scholarly journals Fungal adaptation to plant defenses through convergent assembly of metabolic modules

2018 ◽  
Author(s):  
Emile Gluck-Thaler ◽  
Vinod Vijayakumar ◽  
Jason C. Slot
Keyword(s):  
Plant Defense ◽  
Recurrent Selection ◽  
Gene Clusters ◽  
Metabolic Adaptation ◽  
Primary Role ◽  
Plant Resources ◽  
Experimental Conditions ◽  
Defense Compounds ◽  
Gene Functions ◽  
Convergent Assembly

AbstractThe ongoing diversification of plant defense compounds exerts dynamic selection pressures on the microorganisms that colonize plant tissues. Evolutionary processes that generate resistance towards these compounds increase microbial fitness by giving access to plant resources and increasing pathogen virulence. These processes entail sequence-based mechanisms that result in adaptive gene functions, and combinatorial mechanisms that result in novel syntheses of existing gene functions. However, the priority and interactions among these processes in adaptive resistance remains poorly understood. Using a combination of molecular genetic and computational approaches, we investigated the contributions of sequence-based and combinatorial processes to the evolution of fungal metabolic gene clusters encoding stilbene cleavage oxygenases (SCOs), which catalyze the degradation of biphenolic plant defense compounds known as stilbenes into monophenolic molecules. We present phylogenetic evidence of convergent assembly among three distinct types of SCO gene clusters containing alternate combinations of phenolic catabolism. Multiple evolutionary transitions between different cluster types suggest recurrent selection for distinct gene assemblages. By comparison, we found that the substrate specificities of heterologously expressed SCO enzymes encoded in different clusters types were all limited to stilbenes and related molecules with a 4’-OH group, and differed modestly in substrate range and activity under the experimental conditions. Together, this work suggests a primary role for genome structural rearrangement, and the importance of enzyme modularity, in promoting fungal metabolic adaptation to plant defense chemistry.

Metabolism and force in hypertrophic smooth muscle from rat urinary bladder

1990 ◽  
Vol 258 (5) ◽  
pp. C923-C932 ◽  
Author(s):  
A. Arner ◽  
U. Malmqvist ◽  
B. Uvelius
Keyword(s):  
Outlet Obstruction ◽  
Electrical Field Stimulation ◽  
Metabolic Adaptation ◽  
Active Force ◽  
Force Output ◽  
Experimental Conditions ◽  
Muscle Area ◽  
Rat Urinary Bladder ◽  
High K ◽  
Tension Cost

Ten days of urinary outlet obstruction in the rat induced a threefold increase in bladder weight. Active force of control and hypertrophic bladder muscle strips was measured at varying PO2 levels after high-K+, carbachol, or electrical field stimulation. Highest force output was obtained with carbachol. Force per muscle area was lower in the hypertrophic muscles. The basal rates of oxygen consumption and lactate formation were similar in the two groups. The metabolic tension cost (ATP turnover/active force) was similar in the two groups for activation with high K+ and carbachol. In anoxia the active force decreased, but this was less pronounced in the hypertrophied muscle. Hypertrophied muscle could, in contrast to the controls, maintain a sustained K+ contracture in anoxia. Basal metabolic rates and tension cost were markedly reduced in anoxia for both groups. The lower force per area with unaltered tension cost, in hypertrophic muscles under all experimental conditions, may reflect unaltered intrinsic properties of the contractile system, although the amount of contractile material has decreased relative to cell volume. The increased resistance to anoxia may reflect a metabolic adaptation to impaired oxygen supply to the hypertrophied tissue.

scholarly journals Challenges and Advances in Genome Editing Technologies in Streptomyces

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 734 ◽  
Author(s):  
Yawei Zhao ◽  
Guoquan Li ◽  
Yunliang Chen ◽  
Yinhua Lu
Keyword(s):  
Natural Product ◽  
Genome Editing ◽  
Genetic Manipulation ◽  
Chemical Compounds ◽  
Gene Clusters ◽  
Future Research ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Research Focus ◽  
Experimental Conditions

The genome of Streptomyces encodes a high number of natural product (NP) biosynthetic gene clusters (BGCs). Most of these BGCs are not expressed or are poorly expressed (commonly called silent BGCs) under traditional laboratory experimental conditions. These NP BGCs represent an unexplored rich reservoir of natural compounds, which can be used to discover novel chemical compounds. To activate silent BGCs for NP discovery, two main strategies, including the induction of BGCs expression in native hosts and heterologous expression of BGCs in surrogate Streptomyces hosts, have been adopted, which normally requires genetic manipulation. So far, various genome editing technologies have been developed, which has markedly facilitated the activation of BGCs and NP overproduction in their native hosts, as well as in heterologous Streptomyces hosts. In this review, we summarize the challenges and recent advances in genome editing tools for Streptomyces genetic manipulation with a focus on editing tools based on clustered regularly interspaced short palindrome repeat (CRISPR)/CRISPR-associated protein (Cas) systems. Additionally, we discuss the future research focus, especially the development of endogenous CRISPR/Cas-based genome editing technologies in Streptomyces.

