A Comprehensive Tool Set for Inducible, Cell Type-Specific Gene Expression in Arabidopsis

Abstract

Understanding the context-specific role of gene function is a key objective of modern biology. To this end, we generated a resource for inducible cell-type specific trans-activation based on the well-established combination of the chimeric GR-LhG4 transcription factor and the synthetic pOp promoter. Harnessing the flexibility of the GreenGate cloning system, we produced a comprehensive set of GR-LhG4 driver lines targeting most tissues in the Arabidopsis shoot and root with a strong focus on the indeterminate meristems. We show that, when combined with effectors under control of the pOp promoter, tight temporal and spatial control of gene expression is achieved. In particular, inducible expression in F1 plants obtained from crosses of driver and effector lines allows rapid assessment of the cell type-specific impact of an effector with high temporal resolution. Thus, our comprehensive and flexible toolbox is suited to overcome the limitations of ubiquitous genetic approaches, the outputs of which are often difficult to interpret due to widespread existence of compensatory mechanisms and the integration of diverging effects in different cell types.One sentence summary: A set of lines enabling spatio-temporal control of gene expression in Arabidopsis.

Universal Methods for Transgene Induction Using the Dexamethasone‐Inducible Transcription Activation System pOp6/LhGR in Arabidopsis and Other Plant Species

“…Recently, a comprehensive tool set of inducible activator/driver lines targeting most cell types in Arabidopsis , with the focus on the three main meristems (RAM, SAM and the cambium), was created by Schurholz et al. ().…”

Expansin-controlled cell wall stiffness regulates root growth inArabidopsis

“…Promoter analysis of EXPA10, EXPA14 and EXPA15 identifies ChIP-seq derived binding events for transcription factors (type-B ARABIDOPSIS RESPONSE REGULATORS, ARRs) involved in the cytokinin signalling pathway. Red, blue and green colours depict the peaks from Xie et al, 2018, Zubo et al, 2017and O'Malley et al, 2016 (A) Double hemizygous F1 progeny of a cross between pEXPA14::EXPA14:mCherry and endodermis-specific pSCR>GR>mTurquoise2 (Schurholz et al, 2018). In the transversal (xz) optical section of a primary root, the EXPA14 (red) localizes to cortex, endodermis and background autofluorescence in epidermis is in green.…”

“…In the transversal (xz) optical section of a primary root, the EXPA14 (red) localizes to cortex, endodermis and background autofluorescence in epidermis is in green. (B) Double hemizygous F1 progeny of a cross between pEXPA15::EXPA15:mCherry and phloem-specific pSMXL5>GR>mTurquoise2 (Schurholz et al, 2018)In the z-stack projection of an emerging lateral root EXPA15 (red) localizes to the CW of epidermis, phloem is in green. The 7-day old Arabidopsis seedlings were grown on MS media +Dex to induce the mTurquoise2 ER-specific expression.…”

The stem cell-type transcriptome of bioenergy sorghum reveals the spatial regulation of secondary cell wall networks

“…For example, the homolog of the Arabidopsis thaliana LIPID TRANSFER PROTEIN 1 (AT2G38540, LTP1) that is expressed in epidermal cells (Thoma et al, 1994;Abe et al, 2001;Baroux et al, 2001) is expressed in LCM-derived sorghum stem epidermal cells (Supplemental Data Set 2). Similarly, ALTERED PHLOEM DEVELOPMENT (AT1G79430, APL) that is expressed in Arabidopsis inflorescence stem phloem cells (Abe et al, 2015;Schürholz et al, 2018) and MYB DOMAIN PROTEIN 103 (AT1G63910, AtMYB103) and SULFATE TRANSPORTER 1;2 (AT1G78000, SULTR1;2), genes that are expressed in xylem cells (Zhong et al, 2008), are differentially expressed in the corresponding LCM-derived sorghum stem cell types (Supplemental Data Set 2). No definitive marker gene has been reported for stem pith parenchyma cells (Shi et al, 2021); however, 66 genes with the pith-preferred expression pattern identified in a LCM study of the inflorescence stem in Arabidopsis (Shi et al, 2021) are expressed in a highly specific manner in sorghum stem pith parenchyma cells (Supplemental Data Set 2).…”