A Regulatory Network of Transcription and Hormones Controls PCD and Autophagy in Grape Seed Abortion.

The seedless trait in grapes primarily arises from pseudo-parthenocarpy, driven by early seed abortion involving programmed cell death (PCD) and autophagy. However, the specific regulatory networks governing these pathways remain poorly defined. To address this, we systematically characterized the PCD-related (vacuolar processing enzyme [VPE] and metacaspase [MC]) and autophagy-related (ATG) gene families in the seedless cultivar 'Jingkejing' utilizing comprehensive bioinformatic analyses, spatiotemporal transcriptomic profiling, and transient expression assays. We identified three VPE, six MC, and 33 ATG genes, whose promoters were significantly enriched in hormone-responsive and transcription factor (TF)-binding motifs. Transcriptomic profiling across critical seed abortion stages highlighted VvγVPE and VvMC9 as key differentially expressed genes. Furthermore, protein-protein interaction predictions indicated extensive crosstalk among PCD/ATG proteins, kinases, and ubiquitin system components. Notably, transient expression assays confirmed that two core transcription factors, VvWRKY46 and VvERF71, specifically regulate downstream PCD-related targets, supporting a proposed multi-hormonal and TF-mediated regulatory network during seed abortion. These findings elucidate the molecular mechanisms underlying pseudo-parthenocarpy, providing essential candidate gene resources for the marker-assisted breeding of seedless grapes.