ADJUSTMENTS TO CONSTANT LOW TEMPERATURES IN WHITE RATS LIVING IN GROUPS

1963 ◽  
Vol 41 (3) ◽  
pp. 587-595 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Low Temperatures ◽  
Metabolic Adaptation ◽  
Experimental Conditions ◽  
Cold Stimulus ◽  
White Rats ◽  
Essential Components ◽  
Resting Metabolism ◽  
Increased Sensitivity ◽  
Shivering Thermogenesis ◽  
Fundamental Mechanism

White rats, in groups of 10, were exposed for 3 months in the laboratory to constant temperatures of 19 °C or −10 °C. Grouping the animals did not alter the pattern of metabolic adaptation usually observed in individually cold-acclimated rats and recently observed in group-caged white rats exposed outdoors during the winter. This pattern of adaptation is characterized by an increased capacity for heat production, as shown by a longer survival time at −35 °C, a reduction of shivering, an increased sensitivity to noradrenaline, an increased ear vascularization, a reduction in protein and fat deposition, and an enlargement of heart, liver, and kidneys. Group-caging at constant low temperature (a) prevented the development of cold injuries and the enlargement of pituitary, thyroid, adrenals, which are usually observed in individually cold-exposed rats indoors, (b) resulted in an increased resting metabolism, normal adrenal cortex activity, and no increase in pelt insulation in contrast to that previously found in white rats grouped outdoors during the winter. These different adjustments to cold in white rats exposed to different sets of environmental conditions are compared with similar adjustments found in wild Norway rats.From these comparisons, one must conclude that many of the structural and endocrine adjustments observed in individually cold-acclimated rats in the laboratory are reactions peculiar to continuous cold stimulus, i.e. reactions to a specific set of experimental conditions rather than essential components of the fundamental mechanism for non-shivering thermogenesis.

The Genetic Architecture of Plant Defense Trade-offs in a Common Monkeyflower

2020 ◽  
Author(s):  
Nicholas J Kooyers ◽  
Abigail Donofrio ◽  
Benjamin K Blackman ◽  
Liza M Holeski
Keyword(s):  
Growth Rate ◽  
Plant Defense ◽  
Genetic Linkage ◽  
Genetic Architecture ◽  
Life History Traits ◽  
Total Concentration ◽  
Defense Compounds ◽  
Genetic Constraints ◽  
Trade Offs ◽  
Phenylpropanoid Glycosides

Abstract Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL. While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs. This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.

scholarly journals Bacteria Belonging to Pseudomonas typographi sp. nov. from the Bark Beetle Ips typographus Have Genomic Potential to Aid in the Host Ecology

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 593
Author(s):  
Ezequiel Peral-Aranega ◽  
Zaki Saati-Santamaría ◽  
Miroslav Kolařik ◽  
Raúl Rivas ◽  
Paula García-Fraile
Keyword(s):  
Bark Beetle ◽  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Gene Clusters ◽  
Ips Typographus ◽  
In Vitro Tests ◽  
Defense Compounds ◽  
Genes Encoding ◽  
Host Ecology

European Bark Beetle Ips typographus is a secondary pest that affects dead and weakened spruce trees (Picea genus). Under certain environmental conditions, it has massive outbreaks, resulting in the attacks of healthy trees, becoming a forest pest. It has been proposed that the bark beetle’s microbiome plays a key role in the insect’s ecology, providing nutrients, inhibiting pathogens, and degrading tree defense compounds, among other probable traits yet to be discovered. During a study of bacterial associates from I. typographus, we isolated three strains identified as Pseudomonas from different beetle life stages. A polyphasic taxonomical approach showed that they belong to a new species for which the name Pseudomonas typographi sp nov. is proposed. Genome sequences show their potential to hydrolyze wood compounds and synthesize several vitamins; screening for enzymes production was verified using PNP substrates. Assays in Petri dishes confirmed cellulose and xylan hydrolysis. Moreover, the genomes harbor genes encoding chitinases and gene clusters involved in the synthesis of secondary metabolites with antimicrobial potential. In vitro tests confirmed the capability of the three P. typographi strains to inhibit several Ips beetles’ pathogenic fungi. Altogether, these results suggest that P. typographi aids I. typographi nutrition and resistance to fungal pathogens.

scholarly journals Suppression of the Nuclear Factor Eny2 Increases Insulin Secretion in Poorly Functioning INS-1E Insulinoma Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
P. Dames ◽  
M. Weise ◽  
R. Puff ◽  
B. Göke ◽  
K. G. Parhofer ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Function ◽  
Glucose Sensing ◽  
Metabolic Adaptation ◽  
Nuclear Factor ◽  
Experimental Conditions ◽  
Mouse Pancreatic Islets ◽  
Potential Link ◽  
Insulinoma Cells

