Video Experimental Relacionado
Updated: May 26, 2026
04:32
An Induction System for Clustered Stomata by Sugar Solution Immersion Treatment in Arabidopsis thaliana Seedlings
Published on: February 15, 2019
El eflujo de sacarosa mediado por las proteínas SWEET como un paso clave para el transporte de floema
Li-Qing Chen1, Xiao-Qing Qu, Bi-Huei Hou
1Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA.
Science (New York, N.Y.)
|December 14, 2011
Resumen
Los investigadores descubrieron que los transportadores de eflujo de sacarosa dulce son cruciales para mover los azúcares del mesófilo a las células del floema. Esto identifica un paso clave en el transporte de azúcar vegetal y la carga de floema.
Área de la Ciencia:
- Biología Vegetal Biología Vegetal Biología Vegetal
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Las plantas transportan carbono fijo principalmente en forma de sacarosa, sintetizado en las células mesofílicas y trasladado al floema para su distribución.
- El mecanismo preciso del movimiento de la sacarosa desde los sitios de síntesis hasta el floema, y las células que median el eflujo hacia el apoplasma, sigue sin estar claro.
- El eflujo de sacarosa es un requisito previo para la carga de floema por parte de los cotransportadores (SUT) de sacarosa-H(+) (protones).
Objetivo del estudio:
- Para dilucidar el mecanismo de transporte de la sacarosa desde las células del mesófilo hasta el floema.
- Para identificar los transportadores específicos involucrados en el eflujo de sacarosa en el apoplasma.
- Comprender el papel de los transportadores identificados en la carga del floema.
Principales métodos:
- Utilizó sensores ópticos de sacarosa para monitorear el movimiento de la sacarosa.
- Plantas mutantes generadas con inserciones en genes SWEET específicos (AtSWEET11 y 12).
- Analizó la localización y la función de AtSWEET11 y 12 en la carga de floema.
Principales resultados:
- Se identificó una subfamilia de transportadores de eflujo de sacarosa SWEET.
- AtSWEET11 y 12 se localizaron en la membrana plasmática de las células del floema.
- Las plantas mutantes que carecen de funciones AtSWEET11 y 12 exhibieron defectos en la carga del floema.
- Se reveló un mecanismo de dos pasos: la exportación mediada por SWEET de células de parénquima seguida de la importación acoplada con H(+) en el complejo de células de elemento de tamiz-compañero.
Conclusiones:
- Los transportadores de DULCE desempeñan un papel crítico en el eflujo de sacarosa de las células del parénquima, facilitando la carga de floema.
- Este descubrimiento aclara un paso significativo en el transporte de larga distancia de carbono fotosintético en las plantas.
- Restringir el transporte intercelular de sacarosa puede limitar la disponibilidad de carbono apoplasmático, lo que podría prevenir las infecciones por patógenos.
Videos de Conceptos Relacionados
02:02Phloem and Sugar Transport
Like many living organisms, plants have tissues that specialize in specific plant functions. For example, shoots are well adapted to rapid growth, while roots are structured to acquire resources efficiently. However, sugar production is primarily restricted to the photosynthetic cells that reside in the leaves of angiosperm plants. Sugar and other resources are transported from photosynthetic tissues to other specialized tissues by a process called translocation.
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:55Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:30Membrane Proteins
Plasma membranes have integral transmembrane proteins involved in facilitated transport. These proteins are collectively referred to as transport proteins, and they function as either channels for the material or as carriers themselves. Channel proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and a hydrophilic channel through their core that provides a hydrated opening for solutes to pass through the membrane layers. Passage through the channel allows...
01:27Glucose Transporters
Glucose transporters facilitate the transport of glucose across the cell membrane. In addition to glucose, some glucose transporters can also aid the movement of other hexoses such as fructose, mannose, and galactose.
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes: