VEL1 and VRN5 Identified as Key Regulators of Seed Abortion in Arabidopsis

The VERNALIZATION INSENSITIVE 3-LIKE (VEL) family includes five members, VEL1, VEL2, VEL3, VERNALIZATION INSENSITIVE 3 (VIN3) and VERNALIZATION 5 (VRN5), yet only VEL3 has been genetically linked to seed dormancy and abortion. Here, we employ genetic and transcriptomic assays to dissect the functions of VEL family genes in Arabidopsis thaliana. Loss-of-function analyses establish VEL3 as the sole regulator of primary seed dormancy depth, whereas VEL1 and VRN5 act redundantly to prevent seed abortion without affecting dormancy. Comparative RNA-seq of mature endosperm revealed that both vel3-1 and vel1-2 vrn5-9 mutants upregulate programmed cell-death genes, whereas vel3-1 uniquely deregulates chromatin remodellers and metabolic repressors, consistent with heterochromatin relaxation at germination loci and elevated metabolic activity. Overall, this study strengthens the idea of a modular chromatin framework in which distinct VEL–PRC2 modules uncouple seed viability from dormancy establishment.