Adaxial-abaxial patterning: A novel function of the GABA shunt

Adaxial-abaxial patterning in lateral organ development is important for proper tissue differentiation and the entire shape of the organs. Although many transcriptional regulators are known to be involved in adaxial-abaxial patterning, the molecular mechanisms of the initial step of adaxial-abaxial polarity formation are still unclear. To determine these mechanisms, we have been analyzing the abaxial-specific expression of FILAMENTOUS FLOWER (FIL), which encodes a putative transcription factor. Recently, we found that the enf1 mutant, which has a mutation in the succinicsemialdehyde (SSA)-degrading enzyme, reduces the robustness of FIL expression patterning and has abnormally shaped leaves.1 Here, we show that the transcriptomic data of enf1 provide more information on the relationship between SSA and adaxial-abaxial patterning, and we discuss the novel metabolic pathways of SSA production and the potential that the enf1 mutant represents a new tool in research on adaxial-abaxial polarity formation.