Origin and evolution of jasmonate signaling

Area of Science:

• Evolutionary Biology
• Plant Molecular Biology
• Biochemistry

Background:

• Jasmonate (JA) signaling is vital for plant development, defense mechanisms, and the synthesis of specialized metabolites.
• Understanding the evolutionary trajectory of JA signaling provides insights into plant adaptation from aquatic to terrestrial environments.
• Key components of JA signaling include CORONITINE INSENSITIVE 1 (COI1), JASMONATE ZIM-DOMAIN (JAZ), MYC2, and others.

Purpose of the Study:

• To trace the evolutionary lineage of critical protein domains within JA signaling factors.
• To identify the ancestral origins of key JA signaling components like COI1, JAZ, and MYC2.
• To determine the timeline of JA signaling evolution and its potential drivers.

Main Methods:

• Phylogenetic analysis was employed to trace the lineage of protein domains associated with JA signaling.
• Comparative genomics was used to identify orthologs of JA signaling genes in various plant lineages, from algae to bryophytes.
• Molecular dating techniques were applied to estimate the origin of JA signaling.

Main Results:

• Charophyte algae lack key JA signaling genes (COI1, JAZ, MYC2), but orthologs appear in bryophytes.
• TIFY family genes, precursors to JAZ proteins, were identified in charophyte and chlorophyte algae.
• The origin of JA signaling was dated to the Middle Cambrian–Early Ordovician periods (515–473 million years ago), coinciding with significant biodiversity changes and extinctions.

Conclusions:

• Jasmonate (JA) signaling evolved from TIFY genes in early land plants, likely driven by increased predation pressure during the Cambrian-Ordovician transition.
• The emergence of JA signaling was a critical adaptation for plant survival and defense in terrestrial ecosystems.
• This evolutionary event underpins complex plant development and defense strategies observed today.