Ri-plasmid (root-inducing plasmid)

ABSTRACT Root mat of cucumbers and tomatoes has previously been shown to be caused by Agrobacterium radiobacter strains harboring a root-inducing Ri plasmid (pRi). Nine other pRi-harboring α-Proteobacteria have subsequently been isolated from root mat-infected crops. Fatty acid profiling and partial 16S rRNA sequence analysis identified three of these strains as being in the genus Ochrobactrum, five as being in the genus Rhizobium, and one as being in the genus Sinorhizobium. An in vitro pathogenicity test involving inoculation of cucumber cotyledons was developed. All pRi-harboring α-Proteobacteria induced typical root mat symptoms from the cotyledons. Average transformation rates for rhizogenic Ochrobactrum (46%) and Rhizobium (44%) strains were lower than those observed for rhizogenic A. radiobacter strains (64%). However, individual strains from these three genera all had transformation rates comparable to those observed from cotyledons inoculated with a rhizogenic Sinorhizobium strain (75%).

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Yeast transformation mediated by Agrobacterium strains harboring an Ri plasmid: comparative study between GALLS of an Ri plasmid and virE of a Ti plasmid

Genes to Cells ◽

10.1111/j.1365-2443.2012.01612.x ◽

2012 ◽

Vol 17 (7) ◽

pp. 597-610 ◽

Cited By ~ 6

Author(s):

Kazuya Kiyokawa ◽

Shinji Yamamoto ◽

Yukari Sato ◽

Naoto Momota ◽

Katsuyuki Tanaka ◽

...

Keyword(s):

Comparative Study ◽

Ti Plasmid ◽

Yeast Transformation ◽

Ri Plasmid

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Sequence of the cellular T-DNA in the untransformed genome of Nicotiana glauca that is homologous to ORFs 13 and 14 of the Ri plasmid and analysis of its expression in genetic tumors of N. glauca x N. langsdorffii

MGG Molecular & General Genetics ◽

10.1007/bf00279581 ◽

1994 ◽

Vol 243 (6) ◽

pp. 706-710 ◽

Cited By ~ 32

Author(s):

Seishirō Aoki ◽

Akiyoshi Kawaoka ◽

Masami Sekine ◽

Takanari Ichikawa ◽

Tomomichi Fujita ◽

...

Keyword(s):

Nicotiana Glauca ◽

Ri Plasmid ◽

Genetic Tumors

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Agropine synthase gene of Ri plasmid is different from the homologous gene of Ti plasmid in tissue-specificity

Journal of Plant Physiology ◽

10.1016/s0176-1617(96)80176-3 ◽

1996 ◽

Vol 149 (1-2) ◽

pp. 73-78 ◽

Cited By ~ 2

Author(s):

Masahiko Inoguchi ◽

Mariko Oka ◽

Takahiro Shikada ◽

Jiro Kato

Keyword(s):

Tissue Specificity ◽

Ti Plasmid ◽

Homologous Gene ◽

Ri Plasmid

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Unexpected conservation and global transmission of agrobacterial virulence plasmids

Science ◽

10.1126/science.aba5256 ◽

2020 ◽

Vol 368 (6495) ◽

pp. eaba5256 ◽

Cited By ~ 2

Author(s):

Alexandra J. Weisberg ◽

Edward W. Davis ◽

Javier Tabima ◽

Michael S. Belcher ◽

Marilyn Miller ◽

...

Keyword(s):

Host Species ◽

Evolutionary History ◽

Virulence Plasmids ◽

Ri Plasmid ◽

Accelerated Evolution ◽

Transfer Genes ◽

Global Spread

The accelerated evolution and spread of pathogens are threats to host species. Agrobacteria require an oncogenic Ti or Ri plasmid to transfer genes into plants and cause disease. We developed a strategy to characterize virulence plasmids and applied it to analyze hundreds of strains collected between 1927 and 2017, on six continents and from more than 50 host species. In consideration of prior evidence for prolific recombination, it was surprising that oncogenic plasmids are descended from a few conserved lineages. Characterization of a hierarchy of features that promote or constrain plasticity allowed inference of the evolutionary history across the plasmid lineages. We uncovered epidemiological patterns that highlight the importance of plasmid transmission in pathogen diversification as well as in long-term persistence and the global spread of disease.

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