Spatial transcriptomics uncovers exclusive functions of wheat seed tissues, and crease-specific expression of milling quality associated genes with fascilin-like arabinogalactan proteins

Wheat ( Triticum aestivum L.) flour yield is governed by tissue-specific cellular mechanics. Here, we present a spatial transcriptomic atlas of the developing wheat grain at 14 days post-anthesis (DPA), segmenting the seed into five regions: pericarp, starchy endosperm, transfer cells, crease, and embryo. Functional partitioning revealed a spatial division of labor across all regions, identifying 1,751 region-exclusive functional categories encompassing 4,682 exclusive gene loci. Candidate gene mapping resolved previous ambiguities regarding cell wall adhesion regulators: while Fasciclin-like Arabinogalactan Protein ( FLA ) transcripts were detected at baseline levels across all five seed regions, they exhibited a striking spatial concentration within the crease. The crease-focused FLA subnetwork showed strong connectivity with cell wall-remodelling machinery. As FLAs mediate cell adhesion, their primary concentration at the crease interface provides a mechanical basis for bran-endosperm adhesion during milling. Targeted silencing of crease FLAs offers a biotechnological strategy to improve flour extraction.