Fast and simple fluorometric measurement of phloem loading exposes auxin-dependent regulation of Arabidopsis sucrose transporter AtSUC2.

Autor: Ren Y; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China., Zhang Z; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China., Zhanakhmetova D; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China., Li W; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China., Chen S; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China., Werner T; Institute of Biology, University of Graz, 8010 Graz, Austria., Liesche J; College of Life Sciences, Northwest A&F University, 712100, Yangling, China.; Biomass Energy Center for Arid and Semiarid Lands, Northwest A&F University, 712100, Yangling, China.; Institute of Biology, University of Graz, 8010 Graz, Austria.
Jazyk: angličtina
Zdroj: The Plant journal : for cell and molecular biology [Plant J] 2024 Dec; Vol. 120 (5), pp. 2305-2318. Date of Electronic Publication: 2024 Nov 01.
DOI: 10.1111/tpj.17110
Abstrakt: The rate of sucrose export from leaves is a major factor in balancing whole-plant carbon and energy partitioning. A comprehensive study of its dynamics and relationship to photosynthesis, sink demand, and other relevant processes is hampered by the shortcomings of current methods for measuring sucrose phloem loading. We utilize the ability of sucrose transporter proteins, known as SUCs or SUTs, to specifically transport the fluorescent molecule esculin in a novel assay to measure phloem loading rates. Esculin was administered to source leaves and its fluorescence in the leaf extract was measured after 1 or 2 h. Dicot plants with an active phloem loading strategy showed an export-dependent reduction of esculin fluorescence. Relative leaf esculin export rates correlated with leaf export rates of isotopic carbon and phloem exudate sucrose levels. We used esculin experiments to examine the effects of phytohormones on phloem loading in Arabidopsis, showing, for example, that auxin induces phloem loading while cytokinin reduces it. Transcriptional regulation of AtSUC2 by AUXIN RESPONSE FACTOR1 (ARF1) corroborated the link between auxin signaling and phloem loading. Unlike established methods, the esculin assay is rapid and does not require specialized equipment. Potential applications and limitations of the esculin assay are discussed.
(© 2024 The Author(s). The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)
Databáze: MEDLINE
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