Dataset Information

Mutations in the listerial proB gene leading to proline overproduction: effects on salt tolerance and murine infection.

ABSTRACT: The observed sensitivity of Listeria monocytogenes to the toxic proline analogue L-azetidine-2-carboxylic acid (AZ) suggested that proline synthesis in Listeria may be regulated by feedback inhibition of gamma-glutamyl kinase (GK), the first enzyme of the proline biosynthesis pathway, encoded by the proB gene. Taking advantage of the Epicurian coli mutator strain XL1-Red, we performed random mutagenesis of the recently described proBA operon and generated three independent mutations in the listerial proB homologue, leading to proline overproduction and salt tolerance when expressed in an E. coli (DeltaproBA) background. While each of the mutations (located within a conserved 26-amino-acid region of GK) was shown to confer AZ resistance (AZ(r)) on an L. monocytogenes proBA mutant, listerial transformants failed to exhibit the salt-tolerant phenotype observed in E. coli. Since proline accumulation has previously been linked to the virulence potential of a number of pathogenic bacteria, we analyzed the effect of proline overproduction on Listeria pathogenesis. However, our results suggest that as previously described for proline auxotrophy, proline hyperproduction has no apparent impact on the virulence potential of Listeria.

SUBMITTER: Sleator RD

PROVIDER: S-EPMC93203 | biostudies-literature | 2001 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mutations in the listerial proB gene leading to proline overproduction: effects on salt tolerance and murine infection.

Sleator R D RD Gahan C G CG Hill C C

Applied and environmental microbiology 20011001 10

The observed sensitivity of Listeria monocytogenes to the toxic proline analogue L-azetidine-2-carboxylic acid (AZ) suggested that proline synthesis in Listeria may be regulated by feedback inhibition of gamma-glutamyl kinase (GK), the first enzyme of the proline biosynthesis pathway, encoded by the proB gene. Taking advantage of the Epicurian coli mutator strain XL1-Red, we performed random mutagenesis of the recently described proBA operon and generated three independent mutations in the liste ...[more]

PMID: 11571156

Similar Datasets

Project description:Soybean plants are sensitive to the effects of abiotic stress and belong to the group of crops that are less drought and salt tolerant. The identification of genes involved in mechanisms targeted to cope with water shortage is an essential and indispensable task for improving the drought and salt tolerance of soybean. One of the approaches for obtaining lines with increased tolerance is genetic modification. The dehydration-responsive element binding proteins (DREBs), belonging to the AP2 family, are trans-active transcription factors that bind to the cis-sequences of the promoter for activating the expression of the target genes that mediate drought and salt tolerant responses. In this study, the GmDREB6 transgene was introduced into DT84 cultivar soybean plants, using Agrobacterium-mediated transformation. The efficacy of GmDREB6 overexpression in enhancing the transcriptional level of GmP5CS and proline accumulation in genetically modified (GM) soybean plants was also assayed. The results demonstrated that ten GM soybean plants (T0 generation) were successfully generated from the transformed explants after selecting with kanamycin. Among these plantlets, the presence of the GmDREB6 transgene was confirmed in nine plants by Polymerase Chain Reaction (PCR), and eight plants showed positive results in Southern blot. In the T1 generation, four GM lines, labelled T1-2, T1-4, T1-7, and T1-10, expressed the recombinant GmDREB6 protein. In the T2 generation, the transcriptional levels of the GmP5CS gene were higher in the GM lines than in the non-transgenic plants, under normal conditions and also under conditions of salt stress and drought, ranging from 1.36 to 2.01 folds and 1.58 to 3.16 folds that of the non-transgenic plants, respectively. The proline content was higher in the four GM soybean lines, T2-2, T2-4, T2-7, and T2-10 than in the non-transgenic plants, ranging from 0.82 ?mol/g to 4.03 ?mol/g. The proline content was the highest in the GM T2-7 line (7.77 ?mol/g). In GM soybean lines, T2-2, T2-4, T2-7, and T2-10 proline content increased after plants were subjected to salt stress for seven days, in comparison to that under normal conditions, and ranged from 247.83% to 300%, while that of the non-GM plants was 238.22%. These results suggested that GmDREB6 could act as a potential candidate for genetic engineering for improving tolerance to salt stresses.

Dataset Information

Mutations in the listerial proB gene leading to proline overproduction: effects on salt tolerance and murine infection.

Publications

Mutations in the listerial proB gene leading to proline overproduction: effects on salt tolerance and murine infection.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets