Vernalization alters sink and source identities and reverses phloem translocation from taproots to shoots in sugar beet

Rodrigues CM, Müdsam C, Keller I, Zierer W, Czarnecki O, Corral JM, Reinhardt F, Nieberl P, Fiedler-Wiechers K, Sommer F, Schroda M, Mühlhaus T, Harms K, Flügge UI, Sonnewald U, Koch W, Ludewig F, Ekkehard Neuhaus H, Pommerrenig B (2020)

Publication Type: Journal article

Publication year: 2020

Journal

The Plant Cell American Society of Plant Biologists

Book Volume: 32

Pages Range: 3206-3223

Journal Issue: 10

DOI: 10.1105/tpc.20.00072

Abstract

During their first year of growth, overwintering biennial plants transport Suc through the phloem from photosynthetic source tissues to storage tissues. In their second year, they mobilize carbon from these storage tissues to fuel new growth and reproduction. However, both the mechanisms driving this shift and the link to reproductive growth remain unclear. During vegetative growth, biennial sugar beet (Beta vulgaris) maintains a steep Suc concentration gradient between the shoot (source) and the taproot (sink). To shift from vegetative to generative growth, they require a chilling phase known as vernalization. We studied sugar beet sink-source dynamics upon vernalization and showed that before flowering, the taproot underwent a reversal from a sink to a source of carbohydrates. This transition was induced by transcriptomic and functional reprogramming of sugar beet tissue, resulting in a reversal of flux direction in the phloem. In this transition, the vacuolar Suc importers and exporters TONOPLAST SUGAR TRANSPORTER2;1 and SUCROSE TRANSPORTER4 were oppositely regulated, leading to the mobilization of sugars from taproot storage vacuoles. Concomitant changes in the expression of floral regulator genes suggest that these processes are a prerequisite for bolting. Our data will help both to dissect the metabolic and developmental triggers for bolting and to identify potential targets for genome editing and breeding.

Authors with CRIS profile

Christina Müdsam Lehrstuhl für Biochemie Wolfgang Zierer Lehrstuhl für Biochemie Uwe Sonnewald Lehrstuhl für Biochemie

Involved external institutions

Technische Universität Kaiserslautern DE Germany (DE) Cluster of Excellence on Plant Sciences (CEPLAS) DE Germany (DE) Südzucker AG DE Germany (DE)

How to cite

APA:

Rodrigues, C.M., Müdsam, C., Keller, I., Zierer, W., Czarnecki, O., Corral, J.M.,... Pommerrenig, B. (2020). Vernalization alters sink and source identities and reverses phloem translocation from taproots to shoots in sugar beet. The Plant Cell, 32(10), 3206-3223. https://doi.org/10.1105/tpc.20.00072

MLA:

Rodrigues, Cristina Martins, et al. "Vernalization alters sink and source identities and reverses phloem translocation from taproots to shoots in sugar beet." The Plant Cell 32.10 (2020): 3206-3223.

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