scholarly journals Leafy Gall Formation Is Controlled byfasR, an AraC-Type Regulatory Gene inRhodococcus fascians

2000 ◽  
Vol 182 (20) ◽  
pp. 5832-5840 ◽  
Author(s):  
Wim Temmerman ◽  
Danny Vereecke ◽  
Rozemarijn Dreesen ◽  
Marc Van Montagu ◽  
Marcelle Holsters ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulatory Gene ◽  
Infected Plant ◽  
Nitrogen Sources ◽  
Defined Medium ◽  
Regulatory Proteins ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Rhodococcus Fascians

ABSTRACT Rhodococcus fascians can interact with many plant species and induce the formation of either leafy galls or fasciations. To provoke symptoms, R. fascians strain D188 requires pathogenicity genes that are located on a linear plasmid, pFiD188. Thefas genes are essential for virulence and constitute an operon that encodes, among other functions, a cytokinin synthase gene. Expression of the fas genes is induced by extracts of infected plant tissue only. We have isolated an AraC-type regulatory gene, fasR, located on pFiD188, which is indispensable for pathogenesis and for fas gene expression. The combined results of our experiments show that in vitro expression of thefas genes in a defined medium is strictly regulated and that several environmental factors (pH, carbon and nitrogen sources, phosphate and oxygen content, and cell density) and regulatory proteins are involved. We further show that expression of the fasgenes is controlled at both the transcriptional and the translational levels. The complex expression pattern probably reflects the necessity of integrating a multitude of signals and underlines the importance of the fas operon in the pathogenicity of R. fascians.

scholarly journals Lovastatin Biosynthesis by Aspergillus terreus in a Chemically Defined Medium

2001 ◽  
Vol 67 (6) ◽  
pp. 2596-2602 ◽  
Author(s):  
Hassan Hajjaj ◽  
Peter Niederberger ◽  
Philippe Duboc
Keyword(s):  
Carbon Source ◽  
Aspergillus Terreus ◽  
Glucose Repression ◽  
Nitrogen Sources ◽  
Glucose Consumption ◽  
Defined Medium ◽  
Specific Productivity ◽  
Chemically Defined Medium ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen

ABSTRACT Lovastatin is a secondary metabolite produced by Aspergillus terreus. A chemically defined medium was developed in order to investigate the influence of carbon and nitrogen sources on lovastatin biosynthesis. Among several organic and inorganic defined nitrogen sources metabolized by A. terreus, glutamate and histidine gave the highest lovastatin biosynthesis level. For cultures on glucose and glutamate, lovastatin synthesis initiated when glucose consumption levelled off. When A. terreus was grown on lactose, lovastatin production initiated in the presence of residual lactose. Experimental results showed that carbon source starvation is required in addition to relief of glucose repression, while glutamate did not repress biosynthesis. A threefold-higher specific productivity was found with the defined medium on glucose and glutamate, compared to growth on complex medium with glucose, peptonized milk, and yeast extract.

Effect of carbon and nitrogen sources, pH and temperature on in vitro culture of several isolates of Amanita caesarea (Scop.:Fr.) Pers.

Mycorrhiza ◽  
2005 ◽  
Vol 16 (2) ◽  
pp. 133-136 ◽  
Author(s):  
A. Daza ◽  
J. L. Manjón ◽  
M. Camacho ◽  
L. Romero de la Osa ◽  
A. Aguilar ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Nitrogen Sources ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen

scholarly journals Xylariales): Physiological characterization and structural features of its association with wheat.

2018 ◽  
Vol 53 (2) ◽  
pp. 169-182
Author(s):  
Carolina Rothen ◽  
Victoria Miranda ◽  
Sebastián Fracchia ◽  
Alicia Godeas ◽  
Alejandra Rodríguez
Keyword(s):  
Root Hairs ◽  
Nitrogen Sources ◽  
Structural Features ◽  
Fungal Colonization ◽  
Carbon And Nitrogen Sources ◽  
Wheat Roots ◽  
Transmission Microscopy ◽  
Carbon And Nitrogen ◽  
Microdochium Bolleyi

: Plant roots can be colonized by asymptomatic fungal strains belonging to several taxa, among them, the group defined as Dark Septate Endophytes (DSE). Microdochium bolleyi commonly colonizes wheat roots and other crops. It is considered a weak pathogen or even a non-pathogenic fungal species, which has also been considered as a potential biocontrol agent against aggressive soil-borne pathogens in cereal crops. We isolated a strain of M. bolleyi from wheat roots sampled in a crop field in Argentina, and characterized its abilities to grow in different carbon and nitrogen sources, to produce indole and to solubilize phosphorus; also several enzymatic activities were evaluated. In addition, resynthesis was performed under controlled conditions in order to characterize root fungal colonization under both, optical and transmission microscopy. The strain 22-1 colonized wheat root parenchymal tissue, forming chlamysdospores inside parenchymal cells and root hairs, and poorly grew in carbon and nitrogen sources. This fungus also synthesized indoles in in vitro culture, but it cannot solubilize phosphorus. Only amylase activity was detected out of seven enzymatic activity measured. Microdochium bolleyi (strain 22-1) colonized the roots, it formed typical DSE fungal structures and behaved like a “true endophyte”; however further studies are necessary to elucidate its role in the association with wheat.

scholarly journals Investigating the expression of F10 and G11 xylanases in Aspergillus niger A09 with qPCR

