Transcriptional activation of BolBCAT4 genes enhanced aliphatic glucosinolate accumulation in cabbage

Aliphatic glucosinolates are a large group of plant-specialized metabolites in <i>Brassica</i> vegetables, and some of their degradation products are key nutrients with significant beneficial effects on human health. Increasing the nutritional quality is one of the central research questions and breeding goals for <i>Brassica</i> vegetables. Major progress has been made in understanding transcriptional regulation of aliphatic glucosinolates biosynthesis in the model plant, while little is known about it in <i>Brassica</i> vegetables. In this study, we used cabbage to study the transcriptional regulation of <i>BolBCAT4</i> genes, the first set of biosynthetic genes in methionine-derived aliphatic glucosinolate metabolism, and identified and functionally validated four upstream positive regulators of <i>BolBCAT4</i> genes, BolMYB3R, BolbHLH153, BolMED4 and BolERF74, with consistent phenotypic effects of inducing short-chain aliphatic glucosinolates, including glucoraphanin. Our work confirmed the biological functions of <i>BolBCAT4</i> genes, identified dozens of candidate upstream regulators, and provided valuable regulatory mechanisms and breeding targets for enhancing the nutritional quality of cabbage.