Product Education   |   April 2, 2020

Q&A with Steve Loveday, Product Development Manager, Target Specialty Products

plant defense mechanisms

Have you ever wondered why a disease like dollar spot appears slowly and then spreads over time vs advancing more quickly? Plants, including your turf, are a rich food source for multiple organisms and insects however over the years have evolved to create an elaborate system of detection and defense mechanisms against would be attackers. 

1. How does a plant recognize a threat? Plants have sophisticated detection systems to discern between a stress like drought vs pathogen attack. This is key as the plant will use different strategies to defend against each. Drought stress may require an adjustment in metabolism and hormone composition where pathogen attack will likely require responses leading to immunity. Any damage to a plant’s cell wall is quickly detected and is the trigger that initiates a wellness response and cascade of defense/recovery actions. 

 

2.What are plant defense systems? Dependent upon what type of stress is present the plant will initiate either the jasmonic acid pathway or the salicylic acid pathway to defend itself. Oftentimes as one system is initiated the other is inhibited in an act of resource conservation however it has been proven that in certain situations the plant will use all weapons available and both systems will be called upon for defense. 

3. How do these defense systems work? Once a threat is detected, be it drought, a pathogen, a chewing insect, or a “trigger” from a product, the plant will initiate the appropriate line of defense to match the attacker. It is generally believed the plant will initiate the salicylic acid (SA) pathway for biotrophic threats like rust, powdery mildew and abiotic stresses like high temperature, mechanical injury, drought, etc. The jasmonic acid (JA) pathway is reserved for necrotrophic threats like chewing insects, fusarium, dollar spot, pythium, etc. 

4. What happens once a plant defense system is activated? A genetic response begins the fight against an attacker or threat. This results in the production of PR (pathogenisis related) proteins. These materials can be antimicrobial, attacking the cell walls of bacteria and fungi. The plant will use nutrients to spread the word that an attack is underway. Next the plant will use highly reactive oxygen molecules to damage attacker cell walls and expedite the thickening of plant cell walls. As the plant thickens cell walls it will fill the space in between cells with callose to make it more difficult for the pathogen to invade. A more dramatic next step is called the hypersensitive response (HR). During the HR response the plant will commit cellular suicide at the site of the attack to create somewhat of a firewall, impeding the progress of the attacker. If the attacker is a chewing insect the plant will likely produce and release VOCs or volatile organic compounds to repel or even poison the attacker. 

5. How can a turf manager utilize some of the latest plant defense activation technology? For the past 9 years the Turf Fuel research team has developed multiple plant defense system activation compounds. These materials have been university proven to trigger a wellness response in turf under stress and prolong decline. We’ve coupled the most potent compounds with large amounts of sugars and amino acids to “keep the motor running” as turf fights back. We call this technology NutrifenseTM and it can be found in three of our nutritional products, Photo FuelTM, Respo FuelTM and Element 6TM. Like the diet of a professional athlete, these products were strategically designed to provide turf with the nutrients and supplements needed for performance under extreme stress. To learn more about the NutrifenseTM powered product trio visit TurfFuel.com.