Excess Pyrophosphate Restrains Pavement Cell Morphogenesis and Alters Organ Flatness in Arabidopsis thaliana

Gunji, Shizuka; Oda, Y.; Takigawa-Imamura, Hisako; Tsukaya, Hirokazu; Ferjani, Ali

doi:10.3389/fpls.2020.00031

Cited by 10 publications

(38 citation statements)

References 53 publications

(103 reference statements)

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“…We reported that excess PPi in the H + -PPase loss-of-function fugu5 mutant severely compromises gluconeogenesis from seed storage lipids and inhibits a hypocotyl elongation in etiolated seedlings ( Ferjani et al, 2011 , 2014a , 2018 ), arrests cell division in cotyledonary palisade tissue, and triggers a compensated cell enlargement (CCE; Tsukaya, 2002 , 2008 ; Horiguchi et al, 2005 , 2006a , b ; Ferjani et al, 2007 , 2008 , 2010 , 2011 , 2013a , b ; Amano et al, 2015 ; Katano et al, 2016 ; Takahashi et al, 2017 ; Tabeta et al, 2021 ; Nakayama et al, 2022 ). It is important to note that these phenotypes were recovered by exogenous sucrose (Suc) supply or specific removal of PPi from the fugu5 background by the yeast cytosolic PPase IPP1 under the control of the vacuolar H + -pyrophosphatase AVP1 / FUGU5 promoter in fugu5-1 AVP1 pro ::IPP1 transgenic lines ( Ferjani et al, 2011 , 2014a , b ; Asaoka et al, 2019 ; Gunji et al, 2020 ). Consistently, CE-TOF MS analyses of the major metabolites characteristic of gluconeogenesis from seed storage lipids identify UGPase as the major target of the inhibitory effects of excess PPi in planta ( Ferjani et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

“…Examination of the outermost cotyledon layer in fugu5 revealed an increase in stomatal density (i.e., the number of stomata per unit area) in violation of the one-cell-spacing rule, a defect in stomata closure ( Asaoka et al, 2019 ), and showed that pavement cells (PCs) exhibit defective puzzle-cell formation ( Gunji et al, 2020 ). It is important to note that specific removal of PPi in fugu5-1 AVP1 pro ::IPP1 transgenic lines restored these epidermal phenotypic aberrations in the fugu5 background ( Gunji et al, 2020 ). Furthermore, in fugu5 GC1 pro ::IPP1 transgenic lines, which exclusively express IPP1 in guard cells, stomatal closure recovered, which suggests a role for H + -PPase in stomatal function ( Asaoka et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

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Tissue-targeted inorganic pyrophosphate hydrolysis in a fugu5 mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner

Gunji

Kawade²,

Tabeta³

et al. 2022

Front. Plant Sci.

