scholarly journals The Expression of MaEXP1, a Melilotus alba Expansin Gene, Is Upregulated During the Sweetclover-Sinorhizobium meliloti Interaction

2004 ◽  
Vol 17 (6) ◽  
pp. 613-622 ◽  
Author(s):  
Walter Giordano ◽  
Ann M. Hirsch
Keyword(s):  
Cell Wall ◽  
Sinorhizobium Meliloti ◽  
Plant Cell Wall ◽  
Nodule Development ◽  
Northern Analysis ◽  
Degenerate Primers ◽  
Melilotus Alba ◽  
Expansin Gene ◽  
Rapid Amplification

Expansins are a highly conserved group of cell wall-localized proteins that appear to mediate changes in cell wall plasticity during cell expansion or differentiation. The accumulation of expansin protein or the mRNA for specific expansin gene family members has been correlated with the growth of various plant organs. Because expansin proteins are closely associated with plant cell wall expansion, and as part of a larger study to determine the role of different gene products in the legume-Rhizobium spp. symbiosis, we investigated whether a Melilotus alba (white sweetclover) expansin gene is expressed during nodule development. A cDNA fragment encoding an expansin gene (EXP) was isolated from Sinorhizobium meliloti-inoculated sweetclover root RNA by reverse-transcriptase polymerase chain reaction using degenerate primers, and a full-length sweetclover expansin sequence (MaEXP1) was obtained using 5′ and 3′rapid amplification of cDNA end cloning. The predicted amino acid of the sweetclover expansin is highly conserved with the various α-expansins in the GenBank database. MaEXP1 contains a series of eight cysteines and four tryptophans that are conserved in the α-expansin protein family. Northern analysis and whole-mount in situ hybridization analyses indicate that MaEXP1 mRNA expression is enhanced in roots within hours after inoculation with S. meliloti and in nodules. Western and immunolocalization studies using a cucumber expansin antibody demonstrated that a cross-reacting protein accumulated in the expanding cells of the nodule.

Effects of a Nod-factor-overproducing strain of Sinorhizobium meliloti on the expression of the ENOD40 gene in Melilotus alba

2002 ◽  
Vol 80 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Walter F Giordano ◽  
Michelle R Lum ◽  
Ann M Hirsch
Keyword(s):  
Lateral Root ◽  
Sinorhizobium Meliloti ◽  
Cortical Cell ◽  
Host Cells ◽  
Nodule Development ◽  
Nodule Formation ◽  
Additional Increase ◽  
Nod Factor ◽  
Melilotus Alba ◽  
Different Strains

We have initiated studies on the molecular biology and genetics of white sweetclover (Melilotus alba Desr.) and its responses to inoculation with the nitrogen-fixing symbiont Sinorhizobium meliloti. Early nodulin genes such as ENOD40 serve as markers for the transition from root to nodule development even before visible stages of nodule formation are evident. Using Northern blot analysis, we found that the ENOD40 gene was expressed within 6 h after inoculation with two different strains of S. meliloti, one of which overproduces symbiotic Nod factors. Inoculation with this strain resulted in an additional increase in ENOD40 gene expression over a typical wild-type S. meliloti strain. Moreover, the increase in mRNA brought about by the Nod-factor-overproducing strain 24 h after inoculation was correlated with lateral root formation by using whole-mount in situ hybridization to localize ENOD40 transcripts in lateral root meristems and by counting lateral root initiation sites. Cortical cell divisions were not detected. We also found that nodulation occurred more rapidly on white sweetclover in response to the Nod-factor-overproducing strain, but ultimately there was no difference in nodulation efficiency in terms of nodule number or the number of roots nodulated by the two strains. Also, the two strains could effectively co-colonize the host when inoculated together, although a few host cells were occupied by both strains.Key words: ENOD40, Nod factor, Melilotus, Sinorhizobium, symbiosis.

scholarly journals Role of cytoskeleton in plant cell wall formation

2020 ◽  
Vol 50 (2) ◽  
pp. 176-186
Author(s):  
Yi MAN ◽  
RuiLi LI ◽  
YuFen BU ◽  
Na SUN ◽  
YanPing JING ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Cell Wall Formation ◽  
Wall Formation

scholarly journals Sheep Digestive Physiology and Constituents of Feeds

2021 ◽  
Author(s):  
Samir Medjekal ◽  
Mouloud Ghadbane
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Early Stage ◽  
Growth Period ◽  
Cell Plate ◽  
Soluble Carbohydrates ◽  
Winter Period ◽  
The Common

