Genetic variability in a collection of Stagonospora nodorum isolates from Western Australia

2000 ◽  
Vol 51 (6) ◽  
pp. 679 ◽  
Author(s):  
N. E. Murphy ◽  
R. Loughman ◽  
R. Appels ◽  
E. S. Lagudah ◽  
M. G. K. Jones
Keyword(s):  
Copy Number ◽  
Nuclear Dna ◽  
Genotypic Diversity ◽  
High Copy Number ◽  
Stagonospora Nodorum ◽  
International Studies ◽  
Host Genotype ◽  
Single Location ◽  
Rflp Probe ◽  
High Level

Stagonospora nodorum isolates were collected from the Western Australian grain-belt during 1993. These isolates and a subset of isolates taken from a single location were used to assay the level of variation within the pathogen population. The isolates were compared using anonymous nuclear DNA markers. Three low copy-number and a single high copy-number RFLP probe were used to generate polymorphisms. The collection exhibited a high genotypic diversity for the high copy-number probe, a result consistent with the high level of sexual reproduction previously found in the fungal population. The high level of genotypic diversity was consistent with previous international studies. There was no evidence of differentiation between the total collection of isolates and the subset of isolates taken from the single location. Further work needs to be undertaken to determine if the aggressiveness of the pathogen is influenced by the host genotype.

Expression of a Bacillus thuringiensis δ-endotoxin gene by Bacillus pumilus

1998 ◽  
Vol 44 (3) ◽  
pp. 259-269 ◽  
Author(s):  
L B Selinger ◽  
G G Khachatourians ◽  
J R Byers ◽  
M F Hynes
Keyword(s):  
Bacillus Thuringiensis ◽  
Copy Number ◽  
Bacillus Pumilus ◽  
High Copy Number ◽  
Cry Genes ◽  
Bacillus Thuringiensis Subsp ◽  
High Copy Number Plasmid ◽  
Low Copy Number ◽  
High Level ◽  
Lepidoptera Noctuidae

The δ -endotoxin genes from Bacillus thuringiensis were introduced into a rhizosphere-inhabiting Bacillus pumilus isolate to create a δ -endotoxin expression and delivery system for subterranean feeding insects such as the larvae of pale western cutworm (Agrotis orthogonia Morrison (Lepidoptera: Noctuidae)). Preliminary experiments indicated that Bacillus thuringiensis subsp. kurstaki cultures were toxic to pale western cutworm larvae. Three different cry genes from Bacillus thuringiensis subsp. kurstaki were cloned into high and low copy number vectors and mated into Bacillus pumilus RB8. When carried on high copy number vectors, cry genes appeared to inhibit sporulation and δ -endotoxin production in Bacillus pumilus RB8 cultures, since microscopic examination of these cultures revealed that <0.1% of the cells of late stationary phase cultures had sporulated and produced parasporal inclusions. On low copy number vectors, the cry genes did not inhibit sporulation; however, production of δ -endotoxins was undetectable. Using a heat shock regime for enrichment of sporogenous crystalliferous variants, a Bacillus pumilus isolate, carrying cryIA(c) on a high copy number plasmid, was obtained in which high level δ -endotoxin production occurred concomitant with sporulation. Synthesis of functional δ -endotoxin by this strain was confirmed by Western blot analysis and bioassay with pale western cutworm larvae. These results show that rhizosphere-inhabiting bacilli are indeed a potential route for introduction of δ -endotoxins to the root environment for biocontrol purposes.Key words: Bacillus thuringiensis, δ -endotoxin, conjugation, sporulation, expression.

High-copy-number integration into the ribosomal DNA of Saccharomyces cerevisiae: a new vector for high-level expression

Gene ◽  
1989 ◽  
Vol 79 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Teresa S. Lopes ◽  
Jacobus Klootwijk ◽  
Annemarie E. Veenstra ◽  
Paul C. van der Aar ◽  
Harm van Heerikhuizen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Dna ◽  
Copy Number ◽  
High Copy Number ◽  
High Level Expression ◽  
High Level

High-level secretion of correctly processed β-lactamase from Saccharomyces cerevisiae using a high-copy-number secretion vector

Gene ◽  
1994 ◽  
Vol 142 (1) ◽  
pp. 113-117 ◽  
Author(s):  
L.A. Castelli ◽  
C.J. Mardon ◽  
P.M. Strike ◽  
A.A. Azad ◽  
I.G. Macreadie
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Copy Number ◽  
High Copy Number ◽  
Secretion Vector ◽  
High Level

Rapid Selection Using G418 of High Copy Number Transformants of Pichia pastoris for High–level Foreign Gene Expression

1994 ◽  
Vol 12 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Carol A. Scorer ◽  
Jeffrey J. Clare ◽  
Willam R. McCombie ◽  
Michael A. Romanos ◽  
Koti Sreekrishna
Keyword(s):  
Gene Expression ◽  
Pichia Pastoris ◽  
Copy Number ◽  
High Copy Number ◽  
Foreign Gene ◽  
Foreign Gene Expression ◽  
High Level

Effect of SnTOX effectors on the virulence degree of Stagonospora nodorum isolates

Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 343-351
Author(s):  
S.V. Veselova ◽  
G.F. Burkhanova ◽  
S.D. Rumyantsev ◽  
T.V. Nuzhnaya
Keyword(s):  
Host Plant ◽  
Transcriptional Activity ◽  
Susceptibility Gene ◽  
Stagonospora Nodorum ◽  
Quantitative Composition ◽  
Host Genotype ◽  
Mrna Accumulation ◽  
Gene System ◽  
Compatible Interactions ◽  
Gene For Gene

