Differential and systemic alteration of defence-related gene transcript levels in mycorrhizal bean plants infected with Rhizoctonia solani

2002 ◽  
Vol 80 (3) ◽  
pp. 305-315 ◽  
Author(s):  
C Guillon ◽  
M St-Arnaud ◽  
C Hamel ◽  
S H Jabaji-Hare
Keyword(s):  
Rhizoctonia Solani ◽  
Phenylalanine Ammonia Lyase ◽  
Glomus Intraradices ◽  
Chalcone Synthase ◽  
Arbuscular Mycorrhizal ◽  
Chalcone Isomerase ◽  
Gene Transcript ◽  
Transcript Levels ◽  
Bean Plants ◽  
Defence Genes

The role of arbuscular mycorrhizas in response of plants to soilborne root pathogens is unclear. A time course study was conducted to monitor disease development and expression of mRNA for the defence-related genes phenylalanine ammonia lyase, chalcone synthase, chalcone isomerase, and hydroxyproline-rich glycoprotein in bean (Phasoelus vulgaris L.) plants colonized by the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith and postinfected with the soilborne pathogen Rhizoctonia solani Kühn. Precolonization of bean plants by G. intraradices did not significantly reduce the severity of rot symptoms. RNA blot analysis of the defence-related genes revealed a systemic increase in the four defence genes in response to R. solani infections. On the other hand, precolonization of bean plants with G. intraradices elicited no change in phenylalanine ammonia lyase, chalcone synthase, and chalcone isomerase transcripts. A differential and systemic alteration in the expression of all four defence genes was observed in all tissues only during the pathogenic interaction of arbuscular mycorrhizal beans. Depending on the time after infection with R. solani and the tissue examined, varying responses from stimulation to suppression to no change in transcript levels were detected.Key words: induced resistance, defence-related genes, RNA analysis, Rhizoctonia solani, Glomus intraradices.

Rapid changes in gene expression in response to microbial elicitation

1986 ◽  
Vol 314 (1166) ◽  
pp. 411-426 ◽  
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Chalcone Synthase ◽  
Blot Hybridization ◽  
Enzyme Synthesis ◽  
Chalcone Isomerase ◽  
Colletotrichum Lindemuthianum ◽  
Specific Gene ◽  
Gene Products

Treatment of cell suspension cultures of French bean ( Phaseolus vulgaris ) with polysaccharide elicitor molecules from cell walls of the anthracnose fungus, Colletotrichum lindemuthianum , results in the rapid accumulation of isoflavonoid phytoalexins, deposition of wall-bound phenolic compounds and synthesis of hydroxyproline-rich glycoproteins. These changes are dependent upon a highly selective induction of gene products, including the enzymes L-phenylalanine ammonia-lyase, cytochrome P450-dependent cinnamic acid 4-hydroxylase, chalcone synthase, chalcone isomerase, prolyl hydroxylase and protein: arabinosyl transferase. Use of in vivo labelling, in vitro translation and RNA blot hybridization techniques has shown that these elicitormediated changes arise from rapid but transient induction of enzyme synthesis, resulting from the accumulation of specific mRNAs. Similar phenomena are observed in bean hypocotyls at the onset of phytoalexin synthesis in response to infection by incompatible and compatible races of C. lindemuthianum . In bean, both L-phenylalanine ammonia-lyase and chalcone synthase are encoded by multigene families and, at the protein level, both exhibit subunit and intact enzyme polymorphism. A number of less than full-length phenylalanine ammonialyase copy DNAs containing identical open reading frames have been produced from mRNA from elicitor-induced bean cells. Analysis of phenylalanine ammonia-lyase genomic clones predicts the presence of enzyme forms of differing amino acid sequence. In cultured bean cells, elicitor differentially induces the two apparent phenylalanine ammonia-lyase iso-forms with the lowest K m values. In addition to transcriptional control of the appearance of specific gene products, post-translational processes may result in increased subunit polymorphism for phenylalanine ammonia-lyase, and in the activation of chalcone isomerase. Changes in endogenous phenylpropanoid intermediate pools may signal the rapid removal of phenylalanine ammonia-lyase activity, in addition to exerting less specific inhibitory effects on the formation and/or activity of the mRNAs encoding phenylalanine ammonia-lyase and other phytoalexin biosynthetic enzymes.

Purification of Chalcone Synthase from Tulip Anthers and Comparison with the Synthase from Cosmos Petals

1981 ◽  
Vol 36 (1-2) ◽  
pp. 30-34 ◽  
Author(s):  
Rainer Sütfeld ◽  
Rolf Wiermann
Keyword(s):  
Chalcone Synthase ◽  
In Vitro Assay ◽  
Flavonoid Biosynthesis ◽  
Chalcone Isomerase ◽  
Gel Chromatography ◽  
Purification Procedure ◽  
Reaction Products ◽  
Complete Elimination ◽  
Vitro Assay

Abstract Chalcone synthase was isolated from both anthers of Tulipa cv. “Apeldoorn” and petals of Cosmos sulphureus Cav. After certain prepurification steps, the enzymes were further purified using gel chromatography on Sephadex G-200 followed by repeated hydroxylapatite absorption chromatography. Both the enzymes showed the same chromatographic properties. After gel chromatography as well as after the first hydroxylapatite fractionation, the reaction products appeared as flavanones. However, after the second hydroxylapatite step, production of chalcones was observed. Like the enzyme from tulip anthers, the synthase from Cosmos petals produced the correspondingly substituted chalcones when p-coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA, respectively, were used as substractes. In both the cases, the ratios of the different chalcones produced were found to be about the same. The appearance of chalcone synthesis in this in vitro assay is caused by the complete elimination of chalcone isomerase in the purification procedure. The importance of the isomerase for flavonoid biosynthesis, particularly in plant systems which are accumulating chalcones, is discussed.

scholarly journals Cross-generational feeding of Bt (Bacillus thuringiensis)-maize to zebrafish (Danio rerio) showed no adverse effects on the parental or offspring generations

2013 ◽  
Vol 110 (12) ◽  
pp. 2222-2233 ◽  
Author(s):  
Monica Sanden ◽  
Robin Ornsrud ◽  
Nini H. Sissener ◽  
Susanne Jorgensen ◽  
Jinni Gu ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Danio Rerio ◽  
Fumonisin B1 ◽  
Gene Transcript ◽  
Transcript Levels ◽  
Two Generations ◽  
Feed Utilisation ◽  
Liver Gene ◽  
Caspase 6 ◽  
Mass Increase

In the present study, zebrafish (Danio rerio) were fed casein/gelatin-based diets containing either 19 % Bt (Bacillus thuringiensis)-maize or its parental non-Bt (nBt)-maize control for two generations (F0: sixty fish; F1: forty-two to seventy fish per treatment). The study focused on growth and reproductive performance, liver CuZn superoxide dismutase (SOD) enzyme activity, gene transcript levels targeting important cellular pathways in the liver and mid-intestine, histomorphological evaluation of the intestine, differential leucocyte counts, offspring larva swimming activity and global DNA methylation in offspring embryos. No significant effects were observed in the parental generation. The offspring were either fed the same diets as those fed to their parents (Bt–Bt or nBt–nBt) or switched from the Bt diet to the nBt diet (Bt–nBt). The Bt–Bt offspring exhibited a significantly higher body mass increase, specific growth rate and feed utilisation than fish fed the nBt–nBt diet and/or fish fed the Bt–nBt diet. Liver and mid-intestinal gene transcript levels of CuZn SOD were significantly higher in fish fed the nBt–nBt diet than in those fed the Bt–Bt diet. Liver gene transcript levels of caspase 6 were significantly lower for the nBt–nBt group than for the Bt–Bt group. Overall, enhanced growth performance was observed in fish fed the Bt diet for two generations than in those fed the nBt diet for one and two generations. Effects observed on gene biomarkers for oxidative stress and the cell cycle (apoptosis) may be related to the contamination of nBt-maize with fumonisin B1 and aflatoxin B1. In conclusion, it is suggested that Bt-maize is as safe and nutritious as its nBt control when fed to zebrafish for two generations.

Abstract 15: Glucose-Mediated Remodeling of Cardiac DNA Methylation

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Mark E Pepin ◽  
David K Crossman ◽  
Joseph P Barchue ◽  
Salpy V Pamboukian ◽  
Steven M Pogwizd ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Dna Methylation ◽  
Diabetic Cardiomyopathy ◽  
Left Ventricular ◽  
Epigenetic Mark ◽  
Gene Transcript ◽  
Transcript Levels ◽  
Glycemic Memory

To identify the role of glucose in the development of diabetic cardiomyopathy, we had directly assessed glucose delivery to the intact heart on alterations of DNA methylation and gene expression using both an inducible heart-specific transgene (glucose transporter 4; mG4H) and streptozotocin-induced diabetes (STZ) mouse models. We aimed to determine whether long-lasting diabetic complications arise from prior transient exposure to hyperglycemia via a process termed “glycemic memory.” We had identified DNA methylation changes associated with significant gene expression regulation. Comparing our results from STZ, mG4H, and the modifications which persist following transgene silencing, we now provide evidence for cardiac DNA methylation as a persistent epigenetic mark contributing to glycemic memory. To begin to determine which changes contribute to human heart failure, we measured both RNA transcript levels and whole-genome DNA methylation in heart failure biopsy samples (n = 12) from male patients collected at left ventricular assist device placement using RNA-sequencing and Methylation450 assay, respectively. We hypothesized that epigenetic changes such as DNA methylation distinguish between heart failure etiologies. Our findings demonstrated that type 2 diabetic heart failure patients (n = 6) had an overall signature of hypomethylation, whereas patients listed as ischemic (n = 5) had a distinct hypermethylation signature for regulated transcripts. The focus of this initial analysis was on promoter-associated CpG islands with inverse changes in gene transcript levels, from which diabetes (14 genes; e.g. IGFBP4) and ischemic (12 genes; e.g. PFKFB3) specific targets emerged with significant regulation of both measures. By combining our mouse and human molecular analyses, we provide evidence that diabetes mellitus governs direct regulation of cellular function by DNA methylation and the corresponding gene expression in diabetic mouse and human hearts. Importantly, many of the changes seen in either mouse type 1 diabetes or human type 2 diabetes were similar supporting a consistent mechanism of regulation. These studies are some of the first steps at defining mechanisms of epigenetic regulation in diabetic cardiomyopathy.

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