scholarly journals Overexpression of Douglas-Fir LEAFY COTYLEDON1 (PmLEC1) in Arabidopsis Induces Embryonic Programs and Embryo-Like Structures in the lec1-1 Mutant but Not in Wild Type Plants

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1526
Author(s):  
Mariana A. Vetrici ◽  
Dmytro P. Yevtushenko ◽  
Santosh Misra
Keyword(s):  
Arabidopsis Thaliana ◽  
Somatic Embryo ◽  
Douglas Fir ◽  
Null Mutant ◽  
Wild Type ◽  
Heterologous Host ◽  
Normal Morphology ◽  
Vegetative Tissues ◽  
Developmental Arrest ◽  
Embryo Formation

Somatic embryogenesis (SE) is the most promising method for the quick propagation of desirable plant genotypes. However, application of SE to conifers remains challenging due to our limited knowledge about the genes involved in embryogenesis and the processes that lead to somatic embryo formation. Douglas-fir, an economically important lumber species, possesses a homolog of the angiosperm embryo-regulatory LEC1 gene. In the present study, we analyzed the potential of Douglas-fir PmLEC1 to induce embryonic programs in the vegetative cells of a heterologous host, Arabidopsis thaliana. PmLEC1 complemented the Arabidopsis lec1-1 null mutant and led to a variety of phenotypes ranging from normal morphology to developmental arrest at various stages in the T1 generation. PmLEC1 did not affect the morphology of wild type Arabidopsis T1 plants. More profound results occurred in T2 generations. PmLEC1 expression induced formation of recurrent somatic embryo-like structures in vegetative tissues of the rescued lec1-1 mutant but loss of apical dominance (bushy phenotype) in wild type plants. The activation of embryonic programs in the lec1-1PmLEC1 T2 plants was confirmed by the presence of the embryo-specific transcripts, OLEOSIN and CRUCIFERIN. In contrast, no embryo-like structures, and no OLEOSIN or CRUCIFERIN were observed in PmLEC1-expressing bushy wild type T2 plants.

scholarly journals Development, Maintenance, and Function of the Adrenal Gland in Early Postnatal Proopiomelanocortin-Null Mutant Mice

Endocrinology ◽  
2005 ◽  
Vol 146 (6) ◽  
pp. 2555-2562 ◽  
Author(s):  
Jason Karpac ◽  
Dirk Ostwald ◽  
Stephanie Bui ◽  
Peggy Hunnewell ◽  
Malini Shankar ◽  
...  
Keyword(s):  
Adrenal Glands ◽  
Mutant Mice ◽  
Null Mutant ◽  
Wild Type ◽  
Normal Morphology ◽  
Adrenal Hormones ◽  
Adrenal Cells ◽  
Mouse Mutants ◽  
Null Mutant Mice ◽  
And Function

Abstract Adult mouse mutants homozygous for an engineered proopiomelanocortin (POMC)-null allele lack macroscopically distinct adrenal glands and circulating adrenal hormones. To understand the basis for this adrenal defect, we compared the development of adrenal primordia in POMC-null mice and littermate controls. POMC-null mutant mice are born with adrenal glands that are morphologically indistinguishable from those of their wild-type littermates. However, in mutants adrenal cells fail to proliferate postnatally and adrenals atrophy until they have disappeared macroscopically in the adult. While present, mutant adrenals are differentiated as evidenced by the presence of enzymes for the final steps in the synthesis of corticosterone, aldosterone, and catecholamines. However, in contrast to adrenals of wild-type littermates, adrenals of POMC-null mutants do not produce corticosterone, not even in response to acute stimulation with exogenous ACTH. They do produce aldosterone; however, it is produced at reduced levels correlating with adrenal size. Transplantation of POMC-null mutant adrenals to adrenalectomized wild-type littermates results in adrenals with normal morphology and production of both corticosterone and aldosterone. These findings demonstrate that POMC peptides are not required for prenatal adrenal development and that POMC peptides in addition to ACTH are required for postnatal proliferation and maintenance of adrenal structures capable of producing both glucocorticoids and mineralocorticoids.

scholarly journals TheSchizosaccharomyces pombe spo3+Gene Is Required for Assembly of the Forespore Membrane and Genetically Interacts withpsy1+-encoding Syntaxin-like Protein

