Nepedia
Back to Discover
Advanced Reader
🧬

Jasmonate

life science Maturity 5-7 Next article →

Jasmonates (JA) are a group of lipid-based plant hormones. These chemicals act as vital signaling molecules that regulate many biological processes. They manage everything from growth and photosynthesis to reproductive development. Most importantly, jasmonates are critical for plant defense. They help plants respond to herbivory, which is when animals eat them. They also help plants survive abiotic challenges, like poor environmental conditions. Some jasmonates can even travel through the air as volatile organic compounds (VOCs). This allows plants to communicate with their neighbors about approaching dangers.

Jasminum grandiflorum
Jasminum grandiflorum

The production of jasmonates, known as biosynthesis, follows a specific chemical path. It begins in the chloroplast membranes of the plant cell. Here, the plant converts a fatty acid called linolenic acid into 12-oxo-phytodienoic acid, or OPDA. This is the only step that occurs in the chloroplast. The process then moves to a different part of the cell called the peroxisome. In the peroxisome, the OPDA undergoes a reduction and three rounds of oxidation. This sequence transforms the substance into (+)-7-iso-JA, which is jasmonic acid.

JA signal
JA signal

Once jasmonic acid is made, the plant can change it into different derivatives. These derivatives can be active or inactive. One important derivative is methyl jasmonate (MeJA). MeJA is a volatile compound that can move through the air to signal other plants. Another key form is JA-Ile. This is created when jasmonic acid is conjugated with the amino acid isoleucine. Research suggests that JA-Ile is involved in most jasmonate signaling. The plant can also undergo decarboxylation to produce cis-jasmone.

JA signal
JA signal

The history of these molecules began with the study of scents. In 1962, researchers isolated methyl jasmonate from jasmine oil. This oil comes from the plant *Jasminum grandiflorum*. This discovery allowed scientists to understand the molecular structure of jasmonates. Later, in 1971, Alderidge and colleagues isolated jasmonic acid itself. They found it in a fungus called *Lasiodiplodia theobromae*. These discoveries laid the groundwork for our modern understanding of plant hormones.

Jasmonates play many diverse roles in plant life. When a plant is wounded by an insect, JA biosynthesis is rapidly activated. In tomato plants, this produces defense molecules that inhibit leaf digestion in insect guts. JA is also linked to cell death and leaf senescence, which is the aging of leaves. It can induce mitochondrial death by causing the accumulation of reactive oxygen species (ROSs). These molecules disrupt membranes and cause apoptosis, or programmed cell death. This helps the plant limit the spread of infections.

JA signal
JA signal

Some plants have even repurposed this pathway for unique behaviors. The Venus flytrap uses jasmonate signaling to manage its carnivory. The hormone helps signal the closing of the traps. It also controls the release of enzymes and nutrient transporters used for digestion.

Snap, Digest, Absorb - How the Venus flytrap processes prey 01
Snap, Digest, Absorb - How the Venus flytrap processes prey 01

However, not all carnivorous plants use this system. Butterworts are different and may use methods to regulate enzymes that do not depend on JA.

Inside the cell, the jasmonate pathway works like a sophisticated on-off switch. This mechanism involves proteins called JAZ, which limit the activity of transcription factors. When JA is absent, JAZ proteins bind to these factors and keep them inactive. When JA or its derivatives arrive, they trigger the degradation of JAZ. This process is mediated by a protein called COI1. COI1 is part of an SCF complex that acts as a co-receptor. The JA-Ile molecule binds to both COI1 and a specific motif on the JAZ protein. Once the JAZ protein is removed, transcription factors like the MYC family are freed. These factors then activate the specific genes needed for the plant's response.

JA signal
JA signal
596 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (3)
File:Jasminum grandiflorum.jpg
Jasminum grandiflorum.jpg
File:Snap, Digest, Absorb - How the Venus flytrap processes prey 01.png
Snap, Digest, Absorb - How the Venus...
File:JA signal.jpg
JA signal.jpg
More to explore

✨ What else?

Related topics you might enjoy

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.