scholarly journals Rice Brittle Culm19 Encoding Cellulose Synthase Subunit CesA4 Causes Dominant Brittle Phenotype But Has No Distinct Influence on Growth and Grain Yield

2021 ◽  
Author(s):  
Xiaozhi Ma ◽  
Chunmei Li ◽  
Rui Huang ◽  
Kuan Zhang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mechanical Strength ◽  
Grain Yield ◽  
Missense Mutation ◽  
Mutant Gene ◽  
Cellulose Synthase ◽  
Hybrid Breeding ◽  
Chemical Mutagenesis ◽  
Wild Type Plant ◽  
Wild Type

Abstract Background: Mechanical strength is a crucial agronomic trait in rice (Oryza sativa), and brittle mutants are thought suitable materials to investigate the mechanism of cell wall formation. So far, almost all brittle mutants are recessive, and most of them are defected in multiple morphologies and/or grain yield, limiting their application in hybrid breeding and in rice straw recycling.Results: We identified a semi-dominant brittle mutant Brittle culm19 (Bc19) isolated from the japonica variety Nipponbare through chemical mutagenesis. The mutant showed the same apparent morphologies and grain yield to the wild type plant except for its weak mechanical strength. Its development of secondary cell wall in sclerenchyma cells was affected, along with reduced contents of cellulose, hemicellulose, lignin and sugars in culms and leaves. Positional cloning suggested that the Bc19 gene was allelic to OsCesA4, encoding one of the cellulose synthase A (CesA) catalytic subunits. In this mutant, a C-to-T substitution occurred in the coding sequence of BC19, causing the P507S missense mutation in its encoded product, which was located in the second cytoplasmic region of the OsCesA4 protein. Furthermore, introducing mutant gene Bc19 into the wild-type plant resulted in brittle plants, confirming that the P507S point mutation in OsCesA4 protein was responsible for the semi-dominant brittle phenotype of Bc19 mutant. Reverse correlation was revealed between cellulose contents and expression levels of mutant gene Bc19 among the homozygous mutant, the hybrid F1 plant, and the Bc19 overexpression transgenic plants, implying that gene Bc19 might affect cellulose synthesis in a dosage-dependent manner.Conclusions: Bc19, a semi-dominant brittle mutant allele of gene OsCesA4, was identified using map-based cloning approach. The mutated protein of Bc19 possessing the P507S missense mutation behaved in a dosage-dependent semi-dominant manner. Unique brittle effect on phenotype and semi-dominant genetic quality of gene Bc19 indicated its potential application in grain-straw dual-purpose hybrid rice breeding.

scholarly journals Rice Brittle Culm19 Encoding Cellulose Synthase Subunit CESA4 Causes Dominant Brittle Phenotype But has No Distinct Influence on Growth and Grain Yield

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiaozhi Ma ◽  
Chunmei Li ◽  
Rui Huang ◽  
Kuan Zhang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mechanical Strength ◽  
Grain Yield ◽  
Missense Mutation ◽  
Mutant Gene ◽  
Cellulose Synthase ◽  
Hybrid Breeding ◽  
Chemical Mutagenesis ◽  
Wild Type Plant ◽  
Wild Type

