Combined Genetic and Physical Map of the Complex Genome of Agrobacterium tumefaciens

Abstract

A combined genetic and physical map of the Agrobacterium tumefaciens A348 (derivative of C58) genome was constructed to address the discrepancy between initial single-chromosome genetic maps and more recent physical mapping data supporting the presence of two nonhomologous chromosomes. The combined map confirms the two-chromosome genomic structure and the correspondence of the initial genetic maps to the circular chromosome. The linear chromosome is almost devoid of auxotrophic markers, which probably explains why it was missed by genetic mapping studies.

Disc‐electrospun cellulose acetate butyrate nanofibers show enhanced cellular growth performances

“…Auxotroph Co‐Culture with Plant Tissues To Screen for Controlled Growth. To verify that auxotrophism could be used to control Agrobacteria growth in liquid culture, previously generated kanamycin‐resistant auxotrophs (7) were screened for growth in co‐culture with N. glutinosa roots and BY2 cells. Attenuated growth as indicated by an absorbance ( A 600 ) of less than 0.5 after 3 days of co‐culture was used as a criterion for reasonable control.…”

“…Feasibility Screen. Twenty‐four A. tumefaciens Tn5/Kan R auxotrophs, provided by B. Goodner (7), were screened for the characteristic of reduced growth during co‐culture with plant cell suspensions and root cultures. The bacteria were grown to an absorbance of approximately 0.25 in liquid LB media supplemented with 50 mg/L kanamycin and 20 mg/L rifampicin.…”

“…Transposon generated auxotrophs do not revert to their parent type if the transposase is not present. Agrobacteria auxotrophs have been generated by transposon mutagenesis for the development of genetic and physical maps of the associated genes that were mutated in generating the auxotrophs (7). The auxotrophs generated for genetic mapping utilized transposon inserts conferring kanamycin resistance (Kan R ).…”

A new beginning with new ends: linearisation of circular chromosomes during bacterial evolution

“…Agrobacterium tumefaciens , the causal agent of crown gall disease, harbours one circular chromosome and one non‐homologous large linear DNA molecule. This linear molecule, which is almost devoid of auxotrophic markers, was assumed to correspond to a linear chromosome [4]. In addition, the macrorestriction map of the chromosome of the obligate intracellular proteobacterium Coxiella burnetii suggests linearity [5].…”

Prevention of Grape Crown Gall

“…Crown gall of grape is caused by Agrobacterium vitis (Rhizobium vitis by recently proposed nomenclature [106]) and in some cases -by A. tumefaciens (R. radiobacter) [13,59]. Pathogenic agrobacteria have the ability to transfer the definite segment of Ti plasmid into eukaryotic cells, where it integrates into the genome [21,40]. Pathogens induce crown gall tumors on the representatives of 93 families of dicotyledonous plants [27], but grape, stone fruits and ornamentals are the most being suffered [13,38,65].…”