scholarly journals Cloning and Characterization of a Cyclic Peptide Synthetase Gene from Alternaria alternata Apple Pathotype Whose Product Is Involved in AM-Toxin Synthesis and Pathogenicity

2000 ◽  
Vol 13 (7) ◽  
pp. 742-753 ◽  
Author(s):  
R. D. Johnson ◽  
L. Johnson ◽  
Y. Itoh ◽  
M. Kodama ◽  
H. Otani ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Cyclic Peptide ◽  
Genomic Library ◽  
Disease Symptoms ◽  
Peptide Synthetases ◽  
Peptide Synthetase ◽  
Primary Determinant ◽  
Apple Cultivars ◽  
Alternaria Blotch

Alternaria alternata apple pathotype causes Alternaria blotch of susceptible apple cultivars through the production of a cyclic peptide host-specific toxin, AM-toxin. PCR (polymerase chain reaction), with primers designed to conserved domains of peptide synthetase genes, amplified several products from A. alternata apple pathotype that showed high similarity to other fungal peptide synthetases and were specific to the apple pathotype. Screening of a Lambda Zap genomic library with these PCR-generated probes identified overlapping clones containing a complete cyclic peptide synthetase gene of 13.1 kb in length with no introns. Disruption of this gene, designated AM-toxin synthetase (AMT), by transformation of wild-type A. alternata apple pathotype with disruption vectors resulted in toxin-minus mutants, which were also unable to cause disease symptoms on susceptible apple cultivars. AM-toxin synthetase is therefore a primary determinant of virulence and specificity in the A. alternata apple pathotype/apple interaction.

scholarly journals Ribosomally derived lipopeptides containing distinct fatty acyl moieties

2022 ◽  
Vol 119 (3) ◽  
pp. e2113120119
Author(s):  
Florian Hubrich ◽  
Nina M. Bösch ◽  
Clara Chepkirui ◽  
Brandon I. Morinaka ◽  
Michael Rust ◽  
...  
Keyword(s):  
Natural Products ◽  
Cyclic Peptide ◽  
Fatty Acyl ◽  
Antifungal Drugs ◽  
Guided Discovery ◽  
Bacterial Phyla ◽  
Peptide Synthetases ◽  
Antibacterial And Antifungal ◽  
Microbial Natural Products

Lipopeptides represent a large group of microbial natural products that include important antibacterial and antifungal drugs and some of the most-powerful known biosurfactants. The vast majority of lipopeptides comprise cyclic peptide backbones N-terminally equipped with various fatty acyl moieties. The known compounds of this type are biosynthesized by nonribosomal peptide synthetases, giant enzyme complexes that assemble their products in a non–gene-encoded manner. Here, we report the genome-guided discovery of ribosomally derived, fatty-acylated lipopeptides, termed selidamides. Heterologous reconstitution of three pathways, two from cyanobacteria and one from an arctic, ocean-derived alphaproteobacterium, allowed structural characterization of the probable natural products and suggest that selidamides are widespread over various bacterial phyla. The identified representatives feature cyclic peptide moieties and fatty acyl units attached to (hydroxy)ornithine or lysine side chains by maturases of the GCN5-related N-acetyltransferase superfamily. In contrast to nonribosomal lipopeptides that are usually produced as congener mixtures, the three selidamides are selectively fatty acylated with C10, C12, or C16 fatty acids, respectively. These results highlight the ability of ribosomal pathways to emulate products with diverse, nonribosomal-like features and add to the biocatalytic toolbox for peptide drug improvement and targeted discovery.

scholarly journals A Polymerase Chain Reaction-Based Method to Specifically Detect Alternaria alternata Apple Pathotype (A. mali), the Causal Agent of Alternaria Blotch of Apple

2000 ◽  
Vol 90 (9) ◽  
pp. 973-976 ◽  
Author(s):  
R. D. Johnson ◽  
L. Johnson ◽  
K. Kohmoto ◽  
H. Otani ◽  
C. R. Lane ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Alternaria Alternata ◽  
Crucial Role ◽  
Chain Reaction ◽  
Alternaria Species ◽  
Apple Cultivars ◽  
Polymerase Chain ◽  
Alternaria Blotch ◽  
High Level ◽  
Host Specific Toxins

Alternaria alternata apple pathotype (previously A. mali) causes Alternaria blotch on susceptible apple cultivars through the production of a host-specific toxin, AM-toxin. Identification of some Alternaria species, especially those that produce host-specific toxins, has been extremely difficult due to a high level of variability which extends even to nonpathogenic isolates. We have recently cloned and characterized a gene (AMT) that plays a crucial role in AM-toxin biosynthesis and demonstrated that it is only present in isolates of A. alternata apple pathotype. Using primers designed for the AMT gene, we developed a polymerase chainreaction-based method to specifically detect AM-toxin producing isolates of A. alternata apple pathotype.

scholarly journals Evaluation of 110 Apple Cultivars for Resistance to Alternaria Blotch Caused by Alternaria alternata Apple Pathotype

