Characterization of the Vacuolar Sugar Transporter Early Responsive to Dehydration-Like4 (ERDL4) from Arabidopsis and its Role in Cold and in Dark Induced Senescence

  • Regulation of sucrose transport between source and sink tissues is critical for plant development and properties. In cells, the dynamic vacuolar sugar homeostasis is maintained by the controlled regulation of the activities of sugar importers and exporters residing in the tonoplast. We show here that the EARLY RESPONSE TO DEHYDRATION6-LIKE4 protein, being the closest homolog to the proton/glucose symporter ERDL6, resides in the vacuolar membrane. We raised both, molecular expression and data deriving from non-aqueous fractionation studies indicating that ERDL4 was involved in glucose and fructose allocation across the tonoplast. Surprisingly, overexpression of ERDL4 increased total sugar levels in leaves, which is due to a concomitantly induced stimulation of TST2 expression, coding for the major vacuolar sugar loader. This conclusion is supported by the notion that tst1-2 knockout lines overexpressing ERDL4 lack increased cellular sugar levels. That ERDL4 activity contributes to the coordination of cellular sugar homeostasis is further indicated by two observations. Firstly, ERDL4 and TST genes exhibit an opposite regulation during a diurnal rhythm, secondly, the ERDL4 gene is markedly expressed during cold acclimation representing a situation in which TST activity needs to be upregulated. Moreover, ERDL4-overexpressing plants show larger size of rosettes and roots, a delayed flowering and increased total seed yield. In summary, we identified a novel factor influencing source to sink transfer of sucrose and by this governing plant organ development.

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Author:Azkia Khan
Advisor:Ekkehard Neuhaus
Document Type:Doctoral Thesis
Language of publication:English
Publication Date:2023/03/06
Year of Publication:2023
Publishing Institute:Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
Granting Institute:Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
Acceptance Date of the Thesis:2022/07/14
Date of the Publication (Server):2023/03/06
Number of page:IV, 132
Faculties / Organisational entities:Kaiserslautern - Fachbereich Biologie
DDC-Cassification:5 Naturwissenschaften und Mathematik / 570 Biowissenschaften, Biologie
Licence (German):Creative Commons 4.0 - Namensnennung, nicht kommerziell, keine Bearbeitung (CC BY-NC-ND 4.0)