Molecular Composition of Plant Vacuoles: Important but Less Understood Regulations and Roles of Tonoplast Lipids

Zhang, Chunhua; Hicks, Glenn R.; Raikhel, Natasha V.

doi:10.3390/plants4020320

Cited by 42 publications

(32 citation statements)

References 74 publications

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“…Vacuoles are the largest organelles, often occupying greater than three quarters of the volume inside the plant cell, and we recognize that they are the cellular location for the storage of metabolic products, including sugars and proteins, as nutrients (Zhang et al 2015). Given the abundance of vacuolar lectins, we point out that they may be essential for the role that the vacuole plays in maintaining turgor, exchange and storage of metabolites, detoxification, as well as homeostasis (Marty 1999).…”

Section: The Vacuole As the Hub Of Glycoregulationmentioning

confidence: 89%

The carbon reactions of photosynthesis: role of lectins and glycoregulation

Nonomura¹,

Shevela²,

Komath³

et al. 2020

Photosynt.

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Modulation of glycoregulation in agriculture is reviewed here with emphasis on the elucidation of previously unknown pathways involving vacuolar lectins as well as a bypass of lectins that direct free sugars toward productivity. The reversible binding sequences of the endogenous lectin cycle are compared to an induced lectin bypass, as follows. (1) In the cycle, carbohydrate ligands, with similar binding specificities that compete for binding sites on lectins, are involved in the natural cycle of sugar exchanges. (2) For the bypass, tightly bound ligands that occupy lectins prevent free sugars from binding, making them available for productivity. This bypass is induced by methyl-α-D-mannopyranoside, a biochemical plant growth regulator for photosynthesis. Integration of this novel technology, with structural elements crucial for ligand binding by the lectins and with nitrogen assimilation, provides the basis for successful modulation of glycoregulation in crops for enhancement of quality and quantity.

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Section: The Vacuole As the Hub Of Glycoregulationmentioning

confidence: 89%

The carbon reactions of photosynthesis: role of lectins and glycoregulation

Nonomura¹,

Shevela²,

Komath³

et al. 2020

Photosynt.

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“…Therefore, a hypothetical vacuoleplastid dual targeting mechanism would have to bypass the main protein import pathway. Such a mechanism would be surprising since .70% of the thylakoid membrane consists of monogalactosyldiacylglycerol and digalactosyldiacylglycerol (Dörmann and Benning, 2002), which provide a strikingly different lipid composition compared to that of the tonoplast (Zhang et al, 2015).…”

Section: S-labeled Tpk3 Protein Is Not Imported Into Isolated Intact mentioning

confidence: 99%

Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K⁺ Channel TPK3

et al. 2019

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Photosynthesis is limited by the slow relaxation of nonphotochemical quenching, which primarily dissipates excess absorbed light energy as heat. Because the heat dissipation process is proportional to light-driven thylakoid lumen acidification, manipulating thylakoid ion and proton flux via transport proteins could improve photosynthesis. However, an important aspect of the current understanding of the thylakoid ion transportome is inaccurate. Using fluorescent protein fusions, we show that the Arabidopsis (Arabidopsis thaliana) two-pore K 1 channel TPK3, which had been reported to mediate thylakoid K 1 flux, localizes to the tonoplast, not the thylakoid. The localization of TPK3 outside of the thylakoids is further supported by the absence of TPK3 in isolated thylakoids as well as the inability of isolated chloroplasts to import TPK3 protein. In line with the subcellular localization of TPK3 in the vacuole, we observed that photosynthesis in the Arabidopsis null mutant tpk3-1, which carries a transfer DNA insertion in the first exon, remains unaffected. To gain a comprehensive understanding of how thylakoid ion flux impacts photosynthetic efficiency under dynamic growth light regimes, we performed long-term photosynthesis imaging of established and newly isolated transthylakoid K 1 -and Cl 2 -flux mutants. Our results underpin the importance of the thylakoid ion transport proteins potassium cation efflux antiporter KEA3 and voltage-dependent chloride channel VCCN1 and suggest that the activity of yet unknown K 1 channel(s), but not TPK3, is critical for optimal photosynthesis in dynamic light environments.Photosynthesis provides metabolic energy for nearly all life on earth. During this process, light is utilized for CO 2 fixation, growth and additional energy-dependent metabolic pathways. In oxygenic photosynthesis, light energy induces charge separations at two photosystems. At PSII, electrons are stripped from water molecules releasing protons into the lumen. These electrons move along the thylakoid electron transport chain toward PSI and finally reduce NADP 1 to NADPH. During electron transport, protons are translocated from the chloroplast stroma into the thylakoid lumen, generating a proton motive force (pmf) which drives the ATP synthase to produce ATP. The thylakoid pmf is comprised of two components, a pH gradient (DpH) and a membrane potential (Dc). In addition to providing the driving force for ATP synthesis, the luminal proton concentration has important regulatory functions. Above a certain proton concentration threshold, a photoprotective mechanism is activated that dissipates excess absorbed light energy as heat. This mechanism is called energy-dependent quenching (qE). qE involves

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“…They included lipases, sterol, and sphingolipid biosynthesis genes and phospholipid transport regulators (Supplemental Data Sets 1 and 2). Sphingolipids and sterols are major components of vacuolar membranes in plants (reviewed in Michaelson et al, 2016;Zhang et al, 2015). Three of the genes, J41807, J48977, and J22677, encoded components of sphingolipid biosynthesis and were 2 to 5 times more highly expressed at 18 h in NR-KO14 cells than in the wild type ( Figures 11A to 11C), with BLASTP E-values from 3 3 10 214 to 9 3 10 2103 for alignments to their Arabidopsis homologs (http://www.plantcyc.org).…”

Section: Nr-ko Also Impacts Lipid Metabolism Remodeling and Gene Exmentioning

confidence: 99%

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

et al. 2017

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Molecular Composition of Plant Vacuoles: Important but Less Understood Regulations and Roles of Tonoplast Lipids

Cited by 42 publications

References 74 publications

The carbon reactions of photosynthesis: role of lectins and glycoregulation

The carbon reactions of photosynthesis: role of lectins and glycoregulation

Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K⁺ Channel TPK3

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

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Molecular Composition of Plant Vacuoles: Important but Less Understood Regulations and Roles of Tonoplast Lipids

Cited by 42 publications

References 74 publications

The carbon reactions of photosynthesis: role of lectins and glycoregulation

The carbon reactions of photosynthesis: role of lectins and glycoregulation

Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K+ Channel TPK3

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

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Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K⁺ Channel TPK3