scholarly journals Dicer-like proteins influence Arabidopsis root microbiota independent of RNA-directed DNA methylation

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Richa Kaushal ◽  
Li Peng ◽  
Sunil K. Singh ◽  
Mengrui Zhang ◽  
Xinlian Zhang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Wall ◽  
Plant Defense ◽  
Root Exudates ◽  
Rrna Gene ◽  
Epigenetic Factors ◽  
Callose Deposition ◽  
Arabidopsis Root ◽  
Triple Mutation ◽  
Root Microbiota

Abstract Background Plants are naturally associated with root microbiota, which are microbial communities influential to host fitness. Thus, it is important to understand how plants control root microbiota. Epigenetic factors regulate the readouts of genetic information and consequently many essential biological processes. However, it has been elusive whether RNA-directed DNA methylation (RdDM) affects root microbiota assembly. Results By applying 16S rRNA gene sequencing, we investigated root microbiota of Arabidopsis mutants defective in the canonical RdDM pathway, including dcl234 that harbors triple mutation in the Dicer-like proteins DCL3, DCL2, and DCL4, which produce small RNAs for RdDM. Alpha diversity analysis showed reductions in microbe richness from the soil to roots, reflecting the selectivity of plants on root-associated bacteria. The dcl234 triple mutation significantly decreases the levels of Aeromonadaceae and Pseudomonadaceae, while it increases the abundance of many other bacteria families in the root microbiota. However, mutants of the other examined key players in the canonical RdDM pathway showed similar microbiota as Col-0, indicating that the DCL proteins affect root microbiota in an RdDM-independent manner. Subsequently gene analysis by shotgun sequencing of root microbiome indicated a selective pressure on microbial resistance to plant defense in the dcl234 mutant. Consistent with the altered plant-microbe interactions, dcl234 displayed altered characters, including the mRNA and sRNA transcriptomes that jointly highlighted altered cell wall organization and up-regulated defense, the decreased cellulose and callose deposition in root xylem, and the restructured profile of root exudates that supported the alterations in gene expression and cell wall modifications. Conclusion Our findings demonstrate an important role of the DCL proteins in influencing root microbiota through integrated regulation of plant defense, cell wall compositions, and root exudates. Our results also demonstrate that the canonical RdDM is dispensable for Arabidopsis root microbiota. These findings not only establish a connection between root microbiota and plant epigenetic factors but also highlight the complexity of plant regulation of root microbiota.

SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

1990 ◽  
Vol 48 (3) ◽  
pp. 698-699
Author(s):  
K.S. Walters ◽  
R.D. Sjolund ◽  
K.C. Moore
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Cultured Cells ◽  
Root Hairs ◽  
Callus Cultures ◽  
Callose Deposition ◽  
Culture Cells ◽  
Wall Structures ◽  
Ultraviolet Illumination ◽  
Callose Formation

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

scholarly journals Association of expression of epigenetic molecular factors with DNA methylation and sensitivity to chemotherapeutic agents in cancer cell lines

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Suleyman Vural ◽  
Alida Palmisano ◽  
William C. Reinhold ◽  
Yves Pommier ◽  
Beverly A. Teicher ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Line ◽  
Cell Lines ◽  
Cancer Cell ◽  
Antitumor Agents ◽  
Cancer Cell Lines ◽  
Chemotherapeutic Agents ◽  
Epigenetic Factors ◽  
Expression Of Genes ◽  
Genes Encoding

Abstract Background Altered DNA methylation patterns play important roles in cancer development and progression. We examined whether expression levels of genes directly or indirectly involved in DNA methylation and demethylation may be associated with response of cancer cell lines to chemotherapy treatment with a variety of antitumor agents. Results We analyzed 72 genes encoding epigenetic factors directly or indirectly involved in DNA methylation and demethylation processes. We examined association of their pretreatment expression levels with methylation beta-values of individual DNA methylation probes, DNA methylation averaged within gene regions, and average epigenome-wide methylation levels. We analyzed data from 645 cancer cell lines and 23 cancer types from the Cancer Cell Line Encyclopedia and Genomics of Drug Sensitivity in Cancer datasets. We observed numerous correlations between expression of genes encoding epigenetic factors and response to chemotherapeutic agents. Expression of genes encoding a variety of epigenetic factors, including KDM2B, DNMT1, EHMT2, SETDB1, EZH2, APOBEC3G, and other genes, was correlated with response to multiple agents. DNA methylation of numerous target probes and gene regions was associated with expression of multiple genes encoding epigenetic factors, underscoring complex regulation of epigenome methylation by multiple intersecting molecular pathways. The genes whose expression was associated with methylation of multiple epigenome targets encode DNA methyltransferases, TET DNA methylcytosine dioxygenases, the methylated DNA-binding protein ZBTB38, KDM2B, SETDB1, and other molecular factors which are involved in diverse epigenetic processes affecting DNA methylation. While baseline DNA methylation of numerous epigenome targets was correlated with cell line response to antitumor agents, the complex relationships between the overlapping effects of each epigenetic factor on methylation of specific targets and the importance of such influences in tumor response to individual agents require further investigation. Conclusions Expression of multiple genes encoding epigenetic factors is associated with drug response and with DNA methylation of numerous epigenome targets that may affect response to therapeutic agents. Our findings suggest complex and interconnected pathways regulating DNA methylation in the epigenome, which may both directly and indirectly affect response to chemotherapy.

