Question

More recently discovered plant hormone, Jasmonates, play an important role both in plant defense and development, is derived from which fatty acid?

• A. Palmitic acid
• B. Oleic acid
• C. Linoleic acid
• D. Linolenic acid

Hint:

Associate Jasmonates with plant defense (like responding to being wounded or eaten). Their synthesis starts with the highly unsaturated fatty acid, \(\alpha\)-linolenic acid, being released from the cell membrane.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Jasmonates (like jasmonic acid) are a class of plant hormones that regulate a wide range of processes, most notably responses to stress and insect/pathogen attack. The question asks for the precursor molecule from which they are synthesized.
Step 2: Detailed Explanation:


The biosynthesis of jasmonic acid (JA) is known as the octadecanoid pathway.

This pathway begins with a polyunsaturated fatty acid that is released from the plant cell membrane.

The specific precursor fatty acid is \(\alpha\)-linolenic acid (an 18-carbon fatty acid with three double bonds, C18:3).

Linolenic acid is then converted through a series of enzymatic steps (involving lipoxygenase, allene oxide synthase, and others) into jasmonic acid.

Palmitic acid is a saturated fatty acid. Oleic and Linoleic acids are unsaturated but have fewer double bonds than linolenic acid and are not the direct precursors.

Step 3: Final Answer:
Jasmonates are derived from the fatty acid linolenic acid.