Anatomical and chemical characteristics of culm of rice brittle mutant bc7(t)

2011 ◽  
Vol 38 (3) ◽  
pp. 227
Author(s):  
Cunxu Wei ◽  
Peisong Xie ◽  
Yifang Chen ◽  
Huaguang Yu ◽  
Yanjing Su ◽  
...  
Keyword(s):  
Cell Walls ◽  
Oryza Sativa L ◽  
Normal Growth ◽  
Histochemical Staining ◽  
Agricultural Activity ◽  
Wild Type Plant ◽  
Wild Type ◽  
X Ray ◽  
In The Wild ◽  
Cp Mas Nmr

Brittleness culm is an important agronomic trait that has a potential usefulness in agricultural activity as animal forage. In the present study, the anatomy of culm of rice (Oryza sativa L.) brittle mutant bc7(t) was investigated with light microscopy and electron microscopy. Findings showed bc7(t) exhibited higher area percentages of mechanical and conducting tissues, and lower cell wall thickness of sclerenchyma cells. Chemical analyses and 13C CP/MAS NMR spectra of cell walls indicated that the content of cellulose decreased, and the contents of hemicellulose, lignin and silicon was increased in bc7(t). Lignin histochemical staining and cytochemical localisation revealed that the higher lignin was localised in epidermal, sclerenchyma and vascular bundle cells in bc7(t). The energy dispersive X-ray microanalysis showed that the contents of silicon were higher in bc7(t) than in the wild type. These results indicate that cellulose, hemicellulose, lignin, silicon and the area percentages of mechanical and conducting tissues could be regulated in a compensatory fashion, possibly contributing to metabolic flexibility and a growth advantage to sustain the bc7(t) normal growth habit like the wild-type plant.

scholarly journals CAND2/PMTR1 Is Required for Melatonin-Conferred Osmotic Stress Tolerance in Arabidopsis

2021 ◽  
Vol 22 (8) ◽  
pp. 4014
Author(s):  
Lin-Feng Wang ◽  
Ting-Ting Li ◽  
Yu Zhang ◽  
Jia-Xing Guo ◽  
Kai-Kai Lu ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Stress Tolerance ◽  
Wild Type Plant ◽  
Wild Type ◽  
Melatonin Receptor ◽  
Ros Scavenging ◽  
Exogenous Melatonin ◽  
Osmotic Stress Tolerance ◽  
Osmotic Stress Response ◽  
In The Wild

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.

Caffeoyl Shikimate Esterase (CSE) Is an Enzyme in the Lignin Biosynthetic Pathway in Arabidopsis

Science ◽  
2013 ◽  
Vol 341 (6150) ◽  
pp. 1103-1106 ◽  
Author(s):  
Ruben Vanholme ◽  
Igor Cesarino ◽  
Katarzyna Rataj ◽  
Yuguo Xiao ◽  
Lisa Sundin ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Walls ◽  
Metabolite Profiling ◽  
Biosynthetic Pathway ◽  
Wild Type ◽  
Secondary Cell Walls ◽  
Phenolic Metabolite ◽  
In The Wild ◽  
Lignin Biosynthetic Pathway

Lignin is a major component of plant secondary cell walls. Here we describe caffeoyl shikimate esterase (CSE) as an enzyme central to the lignin biosynthetic pathway. Arabidopsis thaliana cse mutants deposit less lignin than do wild-type plants, and the remaining lignin is enriched in p-hydroxyphenyl units. Phenolic metabolite profiling identified accumulation of the lignin pathway intermediate caffeoyl shikimate in cse mutants as compared to caffeoyl shikimate levels in the wild type, suggesting caffeoyl shikimate as a substrate for CSE. Accordingly, recombinant CSE hydrolyzed caffeoyl shikimate into caffeate. Associated with the changes in lignin, the conversion of cellulose to glucose in cse mutants increased up to fourfold as compared to that in the wild type upon saccharification without pretreatment. Collectively, these data necessitate the revision of currently accepted models of the lignin biosynthetic pathway.