2001 ◽  
Vol 12 (12) ◽  
pp. 3955-3972 ◽  
Author(s):  
Taro Nakamura ◽  
Michiko Nakamura-Kubo ◽  
Aiko Hirata ◽  
Chikashi Shimoda
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Vegetative Growth ◽  
Fluorescent Protein ◽  
Membrane Vesicles ◽  
Null Mutant ◽  
Wild Type ◽  
Normal Morphology ◽  
Novel Proteins ◽  
Green Fluorescent

Formation of the forespore membrane, which becomes the plasma membrane of spores, is an intriguing step in the sporulation of the fission yeast Schizosaccharomyces pombe. Here we report two novel proteins that localize to the forespore membrane.spo3+encodes a potential membrane protein, which was expressed only during sporulation. Green fluorescent protein (GFP) fusion revealed that Spo3 localized to the forespore membrane. The spo3 disruptant was viable and executed meiotic nuclear divisions as efficiently as the wild type but did not form spores. One of the spo3 alleles,spo3-KC51, was dose-dependently suppressed bypsy1+, which encodes a protein similar to mammalian syntaxin-1A, a component of the plasma membrane docking/fusion complex. psy1+was essential for vegetative growth, and its transcription was enhanced during sporulation. As expected, Psy1 localized to the plasma membrane during vegetative growth. Interestingly, Psy1 on the plasma membrane disappeared immediately after first meiotic division and relocalized to the forespore membrane as the second division initiated. In thespo3 null mutant, the forespore membrane was initiated but failed to develop a normal morphology. Electron microscopy revealed that membrane vesicles were accumulated in the cytoplasm of immaturespo3Δ asci. These results suggest that Spo3 is a key component of the forespore membrane and is essential for its assembly acting in collaboration with the syntaxin-like protein.

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 Haploid induction by a maize cenh3 null mutant

2021 ◽  
Vol 7 (4) ◽  
pp. eabe2299 ◽  
Author(s):  
Na Wang ◽  
Jonathan I. Gent ◽  
R. Kelly Dawe
Keyword(s):  
Histone H3 ◽  
Null Mutation ◽  
Null Mutant ◽  
Wild Type ◽  
Haploid Induction ◽  
Cell Divisions ◽  
Gamete Formation ◽  
Simplified Method ◽  
Single Cross ◽  
Subsequent Loss

The production of haploids is an important first step in creating many new plant varieties. One approach used in Arabidopsis involves crossing plants expressing different forms of centromeric histone H3 (CENP-A/CENH3) and subsequent loss of genome with weaker centromeres. However, the method has been ineffective in crop plants. Here, we describe a greatly simplified method based on crossing maize lines that are heterozygous for a cenh3 null mutation. Crossing +/cenh3 to wild-type plants in both directions yielded haploid progeny. Genome elimination was determined by the cenh3 genotype of the gametophyte, suggesting that centromere failure is caused by CENH3 dilution during the postmeiotic cell divisions that precede gamete formation. The cenh3 haploid inducer works as a vigorous hybrid and can be transferred to other lines in a single cross, making it versatile for a variety of applications.

scholarly journals Ectopic overexpression of a type-II DGAT (CeDGAT2-2) derived from oil-rich tuber of Cyperus esculentus enhances accumulation of oil and oleic acid in tobacco leaves

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yu Gao ◽  
Yan Sun ◽  
Huiling Gao ◽  
Ying Chen ◽  
Xiaoqing Wang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Negative Impact ◽  
Value Added ◽  
Cyperus Esculentus ◽  
Wild Type ◽  
Tobacco Leaves ◽  
Vegetative Tissues ◽  
Oil Storage ◽  
Tag Biosynthesis

