Rhamnose in plants - from biosynthesis to diverse functions

Area of Science:

• Plant biochemistry
• Carbohydrate metabolism
• Plant specialized metabolites

Background:

• L-rhamnose is a deoxy sugar found in plant cell walls and specialized metabolites.
• Significant differences exist in rhamnose distribution between dicots and commelinid monocots (grasses).

Purpose of the Study:

• To review current knowledge on l-rhamnose distribution in plants.
• To discuss the biosynthesis, transport, and transfer of UDP-rhamnose.
• To highlight knowledge gaps in rhamnose rescue and catabolism.

Main Methods:

• Literature review of plant rhamnose metabolism.
• Analysis of rhamnose distribution in dicotyledonous and monocotyledonous plants.
• Discussion of enzyme mechanisms (rhamnosyltransferases, rhamnose synthases).

Main Results:

• L-rhamnose is a widespread component of plant polymers and metabolites.
• UDP-rhamnose biosynthesis and transfer mechanisms are detailed.
• Rhamnose synthases exhibit unique substrate specificities, including potential flavonoid modification.

Conclusions:

• Understanding l-rhamnose distribution and function in plants is incomplete.
• Further research is needed on rhamnose salvage pathways and catabolism.
• Comparative studies between dicots and grasses reveal distinct patterns in rhamnose utilization.