Combinatorial interactions of the LEC1 transcription factor specify diverse developmental programs during soybean seed development (PNAS) ($)

LEC1 (LEAFY COTYLEDON 1) transcriptional factor regulates multiple developmental processes during different stages of seed development including macromolecule accumulation, inhibition of germination and morphogenesis. In this paper Jo et al., have uncovered the mechanism of LEC1 functioning with other transcriptional factors through co-expression analysis of genes to regulate downstream gene expression to fine-tune seed development. LEC1 in combination with ABA-RESPONSIVE ELEMENT BINDING PROTEIN3 (AREB3) is shown to regulate morphogenesis. Along with multiple partners like BASIC LEUCINE ZIPPER67 (bZIP67), AREB3 and ABA INSENSITIVE3 (ABI3), LEC1 regulates the photosynthesis which is initiated post-seed morphogenesis. Finally, the combination of all these transcriptional factors was identified to contribute towards the seed maturation. The authors also identified cis-regulatory modules for the transcriptional factors and validated by expressing the cis-region to minimal 35s Promoter tagged to LUCIFERASE in cotyledon protoplasts from EM-stage embryos. Overall this paper has shown the mechanism of an atypical NF-YB transcriptional factor, LEC1 regulating a multitude of seed developmental processes in soybean. (Summary by Suresh Damodaran)  10.1073/pnas.1918441117