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Betydningen af svampemidlernes formulering samt fysiologiske effekter

Physiological Effects of Fungicides Course for Advisers Koldkaergaard / Aarhus, September 6th 2012

Physiological Effects of Fungicides Physiological Effects of Fungicides: Guidelines for presentation Life can only be understood backwards; but it must be lived forwards Motto for advise in plant protection: As little as possible but as much as neccessary Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Preview on Topics: • What are Physiological Effects? • Are Physiological Effects linked with Chemical Classes of Fungicides or rather specific for Individual Compounds? • Case Study with the Strobilurin Fungicide Pyraclostrobin • Physiological Effects in Practical Application: Opportunities, Recommendations and Limits Harald Koehle, BASF Aarhus, September 6th 2012

Physiological Effects of Fungicides Example: shifts in source - sink Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • What are Physiological Effects? Source Sink
• respiration and • starch and protein Assimilates
inhibition of
• metabolism and infected
growth of fungus • wound respiration (decreased leaf surface) • defense reactions Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • What are Physiological Effects? Conclusion: • Since fungal infection interferes with physiology of plant, each active fungicide thus has physiological effects. • However, some fungicides influence physiological processes of the plant directly also in the absence of fungal pathogens. in fact the scientific explanation and practical relevance of such effects are the topics of our consideration now. …the original question Ghita asked: How different fungicide classes* can influence the plant physiology? *Strobe, Triazole, SDHI, Benzophenone, Amines, Anilinopyrimidines – solo and in combinations Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Are Physiological Effects linked with Chemical Classes of Fungicides or rather specific for Individual Compounds? Conditions for physiological effects triggered by compounds directly • Compounds mimic or antagonize plant hormones in interaction with specific rezeptors (example: PGR‘s), • or compounds interfere with signal molecules / signal chains and energy • or compounds alter abundance of key metabolites in central biochemical >> In each case compounds have to get to targets insides the plant symplast >>> uptake, translocation / partitioning, metabolism (degradation, activation) are mainly influenced by physicochemical properties of molecules but do not depend on chemical nomenclature of pharmakophore. Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Are Physiological Effects linked with Chemical Classes of Fungicides or rather specific for Individual Compounds? Conclusions: • Physiological effects of fungicides are immanent with properties of individual compounds. • The quantitative response results by the abundance of compound at target(s), the interaction with targets and the role/relevance of target(s) in stage of plant development: • Although the Biochemical Mode of Action for one chemical class of
actives is assumed to be similar, according to abundance as a parameter,
the quantitative differences in physiological effects can be as
pronounced like between different chemical classes of compounds.
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • However some qualitative grouping is feasible: • Although the Biochemical Mode of Action for one chemical class of
actives is assumed to be similar, according to abundance as a parameter,
the quantitative differences in physiological effects can be as
pronounced like between different chemical classes of compounds.
Harald Koehle, BASF Aarhus, September 6th 2012

Physiological Effects of Fungicides Table source: Ghita Cordsen Nielsen
grouping by Physiological Effects Triazoles (EBI): inhibit gibberellin synthesis and are used as a PGR in winter oil seed rape; "greening effects" Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Table source: Ghita Cordsen Nielsen
grouping by Physiological Effects Amines (EBI): some "greening effects" Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Table source: Ghita Cordsen Nielsen
grouping by Physiological Effects Carboxamides (SDHI) can reduce ethylene production and increase pod stability in osr Source: Prof. Dr. J.A. Verreet Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Table source: Ghita Cordsen Nielsen
grouping by Physiological Effects Benzophenone (SDHI, too) can reduce drought stress Video source: Bayer Crop Science
…example that Physiological Effects do
not depend on chemical classification!
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Table source: Ghita Cordsen Nielsen
grouping by Physiological Effects Strobilurins (ETCI): most pronounced effects in alleviation of plant stress … example that Physiological Effects
differ within one group of chemical
classification!
Influence of strobilurins on ethylene formation induced by drought stress Harald Koehle, BASF Aarhus, September 6th 2012

Physiological Effects of Fungicides Case Study with the Strobilurin Fungicide Pyraclostrobin …before "living forwards" by recommendations for practical application I like to offer "understanding backwards" by a special example… Harald Koehle, BASF Aarhus, September 6th 2012