The role of catalase in hydrogen peroxide resistance in fission yeast Schizosaccharomyces pombe

1999 ◽  
Vol 45 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Norihiro Mutoh ◽  
Chiaki W Nakagawa ◽  
Kenichiro Yamada
Keyword(s):  
Hydrogen Peroxide ◽  
Schizosaccharomyces Pombe ◽  
Catalase Activity ◽  
Parent Strain ◽  
Normal Growth ◽  
Wild Type ◽  
Catalase Gene ◽  
In The Wild ◽  
High Concentrations

The role of catalase in hydrogen peroxide resistance in Schizosaccharomyces pombe was investigated. A catalase gene disruptant completely lacking catalase activity is more sensitive to hydrogen peroxide than the parent strain. The mutant does not acquire hydrogen peroxide resistance by osmotic stress, a treatment that induces catalase activity in the wild-type cells. The growth rate of the disruptant is not different from that of the parent strain. Additionally, transformed cells that overexpress the catalase activity are more resistant to hydrogen peroxide than wild-type cells with normal catalase activity. These results indicate that the catalase of S. pombe plays an important role in resistance to high concentrations of hydrogen peroxide but offers little in the way of protection from the hydrogen peroxide generated in small amounts under normal growth conditions.Key words: catalase, gene disruption, induced hydrogen peroxide resistance, overexpression, Schizosaccharomyces pombe.

scholarly journals Comparative Proteomic Analysis of Wild-Type Physcomitrella patens and an OPDA-Deficient Physcomitrella patens Mutant with Disrupted PpAOS1 and PpAOS2 Genes after Wounding

2020 ◽  
Author(s):  
Weifeng Luo ◽  
Setsuko Komatsu ◽  
Tatsuya Abe ◽  
Hideyuki Matsuura ◽  
Kosaku Talahashi
Keyword(s):  
Protein Synthesis ◽  
Proteomic Analysis ◽  
Vascular Plants ◽  
Acid Metabolism ◽  
Physcomitrella Patens ◽  
Energy Utilization ◽  
Wild Type Plant ◽  
Wild Type ◽  
In The Wild ◽  
Energy Synthesis

Wounding is a serious environmental stress in plants. Oxylipins such as jasmonic acid play an important role in defense against wounding. Mechanisms to adapt to wounding have been investigated in vascular plants; however, those mechanisms in nonvascular plants remain elusive. To examine the response to wounding in Physcomitrella patens, a model moss, a proteomic analysis of wounded P. patens was conducted. Proteomic analysis showed that wounding increased the abundance of proteins related to protein synthesis, amino acid metabolism, protein folding, photosystem, glycolysis, and energy synthesis. 12-Oxo-phytodienoic acid (OPDA) was induced by wounding and inhibited growth. Therefore, OPDA is considered a signaling molecule in this plant. Proteomic analysis of a P. patens mutant in which the PpAOS1 and PpAOS2 genes, which are involved in OPDA biosynthesis, are disrupted showed accumulation of proteins involved in protein synthesis in response to wounding in a similar way to the wild-type plant. In contrast, the fold-changes of the proteins in the wild-type plant were significantly different from those in the aos mutant. This study suggests that PpAOS gene expression enhances photosynthesis and effective energy utilization in response to wounding in P. patens.

scholarly journals Cytokinesis in fra2 Arabidopsis thaliana p60-katanin Mutant: Defects in Cell Plate/Daughter Wall Formation

2021 ◽  
Author(s):  
Emmanuel Panteris ◽  
Anna Kouskouveli ◽  
Dimitris Pappas ◽  
Ioannis-Dimosthenis S. Adamakis
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Higher Plants ◽  
Cell Plate ◽  
Wild Type ◽  
Microtubule Organization ◽  
Root Cells ◽  
Wall Formation ◽  
In The Wild

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate, to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), while deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy, in root cells of the fra2 Arabidopsis thaliana mutant. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls appeared also faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild-type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild-type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.

scholarly journals Cytokinesis in fra2 Arabidopsis thaliana p60-Katanin Mutant: Defects in Cell Plate/Daughter Wall Formation

2021 ◽  
Vol 22 (3) ◽  
pp. 1405
Author(s):  
Emmanuel Panteris ◽  
Anna Kouskouveli ◽  
Dimitris Pappas ◽  
Ioannis-Dimosthenis S. Adamakis
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Higher Plants ◽  
Cell Plate ◽  
Wild Type ◽  
Microtubule Organization ◽  
Root Cells ◽  
Wall Formation ◽  
In The Wild

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast have been reported to occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), in root cells of the fra2 Arabidopsis thaliana loss-of-function mutant. In addition, deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls also appeared faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.

scholarly journals Coiled-coil registry shifts in the F684I mutant of Bicaudal result in cargo-independent activation of dynein motility

2019 ◽  
Author(s):  
Heying Cui ◽  
Kathleen M. Trybus ◽  
M. Yusuf Ali ◽  
Puja Goyal ◽  
Kaiqi Zhang ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Underlying Mechanism ◽  
Structural Flexibility ◽  
Human Homolog ◽  
Wild Type ◽  
Transport Pathways ◽  
X Ray ◽  
In The Wild ◽  
Selection For ◽  
Dependent Transport

