Research on the release mechanism of glucoraphanin and sulforaphane mediated by methyl jasmonate in broccoli hairy roots

Methyl jasmonate (MeJA) is a plant growth regulator, which plays an important role in signaling defense response and regulating plant secondary metabolism. Here, broccoli hairy roots growing for 18 d were treated with MeJA for 0, 3, 6, 9, and 12 h, respectively. Compared with the 0 h control group, the content of glucoraphanin (GRA) and sulforaphane (SF) was increased under MeJA treatment for 3, 6, 9, and 12 h. The activity of myrosinase (MYR) was reduced in broccoli hairy roots. With the broccoli (Brassica oleracea L. var. botrytis L) genome as the reference genome, 4733 DEGs (differentially expressed genes) were detected in the hairy roots that were treated by MeJA for 0, 3, 6, 9, and 12 h; among them, 1024 genes were upregulated and 3709 genes were downregulated. The pathway of “SNARE interaction in vesicular transport” (ko04130) was ranked 1st by KEGG pathway enrichment analysis of commonly upregulated differential genes at 0, 3, 6, 9, and 12 h. The expression of four key genes ABCB19, ABCG6, ABCG36, and ABCB9, which regulated the release of GRA and SF into a liquid medium, was upregulated at 0, 3, 6, and 9 h, respectively. It revealed that the release of GRA and SF from hairy roots was related to the ABC transporter gene family and SNARE protein-mediated exocytosis by transcriptome analysis.