The development of above-ground lateral organs is initiated at the peripheral zone of the shoot apical meristem (SAM). The coordination of cell fate determination and the maintenance of stem cells are achieved through a complex regulatory network comprised of transcription factors. Two AP2/ERF transcription factor family genes,
ESR1/DRN and
ESR2/DRNL/SOB/BOL, regulate cotyledon and flower formation and de novo organogenesis in tissue culture. However, their roles in post-embryonic lateral organ development remain elusive. In this study, we analyzed the genetic interactions among SAM-related genes,
WUS and
STM, two
ESR genes, and one of the HD-ZIP III members,
REV, whose protein product interacts with ESR1 in planta. We found that
esr1 mutations substantially enhanced the
wus and
stm phenotypes, which bear a striking resemblance to those of the
wus rev and
stm rev double mutants, respectively. Aberrant adaxial–abaxial polarity is observed in
wus esr1 at relatively low penetrance. On the contrary, the
esr2 mutation partially suppressed
stm phenotypes in the later vegetative phase. Such complex genetic interactions appear to be attributed to the distinct expression pattern of two
ESR genes because the
ESR1 promoter-driving
ESR2 is capable of rescuing phenotypes caused by the
esr1 mutation. Our results pose the unique genetic relevance of
ESR1 and the SAM-related gene interactions in the development of rosette leaves.
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