Abstract Background Mechanical strength is a crucial agronomic trait in rice (Oryza sativa), and brittle mutants are thought suitable materials to investigate the mechanism of cell wall formation. So far, almost all brittle mutants are recessive, and most of them are defected in multiple morphologies and/or grain yield, limiting their application in hybrid breeding and in rice straw recycling. Results We identified a semi-dominant brittle mutant Brittle culm19 (Bc19) isolated from the japonica variety Nipponbare through chemical mutagenesis. The mutant showed the same apparent morphologies and grain yield to the wild type plant except for its weak mechanical strength. Its development of secondary cell wall in sclerenchyma cells was affected, along with reduced contents of cellulose, hemicellulose, lignin and sugars in culms and leaves. Positional cloning suggested that the Bc19 gene was allelic to OsCESA4, encoding one of the cellulose synthase A (CESA) catalytic subunits. In this mutant, a C-to-T substitution occurred in the coding sequence of BC19, causing the P507S missense mutation in its encoded product, which was located in the second cytoplasmic region of the OsCESA4 protein. Furthermore, introducing mutant gene Bc19 into the wild-type plant resulted in brittle plants, confirming that the P507S point mutation in OsCESA4 protein was responsible for the semi-dominant brittle phenotype of Bc19 mutant. Reverse correlation was revealed between cellulose contents and expression levels of mutant gene Bc19 among the homozygous mutant, the hybrid F1 plant, and the Bc19 overexpression transgenic plants, implying that gene Bc19 might affect cellulose synthesis in a dosage-dependent manner. Conclusions Bc19, a semi-dominant brittle mutant allele of gene OsCESA4, was identified using map-based cloning approach. The mutated protein of Bc19 possessing the P507S missense mutation behaved in a dosage-dependent semi-dominant manner. Unique brittle effect on phenotype and semi-dominant genetic quality of gene Bc19 indicated its potential application in grain-straw dual-purpose hybrid rice breeding.

scholarly journals Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Expansion ◽  
Cortical Microtubule ◽  
Root Apex ◽  
Cellulose Synthase ◽  
Cellulose Biosynthesis ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

scholarly journals Seed-Specific Expression of Arabidopsis AtCYP85A2 Produces Biologically Active Brassinosteroids Such as Castasterone and Brassinolide to Improve Grain Yield and Quality in Seeds of Brachypodium Distachyon

2021 ◽  
Vol 12 ◽  
Author(s):  
Jeehee Roh ◽  
Jinyoung Moon ◽  
Ye Eun Lee ◽  
Chan Ho Park ◽  
Seong-Ki Kim
Keyword(s):  
Transgenic Plants ◽  
Grain Yield ◽  
Brachypodium Distachyon ◽  
Biologically Active ◽  
Wild Type Plant ◽  
Wild Type ◽  
Specific Expression ◽  
Yield And Quality ◽  
Grain Yield And Quality ◽  
Seed Specific Expression

Brachypodium distachyon is a monocotyledonous model plant that contains castasterone (CS) but no brassinolide (BL) as the end product of brassinosteroids (BR) biosynthesis, indicating dysfunction of BL synthase, which catalyzes the conversion of CS to BL. To increase BR activity, Arabidopsis cytochrome P450 85A2 (AtCYP85A2) encoding BR 6-oxidase/BL synthase was introduced into B. distachyon with the seed-specific promoters pBSU1, pAt5g10120, and pAt5g54000. RT-PCR analysis and GUS activity revealed that AtCYP85A2 was only expressed in the seeds of the transgenic plants pBSU1-AtCYP85A2::Bd21-3, pAt5g10120-AtCYP85A2::Bd21-3, and pAt5g54000-AtCYP85A2::Bd21-3. The crude enzyme prepared from the seeds of these three transgenic plants catalyzed the conversion of 6-deoxoCS to CS. The transgenic plants showed greater specific enzyme activity than the wild-type plant for the conversion of 6-deoxoCS to CS, indicating enhanced BR 6-oxidase activity in the transgenic plants. The enzyme solution also catalyzed the conversion of CS into BL. Additionally, BL was identified from the seeds of transgenic plants, verifying that seed-specific AtCYP85A2 encodes a functional BL synthase to increase BR activity in the seeds of transgenic Brachypodium. In comparison with wild-type Brachypodium, the transgenic plants showed better growth and development during the vegetative growing stage. The flowers of the transgenic plants were remarkably larger, resulting in increments in the number, size, and height of seeds. The total starch, protein, and lipid contents in transgenic plants were higher than those in wild-type plants, indicating that seed-specific expression of AtCYP85A2 improves both grain yield and quality in B. distachyon.

scholarly journals Characterization and Fine Mapping of a New Dwarf Mutant in Brassica Napus