HortScience ◽  
2019 ◽  
Vol 54 (8) ◽  
pp. 1268-1274 ◽  
Author(s):  
Ying Li ◽  
Xiao-Li Hu ◽  
Robert N. Trigiano ◽  
Herbert Aldwinckle ◽  
Zong-Ming (Max) Cheng
Keyword(s):  
Alternaria Alternata ◽  
Random Amplified Polymorphic Dna ◽  
Disease Incidence ◽  
Rapd Marker ◽  
Severe Disease ◽  
Field Surveys ◽  
Detached Leaves ◽  
Apple Cultivars ◽  
Alternaria Blotch ◽  
Moderately Resistant

Apple blotch caused by Alternaria alternata apple pathotype is a severe disease of apple (Malus ×domestica Borkh) occurring throughout the world, especially in eastern Asia. Phenotypic and genetic information about resistance/susceptibility of apple germplasm to this disease will be extremely valuable for selecting and developing new disease resistant cultivars. In this study, 110 apple cultivars obtained from the USDA apple germplasm in Geneva, NY, were evaluated for their resistance/susceptibility to apple blotch by field surveys, and inoculation of detached leaves with a suspension of germinated conidia of A. alternata apple pathotype. Disease incidence were different among the cultivars and categorized into resistant (R), moderately resistant (MR), or susceptible (S). Two molecular markers, S428, a random amplified polymorphic DNA (RAPD) marker associated with disease resistance, and a simple sequence repeat (SSR or microsatellite) marker CH05g07, linked to susceptibility were used to correlate the phenotypes expressed in field surveys and laboratory inoculations. The detection using either the S428 marker or the CH05g07 marker in 50 common breeding cultivars was consistent with R or S traits except for ‘Bisbee’ and ‘Priscilla’. These two cultivars were MR to apple blotch through phenotyping. However, SSR markers were detected, but RAPD markers were not and therefore were considered susceptible. Combined with the record of resistance to fire blight from Germplasm Resources Information Network (GRIN), ‘Dayton’, ‘Mildew Immune Seedling’, ‘Puregold’, and ‘Pumpkin Sweet’ were highly resistant to both diseases and considered as the best choices of parents for stacking resistance to multiple diseases in breeding program.

scholarly journals Characterization of Volatile Compounds and Flavor in Spirits of Old Apple and Pear Cultivars from the Balkan Region

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1258
Author(s):  
Nermina Spaho ◽  
Fuad Gaši ◽  
Erich Leitner ◽  
Milenko Blesić ◽  
Asima Akagić ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Sensory Attributes ◽  
Apple Cultivar ◽  
Brand Development ◽  
Balkan Region ◽  
Apple Cultivars ◽  
Gas Chromatography Mass Spectroscopy ◽  
Fruit Spirits

This study was conducted with the aim of developing fruit spirits by utilizing old (autochthonous) apple and pear cultivars that can be attractive to both consumers and producers. Consumers of spirits could enjoy the unique flavor, and producers could gain an opportunity for brand development. In total, eight old apple cultivars (Sarija, Žuja, Samoniklica, Prijedorska zelenika, Bobovec, Masnjača, Lijepocvjetka, and Šarenika) and three pear cultivars (Budaljača, Krakača, and Kalićanka) from Bosnia and Herzegovina were used for the spirits production and for characterizing the flavor of distillates. Golden Delicious was used as a representative of commercial apple cultivar. The aroma profile was conducted through the identification of minor volatile organic compounds (VOCs) and the sensory perception of spirits. Analysis of the VOCs was performed by gas chromatography mass spectroscopy (GC/MS) techniques after enrichment via solid-phase microextraction (SPME). Sensory evaluation was performed by 12 trained panelists. Overall, 35 minor volatile compounds were found in spirits: 13 esters, 7 alcohols, 6 acids, 5 terpenes, and 4 aldehydes. Significant differences were detected in the distribution and quantity of the VOCs, which were fruit cultivar-dependent. Spirits made from Šarenika apple cultivar showed the largest amount of all acids, especially short- and medium-chain fatty acids; however, this richness was not correlated with pleasant sensory attributes. Spirits obtained from Prijedorska zelenika and Masnjača apple cultivars had the best sensory attributes. Budeljača and Krakača pears are promising cultivars as flavoring in spirits production.

scholarly journals Streptogramin B biosynthesis in Streptomyces pristinaespiralis and Streptomyces virginiae: molecular characterization of the last structural peptide synthetase gene.

