Partial conservation of LFY function between rice and Arabidopsis

Area of Science:

• Plant molecular biology
• Evolutionary genetics
• Developmental biology

Background:

• The LFY/FLO gene family encodes plant-specific transcription factors crucial for reproductive transition and floral development.
• Understanding the evolutionary conservation and functional divergence of these genes across plant lineages is essential for comprehending floral evolution.

Purpose of the Study:

• To reconstruct the phylogenetic relationships of LFY/FLO homologs across diverse plant species.
• To investigate the functional conservation and divergence between grass (monocot) and eudicot LFY/FLO genes.
• To elucidate the role of rice LFY homolog (RFL) in Arabidopsis floral development.

Main Methods:

• Phylogenetic analysis of 49 LFY/FLO homologs from various plant species.
• Introduction of the rice RFL gene into the Arabidopsis lfy mutant background.
• Analysis of downstream target gene expression (AP1 and AG) in transgenic Arabidopsis.

Main Results:

• Phylogenetic analysis revealed distinct monophyletic clusters for eudicot and monocot LFY/FLO genes.
• Grass LFY/FLO genes exhibit accelerated amino acid replacement rates compared to eudicots.
• Rice RFL partially rescued the Arabidopsis lfy mutation, indicating partially overlapping functions.
• RFL, unlike LFY, strongly activated AP1 and AG expression in vegetative tissues.
• Transgenic Arabidopsis expressing LFY::RFL showed developmental abnormalities, including leaf curling and ovule-to-carpel transformation.

Conclusions:

• The LFY/FLO gene family shows both conserved and divergent functional properties between rice and Arabidopsis.
• Functional differences in downstream target gene activation and developmental effects highlight evolutionary divergence.
• These findings contribute to understanding the molecular mechanisms underlying floral development and evolution in grasses versus eudicots.