Stagonospora nodorum Berk. is the causal agent of Septoria nodorum blotch (SNB) of wheat (Triticum aestivum L.). It synthesizes host-specific necrotrophic effectors (NEs), which facilitate infection process and ensure virulence of pathogen on host plant with a dominant susceptibility gene. The interaction of virulence genes products of the NEs pathogen (SnTox) with susceptibility genes products of the host plant (Snn) in the S. nodorum - wheat pathosystem is carried out in inverted gene-for-gene system and causes the development of disease. In this study, we tested three main NEs SnToxA, SnTox1, SnTox3, which have already been identified in S. nodorum at the gene level. The NEs role in the development of SNB has already been proven; however, the overall host response to SNB does not always strictly follow the inverted gene-for-gene system, as multiple SnTox-Snn interactions can be additive or epistatic. In this regard, the aim of the work was to identify the NE genes in three S. nodorum isolates and to study effect of NEs genes transcriptional activity on the isolate virulence. We have shown that all three NEs SnToxA, SnTox3 and SnTox1 played an important role in the development of the disease in compatible interactions. Effectors SnTox3 and SnTox1 exhibited epistatic interaction that was removed by a triple compatible interaction (SnTox3-Snn3, SnToxA-Tsn1 and SnTox1-Snn1). This effect was shown by us for the first time. The mechanisms of epistatic and additive interactions, as well as the virulence of the isolate were associated with the regulation of the NEs genes transcriptional activity. The avirulent isolate Sn4VD lacked transcription of all three NEs genes, and the virulent isolate Sn9MH was characterized by a high level of mRNA accumulation of all three NEs genes during infection on susceptible cultivar. We also showed that SnTox expression depended both on the host genotype in SnToxA and SnTox3 and on the number of compatible interactions exhibiting additive or epistatic interactions in SnTox1 and SnTox3. Finally, the virulence of the S. nodorum isolate depended on the qualitative and quantitative composition of NEs.

Genetic interactions between CDC31 and KAR1, two genes required for duplication of the microtubule organizing center in Saccharomyces cerevisiae.

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 407-422 ◽  
Author(s):  
E A Vallen ◽  
W Ho ◽  
M Winey ◽  
M D Rose
Keyword(s):  
Copy Number ◽  
Gene Dosage ◽  
Spindle Pole Body ◽  
Direct Interaction ◽  
Spindle Pole ◽  
High Copy Number ◽  
Temperature Sensitive ◽  
Microtubule Organizing Center ◽  
Recessive Mutations ◽  
Organizing Center

Abstract KAR1 encodes an essential component of the yeast spindle pole body (SPB) that is required for karyogamy and SPB duplication. A temperature-sensitive mutation, kar1-delta 17, mapped to a region required for SPB duplication and for localization to the SPB. To identify interacting SPB proteins, we isolated 13 dominant mutations and 3 high copy number plasmids that suppressed the temperature sensitivity of kar1-delta 17. Eleven extragenic suppressor mutations mapped to two linkage groups, DSK1 and DSK2. The extragenic suppressors were specific for SPB duplication and did not suppress karyogamy-defective alleles. The major class, DSK1, consisted of mutations in CDC31. CDC31 is required for SPB duplication and encodes a calmodulin-like protein that is most closely related to caltractin/centrin, a protein associated with the Chlamydomonas basal body. The high copy number suppressor plasmids contained the wild-type CDC31 gene. One CDC31 suppressor allele conferred a temperature-sensitive defect in SPB duplication, which was counter-suppressed by recessive mutations in KAR1. In spite of the evidence for a direct interaction, the strongest CDC31 alleles, as well as both DSK2 alleles, suppressed a complete deletion of KAR1. However, the CDC31 alleles also made the cell supersensitive to KAR1 gene dosage, arguing against a simple bypass mechanism of suppression. We propose a model in which Kar1p helps localize Cdc31p to the SPB and that Cdc31p then initiates SPB duplication via interaction with a downstream effector.

Characterization of High-Copy-Number Retrotransposons From the Large Genomes of the Louisiana Iris Species and Their Use as Molecular Markers

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 685-697 ◽  
Author(s):  
Edward K Kentner ◽  
Michael L Arnold ◽  
Susan R Wessler
Keyword(s):  
Molecular Markers ◽  
Copy Number ◽  
High Copy Number ◽  
Marker System ◽  
Transposon Display ◽  
Plant Genomes ◽  
Large Plant ◽  
Backcross Hybrids ◽  
Abundance And Distribution

Abstract The Louisiana iris species Iris brevicaulis and I. fulva are morphologically and karyotypically distinct yet frequently hybridize in nature. A group of high-copy-number TY3/gypsy-like retrotransposons was characterized from these species and used to develop molecular markers that take advantage of the abundance and distribution of these elements in the large iris genome. The copy number of these IRRE elements (for iris retroelement), is ∼1 × 105, accounting for ∼6–10% of the ∼10,000-Mb haploid Louisiana iris genome. IRRE elements are transcriptionally active in I. brevicaulis and I. fulva and their F1 and backcross hybrids. The LTRs of the elements are more variable than the coding domains and can be used to define several distinct IRRE subfamilies. Transposon display or S-SAP markers specific to two of these subfamilies have been developed and are highly polymorphic among wild-collected individuals of each species. As IRRE elements are present in each of 11 iris species tested, the marker system has the potential to provide valuable comparative data on the dynamics of retrotransposition in large plant genomes.

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