Journal Article

The roles of AaMIXTA1 in regulating the initiation of glandular trichomes and cuticle biosynthesis in Artemisia annua

Yanan Ma, Ling Li, Qian Shen, Meng Liu, Tingxiang Yan, Xueqing Fu, Pin Liu, Minghui Chen, Xiaolong Hao, Kexuan Tang, Zongyou Lv, Weimin Jiang, Qifang Pan, Xiaofen Sun, Pu Shi, Yueli Tang

2018

Overview

The glandular secretory trichomes (GSTs) on Artemisia annua leaves have the capacity to secrete and store artemisinin, a compound which is the most effective treatment for uncomplicated malaria. An effective strategy to improve artemisinin content is therefore to increase the density of GSTs in A. annua. However, the formation mechanism of GSTs remains poorly understood. To explore the mechanisms of GST initiation in A. annua, we screened myeloblastosis (MYB) transcription factor genes from a GST transcriptome database and identified a MIXTA transcription factor, AaMIXTA1, which is expressed predominantly in the basal cells of GST in A. annua. Overexpression and repression of AaMIXTA1 resulted in an increase and decrease, respectively, in the number of GSTs as well as the artemisinin content in transgenic plants. Transcriptome analysis and cuticular lipid profiling showed that AaMIXTA1 is likely to be responsible for activating cuticle biosynthesis. In addition, dual-luciferase reporter assays further demonstrated that AaMIXTA1 could directly activate the expression of genes related to cuticle biosynthesis. Taken together, AaMIXTA1 regulated cuticle biosynthesis and prompted GST initiation without any abnormal impact on the morphological structure of the GSTs and so provides a new way to improve artemisinin content in this important medicinal plant.

• Publisher: New Phytologist Trust,Wiley Subscription Services, Inc
• Subject: AaMIXTA1 / Amino Acid Sequence / Artemisia annua / Artemisia annua - genetics / Artemisia annua - metabolism / Artemisia annua - ultrastructure / Artemisia annua L / Artemisinin / Artemisinins - metabolism / Basal cells / Biosynthesis / Capacity / Cuticles / epidermal cuticle / Flowers & plants / Gene expression / Gene Expression Regulation, Plant / gene overexpression / Genes / glandular secretory trichomes (GSTs) / Human diseases / leaves / lipid composition / Lipids / Malaria / Medicinal plants / Organ Specificity / Phylogeny / Plant Epidermis - genetics / Plant Epidermis - metabolism / Plant Epidermis - ultrastructure / Plant Proteins - genetics / Plant Proteins - metabolism / Plants, Genetically Modified / Secretion / Sequence Alignment / Transcription / transcription (genetics) / Transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / transcriptome / transcriptomics / Transgenic plants / Trichomes / Trichomes - genetics / Trichomes - metabolism / Trichomes - ultrastructure / Vector-borne diseases