Phloem loading is the first step in sucrose transport from source leaves to sink organs. The phloem loading strategy in rice remains unclear. To determine the potential phloem loading mechanism in rice, yeast invertase (INV) was overexpressed by a 35S promoter specifically in the cell wall to block sugar transmembrane loading in rice. The transgenic lines exhibited obvious phloem loading suppression characteristics accompanied by the accumulation of sucrose and starch, restricted vegetative growth and decreased grain yields. The decreased sucrose exudation rate with p-chloromercuribenzenesulfonic acid (PCMBS) treatment also indicated that rice actively transported sucrose into the phloem. OsSUT1 (SUCROSE TRANSPORTER 1) showed the highest mRNA levels of the plasma membrane-localized OsSUTs in source leaves. Cross sections of the OsSUT::GUS transgenic plants showed that the expression of OsSUT1 and OsSUT5 occurred in the phloem companion cells. Rice ossut1 mutants showed reduced growth and grain yield, supporting the hypothesis of OsSUT1 acting in phloem loading. Based on these results, we conclude that apoplastic phloem loading plays a major role in the export of sugar from rice leaves.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1093/jxb/erab085 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Excess glucose inhibits the cotyledon greening of etiolated seedlings.
Plant Signal Behav
December 2024
School of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
The capability of the transition from skotomorphogenesis-to-photomorphogenesis (de-etiolation) is requisite for seedling survival and development. However, how carbohydrate in germinating seeds controls seedling de-etiolation remains unclear. Mu et al.
View Article and Find Full Text PDFFast and simple fluorometric measurement of phloem loading exposes auxin-dependent regulation of Arabidopsis sucrose transporter AtSUC2.
Plant J
December 2024
College of Life Sciences, Northwest A&F University, 712100, Yangling, China.
Article Synopsis
- * Researchers developed a new method using the fluorescent molecule esculin to measure sucrose phloem loading rates, showing its effectiveness in dicot plants.
- * The findings connect phytohormones like auxin and cytokinin to changes in phloem loading, revealing the underlying genetic mechanisms and offering a faster, simpler alternative to existing measurement techniques.
Foliar-applied zinc promotes cadmium allocation from leaf surfaces to grains in rice.
J Environ Sci (China)
May 2025
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China. Electronic address:
Article Synopsis
- The accumulation of cadmium (Cd) in rice is a health risk, but using foliar zinc (Zn) fertilizer can reduce Cd levels in grains grown in contaminated soils.
- High levels of applied Zn can enhance the transport of Cd to the grains by affecting its movement in the plant, due to reduced retention of Cd in leaf cells and increased desorption from leaf walls.
- Researchers found that while Zn helps with Cd allocation in rice, using it in areas with high atmospheric Cd could lead to unintended grain contamination, so caution is recommended.
Potassium extrusion by plant cells: evolution from an emergency valve to a driver of long-distance transport.
New Phytol
January 2025
Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, D-97082, Würzburg, Germany.
The ability to accumulate nutrients is a hallmark for living creatures and plants evolved highly effective nutrient transport systems, especially for the uptake of potassium (K). However, plants also developed mechanisms that enable the rapid extrusion of K in combination with anions. The combined release of K and anions is probably an ancient extrusion system, as it is found in the Characeae that are closely related to land plants.
View Article and Find Full Text PDFRelieving the transfusion tissue traffic jam: a network model of radial transport in conifer needles.
New Phytol
December 2024
Department of Physics, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
Characteristic of all conifer needles, the transfusion tissue mediates the radial transport of water and sugar between the endodermis and axial vasculature. Physical constraints imposed by the needle's linear geometry introduce two potential extravascular bottlenecks where the opposition of sugar and water flows may frustrate sugar export: one at the vascular access point and the other at the endodermis. We developed a network model of the transfusion tissue to explore how its structure and composition affect the delivery of sugars to the axial phloem.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!