The Transport of Sugars in Developing Fruits of Satsuma Mandarin

García-Luis, Amparo; Didehvar, F.; Guardiola, J. L.; Baker, D. A.

doi:10.1093/oxfordjournals.aob.a088263

Cited by 10 publications

(8 citation statements)

References 12 publications

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“…There was no sucrose uptake in vesicles treated with ATP plus gramicidin (data not shown), eliminating the possibility of a direct ATP-energized sucrose transport system. These results are in accordance with the presence of an electrogenic sucrose carrier at the plasmalemma of citrus juice cells (Garcia-Luis et al, 1991), which mediates transport of sucrose and H + from the apoplast into the cytosol. To our knowledge, this is the fi rst direct demonstration of a sucrose symport at the plasmalemma of storage cells, and further supports the presence of an apoplasmic system of post-phloem transport in citrus fruit (Koch and Avigne, 1990).…”

Section: Resultssupporting

confidence: 86%

Sucrose Transport into Citrus Juice Cells: Evidence for an Endocytic Transport System

Etxeberria¹,

González²,

Pozueta‐Romero³

2005

jashs

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To investigate the mechanisms of sucrose transport and its accumulation into `Murcott' mandarin (Citrus reticulata Blanco) fruit, developmental changes in determinants of sink strength such as sucrose metabolizing enzymes, and sucrose transport across both plasmalemma and tonoplast were analyzed. Concurrently with sucrose levels, sucrose synthase, sucrose phosphate synthase and sucrose phosphate phosphatase increased throughout fruit development. Plasmalemma and tonoplast vesicles isolated from fruit collected at different developmental stages were analyzed for their transport capabilities. Sucrose uptake into energized plasmalemma vesicles was abolished by gramicidin, which is in accordance with the presence of an active symport mechanism of sucrose transport from the apoplast into the cytosol. Unexpectedly, tonoplast vesicles were shown to lack active transport mechanism of sucrose into the vacuole. More importantly, however, and in conformity with recent findings showing the occurrence of an endocytic mechanism of ion uptake in maize (Zea mays L.) root cells, citrus (Citrus L.) juice cells were shown to incorporate membrane impermeable dyes into their vacuoles in the presence of sucrose. High definition confocal microscopy revealed the co-localization of membrane impermeable markers in cytoplasmic vesicles and the formation of vesicles at the plasmalemma. The data provide evidence for an endocytic system of transport that allows direct incorporation of sucrose from the apoplast to the vacuole bypassing both the plasmalemma and tonoplast.

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Section: Resultssupporting

confidence: 86%

Sucrose Transport into Citrus Juice Cells: Evidence for an Endocytic Transport System

Etxeberria¹,

González²,

Pozueta‐Romero³

2005

jashs

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“…One gene EY748567 shows high homology with sugar transporter gene (67% similarity), suggesting that sugar translocation is active in 170 DAF stage. This is consistent with the above mentioned result that photosynthesis are active, and thus the produced sugar has to be transported to juice sac through phloem in citrus [52]. Our physiological data also showed that the stage 170 DAF is also the most important stage for sugar accumulation (data unpublished).…”

Section: Disscussionsupporting

confidence: 92%

Comparative transcripts profiling reveals new insight into molecular processes regulating lycopene accumulation in a sweet orange (Citrus sinensis) red-flesh mutant

Zhu

et al. 2009

BMC Genomics

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BackgroundInterest in lycopene metabolism and regulation is growing rapidly because accumulative studies have suggested an important role for lycopene in human health promotion. However, little is known about the molecular processes regulating lycopene accumulation in fruits other than tomato so far.ResultsOn a spontaneous sweet orange bud mutant with abnormal lycopene accumulation in fruits and its wild type, comparative transcripts profiling was performed using Massively Parallel Signature Sequencing (MPSS). A total of 6,877,027 and 6,275,309 reliable signatures were obtained for the wild type (WT) and the mutant (MT), respectively. Interpretation of the MPSS signatures revealed that the total number of transcribed gene in MT is 18,106, larger than that in WT 17,670, suggesting that newly initiated transcription occurs in the MT. Further comparison of the transcripts abundance between MT and WT revealed that 3,738 genes show more than two fold expression difference, and 582 genes are up- or down-regulated at 0.05% significance level by more than three fold difference. Functional assignments of the differentially expressed genes indicated that 26 reliable metabolic pathways are altered in the mutant; the most noticeable ones are carotenoid biosynthesis, photosynthesis, and citrate cycle. These data suggest that enhanced photosynthesis and partial impairment of lycopene downstream flux are critical for the formation of lycopene accumulation trait in the mutant.ConclusionThis study provided a global picture of the gene expression changes in a sweet orange red-flesh mutant as compared to the wild type. Interpretation of the differentially expressed genes revealed new insight into the molecular processes regulating lycopene accumulation in the sweet orange red-flesh mutant.