scholarly journals The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1665
Author(s):  
Natalia Nikonorova ◽  
Evan Murphy ◽  
Cassio Flavio Fonseca de Lima ◽  
Shanshuo Zhu ◽  
Brigitte van de Cotte ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Growth Regulators ◽  
Growth Regulation ◽  
Phosphorylation Site ◽  
Primary Root ◽  
Root Tip ◽  
Arabidopsis Root ◽  
Growth Promoting ◽  
The Impact

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.

scholarly journals DNA methylation as predictive marker of response to immunotherapy?

2021 ◽  
Author(s):  
Gerwin Heller
Keyword(s):  
Dna Methylation ◽  
Cancer Treatment ◽  
Treatment Efficacy ◽  
Predictive Marker ◽  
Short Review ◽  
Predictive Markers ◽  
Epigenetic Factors

SummaryImmunotherapy is one of the major breakthroughs in cancer treatment. However, many patients do not benefit from this type of therapy. Thus, there is an urgent need for a strategy to predict treatment efficacy before start of therapy. The role of certain genetic and epigenetic factors as potential predictive markers for response to immunotherapy is discussed in this short review.

scholarly journals Actinomadura geliboluensis sp. nov., isolated from soil

2012 ◽  
Vol 62 (Pt_8) ◽  
pp. 2011-2017 ◽  
Author(s):  
Anil Sazak ◽  
Mustafa Camas ◽  
Cathrin Spröer ◽  
Hans-Peter Klenk ◽  
Nevzat Sahin
Keyword(s):  
Cell Wall ◽  
Type Species ◽  
Diaminopimelic Acid ◽  
Rrna Gene ◽  
Phenotypic Data ◽  
Content Type ◽  
Link Type ◽  
Acid Type ◽  
Gene Sequence Analysis ◽  
Taxonomic Approach

A novel actinobacterium, strain A8036T, isolated from soil, was investigated by using a polyphasic taxonomic approach. The organism formed extensively branched substrate hyphae that generated spiral chains of spores with irregular surfaces. The cell wall contained meso-diaminopimelic acid (type III) and cell-wall sugars were glucose, madurose, mannose and ribose. The predominant menaquinones were MK-9(H6) and MK-9(H4). The phospholipids were diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The major cellular fatty acids were iso-C16 : 0, C17 : 1 cis9, C16 : 0, C15 : 0 and 10-methyl C17 : 0. Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of strain A8036T were Actinomadura meyerae DSM 44715T (99.23 % similarity), Actinomadura bangladeshensis DSM 45347T (98.9 %) and Actinomadura chokoriensis DSM 45346T (98.3 %). However, DNA–DNA relatedness and phenotypic data demonstrated that strain A8036T could be clearly distinguished from the type strains of all closely related Actinomadura species. Strain A8036T is therefore considered to represent a novel species of the genus Actinomadura , for which the name Actinomadura geliboluensis sp. nov. is proposed. The type strain is A8036T ( = DSM 45508T = KCTC 19868T).

scholarly journals Interaction between Cell Wall and Plasma Membrane via RGD Motif is Implicated in Plant Defense Responses

1998 ◽  
Vol 39 (11) ◽  
pp. 1245-1249 ◽  
Author(s):  
A. Kiba ◽  
M. Sugimoto ◽  
K. Toyoda ◽  
Y. Ichinose ◽  
T. Yamada ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Defense ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Rgd Motif

A natural case of RIP: degeneration of the DNA sequence in an ancestral tandem duplication

1989 ◽  
Vol 9 (10) ◽  
pp. 4416-4421
Author(s):  
W S Grayburn ◽  
E U Selker
Keyword(s):  
Dna Methylation ◽  
Tandem Duplication ◽  
De Novo ◽  
5S Rrna ◽  
Rrna Genes ◽  
Structural Basis ◽  
Rrna Gene ◽  
Oak Ridge ◽  
5S Rrna Gene ◽  
5S Rrna Genes

