Bridging Disciplines: Unraveling the Morphological Alterations in the Shoot Apical Meristem during Flowering

The life cycle of flowering plants includes a major developmental change known as floral transition, which occurs in response to endogenous signals or environmental variables [1].

During this transition, the shoot apical meristem (SAM), which contains a stem-cell niche, transitions from a vegetative meristem that generates leaves to an inflorescence meristem that initiates flowers.

This identity change is accompanied by substantial morphological alterations, which transform the SAM from a small, flat structure to a larger, domed one [2].

Increasing SAM size at floral transition is proposed to allow more properly spaced flowers to be formed in the inflorescence, but the mechanisms underlying SAM doming remain poorly understood.I hypothesize that SAM doming results from an extensive internal reorganization.

To test this, I will characterize SAM morphology at the tissue and single-cell levels from confocal images of the SAM throughout floral transition. This analysis will provide a time-resolved morphological characterization of the internal organization. This will be complemented by an examination of reporter gene expression domains within the meristem.

The studied genes will include WUSCHEL and CLAVATA3, which maintain the stem-cell niche, and genes related to floral transition such as APETALA2, which contributes to doming.

Subsequently, I will develop a multicellular model of the SAM during floral transition and of the expression domains of those genes and investigate their relationship with tissue organization and the doming process.

This study will provide an unprecedented quantitative characterization of the internal organization of the SAM and will elucidate how tissue internal reorganization affects morphogenesis.