The PcbZIP44-PcWRKY70 Module Mediates Volatile Ester Biosynthesis Via <i>PcAAT1</i> Transcriptional Regulation during Pear Postharvest Ripening

Aroma profoundly influences the flavor profile and commercial appeal of fruits. While the biosynthetic pathways of volatiles are well understood, the regulatory mechanisms governing their transcription remain unclear. This study used 'Starkrimson' fruits (<i>Pyrus communis</i> L.) to explore molecular mechanisms of ester biosynthesis. Integration of gas chromatography-mass spectrometry analysis and RNA sequencing data revealed that the alcohol acyltransferase <i>PcAAT1</i> is involved in ester synthesis. Experiments confirmed transcription factor PcbZIP44 as its upstream activator, and its physical interaction with PcWRKY70, forming a complex that synergistically enhances <i>PcAAT1</i> transcription, affecting pear ester biosynthesis. Our findings clarify a novel transcriptional regulatory module, PcbZIP44-PcWRKY70, whose formed complex synergistically and significantly enhances the expression of <i>PcAAT1</i>, thereby affecting ester biosynthesis in pears. This elucidated PcbZIP44-PcWRKY70 module expands our understanding of transcriptional complexes in aroma regulation and presents potential targets for pear flavor enhancement.