Mannopinic acid and agropinic acid catabolism region of the octopine‐type Ti plasmid pTi15955

Lyi, Sangbom M.; Jafri, Samina; Winans, Stephen C.

doi:10.1046/j.1365-2958.1999.01178.x

Cited by 23 publications

(8 citation statements)

References 35 publications

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“…1), ooxB (SMa2225; Fig. 1), two cyclodeaminases (SMA0486, 1871), and the AgaE-like deaminase (SMA1869), which converts the opine, mannopinic acid, to mannose and glutamate (53,54). If sequence similarity is predictive of function, these enzymes appear sufficient to convert opines to proline.…”

Section: Resultsmentioning

confidence: 99%

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Barnett

Fisher

Jones

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

281

227

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The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti contains three replicons: pSymA, pSymB, and the chromosome. We report here the complete 1,354,226-nt sequence of pSymA. In addition to a large fraction of the genes known to be specifically involved in symbiosis, pSymA contains genes likely to be involved in nitrogen and carbon metabolism, transport, stress, and resistance responses, and other functions that give S. meliloti an advantage in its specialized niche.

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Section: Resultsmentioning

confidence: 99%

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Barnett

Fisher

Jones

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

281

227

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“…and moa genes is induced by agropinic and mannopinic acid, respectively, and is mediated by the MoaR repressor (304). The OccR protein is thought to bind octopine through its C-terminal domain, whereas the N-terminal domain has a DNA binding motif and is probably involved in transcriptional regulation of target genes.…”

Section: Detection Of Opines Released By Crown Gall Tumorsmentioning

confidence: 99%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

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337

208

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Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described

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“…The mannopine and agropine permeases and catabolic enzymes also are induced by the cognate opines, probably via the MocR protein, which resembles the LacI repressor of E. coli. Similarly, regulated expression of the aga and moa genes by the cognate opines requires the MoaR repressor, which resembles yet another family of regulators, including the galacticol repressor of E. coli (70). Expression of the opine catabolism gene sets also is influenced by global control systems.…”

Section: Regulated Expression Of Ti Plasmid-encoded Genesmentioning

confidence: 99%

The Bases of Crown Gall Tumorigenesis

et al. 2000

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3The nine decades since Smith and Townsend demonstrated that Agrobacterium tumefaciens causes plant tumors (95) have been marked by a series of surprises. Among the most important of these was the report in 1958 that these tumors could be excised and propagated in vitro without exogenous plant hormones (7). Equally important were a series of reports beginning about the same time that tumors released compounds that agrobacteria could use as nutrients (24). Perhaps the most exciting discoveries, reported in the 1970s and 1980s, were that tumorigenesis required the transfer of fragments of oncogenic DNA to infected plant cells (10), that this process evolved from a conjugal transfer system (99), and that the genes that direct this process are expressed in response to host-released chemical signals (47). This DNA transfer process has become a cornerstone of plant molecular genetics. The genus Agrobacterium also has provided excellent models for several aspects of host-pathogen interactions, including intercellular transport of macromolecules (11), bacterial detection of host organisms (47), targeting of proteins to plant cell nuclei (3), and interbacterial chemical signaling via autoinducer-type pheromones (120).Most of the genes required for tumorigenesis are found on large extrachromosomal elements called Ti plasmids. Indeed, transfer of Ti plasmids into certain nonpathogenic bacteria converts them into tumorigenic pathogens (43). Ti plasmids are generally referred to by the types of opines whose catabolism they direct (see below). However, this nomenclature is becoming less satisfactory as we discover that all known Ti plasmids direct the catabolism of more than one opine and that opine catabolic genes are found in a variety of combinations in different plasmids. The Ti plasmids pTiA6NC, pTi15955, pTiAch5, pTiR10, and pTiB6S3, which are widely considered to be functionally identical, are generally referred to as octopine-type Ti plasmids (or, less frequently, octopine, mannityl opine-type Ti plasmids). The DNA sequencing of these plasmids was initiated almost 20 years ago (21) and was recently completed in our three laboratories. The resulting 194,140-nucleotide sequence is a composite assembly of sequences from all of the plasmids listed above. The close similarity of these plasmids is exemplified by the sequence of a 42-kb segment of the vir regions of pTiA6NC and pTi15955. These sequences differ at only one base, and this polymorphism is silent at the amino acid level. We have no evidence for polymorphisms elsewhere except for a large deletion that is unique to pTiA6NC (Fig. 1). The restriction map deduced from this sequence agrees almost perfectly with the published restriction map of pTiAch5 (25). All known and suspected genes are depicted in Fig. 1, and their demonstrated or putative functions are described in Table 1. The DNA sequence of this Ti plasmid provides a useful framework to review the roles of this plasmid in the biology of plant infection and colonization.This Ti plasmid contains 155 open readin...

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Mannopinic acid and agropinic acid catabolism region of the octopine‐type Ti plasmid pTi15955

Cited by 23 publications

References 35 publications

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

The Bases of Crown Gall Tumorigenesis

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