The Role of H3K27me3 in Eggplant’s Early Defense Against Frankliniella occidentalis

Epigenetic modifications are emerging as key regulators of plant stress responses. However, their role in eggplant (Solanum melongena)–western flower thrips (WFTs; Frankliniella occidentalis) interactions remains elusive. WFTs cause substantial economic losses in eggplant cultivation worldwide. Understanding the molecular mechanisms underlying eggplants’ defense is critical for developing resistant varieties. We investigated the function of histone H3 lysine 27 trimethylation (H3K27me3) in modulating the early transcriptional reprogramming of eggplants during WFT infestation. We performed ChIP-seq and RNA-seq on eggplant leaves at an early stage of WFT infestation to elucidate the epigenetic landscape and associated gene expression alterations. ChIP-seq analysis showed that genome-wide enrichment of H3K27me3 was mainly at the transcription start sites, with a notable decrease in WFT-infested plants. Concurrently, RNA-seq analysis identified 2822 genes that were upregulated following WFT infestation. Many of these genes associated with abscisic acid, jasmonic acid, and salicylic acid pathways were upregulated, underscoring their central role in early plant defense. Integrated analysis revealed six genes with decreased H3K27me3 levels and concurrent upregulation, potentially involved in ABA and JA signaling. Thus, removal of the repressive H3K27me3 mark may facilitate the transcriptional activation of early defense genes in eggplants that are crucial in their response to insect herbivory.