Eny2, the mammalian ortholog of yeast Sus1 and drosophila E(y)2, is a nuclear factor that participates in several steps of gene transcription and in mRNA export. We had previously found that Eny2 expression changes in mouse pancreatic islets during the metabolic adaptation to pregnancy. We therefore hypothesized that the protein contributes to the regulation of islet endocrine cell function and tested this hypothesis in rat INS-1E insulinoma cells. Overexpression of Eny2 had no effect but siRNA-mediated knockdown of Eny2 resulted in markedly increased glucose and exendin-4-induced insulin secretion from otherwise poorly glucose-responsive INS-1E cells. Insulin content, cellular viability, and the expression levels of several key components of glucose sensing remained unchanged; however glucose-dependent cellular metabolism was higher after Eny2 knockdown. Suppression of Eny2 enhanced the intracellular incretin signal downstream of cAMP. The use of specific cAMP analogues and pathway inhibitors primarily implicated the PKA and to a lesser extent the EPAC pathway. In summary, we identified a potential link between the nuclear protein Eny2 and insulin secretion. Suppression of Eny2 resulted in increased glucose and incretin-induced insulin release from a poorly glucose-responsive INS-1E subline. Whether these findings extend to other experimental conditions or to in vivo physiology needs to be determined in further studies.

Bacteria Associated with a Tree-Killing Insect Reduce Concentrations of Plant Defense Compounds

2013 ◽  
Vol 39 (7) ◽  
pp. 1003-1006 ◽  
Author(s):  
Celia K. Boone ◽  
Ken Keefover-Ring ◽  
Abigail C. Mapes ◽  
Aaron S. Adams ◽  
Jörg Bohlmann ◽  
...  
Keyword(s):  
Plant Defense ◽  
Defense Compounds

Plant Defense Compounds: Systems Approaches to Metabolic Analysis

2012 ◽  
Vol 50 (1) ◽  
pp. 155-173 ◽  
Author(s):  
Daniel J. Kliebenstein
Keyword(s):  
Plant Defense ◽  
Defense Compounds ◽  
Systems Approaches ◽  
Metabolic Analysis

Influences of elevated CO2 and pest damage on the allocation of plant defense compounds in Bt-transgenic cotton and enzymatic activity of cotton aphid

2011 ◽  
Vol 18 (4) ◽  
pp. 401-408 ◽  
Author(s):  
Gang Wu ◽  
Fa-Jun Chen ◽  
Neng-Wen Xiao ◽  
Feng Ge
Keyword(s):  
Enzymatic Activity ◽  
Plant Defense ◽  
Elevated Co2 ◽  
Transgenic Cotton ◽  
Cotton Aphid ◽  
Defense Compounds ◽  
Pest Damage

Effects of xanthotoxin treatment on trichothecene production inFusarium sporotrichioides

2008 ◽  
Vol 54 (12) ◽  
pp. 1023-1031 ◽  
Author(s):  
Nancy J. Alexander ◽  
Susan P. McCormick ◽  
Judith A. Blackburn
Keyword(s):  
Gene Expression ◽  
Reverse Transcriptase ◽  
Plant Defense ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Toxin Production ◽  
Fusarium Sporotrichioides ◽  
Defense Compounds ◽  
Liquid Cultures ◽  
Oxygenase Activity

There are 4 P450 oxygenases involved in the biosynthesis of T-2 toxin in Fusarium sporotrichioides . Exactly how these enzymes react to antimicrobial plant defense compounds is unknown. Xanthotoxin (8-methoxypsoralen) is a phototoxic furanocoumarin that acts as a P450 oxygenase inhibitor. The current study shows that the addition of concentrations of 1.0 mmol/L or less of xanthotoxin to liquid cultures of F. sporotrichioides NRRL3299 can effectively block T-2 toxin production and cause an increase in accumulation of trichodiene, the hydrocarbon precursor of trichothecenes. The addition of xanthotoxin to liquid cultures of a trichodiene-accumulating F. sporotrichioides Tri4–mutant caused a 3- to 10-fold increase in trichodiene accumulation, suggesting that xanthotoxin not only blocks trichothecene oxygenation reactions, but may in some way also promote the synthesis of trichodiene. Feeding studies showed that 2 of the 4 P450 oxygenases, TRI4 and TRI1, were more sensitive to xanthotoxin, while oxygenases TRI11 and TRI13 were unaffected. Quantitative reverse-transcriptase PCR indicated that several of the genes in the toxin biosynthetic pathway were upregulated by xanthotoxin, with Tri4 showing the highest increase in expression. These results indicate that while xanthotoxin inhibits specific P450 oxygenase activity, it also has an effect on gene expression.

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