2020 ◽  
Author(s):  
Xin Li ◽  
Fujiang Xiang ◽  
Wei Zhang ◽  
Jindong Yan ◽  
Xinmei Li ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Grain Yield ◽  
Plant Height ◽  
Fine Mapping ◽  
Plant Architecture ◽  
Hybrid Breeding ◽  
Dwarf Mutant ◽  
Wild Type ◽  
Lodging Resistance ◽  
Commercial Cultivar

Abstract Background: Plant height is an important plant architecture character closely related to yield performance of many crops. Reasonable reduction of plant height of crops is beneficial for enhancing lodging resistance and improving yield. Results: In the present study, we described a Brassica napus dwarf mutant bnd2 induced by ethyl methanesulfonate (EMS) mutagenesis. Compared to wild type, bnd2 showed shorter stature, shorter hypocotyl, as well as shorter petiole leaves. We crossed the bnd2 mutant with its wild type and found that the ratio of the mutant to the wild type in the F2 population was close to 1:3, indicating that bnd2 is a recessive mutation of a single locus. Following bulked segregant analysis (BSA) by resequencing, BND2 was located into the 13.77 Mb-18.08 Mb interval of chromosome A08, with a length of 4.31 Mb. After fine mapping with SNP and InDel markers, the gene was narrowed to a 140-Kb interval ranging from 15.62 Mb to 15.76 Mb. According to reference genome annotation, there are 27 genes in the interval, and one of them BnaA08g20960D has a SNP type variation in the intron between the mutant and its parent, which may be the candidate gene conferring to BND2. The hybrid line derived from a cross between the mutant bnd2 and a commercial cultivar L329 has similar plant height but higher grain yield than the commercial cultivar, suggesting that the allele bnd2 is benefit for hybrid breeding of lodging resistance and high yield in rapeseed.Conclusion: In this study, we found a fresh resource and a new locus for dwarf in rapeseed, which may be benefit for functional analysis of genetic mechanism of plant architecture and grain yield in rapeseed.

Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem

1976 ◽  
Vol 34 ◽  
pp. 54-55
Author(s):  
Karen S. Howard ◽  
H. D. Braymer ◽  
M. D. Socolofsky ◽  
S. A. Milligan
Keyword(s):  
Cell Wall ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Morphological Comparison ◽  
Small Areas ◽  
Solid Media ◽  
Thin Sectioning ◽  
X Cells ◽  
Mutant Cells ◽  
Isolated Cell

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).

IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

1970 ◽  
pp. 33-36
Author(s):  
А. I. Grabovets ◽  
V. P. Kadushkina ◽  
S. А. Kovalenko
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Correlation Coefficient ◽  
Harvest Index ◽  
Unit Area ◽  
Correlation Coefficients ◽  
Chemical Mutagenesis ◽  
Main Method ◽  
The Relationship ◽  
Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the  breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

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.

scholarly journals A CACNA1A variant associated with trigeminal neuralgia alters the gating of Cav2.1 channels

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Eder Gambeta ◽  
Maria A. Gandini ◽  
Ivana A. Souza ◽  
Laurent Ferron ◽  
Gerald W. Zamponi
Keyword(s):  
Trigeminal Neuralgia ◽  
Missense Mutation ◽  
Neurotransmitter Release ◽  
Trigeminal System ◽  
Wild Type ◽  
Calcium Dependent ◽  
Whole Cell Patch Clamp ◽  
C Terminus ◽  
Dependent Inactivation