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Excess PPi triggers developmental defects in a cell-autonomous manner. The level of inorganic pyrophosphate (PPi) must be tightly regulated in all kingdoms for the proper execution of cellular functions. In plants, the vacuolar proton pyrophosphatase (H+-PPase) has a pivotal role in PPi homeostasis. We previously demonstrated that the excess cytosolic PPi in the H+-PPase loss-of-function fugu5 mutant inhibits gluconeogenesis from seed storage lipids, arrests cell division in cotyledonary palisade tissue, and triggers a compensated cell enlargement (CCE). Moreover, PPi alters pavement cell (PC) shape, stomatal patterning, and functioning, supporting specific yet broad inhibitory effects of PPi on leaf morphogenesis. Whereas these developmental defects were totally rescued by the expression of the yeast soluble pyrophosphatase IPP1, sucrose supply alone canceled CCE in the palisade tissue but not the epidermal developmental defects. Hence, we postulated that the latter are likely triggered by excess PPi rather than a sucrose deficit. To formally test this hypothesis, we adopted a spatiotemporal approach by constructing and analyzing fugu5-1 PDF1pro::IPP1, fugu5-1 CLV1pro::IPP1, and fugu5-1 ICLpro::IPP1, whereby PPi was removed specifically from the epidermis, palisade tissue cells, or during the 4 days following seed imbibition, respectively. It is important to note that whereas PC defects in fugu5-1 PDF1pro::IPP1 were completely recovered, those in fugu5-1 CLV1pro::IPP1 were not. In addition, phenotypic analyses of fugu5-1 ICLpro::IPP1 lines demonstrated that the immediate removal of PPi after seed imbibition markedly improved overall plant growth, abolished CCE, but only partially restored the epidermal developmental defects. Next, the impact of spatial and temporal removal of PPi was investigated by capillary electrophoresis time-of-flight mass spectrometry (CE-TOF MS). Our analysis revealed that the metabolic profiles are differentially affected among all the above transgenic lines, and consistent with an axial role of central metabolism of gluconeogenesis in CCE. Taken together, this study provides a conceptual framework to unveil metabolic fluctuations within leaf tissues with high spatio–temporal resolution. Finally, our findings suggest that excess PPi exerts its inhibitory effect in planta in the early stages of seedling establishment in a tissue- and cell-autonomous manner.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tissue-targeted inorganic pyrophosphate hydrolysis in a fugu5 mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner

Gunji

Kawade²,

Tabeta³

et al. 2022

Front. Plant Sci.

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“…In conclusion, we developed a framework to capture and analyze 4D information of cotyledon pavement cell growth and morphogenesis. We believe that this framework should aid analysis of mutant phenotypes, especially in the 3D deformation of the cotyledon surface, as recently reported by Gunji et al 2020. Additionally, our accurate and high-throughput acquisition of growing cell structures might be suitable for use in making an in silico model cell structure, which is generated by the observed data.…”

Section: Resultsmentioning

confidence: 57%

Four-dimensional imaging with virtual reality to quantitatively explore jigsaw puzzle-like morphogenesis of <i>Arabidopsis</i> cotyledon pavement cells

Higaki

Mizuno

2020

Plant Biotechnology

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In most dicotyledonous plants, leaf pavement cells exhibit complex jigsaw puzzle-like cell morphogenesis during leaf expansion. Although detailed molecular biological information and mathematical modeling of this jigsaw puzzle-like cell morphogenesis are now available, a full understanding of this process remains elusive. Recent reports have highlighted the importance of three-dimensional (3D) structures (i.e., anticlinal and periclinal cell wall) in understanding the mechanical models that describe this morphogenetic process. We believe that it is important to acquire 3D shapes of pavement cells over time, i.e., acquire and analyze four-dimensional (4D) information when studying the relationship between mechanical modeling and simulations and the actual cell shape. In this report, we have developed a framework to capture and analyze 4D morphological information of Arabidopsis thaliana cotyledon pavement cells by using both direct water immersion observations and computational image analyses, including segmentation, surface modeling, virtual reality and morphometry. The 4D cell models allowed us to perform time-lapse 3D morphometrical analysis, providing detailed quantitative information about changes in cell growth rate and shape, with cellular complexity observed to increase during cell growth. The framework should enable analysis of various phenotypes (e.g., mutants) in greater detail, especially in the 3D deformation of the cotyledon surface, and evaluation of theoretical models that describe pavement cell morphogenesis using computational simulations. Additionally, our accurate and high-throughput acquisition of growing cell structures should be suitable for use in generating in silico model cell structures.

