Abstract
BackgroundPlant root apex is the major part to direct the root growth and development by responding to various signals/cues from internal and soil environments. To study and understand root system biology particularly at a molecular and cellular level, an Arabidopsis T-DNA insertional enhancer trap line J3411 expressing reporters (GFP) only in the root tip was adopted in this study to isolate a DNA fragment.ResultsUsing nested PCR, DNA sequencing and sequence homology search, the T-DNA insertion site(s) and its flanking genes were characterised in J3411 line. Subsequently, a 2000 bp plant DNA-fragment (Ertip1) upstream of the insert position of the coding T-DNA was in silico analysed, revealing certain putative promoter/enhancer cis-regulatory elements. Cloning and transformation of this DNA fragment and its truncated segments tagged with or without 35S minimal promoter (35Smini), all of which were fused with a GFP or GUS reporter, allowed to detect GFP and GUS expression mediated only by Ertip1 + 35mini (PErtip1+35Smini) specifically in the Arabidopsis root tip region. The PErtip1+35Smini activity was further tested to be strong and stable under many different growth conditions but suppressed by cold, salt, alkaline pH and higher ammonium and phosphorus.ConclusionThis work describes a promising strategy to isolate a tissue-/cell-specific enhancer sequence from the enhancer trap lines, which are publically available. The reported synthetic promoter i.e. PErtip1+35Smini may provide a valuable and potent molecular-tool for comprehensive investigation of a gene function related to root growth and development as well as molecular engineering of root-architectural formation aiming to improve plant growth.
Highlights
Plant root apex is the major part to direct the root growth and development by responding to vari‐ ous signals/cues from internal and soil environments
Identification of a genomic region involved in green fluorescent protein (GFP) specific‐expression in the root apex of an enhancer trap line To isolate a putative root tip-specific promoter or enhancer, we inspected T-DNA-containing GAL4VP16/GAL4 upstream activation sequence (UAS)-GFP enhancer trap plants in the “Haseloff ” database and obtained a valuable line (i.e. J3411), where GAL4-dependent GFP occurrence is restricted to the root tip area
Surveying gene expression patterns in public microarray databases [34] revealed that among the above four genes, only At2g36380 was highly transcribed in root tissues during plant development (Fig. 1b). Such data proposes that the 4258 bp intergenic sequence might contain a promoter and/or enhancer region to regulate the expression of both GAL4/GFP and At2g36380 in the root tip/apex
Summary
Plant root apex is the major part to direct the root growth and development by responding to vari‐ ous signals/cues from internal and soil environments. Zhang et al Plant Methods (2019) 15:8 of phosphorus and magnesium on the development of root system morphology was observed in Arabidopsis via auxin signaling, which regulates the elongation and directional growth of the primary root [5]. A study with Arabidopsis showed that the treatment with 5 mM K NO3 could inhibit the primary root growth by 30–100% in 3 days, depending on an effect associated with a significant increase in auxin concentration at the root apex [7]. Medici et al [8] described that a reasonable molecular gate integrating phosphate (Pi)- and NO3−-signalling via AtNIGT1/HRS1 actions might exist at the Arabidopsis root apex, regulating the response of root system growth to environmental Pi and NO3−. Physiological and molecular determinants necessary for the architectural formation of root system, directed by the root apex in response to varied environment cues, are largely unknown
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