Sheep have a gastrointestinal tract similar to that of other ruminants. Their stomach is made up of four digestive organs: the rumen, the reticulum, the omasum and the abomasum. The rumen plays a role in storing ingested foods, which are fermented by a complex anaerobic rumen microbiota population with different types of interactions, positive or negative, that can occur between their microbial populations. Sheep feeding is largely based on the use of natural or cultivated fodder, which is exploited in green by grazing during the growth period of the grass and in the form of fodder preserved during the winter period. Ruminant foods are essentially of plant origin, and their constituents belong to two types of structures: intracellular constituents and cell wall components. Cellular carbohydrates play a role of metabolites or energy reserves; soluble carbohydrates account for less than 10% dry matter (DM) of foods. The plant cell wall is multi-layered and consists of primary wall and secondary wall. Fundamentally, the walls are deposited at an early stage of growth. A central blade forms the common boundary layer between two adjacent cells and occupies the location of the cell plate. Most of the plant cell walls consist of polysaccharides (cellulose, hemicellulose and pectic substances) and lignin, these constituents being highly polymerized, as well as proteins and tannins.

Impact of plant cell wall network on biodegradation in soil: Role of lignin composition and phenolic acids in roots from 16 maize genotypes

2011 ◽  
Vol 43 (7) ◽  
pp. 1544-1552 ◽  
Author(s):  
Gaylord Erwan Machinet ◽  
Isabelle Bertrand ◽  
Yves Barrière ◽  
Brigitte Chabbert ◽  
Sylvie Recous
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Phenolic Acids ◽  
Plant Cell Wall ◽  
Maize Genotypes ◽  
Lignin Composition ◽  
Biodegradation In Soil

scholarly journals Role of murE in the Expression of β-Lactam Antibiotic Resistance in Staphylococcus aureus

2004 ◽  
Vol 186 (6) ◽  
pp. 1705-1713 ◽  
Author(s):  
S. Gardete ◽  
A. M. Ludovice ◽  
R. G. Sobral ◽  
S. R. Filipe ◽  
H. de Lencastre ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Methicillin Resistance ◽  
Inducible Promoter ◽  
Northern Analysis ◽  
Penicillin Binding Protein ◽  
Drastic Reduction ◽  
Precursor Pool ◽  
Lactam Antibiotic

ABSTRACT It was shown earlier that Tn551 inserted into the C-terminal region of murE of parental methicillin-resistant Staphylococcus aureus strain COL causes a drastic reduction in methicillin resistance, accompanied by accumulation of UDP-MurNAc dipeptide in the cell wall precursor pool and incorporation of these abnormal muropeptides into the peptidoglycan of the mutant. Methicillin resistance was recovered in a suppressor mutant. The murE gene of the same strain was then put under the control of the isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible promoter P spac . Bacteria grown in the presence of suboptimal concentrations of IPTG accumulated UDP-MurNAc dipeptide in the cell wall precursor pool. Both growth rates and methicillin resistance levels (but not resistance to other antibiotics) were a function of the IPTG concentration. Northern analysis showed a gradual increase in the transcription of murE and also in the transcription of pbpB and mecA, parallel with the increasing concentrations of IPTG in the medium. A similar increase in the transcription of pbpB and mecA, the structural genes of penicillin-binding protein 2 (PBP2) and PBP2A, was also detected in the suppressor mutant. The expression of these two proteins, which are known to play critical roles in the mechanism of staphylococcal methicillin resistance, appears to be—directly or indirectly—under the control of the murE gene. Our data suggest that the drastic reduction of the methicillin MIC seen in the murE mutant may be caused by the insufficient cellular amounts of these two PBPs.

scholarly journals Induction of Fusarium lytic Enzymes by Extracts from Resistant and Susceptible Cultivars of Pea (Pisum sativum L.)

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 976
Author(s):  
Lakshmipriya Perincherry ◽  
Chaima Ajmi ◽  
Souheib Oueslati ◽  
Agnieszka Waśkiewicz ◽  
Łukasz Stępień
Keyword(s):  
Cell Wall ◽  
Plant Extracts ◽  
Plant Cell Wall ◽  
Pathogenic Fungi ◽  
Human Beings ◽  
Cell Wall Degrading Enzymes ◽  
Lytic Enzymes ◽  
Mycelium Growth ◽  
Oat Bran

