AaABCG20 transporter involved in cutin and wax secretion affects the initiation and development of glandular trichomes in Artemisia annua

Abstract

Glandular trichomes are specialized structures found on the surface of plants to produce specific compounds, including terpenes, alkaloids, and other organic substances. Artemisia annua, commonly known as sweet wormwood, synthesizes and stores the antimalarial drug artemisinin in glandular trichomes. Previous research indicated that increasing the glandular trichome density could enhance artemisinin production, and the cuticle synthesis affected the initiation and development of glandular trichomes in A. annua. In this study, AaABCG12 and AaABCG20 were isolated from A. annua that exhibited similar expression patterns to artemisinin biosynthetic genes. Of the two, AaABCG20 acted as a specific transporter in glandular trichomes. Downregulating the expression of AaABCG20 resulted in a notable reduction in the density of glandular trichome, while overexpressing AaABCG20 resulted in an increase in glandular trichome density. GC-MS analysis demonstrated that AaABCG20 was responsible for the transport of cutin and wax in A. annua. These findings indicated that AaABCG20 influenced the initiation and development of glandular trichomes through transporting cutin and wax in A. annua. This glandular trichome specific half-size ABCG-type transporter is crucial in facilitating the transportation of cutin and wax components, ultimately contributing to the successful initiation and development of glandular trichomes.