UNIFOLIATA regulates leaf and flower morphogenesis in pea

Area of Science:

• Plant developmental genetics
• Evolutionary botany

Background:

• The pea unifoliata (uni) mutant exhibits simplified leaves and altered flowers, resembling floral meristem identity mutants.
• Floral meristem identity genes like FLO/LFY in Antirrhinum and Arabidopsis primarily affect flower development.
• The tobacco homologue, NFL, suggests a role in specifying determinacy for both leaf and flower progenitors.

Purpose of the Study:

• To characterize the pea homologue of the floral meristem identity gene FLORICAULA/LEAFY (FLO/LFY).
• To investigate the role of this gene in pea vegetative and floral development.

Main Methods:

• Mapping of the pea FLO/LFY homologue, PEAFLO, to the uni locus using recombinant-inbred mapping populations.
• Analysis of spontaneous uni mutant alleles, including deletion and point mutations in PEAFLO coding sequences.

Main Results:

• PEAFLO was mapped to the uni locus, and markers based on PEAFLO cosegregated with uni.
• Characterization of uni alleles revealed mutations within PEAFLO, indicating PEAFLO corresponds to UNI.
• Defective PEAFLO was identified as the cause of the mutant vegetative phenotype.

Conclusions:

• The uni mutant highlights shared regulatory mechanisms in leaf and flower morphogenesis.
• Floral meristem identity genes, like UNI, possess extended roles in plant development.
• The pleiotropic nature of UNI supports the hypothesis of a common ancestral sporophyll structure for leaves and flowers, potentially reflecting a primitive function in pre-angiosperm evolution.