English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background   Pseudomonas syringae  pv. phaseolicola 1448a ( P. syringae  1448a), the causative agent of bean halo blight, is a bacterium capable of occupying diverse biological niches. Under conditions of iron starvation  P. syringae  1448a secretes siderophores for active uptake of iron. The primary siderophore of  P. syringae  1448a is pyoverdine, a fluorescent molecule that is assembled from amino acid precursors by non-ribosomal peptide synthetase (NRPS) enzymes. Whereas other species of  Pseudomonas  often exhibit structural variations in the pyoverdine produced by different strains, all  P. syringae  pathovars previously tested have been found to make an identical pyoverdine molecule.  P. syringae  1448a also appears to have the genetic potential to make two secondary siderophores, achromobactin and yersiniabactin, each of which has previously been detected in different  P. syringae  pathovars.    Results  Five putative pyoverdine NRPS genes in  P. syringae  1448a were characterized  in-silico  and their role in pyoverdine biosynthesis was confirmed by gene knockout. Pyoverdine was purified from  P. syringae  1448a and analyzed by MALDI-TOF and MS/MS spectroscopy. Peaks were detected corresponding to the expected sizes for the pyoverdine structure previously found in other  P. syringae  pathovars, but surprisingly  P. syringae  1448a appears to also produce a variant pyoverdine species that has an additional 71 Da monomer incorporated into the peptide side chain. Creation of pyoverdine null mutants of  P. syringae  1448a revealed that this strain also produces achromobactin as a temperature-regulated secondary siderophore, but does not appear to make yersiniabactin. Pyoverdine and achromobactin null mutants were characterized in regard to siderophore production, iron uptake, virulence and growth in iron limited conditions.    Conclusions  This study provides the first evidence of a  P. syringae  pathovar producing a side chain variant form of pyoverdine. We also describe novel IC 50  and liquid CAS assays to quantify the contribution of different siderophores across a range of iron starvation conditions, and show that although achromobactin has potential to contribute to fitness its contribution is masked by the presence of pyoverdine, which is a significantly more effective siderophore. Neither pyoverdine nor achromobactin appear to be required for  P. syringae  1448a to cause bean halo blight, indicating that these siderophores are not promising targets for crop protection strategies.

Characterization of pyoverdine and achromobactin in Pseudomonas syringae pv. phaseolicola 1448a