The ATP-Citrate Lyase Subunit ACLA, Coordinates Rice Pollen Development by Coupling Transcriptional Regulation with Metabolic Homeostasis

ATP-citrate lyase (ACL) is a key enzyme that catalyzes the synthesis of cytosolic acetyl-CoA, providing an essential precursor for lipid metabolism and protein modification. While prior studies have implicated ACLA in rice anther development, its regulatory role in tapetal programmed cell death (PCD) and pollen wall formation remains unclear. In this study, we identified a novel ACLA allelic mutant, acla, from the rice variety Wuyunjing 7. In this mutant, the tapetum undergoes premature degradation during the late meiotic phase, accompanied by the absence of Ubisch bodies, disordered pollen exine structure, and microspore abortion. Biochemical assays revealed a significant reduction in ACL enzyme activity in the acla mutant. Transcriptome analysis further demonstrated systematic dysregulation of genes involved in reactive oxygen species (ROS) homeostasis, lipid metabolism, ubiquitination, and cell death-related pathways. Protein-protein interaction assays confirmed that ACLA directly interacts with TDR and PTC1, two core transcription factors that regulate tapetal PCD, as well as CAD8C, a key enzyme in phenylpropanoid metabolism. Subcellular localization and bimolecular fluorescence complementation (BiFC) assays further demonstrated that ACLA co-localizes and directly interacts with these proteins in the nucleus. Collectively, these results suggest that ACLA may participate in anther development through two potential routes. One provides acetyl-CoA to sustain metabolism and another interacts with tapetum-development-related transcription factors and metabolic enzymes, thereby potentially involving a transcription-metabolism synergistic regulatory network. These findings provide new experimental evidence for understanding the molecular mechanisms underlying male fertility in rice.