tests….
Phase III : Regulatory process
 Toxicity studies, environmental impact…
Phase IV : Commercial development
From the identification of active compounds to the development
of commercial products
Development costs:
 Chemical: ~250 million $
 Biological product: ?

6. Neoprotec (2010 – 2014):
a collaborative project to develop new biological products

7. Identification of active compounds from natural extracts
 Development of high-throughput screening tests on model
plants (Arabidopsis, tobacco….)
 Mode of action: high-troughput gene expression assays
using a « plant immunity chip » (96 biomarkers) to monitor
immune responses
Samples
(treated plants)
Primers
(Biomarkers) 9216 Q-PCR
(4h)
BioMark™ HD System
(Fluidigm)
Compounds active on plant immune responses

8. Take-home messages
 Strong need of environmentally-friendly strategies to control plant diseases
 Biocontrol products (living microorganisms, natural extracts) can offer
alternative solutions
 Development of high-throughput screening tests to identify compounds able to
stimulate natural plant immune responses
 Identification of new formulations to improve the stability and efficacy of
active compounds in the field

9. Acknowledgements
 Sophie Vergnes
 The Plant-Microbe Interactions team, LRSV
Industrial partners