Abstract
Development of higher plants once interrupted through seed formation resumes by seed germination. Gene expression programs operating after the onset of germination are drastically altered relative to those operating during embryogenesis; the programs conferring seed characters are terminated, and those for postgerminative development are initiated. Mutants of the seed maturation master regulators, LEC1, LEC2 and FUS3, are broadly impaired with seed maturation-related events. In addition, the mutants show heterochronic characters as exemplified by true leaf-like cotyledons, and SAM and RAM activation during seed development. Our transcriptome analysis indicates that a wide range of genes expressed during postgerminative development are up-regulated in the mutant embryos. Onset of such heterochronic gene expression is detected as early as before the heart stage. These data suggest that postgerminative gene programs are actively repressed during embryogenesis through the function of the LEC/FUS3 factors. Base on these analysis as well as trascripotome data of various source, we will discuss about seed dormancy and germination viewed from switching of gene expression programs.