ABSTRACTThe dynein adaptor Drosophila Bicaudal D (BicD) is auto-inhibited and activates dynein motility only after cargo is bound, but the underlying mechanism is elusive. In contrast, we show that the full-length BicD/F684I mutant activates dynein processivity even in the absence of cargo. Our X-ray structure of the C-terminal domain of the BicD/F684I mutant reveals a coiled-coil registry shift; in the N-terminal region, the two helices of the homodimer are aligned, whereas they are vertically shifted in the wild-type. One chain is partially disordered and this structural flexibility is confirmed by computations, which reveal that the mutant transitions back and forth between the two registries. We propose that a coiled-coil registry shift upon cargo binding activates BicD for dynein recruitment. Moreover, the human homolog BicD2/F743I exhibits diminished binding of cargo adaptor Nup358, implying that a coiled-coil registry shift may be a mechanism to modulate cargo selection for BicD2–dependent transport pathways.

scholarly journals The Tension-sensitive Ion Transport Activity of MSL8 is Critical for its Function in Pollen Hydration and Germination

2016 ◽  
Author(s):  
Eric S. Hamilton ◽  
Elizabeth S. Haswell
Keyword(s):  
Pollen Germination ◽  
Pollen Viability ◽  
Point Mutations ◽  
Normal Growth ◽  
Loss Of Function ◽  
Transport Activity ◽  
Wild Type ◽  
Gated Channel ◽  
In The Wild ◽  
Pore Lining

AbstractAll cells respond to osmotic challenges, including those imposed during normal growth and development. Mechanosensitive (MS) ion channels provide a conserved mechanism for regulating osmotic forces by conducting ions in response to increased membrane tension. We previously demonstrated that the MS ion channel MscS-Like 8 (MSL8) is required for pollen to survive multiple osmotic challenges that occur during the normal process of fertilization, and that it can inhibit pollen germination. However, it remained unclear whether these physiological functions required ion flux through a mechanically gated channel provided by MSL8. We introduced two point mutations into the predicted pore-lining domain of MSL8 that disrupted normal channel function in different ways. The Ile711Ser mutation increased the tension threshold of the MSL8 channel while leaving conductance unchanged, and the Phe720Leu mutation severely disrupted the MSL8 channel. Both of these mutations impaired the ability of MSL8 to preserve pollen viability during hydration and to maintain the integrity of the pollen tube when expressed at endogenous levels. When overexpressed in a msl8-4 null background, MSL8I711S could partially rescue loss-of-function phenotypes, while MSL8F720L could not. When overexpressed in the wild type Ler background, MSL8I711S suppressed pollen germination, similar to wild type MSL8. In contrast, MSL8F720L failed to suppress pollen germination and increased pollen bursting, thereby phenocopying the msl8-4 mutant. Thus, an intact MSL8 channel is required to for normal pollen function during hydration and germination. These data establish MSL8 as the first plant MS channel to fulfill previously established criteria for assignment as a mechanotransducer.

Whole-plant growth and N allocation in transgenic rice plants with decreased content of ribulose-1,5-bisphosphate carboxylase under different CO2 partial pressures

2000 ◽  
Vol 27 (1) ◽  
pp. 1 ◽  
Author(s):  
Amane Makino ◽  
Masayo Harada ◽  
Kentaro Kaneko ◽  
Tadahiko Mae ◽  
Takiko Shimada ◽  
...  
Keyword(s):  
Transgenic Rice ◽  
Oryza Sativa L ◽  
Early Stage ◽  
N Use Efficiency ◽  
Wild Type Plant ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Whole Plant ◽  
Use Efficiency ◽  
N Use

Growth of transgenic rice (Oryza sativa L.) with an antisense gene to the small subunit of Rubisco was analysed under 36 and 100 Pa CO2 during a 14-h photoperiod (1000 mol quanta m–2 s–1). Two lines of the antisense plants were used; one with 65% wild-type Rubisco and the other with 40% wild-type Rubisco. The plants were grown hydroponically for 70 d. The final biomass of the antisense plants grown in 36 Pa CO2 was much smaller than that of the wild-type plant. However, several compen-sation phenomena were found in the antisense plants. Increased biomass allocation to leaf blades and preferential N investment in leaf blades were observed. Leaf senescence was also delayed. Elevated CO2 levels up to 100 Pa caused the antisense plants to achieve a size similar to that of the wild-type plant. However, although the antisense plant with 65% wild-type Rubisco was selected as a plant with optimal Rubisco content for CO2 -saturated photosynthesis, its final biomass was not greater than that of the wild-type plant. This may have been caused by a relatively strong Rubisco-antisense effect during the early stage of growth (21–42 d). N-use efficiency for growth after d 42 was greater in the selected antisense plant. Thus, improvement of N-use efficiency at the level of a single leaf did not necessarily lead to greater production of biomass at the whole-plant level.

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