Physiological Effects of Fungicides Basic Mode of Action in Fungi
Study with the Strobilurin Fungicide Pyraclostrobin Inhibition of Electron
Transport in Fungal
Fungicidal Activity
Harald Koehle, BASF Aarhus, September 6th 2012 Less Disease

Physiological Effects of Fungicides Basic Mode of Action in Fungi
• Case Study with the and Plants
Fungicide Pyraclostrobin Inhibition of Electron
Inhibition of Electron
Transport in Plant
Transport in Fungal
of:
Fungicidal Activity
Increased Nitrogen
Better Plant Growth
Less Disease
Higher Yield
Physiological Effects of Fungicides Basic Mode of Action in Fungi
• Case Study with the and Plants
Fungicide Pyraclostrobin Inhibition of Electron
Inhibition of Electron
Transport in Plant
Transport in Fungal
of:
Fungicidal Activity
Regulation of Signal-Chains of
Increased Nitrogen
Stress-Detection and -Defense
Better Plant Growth
Less Disease
More Vitality
Higher Yield
Physiological Effects of Fungicides Nitric Oxide is an important
Messenger in Biology
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Viagra and NO…
effects on
Strobil t Flo
urin wers
Fungici de Pyraclostrobin Mercedes roses 7 days after sell-by date Nontreated control 30 ppm Sildenafil (a.i. of Viagra) Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Antagonism of Ethylene and NO
• Case Study with the Strobilurin Fungicide Pyraclostrobin Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Antagonism of Ethylene and NO
• Case Study with the Strobilurin Fungicide Pyraclostrobin Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides NO: an universal Messenger in Biology
• Case Study with the Strobilurin Fungicide Pyraclostrobin Influence on rooting In plants, nitric oxide (NO) mediates indole-3-acetic acid (IAA)-signaling pathways leading to both lateral (LR) and adventitious (AR) root formation root
formation
Delledonne (modified) Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Stimulation of Root Growth
• Case Study with the Strobilurin Fungicide Pyraclostrobin Influence on rooting Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides The Effect of NO on the Induction of adventitious
t Formation is
urin Fun nde
Influence on rooting Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides NO: an universal Messenger in Biology
• Case Study with the Strobilurin Fungicide Pyraclostrobin Priming of Plants for Defense root
formation
Delledonne (modified) Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Lesion Formation and Defense Activation
• in primed
the primed T
de Pyraclostrobin Transgenic PR-10::GUS tobacco (cv Samsun NN)
Primary infection w/ Pss (7d), challenge infection w/ TMV (7d)
Photograph courtesy of Luis Mur (University of Wales)
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Plants primed by can better resist
• Viruse
Study wi Bact
th the eria
Strobilurin Fungicide Pyraclostrobin Priming of Plants for Defense Pyraclostrobin induces tolerance against Pseudomonas syringae infection in tobacco before inoculation
with inoculation
pretreatment neccessary! .without direct effects on bacterial growth Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Plants primed by can better resist
Study wi iruses
th the and
urin Fun ria
de Pyraclostrobin Priming of Plants for Defense Tobacco mosaic virus, lesion size [mm] Source: Prof. Conrath, Univ. Kaiserlautern, 2002 TMV  inoculation 24 h after application Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Anti-Oxidative Capacity:
• Case less Da
urin Fun gicide Pyraclostrobin Priming of Plants for Defense Untreated
Headline 6 oz/a
228 bu/a
251 bu/a
Ozone Damage – Field Corn – Salisbury, MD
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Abiotic Stress – Chill
Study with n incre
urin Cold
gici olera
Priming of Plants for Defense Untreated
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Abiotic Stress – Drought
Case 0® Impac
Study with t on
the Canopy
Strobilurin Temper
Priming of Plants for Defense (ICARDA) International Center for Agricultural Research in the Dry Areas, 2007 Cooler canopy temperature – less stressed plants by Pyraclostrobin treatment
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Case Study with the Strobilurin Fungicide Pyraclostrobin Priming of Plants for Defense blank form.
Pyraclostr.
Standard
irrigation
of standard
of standard
 Pyraclostrobin treatment: higher yields under drought conditions
Pyraclostrobin & Drought Stress Corn, Dinuba 2007
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Extreme Environments require specific
• Case Study with the Strobilurin Fungicide Pyraclostrobin Priming of Plants for Defense how can Pyraclostrobin
increase stress resistance
in both extremes?
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Linkage
Study with n
the differe
Strobil nt
urin Kind
de Stress
Priming of Plants for Defense Stress triggers similar processes in: • Biochemistry • Sensing and regulation Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Universal Actors in Plant Stress:
• Case Study with the Strobilurin Fungicide Pyraclostrobin Reactive Oxygen Species (ROS)*
Priming of Plants for Defense Environmental factors that cause oxidative stress: • air pollution (Ozone, SO ) • Salt and heavy metals • Drought and Flooding • Heat and Chilling • Photoinhibiting high light intensities, UV Oxidative stress is the consequence of all kinds of primary stress. Priming of plants contributes to stress alleviation in general *ROS: singlet oxygen, H O , superoxide anion, (per)hydroxyl radicals from mitochondrial or chloroplast electron transfer chains Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Universal Actors in Plant Stress:
• Case Study with the Strobilurin Fungicide Pyraclostrobin Reactive Oxygen Species (ROS)
Priming of Plants for Defense Schematic representation of ROS-dependent pathways
ROS production provokes the accumulation of phytotoxic levels of ROS leading to cell death e Reaction) Protection Repair mechanisms Pathogens, environmental and Transient increases may initiate developmental changes signal transduction cascades stimulate the production of ROS involving cross talk with other through various organelles and phytohormones, SA, jasmonate, ethylene, and NO. Van Breusegem F., Dat J. F. Plant Physiol. 2010:141:384-390 (modified)
Physiological Effects of Fungicides Functional Model:
Case ade of
Study wi Effe
th the cts &
Strobil Key
urin Para
Fungici met
Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Case Study with the Strobilurin Fungicide Pyraclostrobin Conclusions: • Physiological effects can be highly complex, depending on many different parameters: Effect(s) = abundance at target x interaction with target x importance of target • Pyraclostrobin transiently increases nitrogen assimilation which can result in a headstart of growth. • Pyraclostrobin indirectly can stimulate root growth and inhibits the formation of stress ethylene, such preventing premature senescence. • Pyraclostrobin can trigger the priming of plants, preparing plants for defense and resulting in enhanced capability to alleviate both biotic and abiotic stresses within certain limits. Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Physiological Effects in Practical Application: Opportunities, Recommendations and Limits • Since the biochemical pathways, the signaling and mechanisms of priming of defense in all plants in principle are the same, compounds which trigger physiological effects work similar in all crops. • Different than pesticides without influence on physiology of plants, compounds like Pyraclostrobin can both improve the nitrogen use efficiency and on top the tolerance to abiotic stress like transient drought or extreme temperatures, which might result in increase of yield and quality of harvest. Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Physiological Effects in Practical Application: Opportunities, Recommendations and Limits • Do not expect any dramatic effects striking like pesticides kills weeds, • Accept that physiological effects of fungicides depend on the plant itself in interaction with the environment. As there is no guarantee on long term weather forecasts there can be none for benefits of physiological effects. • However there are some rules of thumb for Pyraclostrobin: • Split applications work better by boosting than single shots • Apply as early as possible for Priming in general or at least one day before stress impact might happen (special case: chilling) • To make use of increased Nitrogen Efficiency application is best when nitrogen uptake is the bottleneck for assimilation. • Don‘t overpromise, and don‘t wait for physiological effects when growing conditions are close to perfect! Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides • Physiological Effects in Practical Application: Opportunities, Recommendations and Limits • Since environmental conditions are highly variable in agri- and horticulture, even plants with increased capability for compensation frequently become overcharged. • Opposite, plants growing under almost perfect conditions will not show any positive response. • Different than PGR‘s none of the registrated fungicidal actives (including Benzothiodiazole (BTH) which actally is a plant defense activator) so far had been selected and optimized for physiological effects – so frankly it is rather a matter of coincidence and serendipity that some fungicides show such properties more pronounced than others. • Applications of products are ruled by the registration as fungicides in terms of crops, amounts and timing, which might be not optimal to get the best protective benefits by physiological effects. Harald Koehle, BASF Aarhus, September 6th 2012 Physiological Effects of Fungicides Hopefully the backward understanding might help a little to advise your customers in making best decisions for their future cropping system! Harald Koehle, BASF Aarhus, September 6th 2012

Source: https://www.landbrugsinfo.dk/Planteavl/Plantevaern/Plantesygdomme/Kemisk-bekaempelse/Filer/pl_km_12_485_Harald_Koehle.pdf