Gene expression profiling of reproductive meristem types in early rice inflorescences by laser microdissection
Résumé
n rice, inflorescence architecture is established at early stages of reproductive development and contributes
directly to grain yield potential. After induction of flowering, the complexity of branching, and therefore the
number of seeds on the panicle, is determined by the activity of different meristem types and the timing of
transitions between them. Although some of the genes involved in these transitions have been identified,
an understanding of the network of transcriptional regulators controlling this process is lacking. To address
this we used a precise laser microdissection and RNA-sequencing approach in Oryza sativa ssp. japonica cv.
Nipponbare to produce quantitative data that describe the landscape of gene expression in four different
meristem types: the rachis meristem, the primary branch meristem, the elongating primary branch meris-
tem (including axillary meristems), and the spikelet meristem. A switch in expression profile between apical
and axillary meristem types followed by more gradual changes during transitions in axillary meristem iden-
tity was observed, and several genes potentially involved in branching were identified. This resource will be
vital for a mechanistic understanding of the link between inflorescence development and grain yield.