Phloem Mobility and Stability of Sucrose Transporter Transcripts

He, Hongqing; Chincinska, Izabela Anna; Hackel, Aleksandra; Grimm, Bernhard; Kühn, Christina

doi:10.2174/1874294700801010001

Cited by 15 publications

(21 citation statements)

References 37 publications

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“…Indeed, experiments in potato have demonstrated the potential for the regulation of SUT activity through differential intracellular localization of SUT1 (Liesche et al, 2010), as well as through dimerization and mRNA stability (He et al, 2008). The existence of posttranslational control of SUT activity has also been shown in Arabidopsis, where the amount of AtSUC2 protein was found to not correlate with Suc transport rate (Sakr et al, 1997).…”

Section: Sut Expression Does Not Always Correspond To Phloem Loadingmentioning

confidence: 99%

Regulation of Sucrose Transporters and Phloem Loading in Response to Environmental Cues

et al. 2017

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Suc transporters (SUTs) play a key role in the allocation and partitioning of photosynthetically fixed carbon in plants. While a function could be assigned to many members of the SUT family, almost no information is available on their regulation. Here, the transcriptional regulation of SUTs in response to various environmental stimuli in the leaves of five dicots (Arabidopsis Extensive data on expression of SUTs in relation to changes of environmental conditions were obtained through a global analysis of 168 transcriptomics data sets. Results were validated by quantitative PCR measurements and extended by the measurement of photosynthesis rate and phloem sugar content to draw insight on the correlation of SUT expression and sugar export from leaves. For the apoplasmic phloem loaders, a clear difference in transcriptional regulation in response to different environmental stimuli was observed. The consistent patterns of SUT expression under abiotic stress indicates which types of SUTs are involved in the regulation of leaf sugar status and in stress signaling. Furthermore, it is shown that down-regulation of phloem loading is likely to be caused by transcriptional regulation of SUTs, while up-regulation depends on post-transcriptional regulation. In poplar, expression of PtaSUT4 was found to consistently respond to environmental stimuli, suggesting a significant role in the regulation of sugar export from leaves in this passive symplasmic phloem loader.

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Section: Sut Expression Does Not Always Correspond To Phloem Loadingmentioning

confidence: 99%

Regulation of Sucrose Transporters and Phloem Loading in Response to Environmental Cues

et al. 2017

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“…The application of synthetic auxin induced potato sucrose transporter StSUT1 (84% similarity to NtSUT1-L) within a few hours at transcriptional (Harms et al 1994) and translational (He et al 2008) levels. The omission of 2,4-D from the culture medium triggered several changes, such as starch accumulation, cessation of cell proliferation and cell elongation, while the application of auxin promoted cell elongation in BY-2 tobacco cells (Miyazawa et al 1999).…”

Section: Expression Of Ntsut1 Is Auxin-dependentmentioning

confidence: 99%

“…The expression of sucrose transporter genes has been reported to be, in addition to auxin, regulated by another class of phytohormones, cytokinins (Harms et al 1994;He et al 2008). Some variations in response to phytohormones have been reported among SUT1's of different plant origins.…”

Section: Expression Of Ntsut1 Is Auxin-dependentmentioning

confidence: 99%

Sucrose transporter NtSUT1 confers aluminum tolerance on cultured cells of tobacco (Nicotiana tabacumL.)