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“…Our results indicate that in juice sacs from mature grapefruit fruit the uptake of sucrose into the cells is insaturable in vitro. Garcia-Luis et al (1991) also reported that in albedo (the white portion of the peel) and juice sacs of developing 'Satsuma' mandarin sucrose uptake was insaturable up to 300 mM The authors concluded that the uptake was almost entirely metabolically independent, and thus passive, or that the metabolic inhibitors p-chloromercuribenzene sulphonic acid (PCMBS), dinitrophenol (DNP), erythrosine and vanadate were unable to reach the site of any active accumulation. In contrast, the uptake of sucrose moieties, fructose and glucose, into the juice sacs of grapefruit fruit were insaturable, and occur mostly by a µH + -independent process, which was affected by metabolic inhibitors.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the relatively high concentration of soluble sugars Abbreviations used: CCCP, carbonylcyanide m-chlorophenylhydrazone; DNP, dinitrophenol; PCMBS, p-chloromercuribenzene sulphonic acid; TCA, tricarboxylic acid. stored in the vacuole of juice cells (Echeverria and Valich 1988;Echeverria and Burns 1989;Garcia-Luis et al 1991), the less abundant organic acids have been considered as both the primary energy and the carbon source during later stages of fruit development. Murata (1977), who studied [1,5-14 C]citric acid metabolism in 'Satsuma' mandarin fruit segments during storage, found that citric acid was rapidly respired as 14 CO 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Post-phloem transport of photoassimilates into Citrus fruits is believed to occur thorough the apoplast (Koch 1984;Garcia-Luis et al 1991) and with apparently very little sucrose inversion (Koch and Avingne 1990). From the apoplast, sugars are transported into the juice-sac cells to support an entire array of metabolic activities and, during later stages of development, accumulation into the large central vacuole.…”

Section: Introductionmentioning

confidence: 99%

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In vitro sugar uptake by grapefruit (Citrus paradisi) juice-sac cells

Huberman

Zehavi

Stein

et al. 2005

Functional Plant Biol.

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To further our understanding of the mechanisms of sugar uptake and accumulation into grapefruit (Citrus paradisi Macf. cv. Marsh seedless), the patterns of uptake and utilisation of sucrose, glucose and fructose by Citrus juice cells was investigated. Analyses were conducted on sliced juice sacs that were incubated in radioactive [14C]-sugar solutions with unlabelled sugars, in the presence or absence of metabolic inhibitors. Both hexoses demonstrated an initial uptake peak in December and a second uptake peak in February–March. From March through April the rates of sucrose uptake increased to levels comparable to those of glucose and fructose. Sucrose and its moieties fructose and glucose entered the juice cells of Citrus juice fruit by an insaturable, and mostly by an independent, process. However, NaN3 and carbonylcyanide m-chlorophenylhydrazone (CCCP) produced slight inhibition of these processes. Cells took up hexoses at a greater rate than sucrose, with accumulation reaching a plateau by 4–8 h, and then continuing unabated, in the case of glucose, for 42 h. Uptake of all three sugars increased linearly in the range of sugar concentrations tested, which extended from 0.01 to 320 mm, denoting an insaturable system for sugar uptake. 14CO2 evolution was relatively low in all the experiments, the lowest evolution being recorded when the uptake of [14C]-sucrose was studied, while the highest 14CO2 evolution was recorded when the uptake of [14C]-glucose was studied. The data demonstrate a preferential utilisation of glucose over fructose and sucrose. In all the experiments, the two metabolic inhibitors significantly inhibited the decarboxylation of the three sugars.

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The Transport of Sugars in Developing Fruits of Satsuma Mandarin

Cited by 10 publications

References 12 publications

Sucrose Transport into Citrus Juice Cells: Evidence for an Endocytic Transport System

Sucrose Transport into Citrus Juice Cells: Evidence for an Endocytic Transport System

Comparative transcripts profiling reveals new insight into molecular processes regulating lycopene accumulation in a sweet orange (Citrus sinensis) red-flesh mutant

In vitro sugar uptake by grapefruit (Citrus paradisi) juice-sac cells

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