Comprehensive analysis of JAZ family members inGinkgo bilobareveals the regulatory role of the GbCOI1/GbJAZs/GbMYC2 module in ginkgolide biosynthesis

Ginkgo bilobaL., an ancient relict plant known as a ‘living fossil’, has a high medicinal and nutritional value in its kernels and leaves. Ginkgolides are unique diterpene lactone compounds inG. biloba, with favorable therapeutic effects on cardiovascular and cerebrovascular diseases. Thus, it is essential to study the biosynthesis and regulatory mechanism of ginkgolide, which will contribute to quality improvement and medication requirements. In this study, the regulatory roles of theJAZgene family and GbCOI1/GbJAZs/GbMYC2 module in ginkgolide biosynthesis were explored based on genome and methyl jasmonate-induced transcriptome. Firstly, 18 JAZ proteins were identified fromG. biloba, and the gene characteristics and expansion patterns along with evolutionary relationships of theseGbJAZswere analyzed systematically. Expression patterns analysis indicated that most GbJAZs expressed highly in the fibrous root and were induced significantly by methyl jasmonate. Mechanistically, yeast two-hybrid assays suggested that GbJAZ3/11 interacted with both GbMYC2 and GbCOI1, and several GbJAZ proteins could form homodimers or heterodimers between the GbJAZ family. Moreover, GbMYC2 is directly bound to the G-box element in the promoter ofGbLPS, to regulate the biosynthesis of ginkgolide. Collectively, these results systematically characterized theJAZgene family inG. bilobaand demonstrated that the GbCOI1/GbJAZs/GbMYC2 module could regulate ginkgolides biosynthesis, which provides a novel insight for studying the mechanism of JA regulating ginkgolide biosynthesis.