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“…To detect morphological differences in pavement cells of 20day-old leaves, SEM analysis was performed. Pavement cells usually exhibit puzzle-cell formation, but very recently Gunji et al (2020) reported that the complexity of cotyledon pavement cells was reduced by PPi accumulation via inhibiting microtubule dynamics. On both MGRL and MGRL Am , WT leaves showed normal pavement cell structure ( Figures 2F,G).…”

Section: Morphological Phenotypes Of Leaf Of Fugu5mentioning

confidence: 99%

“…A T-DNA insertion H + -PPase knockout mutant vhp1-1 of Arabidopsis thaliana (A. thaliana) and amino acid exchange and deletion mutants of H + -PPase (fugu5s) showed abnormal cotyledon shape, with fewer and larger cells, when seedlings were grown in the absence of sucrose (Ferjani et al, 2011), as well as a mild suppression of plant growth (Asaoka et al, 2016), and delayed stomatal closure (Asaoka et al, 2019). Very recently, excess PPi has been reported to limit cotyledon pavement cell morphogenesis and to alter cotyledon flatness (Gunji et al, 2020). On the contrary, V-ATPase knockout mutant vha-a2 vha-a3 showed severer growth defect and higher vacuolar pH than fugu5, suggesting that V-ATPase is the primary vacuolar proton pump (Krebs et al, 2010;Kriegel et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Lack of Vacuolar H+ -Pyrophosphatase and Cytosolic Pyrophosphatases Causes Fatal Developmental Defects in Arabidopsis thaliana

et al. 2020

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The cytosolic level of inorganic pyrophosphate (PPi) is finely regulated, with PPi hydrolyzed primarily by the vacuolar H +-pyrophosphatase (H +-PPase, VHP1/FUGU5/AVP1) and secondarily by five cytosolic soluble pyrophosphatases (sPPases; PPa1-PPa5) in Arabidopsis thaliana. Loss-of-function mutants of H +-PPase (fugu5s) have been reported to show atrophic phenotypes in their rosette leaves when nitrate is the sole nitrogen source in the culture medium. For this phenotype, two questions remain unanswered: why does atrophy depend on physical contact between shoots and the medium, and how does ammonium prevent such atrophy. To understand the mechanism driving this phenotype, we analyzed the growth and phenotypes of mutants on ammonium-free medium in detail. fugu5-1 showed cuticle defects, cell swelling, reduced β-glucan levels, and vein malformation in the leaves, suggesting cell wall weakening and cell lethality. Based on the observation in the double mutants fugu5-1 ppa1 and fugu5-1 ppa4 of more severe atrophy compared to fugu5-1, the nitrogen-dependent phenotype might be linked to PPi metabolism. To elucidate the role of ammonium in this process, we examined the fluctuations of sPPase mRNA levels and the possibility of alternative PPi-removing factors, such as other types of pyrophosphatase. First, we found that both the protein and mRNA levels of sPPases were unaffected by the nitrogen source. Second, to assess the influence of other PPi-removing factors, we examined the phenotypes of triple knockout mutants of H +-PPase and two sPPases on ammonium-containing medium. Both fugu5 ppa1 ppa2 and fugu5 ppa1 ppa4 had nearly lethal embryonic phenotypes, with the survivors showing striking dwarfism and abnormal morphology. Moreover, fugu5 ppa1 +/− ppa4 showed severe atrophy at the leaf margins. The other triple mutants, fugu5 ppa1 ppa5 and fugu5 ppa2 ppa4, exhibited death of root hairs and were nearly sterile due to deformed pistils, respectively, even when grown on standard medium. Together,

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Excess Pyrophosphate Restrains Pavement Cell Morphogenesis and Alters Organ Flatness in Arabidopsis thaliana

Cited by 10 publications

References 53 publications

Tissue-targeted inorganic pyrophosphate hydrolysis in a fugu5 mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner

Tissue-targeted inorganic pyrophosphate hydrolysis in a fugu5 mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner

Four-dimensional imaging with virtual reality to quantitatively explore jigsaw puzzle-like morphogenesis of <i>Arabidopsis</i> cotyledon pavement cells

Lack of Vacuolar H+ -Pyrophosphatase and Cytosolic Pyrophosphatases Causes Fatal Developmental Defects in Arabidopsis thaliana

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