Trans-cinnamic acid coordinates PAL repression and C4H induction to modulate lignification in bamboo

Area of Science:

• Biochemistry
• Plant Biology
• Metabolic Regulation

Background:

• Lignin deposition in bamboo culm requires metabolic coordination.
• Regulatory mechanisms for phenylpropanoid precursors are not fully understood.

Purpose of the Study:

• Identify regulatory mechanisms balancing precursor supply and demand in bamboo lignification.
• Investigate the role of trans-cinnamic acid (t-CA) in this process.

Main Methods:

• Transcriptomic and biochemical analyses.
• Gene expression and enzymatic activity assays.
• Evolutionary analyses.

Main Results:

• Identified a bidirectional PAL-C4H module regulated by t-CA.
• t-CA upregulates downstream lignin biosynthesis (PeC4H1/2) and suppresses upstream PAL (PePAL10/11).
• t-CA mediates posttranslational control of PAL via ubiquitination (PeKFB9).

Conclusions:

• A feedback loop ensures resource prioritization for secondary cell wall formation in bamboo.
• Bamboo exhibits unique regulatory optimization for rapid growth kinetics.
• Findings provide targets for precision breeding of bamboo as a plastic substitute.