scholarly journals Functional Characterization of the Arabidopsis AtSUC2 Sucrose/H+ Symporter by Tissue-Specific Complementation Reveals an Essential Role in Phloem Loading But Not in Long-Distance Transport

2008 ◽  
Vol 148 (1) ◽  
pp. 200-211 ◽  
Author(s):  
Avinash C. Srivastava ◽  
Savita Ganesan ◽  
Ihab O. Ismail ◽  
Brian G. Ayre
Keyword(s):  
Essential Role ◽  
Functional Characterization ◽  
Phloem Loading ◽  
Long Distance ◽  
Tissue Specific ◽  
Long Distance Transport ◽  
Distance Transport

scholarly journals A Tobacco Syringe Agroinfiltration-Based Method for a Phytohormone Transporter Activity Assay Using Endogenous Substrates

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiangzhe Zhao ◽  
Min Ju ◽  
Jiayun Qian ◽  
Mengyuan Zhang ◽  
Ting Liu ◽  
...  
Keyword(s):  
Stress Responses ◽  
Large Scale ◽  
Functional Characterization ◽  
Endogenous Hormones ◽  
Activity Assay ◽  
Long Distance ◽  
Multiple Substrates ◽  
Long Distance Transport ◽  
Endogenous Substrates

Phytohormones are a group of small chemical molecules that play vital roles in plant development, metabolism, and stress responses. Phytohormones often have distinct biosynthesis and signaling perception sites, requiring long- or short-distance transportation. Unlike biosynthesis and signal transduction, phytohormone transport across cells and organs is poorly understood. The transporter activity assay is a bottleneck for the functional characterization of novel phytohormone transporters. In the present study, we report a tobacco syringe agroinfiltration and liquid chromatography tandem mass spectrometry (TSAL)-based method for performing a phytohormone transporter activity assay using endogenous hormones present in tobacco (Nicotiana benthamiana) leaves. A transporter activity assay using this method does not require isotope-labeled substrates and can be conveniently performed for screening multiple substrates by using endogenous hormones in tobacco leaves. The transporter activities of three known hormone transporters, namely AtABCG25 for abscisic acid, AtABCG16 for jasmonic acid, and AtPUP14 for cytokinin, were all successfully validated using this method. Using this method, cytokinins were found to be the preferred substrates of an unknown maize (Zea mays) transporter ZmABCG43. ZmABCG43 transporter activities toward cytokinins were confirmed in a cytokinin long-distance transport mutant atabcg14 through gene complementation. Thus, the TSAL method has the potential to be used for basic substrate characterization of novel phytohormone transporters or for the screening of novel transporters for a specific phytohormone on a large scale.

scholarly journals Passive phloem loading and long-distance transport in a synthetic tree-on-a-chip

Nature Plants ◽  
2017 ◽  
Vol 3 (4) ◽  
Author(s):  
Jean Comtet ◽  
Kaare H. Jensen ◽  
Robert Turgeon ◽  
Abraham D. Stroock ◽  
A. E. Hosoi
Keyword(s):  
Phloem Loading ◽  
Long Distance ◽  
Long Distance Transport ◽  
Distance Transport

scholarly journals Constitutive and Companion Cell-Specific Overexpression of AVP1, Encoding a Proton-Pumping Pyrophosphatase, Enhances Biomass Accumulation, Phloem Loading, and Long-Distance Transport

2015 ◽  
Vol 170 (1) ◽  
pp. 401-414 ◽  
Author(s):  
Aswad S. Khadilkar ◽  
Umesh P. Yadav ◽  
Carolina Salazar ◽  
Vladimir Shulaev ◽  
Julio Paez-Valencia ◽  
...  
Keyword(s):  
Biomass Accumulation ◽  
Phloem Loading ◽  
Proton Pumping ◽  
Companion Cell ◽  
Long Distance ◽  
Long Distance Transport ◽  
Distance Transport

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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