title: TRANSLUCENT GREEN, an ERF family transcription factor, controls water balance in Arabidopsis by activating the expression of aquaporin genes.
abstract: Water is the most abundant molecule in almost all living organisms. Aquaporins are channel proteins that play critical roles in controlling the water content of cells. Here, we report the identification of an AP2/EREBP family transcription factor in Arabidopsis thaliana, TRANSLUCENT GREEN (TG), whose overexpression in transgenic plants gave enhanced drought tolerance and vitrified leaves. TG protein is localized in the nucleus, binds DRE and GCC elements in vitro, and acts as a transcriptional activator in yeast cells. Microarray analysis revealed a total of 330 genes regulated by TG, among which five genes encode aquaporins. A transient expression assay showed that TG directly binds to the promoters of three aquaporin genes, such as AtTIP1;1, AtTIP2;3, and AtPIP2;2, indicating that TG directly regulates the expression of these genes. Moreover, overexpression of AtTIP1;1 resulted in vitrified phenotypes in transgenic Arabidopsis plants, similar to those observed in TG overexpression lines. Water injection into wild-type leaves recapitulated the vitrified leaf phenotypes, which was reversed by cutting off the water supply from vascular bundles. Taken together, our data support that TG controls water balance in Arabidopsis through directly activating the expression of aquaporin genes.
authors.affiliation: a State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Danling
authors.initials: D
authors.lastname: Zhu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wu
authors.forename: Guangyu
authors.initials: G
authors.lastname: Cao
authors.forename: Jigang
authors.initials: J
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Wei
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Tsuge
authors.forename: Hongya
authors.initials: H
authors.lastname: Gu
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoyama
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Qu
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; D014157:Transcription Factors
keywords: AP2/EREBP; TRANSLUCENT GREEN; aquaporin.; transcriptional regulation; vitrified leaf