Disruption of early seed developmental programs underlies abnormal seed formation in Brassica napus

A proportion of seeds exhibit growth retardation during early development after pollination, and this early stage is critical for determining subsequent seed abortion and final yield in Brassica napus L. However, the mechanisms underlying the formation of these abnormal seeds remain largely unknown. We combined continuous phenotypic characterization with transcriptome profiling to investigate the developmental process and regulatory mechanisms underlying abnormal seed formation.

The results showed that the size difference between abnormal and normal seeds was already established at 4 days after pollination (DAP). It is suggested that extensive disturbance in abnormal seeds at 4 DAP, accompanied by disruptions in key biological processes including endosperm development and phytohormone responses. Several candidate genes, including BnaCYP78A9 and BnaWRKY10, were highly expressed in normally developing seeds but were significantly downregulated in abnormal seeds, indicating that they may be associated with the regulation of early seed development.