ABSTRACT
Pectobacterium carotovorum subsp. carotovorum strain PccS1, a bacterial pathogen causing soft rot disease of Zantedeschia elliotiana (colored calla), was investigated for virulence genes induced by the host plant. Using a promoter-trap transposon (mariner), we obtained 500 transposon mutants showing kanamycin resistance dependent on extract of Z. elliotiana. One of these mutants, PM86, exhibited attenuated virulence on both Z. elliotiana and Brassica rapa subsp. pekinensis. The growth of PM86 was also reduced in minimal medium (MM), and the reduction was restored by adding plant extract to the MM. The gene containing the insertion site was identified as rplY. The deletion mutant ΔrplY, exhibited reduced virulence, motility and plant cell wall-degrading enzyme production but not biofilm formation. Analysis of gene expression and reporter fusions revealed that the rplY gene in PccS1 is up-regulated at both the transcriptional and the translational levels in the presence of plant extract. Our results suggest that rplY is induced by Z. elliotiana extract and is crucial for virulence in P. carotovorum subsp. carotovorum.
Subject(s)
Bacterial Proteins/metabolism , Pectobacterium carotovorum/pathogenicity , Plant Extracts/pharmacology , Zantedeschia/chemistry , Amino Acid Sequence , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial/drug effects , Plant Extracts/chemistry , VirulenceABSTRACT
We aimed to identify the main compounds responsible for low temperature-induced yellow pigmentation of the bracts of Zantedeschia aethiopica 'Wedding March'. On the basis of the area ratios estimated from absorbance at 400 nm in HPLC analyses, we identified two flavonoids, isoorientin and swertiajaponin, as such compounds. We also identified two additional flavonoids, isovitexin and swertisin, which do not contribute considerably to the yellow pigmentation. Flavonoids of Zantedeschia bracts seem to belong to the class of flavone C-glycosides.
Subject(s)
Cold Temperature , Flavones/chemistry , Flowers/physiology , Glucosides/chemistry , Pigments, Biological/chemistry , Zantedeschia/physiology , Flowers/chemistry , Molecular Structure , Zantedeschia/chemistryABSTRACT
A new lectin gene was isolated by using genomic walker technology and revealed to encode a mannose-binding lectin. Analysis of a 2233 bp segment revealed a gene including a 1169 bp 5' flanking region, a 417 bp open reading frame (ORF) and a 649 bp 3' flanking region. There are two putative TATA boxes and eight possible CAAT boxes lie in the 5' flanking region. The ORF encodes a 15.1 kDa precursor, which contains a 24-amino acid signal peptide. One possible polyadenylation signal is found in the 3'-flanking region. No intron was detected within the region of genomic sequence corresponding to zaa (Zantedeschia aethiopica agglutinin) full-length cDNA, which is typical of other mannose-binding lectin gene that have been reported. The deduced amino acid sequence of the lectin gene coding region shares 49-54% homology with other known lectins. The cloning of this new lectin gene will allow us to further study its structure, expression and regulation mechanisms.
