Genetic Transfer of Episomic Elements Among Erwinia Species and Other Enterobacteria: F′ lac ⁺

Abstract

The episomic element F'lac+ was transferred, probably by conjugation, from Escherichia coli to Lacstrains of Erwinia herbicola, Erwinia amylovora, and Erwinia chrysanthemi (but not to several other Erwinia spp. In preliminary trials). The lac genes in the exconjugants of the Erwinia spp. showed varying degrees of stability depending on the strain (stable in E. herbicola strains Y46 and Y74 and E. amylovora strain EA178, but markedly unstable in E. chrysanthemi strain EC16). The lac genes and the sex factor (F) were eliminated from the exconjugants by treatment with acridine orange, thus suggesting that both lac and F are not integrated in the Erwinia exconjugants. All of the tested Lac+ exconjugants of E. herbicola strains Y46 and Y74 and E. amylovora strain EA178, but not of E. chrysanthemi strain EC 16, were sensitive to the F-specific phage M13. The heterogenotes (which harbored F'lac+) of E. herbicola strains Y46 and Y74, E. amylovora strain EA178, and E. chrysanthemi strain EC16 were able to transfer lac genes by conjugation to strains of E. herbicola, E. amylovora, E. chrysanthemi, Escherichia coli, and Shigella dysenteriae. The frequency of such transfer from Lac+ exconjugants of Erwinia spp. was comparable to that achieved by using E. coli F'lac+ as donors, thus indicating the stability, expression, and restriction-and-modification properties of the sex factor (F) in Erwinia spp.

Humus bacteria of Norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity

“…The plates were incubated at 28³C and zones of chitin clearing recorded after 7^14 days. Hydrolysis of pectin was detected by the method of Chatterjee and Starr [28]. Carboxymethylcellulase (CMCase) activity was detected according to [29].…”

Gene Transmission Among Strains of Erwinia amylovora

“…The transfers of the episomic element F'lac from Escherichia coli and of R factors from E. coli and a clinical isolate of Shigella flexneri la to Erwinia spp. have been reported by us (4,5). Subsequently, we sought and found some Lac+ heterogenotes of Erwinia amylovora and E. herbicola (derived from crosses between E. coli F'lac and the Erwinia spp.…”

“…Media. The compositions of media have been described in our earlier report (4). The minimal medium was supplemented by amino acids (50 #g/ml) and vitamins (nicotinic acid, 50 pug/ml; thiamine, 1 sg/ml), depending upon the growth requirement of the organisms.…”

“…Acridine orange "curing." The effect of acridine orange on the elimination of lac was determined in Penassay broth by the procedure described earlier (4 (confluent growth in the region where the donor cultures were spotted) than with the other clones. No recombinant clones were observed when EA178-M107S1 was used as the recipient.…”

“…' The various M64S1 strains are auxotrophs derived from Erwinia amylovora strain EA178. EA178R1 is an Erwinia amylovora strain derived from EA178 and harboring an E. coli F'lac (4). Donor strains EA178R,-99 and EA178R1-111 were derived from EA178R1 by acridine orange treatment.…”