Sameeullah

Sasaki

Yamamoto

2013

Soil Science and Plant Nutrition

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The role of plasma membrane-localized sucrose transporter (NtSUT1) was investigated using cultured tobacco cell (Nicotiana tabacum L.) line BY-2. The wild type (WT) cells were first transformed with the NtSUT1 gene or its fragments cloned from tobacco cell line SL to form the over-expression (OX) and suppression (RNAi) cell lines, respectively. Using OX and RNAi transgenics, the role of NtSUT1 in growth capacity of actively growing cells and in aluminum (Al)-treated cells was examined. During the logarithmic phase of growth in nutrient medium containing 2,4-dichlorophenoxyacetic acid (2,4-D), both the rate of sucrose uptake measured with radio-tracer and the content of soluble sugars were higher in OX and lower in RNAi cell lines compared to WT. Overall, the content of soluble sugars negatively correlated with the time necessary for doubling mass (fresh weight). When cells were treated without (control) or with Al in a simple medium containing calcium, sucrose and 2-(N-morpholino)ethanesulfonic acid (MES; pH 5.0) for up to 18 h, the expression of NtSUT1 under its native promoter, or under the control of strong constitutive cauliflower mosaic virus (CaMV) 35S promoter, was strongly dependent on the presence of 2,4-D. Thereafter, the cells were preferentially treated in the presence of 2,4-D. During 6 h after a start of the control treatment, sucrose uptake rates were, compared to WT, slightly higher and lower in OX and RNAi lines respectively. The addition of Al reduced the sucrose uptake rates of OX and WT to the level of RNAi line, indicating that Al inhibits sucrose uptake via NtSUT1. During the post-Al culture of control and Al-treated cells in a nutrient medium, sucrose uptake rates were much higher in OX compared to WT and RNAi lines, which closely and positively correlated with the growth capacity of the cells. Judging from the growth capacity of Al-treated cells relative to that of control cells, OX cells were more tolerant to Al than WT and RNAi. In summary, we conclude that over-expression of NtSUT1 confers higher growth capacity in actively growing cells as well as in Al-treated cells.

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“…Simultaneous incubation of infiltrated leaves with brefeldin A along with cycloheximide to inhibit de novo protein biosynthesis for 2 h leads to internal vesicle formation ( Figure 5H). The half-life of the St SUT1 protein is very short (Kü hn et al, 1997;He et al, 2008). Therefore, vesicles detected under these conditions are most likely due to endocytic events, rather than to inhibited vesicle fusion to the PM.…”

Section: St Sut1 Targeting In Plantsmentioning

confidence: 99%

Transport and Sorting of the Solanum tuberosum Sucrose Transporter SUT1 Is Affected by Posttranslational Modification

et al. 2008

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The plant sucrose transporter SUT1 from Solanum tuberosum revealed a dramatic redox-dependent increase in sucrose transport activity when heterologously expressed in Saccharomyces cerevisiae. Plant plasma membrane vesicles do not show any change in proton flux across the plasma membrane in the presence of redox reagents, indicating a SUT1-specific effect of redox reagents. Redox-dependent sucrose transport activity was confirmed electrophysiologically in Xenopus laevis oocytes with SUT1 from maize (Zea mays). Localization studies of green fluorescent protein fusion constructs showed that an oxidative environment increased the targeting of SUT1 to the plasma membrane where the protein concentrates in 200-to 300-nm raft-like microdomains. Using plant plasma membranes, St SUT1 can be detected in the detergent-resistant membrane fraction. Importantly, in yeast and in plants, oxidative reagents induced a shift in the monomer to dimer equilibrium of the St SUT1 protein and increased the fraction of dimer. Biochemical methods confirmed the capacity of SUT1 to form a dimer in plants and yeast cells in a redox-dependent manner. Blue native PAGE, chemical cross-linking, and immunoprecipitation, as well as the analysis of transgenic plants with reduced expression of St SUT1, confirmed the dimerization of St SUT1 and Sl SUT1 (from Solanum lycopersicum) in planta. The ability to form homodimers in plant cells was analyzed by the split yellow fluorescent protein technique in transiently transformed tobacco (Nicotiana tabacum) leaves and protoplasts. Oligomerization seems to be cell type specific since under native-like conditions, a phloem-specific reduction of the dimeric form of the St SUT1 protein was detectable in SUT1 antisense plants, whereas constitutively inhibited antisense plants showed reduction only of the monomeric form. The role of redox control of sucrose transport in plants is discussed.

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Phloem Mobility and Stability of Sucrose Transporter Transcripts

Cited by 15 publications

References 37 publications

Regulation of Sucrose Transporters and Phloem Loading in Response to Environmental Cues

Regulation of Sucrose Transporters and Phloem Loading in Response to Environmental Cues

Sucrose transporter NtSUT1 confers aluminum tolerance on cultured cells of tobacco (Nicotiana tabacumL.)

Transport and Sorting of the Solanum tuberosum Sucrose Transporter SUT1 Is Affected by Posttranslational Modification

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