Articles
GENETIC ANALYSIS OF THE UBIQUITOUS PLASMID PEA29 AND TWO NEW ERWINIA AMYLOVORA PLASMIDS
Article number
704_67
Pages
423 – 430
Language
English
Abstract
All naturally-occurring strains of Erwinia amylovora contain a nontransmissible plasmid called pEA29 or pEA28. While not required for pathogenesis, the presence of this plasmid significantly enhances virulence in an immature pear fruit inoculation assay.
We cloned the putative promoter regions of 10 genes from pEA29 (aldD, aldehyde dehydrogenase; betT, choline transporter; ctpE, methyl-accepting chemotaxis transducer; msrA, peptide methionine sulfoxide reductase; orf7, orf11, orf15, and orf20, unknown function; thiO, thiamine biosynthetic gene operon; trlA, transcriptional regulator) into a
-glucuronidase reporter vector and found that expression driven from several of these sequences was elevated during pear fruit infection.
The expression of the chromosomal amylovoran biosynthetic operon promoter was also significantly elevated in the wild-type Ea110 strain compared to the Ea110/pEA29-cured strain.
The nucleotide sequence of two new E. amylovora plasmids (pEU30 and pEL60) was determined.
Plasmids pEU30 (30,314 bp) and pEL60 (60,145 bp) encode mostly plasmid-specific replication, maintenance, and conjugation functions; however, pEU30 also encodes several transcriptional regulators that could play a role in the interaction of E. amylovora and its plant host.
The gene content of pEU30 was similar to that of plasmids found in plant-associated bacteria while the IncL/M plasmid pEL60 more closely resembled enterobacterial plasmids.
Detection experiments indicated that pEU30 and pEL60 were only present in strains from the western United States and Lebanon, respectively.
The newly-identified pEU30 and pEL60 will provide additional tools in the molecular tracking of E. amylovora in nature.
We cloned the putative promoter regions of 10 genes from pEA29 (aldD, aldehyde dehydrogenase; betT, choline transporter; ctpE, methyl-accepting chemotaxis transducer; msrA, peptide methionine sulfoxide reductase; orf7, orf11, orf15, and orf20, unknown function; thiO, thiamine biosynthetic gene operon; trlA, transcriptional regulator) into a
-glucuronidase reporter vector and found that expression driven from several of these sequences was elevated during pear fruit infection.The expression of the chromosomal amylovoran biosynthetic operon promoter was also significantly elevated in the wild-type Ea110 strain compared to the Ea110/pEA29-cured strain.
The nucleotide sequence of two new E. amylovora plasmids (pEU30 and pEL60) was determined.
Plasmids pEU30 (30,314 bp) and pEL60 (60,145 bp) encode mostly plasmid-specific replication, maintenance, and conjugation functions; however, pEU30 also encodes several transcriptional regulators that could play a role in the interaction of E. amylovora and its plant host.
The gene content of pEU30 was similar to that of plasmids found in plant-associated bacteria while the IncL/M plasmid pEL60 more closely resembled enterobacterial plasmids.
Detection experiments indicated that pEU30 and pEL60 were only present in strains from the western United States and Lebanon, respectively.
The newly-identified pEU30 and pEL60 will provide additional tools in the molecular tracking of E. amylovora in nature.
Publication
Authors
G.W. Sundin, G.C. McGhee, G.C. Foster, A.L. Jones
Keywords
virulence, amylovoran, transcriptional fusions, virB operon, Citrobacter freundii
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