2016 ◽  
Vol 62 (9) ◽  
pp. 744-752
Author(s):  
Shixiu Cui ◽  
Tianwen Wang ◽  
Hong Hu ◽  
Liangwei Liu ◽  
Andong Song ◽  
...  
Keyword(s):  
Gene Expression ◽  
Aspergillus Niger ◽  
Culture Media ◽  
Xylanase Activity ◽  
Nitrogen Sources ◽  
Transcript Abundance ◽  
Culture Conditions ◽  
Clear Understanding ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen

There exist significant differences between the 2 main types of xylanases, family F10 and G11. A clear understanding of the expression pattern of microbial F10 and G11 under different culture conditions would facilitate better production and industrial application of xylanase. In this study, the fungal xylanase producer Aspergillus niger A09 was systematically investigated in terms of induced expression of xylanase F10 and G11. Results showed that carbon and nitrogen sources could influence xylanase F10 and G11 transcript abundance, with G11 more susceptible to changes in culture media composition. The most favorable carbon and nitrogen sources for high G11 and low F10 production by A. niger A09 were xylan (2%) and (NH4)2C2O4 (0.3%), respectively. Following cultivation at 33 °C for 60 h, the highest xylanase activity (1132 IU per gram of wet mycelia) was observed. On the basis of differential gene expression of F10 and G11, as well as their different properties, we deduced that the F10 protein initially targeted xylan and hydrolyzed it into fragments including xylose, after which xylose acted as the inducer of F10 and G11 gene expression. These speculations also accounted for our failure to identify conditions favoring the high production of F10 but a low production of G11.

scholarly journals Influence of Carbon - Nitrogen Supplements and pH on Growth of Sugarcane Stem rot Pathogen Fusarium Solani NVS671

2020 ◽  
Vol 1 (1) ◽  
pp. 27-32
Author(s):  
Prittesh Patel
Keyword(s):  
Fusarium Solani ◽  
Mycelial Growth ◽  
Growth Promotion ◽  
Nitrogen Sources ◽  
Cultural Analysis ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
N Sources ◽  
Sugarcane Stem

Fusarium solani NVS671 identified from infected sugarcane stem of Co 671 as a new pathogen was subjected to various cultural conditions to understand its physiological profile. In continuation with our previous work, cultural analysis was carried out under in vitro condition by supplementing various carbon and nitrogen sources in Czapek-Dox agar (CDA). Under different hydrogen ion concentrations, it was found that the growth of Fusarium solaniNVS671 was less at pH 4 and pH 10 and could reach up to 5 cm after 7 days of incubation on Potato Dextrose Agar (PDA). It is observed that the pH around 7 to 8 was optimum for the growth of F. solani. Ten different nitrogenous (N) sources and nine different carbon sources were tested on CDA medium to know their effect on the mycelial growth rate and characteristics of the fungus. Among the N sources evaluated, ammonium chloride (7.96±0.11 cm) was found to be most efficient for mycelial growth promotion followed by ammonium nitrate (7.7±0.1 cm) and ammonium sulphate (7.3±0.1 cm). The most preferred carbon source recorded to promote best radial mycelial growth was starch (7.96±0.05 cm) and sucrose (7.93±0.05 cm). Capabilities of using different carbon and nitrogen sources and ability to grow at different pH levels may allow species to adapt to specific soil conditions.This study is important to understand the physiology and metabolite preference of F. solani.

A COMPARISON OF ISOLATES OF CLAVICEPS SPP. FOR THE ABILITY TO GROW AND TO PRODUCE ERGOT ALKALOIDS ON CERTAIN NUTRIENTS

1960 ◽  
Vol 6 (3) ◽  
pp. 355-365 ◽  
Author(s):  
W. A. Taber ◽  
L. C. Vining
Keyword(s):  
Carbon Source ◽  
Carbon Sources ◽  
Ergot Alkaloids ◽  
Nitrogen Sources ◽  
Claviceps Purpurea ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Different Strains ◽  
Do So

Isolates of Claviceps purpurea and Claviceps spp. obtained from various geographical areas were compared for their ability to grow and to produce ergot alkaloids in vitro on various carbon and nitrogen sources. While some differences in utilization of carbon sources for growth were found, there was no observed correlation between utilization of carbohydrates and the capacity to produce ergot alkaloids. The amount of alkaloid produced by different strains depended upon both the carbon and nitrogen sources. In general, those cultures capable of alkaloid production were able to do so on more than one carbon source, but the carbon source allowing greatest production differed from one strain to another. Both producing and non-producing strains could utilize succinic acid as a carbon source for growth, but neither could utilize L-tryptophane as a carbon or nitrogen source for growth.

scholarly journals Germination of Conidia of Peronospora Tabacina Adam I. Germination in Vitro

1962 ◽  
Vol 15 (3) ◽  
pp. 483 ◽  
Author(s):  
CJ Shepherd
Keyword(s):  
Germ Tube ◽  
Nitrogen Sources ◽  
Magnesium Ions ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Liquid Suspension ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions ◽  
Germ Tube Elongation

Washed conidia of Perono8pora tabacina Adam germinated poorly or not at all in water alone, but germinated in the presence of riboflavin. The rate of germination of conidia in liquid suspension was enhanced by the presence of carbon and nitrogen sources, phosphate, and calcium and magnesium ions. The effects of 141 metabolites on germination and germ-tube elongation have been tested.

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