By Kristin Nicole Telford
In this week’s lecture, we learned about the immunity response that occurs in plants in response to a phytopathogenic bacterium. This interaction between plant and pathogen is represented through a zig-zag model. First, a pathogen is recognized by a plant. This recognition triggers Pattern-Triggered immunity (PTI) which then leads to an increased amount of defense for the plant. However, the pathogen has the ability to produce effectors that enhance the virulence of the pathogen by suppressing the plant’s immune response or contributing to the pathogen’s ability to be successful. Once the effectors suppress the defense response of the plant, the plant is now more susceptible to getting sick because its defense response has been lowered. Luckily, some plants have special proteins that allow them to recognize the effector. This recognition will then trigger Effector-Triggered Immunity (ETI) within the plant. ETI acts as the strongest defense response within a plant.
To better understand the process of the immunity response that occurs within plants, we played a game called veggie vaders. This game was played between two people with one person acting as the plant and the other person acting as the pathogen. The person acting as the plant would randomly draw from a stack of cards for plants only, and the person acting as the pathogen would randomly draw from a stack of cards for pathogens only. Because plants have two lines of defense, PTI and ETI, the game was essentially separated into two stages. During the first stage the plant would place down their randomly drawn cards onto the board. Following this, the pathogen would place down their randomly drawn cards. If the pathogen placed down two different cards that directly matched two different plant cards, then the pathogen received points during the first stage. If the pathogen cards did not directly match any of the plant cards, then the plant received points for the first stage. During the second stage the plant placed down another set of randomly drawn cards and then the pathogen placed down another set of randomly drawn cards onto the board. This second stage represented the ETI (effector-triggered immunity stage). If the plant recognized (directly matched) at least one effector placed down by the pathogen, then the plant would win the game through ETI despite what may have occurred during the first stage of the game because ETI is the strongest level of defense for plants. If the plant did not recognize any of the effectors placed down by the pathogen, then the pathogen wins the game. The games played during class were very intense considering some really good candy choices were our prizes and the winner was allowed to choose first. The winner of the game was Travoris Cameron.
Although this game was purely for fun, it did a great job of showing how the plant immunity response really works. There are many effectors produced by pathogens, so it is a game of chance even in the natural environment. If the plant does not have the special protein necessary to produce and effector-triggered response to increase its defense response it is likely that the plant will die.