Universität zu Köln

Radchuk, Volodymyr, Riewe, David, Peukert, Manuela ORCID: 0000-0003-1781-7722, Matros, Andrea ORCID: 0000-0002-4399-6149, Strickert, Marc, Radchuk, Ruslana ORCID: 0000-0001-8994-040X, Weier, Diana, Steinbiss, Hans-Henning, Sreenivasulu, Nese ORCID: 0000-0002-3998-038X, Weschke, Winfriede and Weber, Hans (2017). Down-regulation of the sucrose transporters HvSUT1 and HvSUT2 affects sucrose homeostasis along its delivery path in barley grains. J. Exp. Bot., 68 (16). S. 4595 - 4613. OXFORD: OXFORD UNIV PRESS. ISSN 1460-2431

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Abstract

Sucrose transport and partitioning are crucial for seed filling. While many plasma-membrane-localised sucrose transporters (SUT1 family members) have been analysed in seeds, the functions of vacuolar SUT2 members are still obscure. In barley grains, expression of HvSUT1 and HvSUT2 overlap temporally and spatially, suggesting concerted functions to regulate sucrose homeostasis. Using HvSUT2-RNAi plants, we found that grains were also deficient in HvSUT1 expression and seemingly sucrose-limited during mid-to-late grain filling. Transgenic endosperms accumulated less starch and dry weight, although overall sucrose and hexose contents were higher. Comprehensive transcript and metabolite profiling revealed that genes related to glycolysis, the tricarboxylic acid cycle, starch and amino acid synthesis, grain maturation, and abscisic acid signalling were down-regulated together with most glycolytic intermediates and amino acids. Sucrose was increased along the sucrose delivery route in the nucellar projection, the endosperm transfer cells, and the starchy endosperm, indicating that suppressed transporter activity diminished sucrose efflux from vacuoles, which generated sugar deficiency in the cytoplasm. Thus, endosperm vacuoles may buffer sucrose concentrations to regulate homeostasis at grain filling. Transcriptional changes revealed that limited endosperm sucrose initiated sugar starvation responses, such as sugar recycling from starch, hemicelluloses and celluloses together with vacuolar protein degradation, thereby supporting formation of nucleotide sugars. Barley endosperm cells can thus suppress certain pathways to retrieve resources to maintain essential cell functions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Radchuk, Volodymyr UNSPECIFIED UNSPECIFIED UNSPECIFIED Riewe, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Peukert, Manuela UNSPECIFIED orcid.org/0000-0003-1781-7722 UNSPECIFIED Matros, Andrea UNSPECIFIED orcid.org/0000-0002-4399-6149 UNSPECIFIED Strickert, Marc UNSPECIFIED UNSPECIFIED UNSPECIFIED Radchuk, Ruslana UNSPECIFIED orcid.org/0000-0001-8994-040X UNSPECIFIED Weier, Diana UNSPECIFIED UNSPECIFIED UNSPECIFIED Steinbiss, Hans-Henning UNSPECIFIED UNSPECIFIED UNSPECIFIED Sreenivasulu, Nese UNSPECIFIED orcid.org/0000-0002-3998-038X UNSPECIFIED Weschke, Winfriede UNSPECIFIED UNSPECIFIED UNSPECIFIED Weber, Hans UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-224813
DOI:	10.1093/jxb/erx266
Journal or Publication Title:	J. Exp. Bot.
Volume:	68
Number:	16
Page Range:	S. 4595 - 4613
Date:	2017
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1460-2431
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ENDOSPERM TRANSFER CELLS; SEED DEVELOPMENT; MOLECULAR CHARACTERIZATION; ARABIDOPSIS-THALIANA; TONOPLAST; SUGAR; RICE; GENE; METABOLISM; EXPRESSION Multiple languages Plant Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22481