Being pathogenic fungi, Fusarium produce various extracellular cell wall-degrading enzymes (CWDEs) that degrade the polysaccharides in the plant cell wall. They also produce mycotoxins that contaminate grains, thereby posing a serious threat to animals and human beings. Exposure to mycotoxins occurs through ingestion of contaminated grains, inhalation and through skin absorption, thereby causing mycotoxicoses. The toxins weaken the host plant, allowing the pathogen to invade successfully, with the efficiency varying from strain to strain and depending on the plant infected. Fusariumoxysporum predominantly produces moniliformin and cyclodepsipeptides, whereas F. proliferatum produces fumonisins. The aim of the study was to understand the role of various substrates and pea plant extracts in inducing the production of CWDEs and mycotoxins. Additionally, to monitor the differences in their levels when susceptible and resistant pea plant extracts were supplemented. The cultures of F. proliferatum and F. oxysporum strains were supplemented with various potential inducers of CWDEs. During the initial days after the addition of substrates, the fungus cocultivated with pea extracts and other carbon substrates showed increased activities of β-glucosidase, xylanase, exo-1,4-glucanase and lipase. The highest inhibition of mycelium growth (57%) was found in the cultures of F. proliferatum strain PEA1 upon the addition of cv. Sokolik extract. The lowest fumonisin content was exhibited by the cultures with the pea extracts and oat bran added, and this can be related to the secondary metabolites and antioxidants present in these substrates.

scholarly journals The regulatory and transcriptional landscape associated with carbon utilization in a filamentous fungus

2020 ◽  
Vol 117 (11) ◽  
pp. 6003-6013 ◽  
Author(s):  
Vincent W. Wu ◽  
Nils Thieme ◽  
Lori B. Huberman ◽  
Axel Dietschmann ◽  
David J. Kowbel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Plant Biomass ◽  
Carbon Sources ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Genes Encoding

Filamentous fungi, such asNeurospora crassa, are very efficient in deconstructing plant biomass by the secretion of an arsenal of plant cell wall-degrading enzymes, by remodeling metabolism to accommodate production of secreted enzymes, and by enabling transport and intracellular utilization of plant biomass components. Although a number of enzymes and transcriptional regulators involved in plant biomass utilization have been identified, how filamentous fungi sense and integrate nutritional information encoded in the plant cell wall into a regulatory hierarchy for optimal utilization of complex carbon sources is not understood. Here, we performed transcriptional profiling ofN. crassaon 40 different carbon sources, including plant biomass, to provide data on how fungi sense simple to complex carbohydrates. From these data, we identified regulatory factors inN. crassaand characterized one (PDR-2) associated with pectin utilization and one with pectin/hemicellulose utilization (ARA-1). Using in vitro DNA affinity purification sequencing (DAP-seq), we identified direct targets of transcription factors involved in regulating genes encoding plant cell wall-degrading enzymes. In particular, our data clarified the role of the transcription factor VIB-1 in the regulation of genes encoding plant cell wall-degrading enzymes and nutrient scavenging and revealed a major role of the carbon catabolite repressor CRE-1 in regulating the expression of major facilitator transporter genes. These data contribute to a more complete understanding of cross talk between transcription factors and their target genes, which are involved in regulating nutrient sensing and plant biomass utilization on a global level.

scholarly journals MtBZR1 Plays an Important Role in Nodule Development in Medicago truncatula

2019 ◽  
Vol 20 (12) ◽  
pp. 2941
Author(s):  
Can Cui ◽  
Hongfeng Wang ◽  
Limei Hong ◽  
Yiteng Xu ◽  
Yang Zhao ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Normal Growth ◽  
Dry Mass ◽  
Growth Conditions ◽  
Nodule Development ◽  
Functional Study ◽  
Loss Of Function ◽  
Wild Type

Brassinosteroid (BR) is an essential hormone in plant growth and development. The BR signaling pathway was extensively studied, in which BRASSINAZOLE RESISTANT 1 (BZR1) functions as a key regulator. Here, we carried out a functional study of the homolog of BZR1 in Medicago truncatula R108, whose expression was induced in nodules upon Sinorhizobium meliloti 1021 inoculation. We identified a loss-of-function mutant mtbzr1-1 and generated 35S:MtBZR1 transgenic lines for further analysis at the genetic level. Both the mutant and the overexpression lines of MtBZR1 showed no obvious phenotypic changes under normal growth conditions. After S. meliloti 1021 inoculation, however, the shoot and root dry mass was reduced in mtbzr1-1 compared with the wild type, caused by partially impaired nodule development. The transcriptomic analysis identified 1319 differentially expressed genes in mtbzr1-1 compared with wild type, many of which are involved in nodule development and secondary metabolite biosynthesis. Our results demonstrate the role of MtBZR1 in nodule development in M. truncatula, shedding light on the potential role of BR in legume–rhizobium symbiosis.

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