Abstract Background Engineering triacylglycerol (TAG) accumulation in vegetative tissues of non-food crops has become a promising way to meet our increasing demand for plant oils, especially the renewable production of biofuels. The most important target modified in this regard is diacylglycerol acyltransferase (DGAT) enzyme responsible for the final rate-limiting step in TAG biosynthesis. Cyperus esculentus is a unique plant largely accumulating oleic acid-enriched oil in its underground tubers. We speculated that DGAT derived from such oil-rich tubers could function more efficiently than that from oleaginous seeds in enhancing oil storage in vegetative tissues of tobacco, a high-yielding biomass crops. Results Three CeDGAT genes namely CeDGAT1, CeDGAT2-1 and CeDGAT2-2 were identified in C. esculentus by mining transcriptome of developing tubers. These CeDGATs were expressed in tissues tested, with CeDGAT1 highly in roots, CeDGAT2-1 abundantly in leaves, and CeDGAT2-2 predominantly in tubers. Notably, CeDGAT2-2 expression pattern was in accordance with oil dynamic accumulation during tuber development. Overexpression of CeDGAT2-2 functionally restored TAG biosynthesis in TAG-deficient yeast mutant H1246. Oleic acid level was significantly increased in CeDGAT2-2 transgenic yeast compared to the wild-type yeast and ScDGA1-expressed control under culture with and without feeding of exogenous fatty acids. Overexpressing CeDGAT2-2 in tobacco led to dramatic enhancements of leafy oil by 7.15- and 1.7-fold more compared to the wild-type control and plants expressing Arabidopsis seed-derived AtDGAT1. A substantial change in fatty acid composition was detected in leaves, with increase of oleic acid from 5.1% in the wild type to 31.33% in CeDGAT2-2-expressed tobacco and accompanied reduction of saturated fatty acids. Moreover, the elevated accumulation of oleic acid-enriched TAG in transgenic tobacco exhibited no significantly negative impact on other agronomic traits such as photosynthesis, growth rates and seed germination except for small decline of starch content. Conclusions The present data indicate that CeDGAT2-2 has a high enzyme activity to catalyze formation of TAG and a strong specificity for oleic acid-containing substrates, providing new insights into understanding oil biosynthesis mechanism in plant vegetative tissues. Overexpression of CeDGAT2-2 alone can significantly increase oleic acid-enriched oil accumulation in tobacco leaves without negative impact on other agronomy traits, showing CeDGAT2-2 as the desirable target gene in metabolic engineering to enrich oil and value-added lipids in high-biomass plants for commercial production of biofuel oils.

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.

scholarly journals CodY Is a Global Regulator of Virulence-Associated Properties for Clostridium perfringens Type D Strain CN3718

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Jihong Li ◽  
Menglin Ma ◽  
Mahfuzur R. Sarker ◽  
Bruce A. McClane
Keyword(s):  
Clostridium Perfringens ◽  
Null Mutant ◽  
Intestinal Infection ◽  
Wild Type ◽  
Global Regulator ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Type D ◽  
Epsilon Toxin ◽  
Virulence Properties

ABSTRACT CodY is known to regulate various virulence properties in several Gram-positive bacteria but has not yet been studied in the important histotoxic and intestinal pathogen Clostridium perfringens. The present study prepared an isogenic codY-null mutant in C. perfringens type D strain CN3718 by insertional mutagenesis using the Targetron system. Western blot analysis indicated that, relative to wild-type CN3718 or a complementing strain, this isogenic codY mutant produces reduced levels of epsilon toxin (ETX). Using supernatants from cultures of the wild-type, codY-null mutant, and complementing strains, CodY regulation of ETX production was shown to have cytotoxic consequences for MDCK cells. The CodY regulatory effect on ETX production was specific, since the codY-null mutant still made wild-type levels of alpha-toxin and perfringolysin O. Sialidase activity measurements and sialidase Western blot analysis of supernatants from CN3718 and its isogenic derivatives showed that CodY represses overall exosialidase activity due to a reduced presence of NanH in culture supernatants. Inactivation of the codY gene significantly decreased the adherence of CN3718 vegetative cells or spores to host Caco-2 cells. Finally, the codY mutant showed increased spore formation under vegetative growth conditions, although germination of these spores was impaired. Overall, these results identify CodY as a global regulator of many C. perfringens virulence-associated properties. Furthermore, they establish that, via CodY, CN3718 coordinately regulates many virulence-associated properties likely needed for intestinal infection. IMPORTANCE Clostridium perfringens is a major human and livestock pathogen because it produces many potent toxins. C. perfringens type D strains cause intestinal infections by producing toxins, especially epsilon toxin (ETX). Previous studies identified CodY as a regulator of certain virulence properties in other Gram-positive bacteria. Our study now demonstrates that CodY is a global regulator of virulence-associated properties for type D strain CN3718. It promotes production of ETX, attachment of CN3718 vegetative cells or spores to host enterocyte-like Caco-2 cells, and spore germination; the last two effects may assist intestinal colonization. In contrast, CodY represses sporulation. These results provide the first evidence that CodY can function as a global regulator of C. perfringens virulence-associated properties and that this strain coordinately regulates its virulence-associated properties using CodY to increase ETX production, host cell attachment, and spore germination but to repress sporulation, as would be optimal during type D intestinal infection.

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