The hormone jasmonic acid plays an important role in immune and growth of plants. The effect of jasmonic acid is already well understood. But one important element is missing: what causes the amount of jasmonic acid to decrease, when an attack by a fungus or insect is repelled? Plant biologists at Utrecht University and colleagues from the University of Amsterdam have now discovered how plants break down jasmonic acid and thus produce the "safe signal". The steering mechanism has the potential to increase the resistance of plants to fungi and insects. The results of the study were published Tuesday, May 30 in the scientific journal PNAS.
Once a plant notice an insect or fungus, the plant hormone jasmonic acid is produced. It causes an immune reaction to be put in motion, which prevents further damage. Soon after the jasmonic acid is broken again. This is because the hormone inhibits the growth and development of the plant.
Until now it was unknown how jasmonic acid is broken down in the plant. There appears to be four related enzymes, allowing the biologists at the University of Utrecht and see the University of Amsterdam in their research on Arabidopsis, the model plant Arabidopsis thaliana .
Each of the four enzymes causes a chemical reaction in which an oxygen atom is linked to jasmonic acid. This results in a variation of the hormone, the inactive 12-hydroxy-jasmonic acid. While the immune system comes into action immediately when a high concentration of jasmonic acid, which does not happen with the inactive variant. This discovery is an important missing link in the effect of jasmonic acid found.
"Now that we know this circuit, we have the ability to control the concentration of jasmonic acid, thereby increasing the resistance of the plant" to light investigator prof. Guido van den Ackerveken Utrecht University. "In our study, we also show that plants are much more resistant to insects and pathogenic fungi as we turn the four enzymes in a plant. One important disadvantage is that it remains behind the growth and development of the plant. So it's finding the right balance. "
Caarls, L., Elberse, J., Awwanah, M., Ludwig, N. R., de Vries, M., Zeilmaker, T., ... & Van den Ackerveken, G. (2017). Arabidopsis JASMONATE-INDUCED OXYGENASES down-regulate plant immunity by hydroxylation and inactivation of the hormone jasmonic acid. bioRxiv, 102103.