Identification and expression pattern analysis of the glucosinolate biosynthetic gene <Emphasis Type="Italic">BoCYP83B1</Emphasis> from broccoli

Glucosinolates are a branch of amino acid-derived metabolites, which are specifically found in Brassicales. In Arabidopsis, tryptophan derived indolic glucosinolates are required for plant defense against a wide range of pathogens and herbivores due to their strong antimicrobial activity and potential signaling function. An important enzyme in indolic glucosinolate biosynthesis pathway is CYP83B1, which oxidizes indole-3-acetaldoxime, a precursor of indole-3-acetic acid (IAA). In this study, we reported isolation and expression characterization of a CYP83B1 gene from Brassica oleracea L. var. italica Plenck, which we termed BoCYP83B1. Overexpression of BoCYP83B1 in Arabidopsis resulted in an altered glucosinolate profile and early flowering phenotype. By expressing the reporter gene β-glucuronidase under the control of the BoCYP83B1 promoter in Arabidopsis, we analyzed the spatial expression pattern of BoCYP83B1 under normal growth conditions as well as in response to several hormones and stresses. The BoCYP83B1 was primarily expressed in vascular tissue through the almost whole plant. It was strongly induced by methyl jasmonate, 1-amino-1-cyclopropanecarboxylic acid, salicylic acid (SA), gibberellin, and IAA, suggesting its involvement in complex signaling pathways. Mannitol, NaCl, UV, and Flagelin 22 significantly up-regulated BoCYP83B1 expression, indicating its possible role in stress response. Interestingly, the response of BoCYP83B1 to SA and NaCl showed tissue specificity. Thus, BoCYP83B1 might have different functions in different tissues.