Physiological basis for enhanced sucrose accumulation in an engineered sugarcane cell line

Wu, Luguang and Birch, Robert G. (2010) Physiological basis for enhanced sucrose accumulation in an engineered sugarcane cell line. Functional Plant Biology, 37 12: 1161-1174. doi:10.1071/FP10055


Author Wu, Luguang
Birch, Robert G.
Title Physiological basis for enhanced sucrose accumulation in an engineered sugarcane cell line
Journal name Functional Plant Biology   Check publisher's open access policy
ISSN 1445-4408
1445-4416
Publication date 2010-11-17
Sub-type Article (original research)
DOI 10.1071/FP10055
Volume 37
Issue 12
Start page 1161
End page 1174
Total pages 14
Place of publication Collingwood, Australia
Publisher C S I R O Publishing
Collection year 2011
Language eng
Formatted abstract
Transgenic sugarcane (Saccharum officinarum L. interspecific hybrids) line N3.2 engineered to express a
vacuole-targeted sucrose isomerase was found to accumulate sucrose to twice the level of the background genotype Q117 in
heterotrophic cell cultures, without adverse effects on cell growth. Isomaltulose levels declined over successive subcultures,
but the enhanced sucrose accumulation was stable. Detailed physiological characterisation revealed multiple processes
altered in line N3.2 in a direction consistent with enhanced sucrose accumulation. Striking differences from the Q117 control
included reduced extracellular invertase activity, slower extracellular sucrose depletion, lower activities of symplastic
sucrose-cleavage enzymes (particularly sucrose synthase breakage activity), and enhanced levels of symplastic hexose-6-
phosphate and trehalose-6-phosphate (T6P) in advance of enhanced sucrose accumulation. Sucrose biosynthesis by sucrose
phosphate synthase (SPS) and sucrose phosphate phosphatase (SPP) was substantially faster in assays conducted to reflect
the elevation in key allosteric metabolite glucose-6-phosphate (G6P). Sucrose-non-fermenting-1-related protein kinase 1
(SnRK1, which typically activates sucrose synthase breakage activity while downregulating SPS in plants) was significantly
lower in line N3.2 during the period of fastest sucrose accumulation. For the first time, T6P is also shown to be a negative
regulator of SnRK1 activity from sugarcane sink cells, hinting at a control circuitry for parallel activation of key enzymes for
enhanced sucrose accumulation in sugarcane. © 2010 CSIRO.
Keyword Invertase
Isomaltulose
Parallel activation
Saccharum
SnRK1
Sucrose isomerase
Sucrose phosphate synthase
Sucrose synthase
Suspension culture
Trehalose-6-phosphate
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Biological Sciences Publications
 
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Created: Sun, 12 Dec 2010, 00:07:29 EST