1997 ◽  
Vol 41 (9) ◽  
pp. 1904-1909 ◽  
Author(s):  
V de Crécy-Lagard ◽  
W Saurin ◽  
D Thibaut ◽  
P Gil ◽  
L Naudin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Activation ◽  
Activation Domains ◽  
Amino Acid Activation ◽  
Streptomyces Virginiae ◽  
Streptomyces Pristinaespiralis ◽  
Degenerate Oligonucleotide ◽  
Peptide Synthetase ◽  
Different Origins

Streptomyces pristinaespiralis and S. virginiae both produce closely related hexadepsipeptide antibiotics of the streptogramin B family. Pristinamycins I and virginiamycins S differ only in the fifth incorporated precursor, di(mono)methylated amine and phenylalanine, respectively. By using degenerate oligonucleotide probes derived from internal sequences of the purified S. pristinaespiralis SnbD and SnbE proteins, the genes from two streptogramin B producers, S. pristinaespiralis and S. virginiae, encoding the peptide synthetase involved in the activation and incorporation of the last four precursors (proline, 4-dimethylparaaminophenylalanine [for pristinamycin I(A)] or phenylalanine [for virginiamycin S], pipecolic acid, and phenylglycine) were cloned. Analysis of the sequence revealed that SnbD and SnbE are encoded by a unique snbDE gene. SnbDE (4,849 amino acids [aa]) contains four amino acid activation domains, four condensation domains, an N-methylation domain, and a C-terminal thioesterase domain. Comparison of the sequences of 55 amino acid-activating modules from different origins confirmed that these sequences contain enough information for the performance of legitimate predictions of their substrate specificity. Partial sequencing (1,993 aa) of the SnbDE protein of S. virginiae allowed comparison of the proline and aromatic acid activation domains of the two species and the identification of coupled frameshift mutations.

scholarly journals Cloning and characterization of four SIR genes of Saccharomyces cerevisiae.

1986 ◽  
Vol 6 (2) ◽  
pp. 688-702 ◽  
Author(s):  
J M Ivy ◽  
A J Klar ◽  
J B Hicks
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Blot Analysis ◽  
Transcriptional Control ◽  
Genomic Library ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mating Type Genes ◽  
Rna Blots

Mating type in the yeast Saccharomyces cerevisiae is determined by the MAT (a or alpha) locus. HML and HMR, which usually contain copies of alpha and a mating type information, respectively, serve as donors in mating type interconversion and are under negative transcriptional control. Four trans-acting SIR (silent information regulator) loci are required for repression of transcription. A defect in any SIR gene results in expression of both HML and HMR. The four SIR genes were isolated from a genomic library by complementation of sir mutations in vivo. DNA blot analysis suggests that the four SIR genes share no sequence homology. RNA blots indicate that SIR2, SIR3, and SIR4 each encode one transcript and that SIR1 encodes two transcripts. Null mutations, made by replacement of the normal genomic allele with deletion-insertion mutations created in the cloned SIR genes, have a Sir- phenotype and are viable. Using the cloned genes, we showed that SIR3 at a high copy number is able to suppress mutations of SIR4. RNA blot analysis suggests that this suppression is not due to transcriptional regulation of SIR3 by SIR4; nor does any SIR4 gene transcriptionally regulate another SIR gene. Interestingly, a truncated SIR4 gene disrupts regulation of the silent mating type loci. We propose that interaction of at least the SIR3 and SIR4 gene products is involved in regulation of the silent mating type genes.

scholarly journals Molecular Cloning and Characterization of Bifidobacterium bifidum 1,2-α-l-Fucosidase (AfcA), a Novel Inverting Glycosidase (Glycoside Hydrolase Family 95)

2004 ◽  
Vol 186 (15) ◽  
pp. 4885-4893 ◽  
Author(s):  
Takane Katayama ◽  
Akiko Sakuma ◽  
Takatoshi Kimura ◽  
Yutaka Makimura ◽  
Jun Hiratake ◽  
...  
Keyword(s):  
Amino Acid ◽  
Genomic Library ◽  
Bifidobacterium Bifidum ◽  
Glycoside Hydrolases ◽  
Glycoside Hydrolase Family ◽  
Amino Acid Residues ◽  
Gene Encoding ◽  
Sugar Chain ◽  
Hydrolysis Of

ABSTRACT A genomic library of Bifidobacterium bifidum constructed in Escherichia coli was screened for the ability to hydrolyze the α-(1→2) linkage of 2′-fucosyllactose, and a gene encoding 1,2-α-l-fucosidase (AfcA) was isolated. The afcA gene was found to comprise 1,959 amino acid residues with a predicted molecular mass of 205 kDa and containing a signal peptide and a membrane anchor at the N and C termini, respectively. A domain responsible for fucosidase activity (the Fuc domain; amino acid residues 577 to 1474) was localized by deletion analysis and then purified as a hexahistidine-tagged protein. The recombinant Fuc domain specifically hydrolyzed the terminal α-(1→2)-fucosidic linkages of various oligosaccharides and a sugar chain of a glycoprotein. The stereochemical course of the hydrolysis of 2′-fucosyllactose was determined to be inversion by using 1H nuclear magnetic resonance. The primary structure of the Fuc domain exhibited no similarity to those of any glycoside hydrolases (GHs) but showed high similarity to those of several hypothetical proteins in a database. Thus, it was revealed that the AfcA protein constitutes a novel inverting GH family (GH family 95).

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