AUTHOR=Wang Lishan , Xue Wanjie , Li Xueqi , Li Jingyao , Wu Jiayan , Xie Linan , Kawabata Saneyuki , Li Yuhua , Zhang Yang 

TITLE=EgMIXTA1, a MYB-Type Transcription Factor, Promotes Cuticular Wax Formation in Eustoma grandiflorum Leaves

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.524947

DOI=10.3389/fpls.2020.524947

ISSN=1664-462X

ABSTRACT=<p>In the aerial plant organs, cuticular wax forms a hydrophobic layer that can protect cells from dehydration, repel pathogen attacks, and prevent organ fusion during development. The <italic>MIXTA</italic> gene encodes an MYB-like transcription factor, which is associated with epicuticular wax biosynthesis to increase the wax load on the surface of leaves. In this study, the <italic>AmMIXTA</italic>-homologous gene <italic>EgMIXTA1</italic> was functionally characterized in the <italic>Eustoma grandiflorum</italic>. <italic>EgMIXTA1</italic> was ubiquitously, but highly, expressed in leaves and buds. We identified the <italic>Eustoma</italic> MIXTA homolog and developed the plants for overexpression. EgMIXTA1-overexpressing plants had more wax crystal deposition on the leaf surface compared to wild-type and considerably more overall cuticular wax. In the leaves of the overexpression line, the cuticular transpiration occurred more slowly than in those of non-transgenic plants. Analysis of gene expression indicated that several genes, such as <italic>EgCER3</italic>, <italic>EgCER6</italic>, <italic>EgCER10</italic>, <italic>EgKCS1</italic>, <italic>EgKCR1</italic>, and <italic>EgCYP77A6</italic>, which are known to be involved in wax biosynthesis, were induced by EgMIXTA1-overexpression lines. Expression of another gene, <italic>WAX INDUCER1/SHINE1</italic>, encoding a transcription factor that stimulates the production of cutin, was also significantly higher in the overexpressors than in wild-type. However, the expression of a lipid-related gene, <italic>EgABCG12</italic>, did not change relative to the wild-type. These results suggest that <italic>EgMIXTA1</italic> is involved in the biosynthesis of cuticular waxes.</p>