Biologists find missing link for the 'safe' signal in plants

Arabidopsis with caterpillar. Credit: Hans van Pelt, Utrecht University

The hormone jasmonic acid plays a major role from the plant immune system along with in regulating growth. Scientists have already learned much about how jasmonic acid works, although one important link was missing: what makes the plant’s jasmonic acid level go down once the attack by a fungus or insect has been warded off? Plant biologists at Utrecht University along with colleagues by the University of Amsterdam, have today discovered how the plant metabolises jasmonic acid, issuing the signal ‘safe’. Controlling which mechanism may present fresh opportunities to improve resistance of crops to fungi along with insects. The results of their research were published from the scientific journal PNAS on Tuesday 30 May.


Once a plant detects an insect or fungus, which begins to produce the hormone jasmonic acid, which initiates an immune response which prevents further damage. After the attack, jasmonic acid is actually quickly broken down again. which is actually necessary because the hormone inhibits plant growth along with development.

Four enzymes

Until today, scientists did not know how jasmonic acid is actually broken down from the plant. although in their research on the design plant Arabidopsis thaliana, biologists at Utrecht University along with the University of Amsterdam have discovered which four related enzymes have which activity.

Missing link

Each of these four enzymes can perform a chemical reaction in which an oxygen atom is actually added to jasmonic acid. which creates an inactive variant of the hormone, 12-hydroxy-jasmonic acid. While high concentrations of jasmonic acid activate the plant’s immune system, which does not occur with the inactive variant. With which discovery, the scientists have found an important missing link as to how the plant controls its levels of jasmonic acid.

Left a ‘normal’ plant having a fungal infection, right a plant in which the enzymes have been switched off. By switching off the enzymes, the plant on the right has increased resistance to the fungus, along with therefore displays less disease symptoms. although which clearly also has consequences for the plant’s growth along with development. Credit: Utrecht University

Increasing resistance

“today which we know about these enzymes, we contain the opportunity to control the concentration of jasmonic acid in order to improve the plant’s resistance”, explains research leader Prof. Guido Van den Ackerveken by Utrecht University. “Our research shows which plants are much more resistant to insects along with pathogenic fungi if we turn off the four enzymes in a plant. One major disadvantage to which, however, is actually which which inhibits the plant’s growth along with development. So the trick is actually to find the right balance.”.


Explore further:
Picture which—biosecurity seen by the inside

More information:
‘Arabidopsis JASMONATE-INDUCED OXYGENASES down-regulate plant immunity by hydroxylation along with inactivation of the hormone jasmonic acid’ PNAS, 30 May 2017

Journal reference:
Proceedings of the National Academy of Sciences

Provided by:
Utrecht University

Biologists find missing link for the 'safe' signal in plants

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