Transcriptomic Analysis Reveals the Opposite Regulatory Effects of WRKY and CAMTA Transcription Factors on Total Tannin Production in Fruit.

Tannins are prevalent compounds found in plant fruits, contributing to the bitter taste often associated with these fruits and nuts, thereby influencing their overall taste quality. Numerous studies have been conducted to investigate the regulatory factors involved in tannin synthesis. Among these factors, transcription factors exhibit the most significant capacity to regulate tannin production as they can modulate the expression of several key enzyme genes within the tannin synthesis pathway. In this study, we focused on acorns from , a species abundant in subtropical China. Utilizing transcriptome data from acorns with previously established significant differences in tannin content, we identified novel genes that are capable of regulating tannin synthesis. Specifically, we discovered one transcription factor from the WRKY family and one from the CAMTA family. Promoter response element analysis revealed that the downstream target genes regulated by these two transcription factors are highly similar, and all play crucial roles as enzyme genes in the tannin synthesis pathway. In addition, by detecting the expression levels of two transcription factor genes and target genes, we found that the two transcription factors regulate the target genes in exactly opposite ways. This study not only identifies new transcription factors involved in the regulation of tannin synthesis but also introduces a novel set of molecular biology techniques aimed at effectively modulating tannin content in plant fruits, thereby enhancing fruit quality.