AbstractA novel missense mutation in the CACNA1A gene that encodes the pore forming α1 subunit of the CaV2.1 voltage-gated calcium channel was identified in a patient with trigeminal neuralgia. This mutation leads to a substitution of proline 2455 by histidine (P2455H) in the distal C-terminus region of the channel. Due to the well characterized role of this channel in neurotransmitter release, our aim was to characterize the biophysical properties of the P2455H variant in heterologously expressed CaV2.1 channels. Whole-cell patch clamp recordings of wild type and mutant CaV2.1 channels expressed in tsA-201 cells reveal that the mutation mediates a depolarizing shift in the voltage-dependence of activation and inactivation. Moreover, the P2455H mutant strongly reduced calcium-dependent inactivation of the channel that is consistent with an overall gain of function. Hence, the P2455H CaV2.1 missense mutation alters the gating properties of the channel, suggesting that associated changes in CaV2.1-dependent synaptic communication in the trigeminal system may contribute to the development of trigeminal neuralgia.

scholarly journals Transcriptome and metabolome profiling provide insights into molecular mechanism of pseudostem elongation in banana

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Guiming Deng ◽  
Fangcheng Bi ◽  
Jing Liu ◽  
Weidi He ◽  
Chunyu Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Elongation ◽  
Molecular Mechanisms ◽  
Specific Gene ◽  
Wild Type ◽  
Banana Plant ◽  
Cell Wall Modification ◽  
Dwarf Cultivar ◽  
Important Trait ◽  
Metabolome Profiling

AbstractBackgroundBanana plant height is an important trait for horticultural practices and semi-dwarf cultivars show better resistance to damages by wind and rain. However, the molecular mechanisms controlling the pseudostem height remain poorly understood. Herein, we studied the molecular changes in the pseudostem of a semi-dwarf banana mutant Aifen No. 1 (Musaspp. Pisang Awak sub-group ABB) as compared to its wild-type dwarf cultivar using a combined transcriptome and metabolome approach.ResultsA total of 127 differentially expressed genes and 48 differentially accumulated metabolites were detected between the mutant and its wild type. Metabolites belonging to amino acid and its derivatives, flavonoids, lignans, coumarins, organic acids, and phenolic acids were up-regulated in the mutant. The transcriptome analysis showed the differential regulation of genes related to the gibberellin pathway, auxin transport, cell elongation, and cell wall modification. Based on the regulation of gibberellin and associated pathway-related genes, we discussed the involvement of gibberellins in pseudostem elongation in the mutant banana. Genes and metabolites associated with cell wall were explored and their involvement in cell extension is discussed.ConclusionsThe results suggest that gibberellins and associated pathways are possibly developing the observed semi-dwarf pseudostem phenotype together with cell elongation and cell wall modification. The findings increase the understanding of the mechanisms underlying banana stem height and provide new clues for further dissection of specific gene functions.

scholarly journals Degradation of trinitrotoluene by transgenic nitroreductase in Arabidopsis plants

2018 ◽  
Vol 64 (No. 8) ◽  
pp. 379-385 ◽  
Author(s):  
Zhu Bo ◽  
Han Hongjuan ◽  
Fu Xiaoyan ◽  
Li Zhenjun ◽  
Gao Jianjie ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Transgenic Arabidopsis ◽  
Environmental Pollutant ◽  
Specific Rate ◽  
Wild Type Plant ◽  
Wild Type ◽  
Fresh Weight ◽  
Human Carcinogen ◽  
Specific Rate Constant ◽  
Nitroreductase Activity

The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic and persistent environmental pollutant. TNT is toxic to many organisms, it is known to be a potential human carcinogen, and is persistent in the environment. This study presents a system of phytoremediation by Arabidopsis plants developed on the basis of overexpression of NAD(P)H-flavin nitroreductase (NFSB) from the Sulfurimonas denitrificans DSM1251. The resulting transgenic Arabidopsis plants demonstrated significantly enhanced TNT tolerance and a strikingly higher capacity to remove TNT from their media. The highest specific rate constant of TNT disappearance rate was 1.219 and 2.297 mL/g fresh weight/h for wild type and transgenic plants, respectively. Meanwhile, the nitroreductase activity in transgenic plant was higher than wild type plant. All this indicates that transgenic plants show significantly enhanced tolerances to TNT; transgenic plants also exhibit strikingly higher capabilities of removing TNT from their media and high efficiencies of transformation.

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