The Search for Proteins Interacting with the Transcription Factor SeAPRR2 are Involved in the Regulation of Chlorophyll Biosynthesis in Sechium edule Fruits

To elucidate the molecular mechanism underlying fruit peel coloration in chayote, this study focused on the interaction network of SeAPRR2, a key gene involved in chlorophyll metabolism. A yeast cDNA library was constructed from chayote fruit using the Gateway BP/LR recombination system. The secondary library exhibited a titer of 1.28 × 107 clones, with an average insert size >1000 bp and a recombination efficiency of 100%. Screening was performed using the yeast two-hybrid (Y2H) system with pGBKT7-SeAPRR2 as the bait. This screening identified 45 candidate interacting proteins. Subsequent one-on-one verification confirmed seven authentic interactors. Further validation by luciferase complementation imaging (LCI) and bimolecular fluorescence complementation (BiFC) assays demonstrated specific interactions between SeAPRR2 and the transcription factor SeCDF2 as well as the chaperone protein SeDnaJ1. These results suggest that SeAPRR2 likely regulates chlorophyll synthesis in chayote peel through cooperative interactions with SeCDF2 and SeDnaJ1, offering molecular targets for the improvement of fruit coloration.