Intergeneric conjugal gene transfer from Escherichia coli to the sweet potato pathogen Streptomyces ipomoeae.
OBJECTIVE
To develop an effective gene transfer system for Streptomyces ipomoeae, the causative agent of soil rot disease of sweet potatoes.


RESULTS
Of the several methods investigated, introduction of genes into S. ipomoeae could only be achieved using intergeneric conjugation from Escherichia coli. However, even results for that method varied greatly and were dependent on using particular media for S. ipomoeae spore preparation and conjugation. Transconjugant to recipient ratios as great as 4.1 x 10(-5) were achieved when International Streptomyces Project Medium 4 was used for both sporulation and conjugation protocols. Both site-specifically integrating and autonomously replicating plasmids could be introduced and maintained in S. ipomoeae, and plasmids could be introduced with approximate equivalent frequencies from either methyl-proficient or methyl- deficient E. coli donors; the latter result indicates a likely absence of relevant methyl-specific restriction in S. ipomoeae.


CONCLUSIONS
Efficient transfer of genes into S. ipomoeae was achieved here by using an optimized intergeneric mating procedure.


CONCLUSIONS
The described protocol will facilitate further genetic manipulation of this agriculturally important pathogen.
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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Pettis
D003227:Conjugation, Genetic; D003470:Culture Media / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D027723:Ipomoea batatas / Q000382:microbiology; D008967:Molecular Biology / Q000379:methods*; D010957:Plasmids; D013302:Streptomyces / Q000235:genetics* / Q000502:physiology
D003470:Culture Media