Evolutionary dynamics of the proanthocyanidin biosynthesis gene LAR

Area of Science:

• Plant molecular biology
• Evolutionary genomics
• Biochemistry

Background:

• Leucoanthocyanidin reductase (LAR) is crucial for proanthocyanidin biosynthesis, converting leucoanthocyanidins to catechins.
• Flavonoid pathway terminal branches, like LAR, show lineage-specific evolution.
• Understanding LAR evolution is key to comprehending plant metabolic diversity.

Purpose of the Study:

• Investigate the evolutionary dynamics and functional divergence of LAR genes across major plant clades.
• Explore how LAR gene evolution contributes to variations in plant flavonoid profiles.
• Provide insights for breeding and metabolic engineering of plant traits.

Main Methods:

• Large-scale comparative and phylogenetic analyses across plant clades.
• Coexpression, sequence, and promoter analyses.
• Synteny analyses to infer gene presence/absence.

Main Results:

• Phylogenetic analysis revealed independent LAR gene duplications and lineage-specific expansions, especially in dicots and gymnosperms.
• Dicots show differential retention and diversification of LAR1 and LAR2; gymnosperm LAR homologs suggest ancient duplication and neofunctionalization.
• Paralog-specific expression, conserved/clade-specific domains, and regulatory differences (promoter analysis) support functional divergence; LAR may be absent in some Brassicales.

Conclusions:

• LAR evolution is shaped by coding and regulatory changes, explaining flavonoid profile variations in gymnosperms and angiosperms.
• Evolutionary dynamics of LAR deepen understanding of metabolic pathway evolution.
• Insights into LAR evolution are relevant for breeding and engineering plant pigmentation, stress resilience, and nutritional quality.