Ti- and cryptic-plasmid-borne virulence of wild-type Agrobacterium tumefaciens strain CNI5 isolated from chrysanthemum (Dendranthema grandiflora Tzvelev)

Mii, M

M. Mii, Ti- and cryptic-plasmid-borne virulence of wild-type Agrobacterium tumefaciens strain CNI5 isolated from chrysanthemum (Dendranthema grandiflora Tzvelev), ARCH MICROB, 176(5), 2001, pp. 315-322

59

INGLESE

Article

Microbiology

ARCHIVES OF MICROBIOLOGY

0302-8933 → ACNP

176

5

2001

315 - 322

ISI

0302-8933(200111)176:5<315:TACVOW>2.0.ZU;2-9

The genetic similarity between pTiBo542 and pTiCNI5, which are harbored, re spectively by the supervirulent Agrobacterium tumefaciens strain A281 and b y the highly tumorigenic wild-type strain CNI5 isolated from chrysanthemum was investigated by Southern hybridization. pTiCNI5 and pTiBo542 exhibited highly similar hybridization patterns in both BamHI- and EcoRI-digested pla smids by using four vir-region-specific probes, whereas similarity in these two plasmids was not observed by probing with five TL-DNA-specific probes. The characteristics related to tumor formation of cryptic plasmids carried by strain CNI5 were investigated by using single-plasmid-cured derivatives . pTiCNI5-cured derivatives predictably failed to utilize agropine and mann opine and failed to induce tumors on chrysanthemum and tobacco leaf explant s, while pAtCNI5a-, pAtCNI5c- and pAtCNI5d-cured derivatives could utilize these opines similar to the parent strain CNI5. Interestingly, pAtCNI5c- an d pAtCNI5d-cured derivatives showed low tumorigenicity in comparison with s train CNI5 or with the pAtCNI5a-cured derivative. These results suggest tha t the highly virulent phenotype of strain CNI5 may be due to one or more vi r genes, which exhibit cartographic similarity to those of pTiBo542. The re sults also suggest that the gene(s) related to tumor formation of strain CN I5 may exist not only on pTiCNI5 but also on cryptic plasmids pAtCNI5c- and pAtCNI5d.