5S rRNA genes of Neurospora crassa are generally dispersed in the genome and are unmethylated. The xi-eta region of Oak Ridge strains represents an informative exception. Most of the cytosines in this region, which consists of a diverged tandem duplication of a 0.8-kilobase-pair segment including a 5S rRNA gene, appear to be methylated (E. U. Selker and J. N. Stevens, Proc. Natl. Acad. Sci. USA 82:8114-8118, 1985). Previous work demonstrated that the xi-eta region functions as a portable signal for de novo DNA methylation (E. U. Selker and J. N. Stevens, Mol. Cell. Biol. 7:1032-1038, 1987; E. U. Selker, B. C. Jensen, and G. A. Richardson, Science 238:48-53, 1987). To identify the structural basis of this property, we have isolated and characterized an unmethylated allele of the xi-eta region from N. crassa Abbott 4. The Abbott 4 allele includes a single 5S rRNA gene, theta, which is different from all previously identified Neurospora 5S rRNA genes. Sequence analysis suggests that the xi-eta region arose from the theta region by duplication of a 794-base-pair segment followed by 267 G.C to A.T mutations in the duplicated DNA. The distribution of these mutations is not random. We propose that the RIP process of N. crassa (E. U. Selker, E. B. Cambareri, B. C. Jensen, and K. R. Haack, Cell 51:741-752, 1987; E. U. Selker, and P. W. Garrett, Proc. Natl. Acad. Sci. USA 85:6870-6874, 1988; E. B. Cambareri, B. C. Jensen, E. Schabtach, and E. U. Selker, Science 244:1571-1575, 1989) is responsible for the numerous transition mutations and DNA methylation in the xi-eta region. A long homopurine-homopyrimidine stretch immediately following the duplicated segment is 9 base pairs longer in the Oak Ridge allele than in the Abbott 4 allele. Triplex DNA, known to occur in homopurine-homopyrimidine sequences, may have mediated the tandem duplication.

DNA methylation inhibits transcription by RNA polymerase III of a tRNA gene, but not of a 5S rRNA gene

FEBS Letters ◽  
1990 ◽  
Vol 269 (2) ◽  
pp. 358-362 ◽  
Author(s):  
Daniel Besser ◽  
Frank Götz ◽  
Kai Schulze-Forster ◽  
Herbert Wagner ◽  
Hans Kröger ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Rna Polymerase ◽  
Trna Gene ◽  
Rna Polymerase Iii ◽  
5S Rrna ◽  
Rrna Gene ◽  
Polymerase Iii ◽  
5S Rrna Gene

scholarly journals The Role of Arabinogalactan Type II Degradation in Plant-Microbe Interactions

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Guadalupe Villa-Rivera ◽  
Horacio Cano-Camacho ◽  
Everardo López-Romero ◽  
María Guadalupe Zavala-Páramo
Keyword(s):  
Cell Wall ◽  
Plant Defense ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Degradation Products ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Plant Interactions ◽  
Root Tips ◽  
Microbe Interactions

Arabinogalactans (AGs) are structural polysaccharides of the plant cell wall. A small proportion of the AGs are associated with hemicellulose and pectin. Furthermore, AGs are associated with proteins forming the so-called arabinogalactan proteins (AGPs), which can be found in the plant cell wall or attached through a glycosylphosphatidylinositol (GPI) anchor to the plasma membrane. AGPs are a family of highly glycosylated proteins grouped with cell wall proteins rich in hydroxyproline. These glycoproteins have important and diverse functions in plants, such as growth, cellular differentiation, signaling, and microbe-plant interactions, and several reports suggest that carbohydrate components are crucial for AGP functions. In beneficial plant-microbe interactions, AGPs attract symbiotic species of fungi or bacteria, promote the development of infectious structures and the colonization of root tips, and furthermore, these interactions can activate plant defense mechanisms. On the other hand, plants secrete and accumulate AGPs at infection sites, creating cross-links with pectin. As part of the plant cell wall degradation machinery, beneficial and pathogenic fungi and bacteria can produce the enzymes necessary for the complete depolymerization of AGs including endo-β-(1,3), β-(1,4) and β-(1,6)-galactanases, β-(1,3/1,6) galactanases, α-L-arabinofuranosidases, β-L-arabinopyranosidases, and β-D-glucuronidases. These hydrolytic enzymes are secreted during plant-pathogen interactions and could have implications for the function of AGPs. It has been proposed that AGPs could prevent infection by pathogenic microorganisms because their degradation products generated by hydrolytic enzymes of pathogens function as damage-associated molecular patterns (DAMPs) eliciting the plant defense response. In this review, we describe the structure and function of AGs and AGPs as components of the plant cell wall. Additionally, we describe the set of enzymes secreted by microorganisms to degrade AGs from AGPs and its possible implication for plant-microbe interactions.

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