New Cyt-like δ-endotoxins from Dickeya dadantii: structure and aphicidal activity

ABSTRACT Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

Download Full-text

Modeling the bioconversion of polysaccharides in a continuous reactor: A case study of the production of oligogalacturonates by Dickeya dadantii

Journal of Biological Chemistry ◽

10.1074/jbc.ra118.004615 ◽

2018 ◽

Vol 294 (5) ◽

pp. 1753-1762 ◽

Cited By ~ 2

Author(s):

Jacques-Alexandre Sepulchre ◽

Sylvie Reverchon ◽

Jean-Luc Gouzé ◽

William Nasser

Keyword(s):

A Priori ◽

Pectate Lyase ◽

Degradation Process ◽

Continuous Reactor ◽

Practical Implementation ◽

Dickeya Dadantii ◽

Pectate Lyases ◽

Upper Limit ◽

Promising Avenue

In the quest for a sustainable economy of the Earth's resources and for renewable sources of energy, a promising avenue is to exploit the vast quantity of polysaccharide molecules contained in green wastes. To that end, the decomposition of pectin appears to be an interesting target because this polymeric carbohydrate is abundant in many fruit pulps and soft vegetables. To quantitatively study this degradation process, here we designed a bioreactor that is continuously fed with de-esterified pectin (PGA). Thanks to the pectate lyases produced by bacteria cultivated in the vessel, the PGA is depolymerized into oligogalacturonates (UGA), which are continuously extracted from the tank. A mathematical model of our system predicted that the conversion efficiency of PGA into UGA increases in a range of coefficients of dilution until reaching an upper limit where the fraction of UGA that is extracted from the bioreactor is maximized. Results from experiments with a continuous reactor hosting a strain of the plant pathogenic bacterium Dickeya dadantii and in which the dilution coefficients were varied quantitatively validated the predictions of our model. A further theoretical analysis of the system enabled an a priori comparison of the efficiency of eight other pectate lyase–producing microorganisms with that of D. dadantii. Our findings suggest that D. dadantii is the most efficient microorganism and therefore the best candidate for a practical implementation of our scheme for the bioproduction of UGA from PGA.

Download Full-text

The EnvZ-OmpR Two-Component Signaling System Is Inactivated in a Mutant Devoid of Osmoregulated Periplasmic Glucans in Dickeya dadantii

Frontiers in Microbiology ◽

10.3389/fmicb.2018.02459 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 3

Author(s):

Marine Caby ◽

Sébastien Bontemps-Gallo ◽

Peggy Gruau ◽

Brigitte Delrue ◽

Edwige Madec ◽

...

Keyword(s):

Signaling System ◽

Dickeya Dadantii ◽

Two Component

Download Full-text

Complete Genome Sequence of Dickeya dadantii subsp. dieffenbachiae Strain S3-1, Isolated from a White-Flowered Calla Lily in Taiwan

Microbiology Resource Announcements ◽

10.1128/mra.00620-21 ◽

2021 ◽

Vol 10 (37) ◽

Author(s):

Yung-An Lee ◽

Kuan-Pei Chen

Keyword(s):

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Soft Rot ◽

Erwinia Chrysanthemi ◽

Bacterial Soft Rot ◽

Plant Host ◽

Dickeya Dadantii ◽

Content Type ◽

Calla Lily

Erwinia chrysanthemi S3-1 is a bacterial soft rot pathogen of the white-flowered calla lily. The complete genome sequence of the strain was determined and used to reclassify the strain as Dickeya dadantii subsp. dieffenbachiae . The sequence will be useful to study plant host-driven speciation in strains of D. dadantii .

Download Full-text

Characterization of the early response of Arabidopsis thaliana to Dickeya dadantii infection using expression profiling

10.1101/415380 ◽

2018 ◽

Author(s):

Frédérique Van Gijsegem ◽

Frédérique Bitton ◽

Anne-Laure Laborie ◽

Yvan Kraepiel ◽

Jacques Pédron

Keyword(s):

Arabidopsis Thaliana ◽

Early Stage ◽

Plant Defence ◽

Plant Responses ◽

Type I ◽

In Planta ◽

Secretion Systems ◽

Dickeya Dadantii ◽

A Genome

AbstractTo draw a global view of plant responses to interactions with the phytopathogenic enterobacterale Dickeya dadantii, a causal agent of soft rot diseases on many plant species, we analysed the early Arabidopsis responses to D. dadantii infection. We performed a genome-wide analysis of the Arabidopsis thaliana transcriptome during D. dadantii infection and conducted a genetic study of identified responses.A limited set of genes related to plant defence or interactions with the environment were induced at an early stage of infection, with an over-representation of genes involved in both the metabolism of indole glucosinolates (IGs) and the jasmonate (JA) defence pathway. Bacterial type I and type II secretion systems are required to trigger the induction of IG and JA-related genes while the type III secretion system appears to partially inhibit these defence pathways. Using Arabidopsis mutants impaired in JA biosynthesis or perception, we showed that induction of some IG metabolism genes was COI1-dependent but, surprisingly, JA-independent. Moreover, characterisation of D. dadantii disease progression in Arabidopsis mutants impaired in JA or IG pathways showed that JA triggers an efficient plant defence response that does not involve IGs.The induction of the IG pathway by bacterial pathogens has been reported several times in vitro. This study shows for the first time, that this induction does indeed occur in planta, but also that this line of defence is ineffective against D. dadantii infection, in contrast to its role to counteract herbivorous or fungal pathogen attacks.

Download Full-text

Aphicidal Activity of Different Fraction Extracts of Culture Filtrate of Beauveria bassiana Isolate against Aphids

Korean Journal of Organic Agricultue ◽

10.11625/kjoa.2017.25.1.113 ◽

2017 ◽

Vol 25 (1) ◽

pp. 113-124

Author(s):

Jeong, Ga-Young ◽

◽

Han, Ji-Hee ◽

Kim, Jeong-Jun ◽

Lee, Sang-Yeob

Keyword(s):

Beauveria Bassiana ◽

Culture Filtrate ◽

Aphicidal Activity

Download Full-text

Three Highly Sensitive and High-Throughput Serological Approaches for Detecting Dickeya dadantii in Sweet Potato

Plant Disease ◽

10.1094/pdis-07-20-1551-re ◽

2021 ◽

Vol 105 (4) ◽

pp. 832-839

Author(s):

Wanqin He ◽

Deqing Huang ◽

Jiayu Wu ◽

Xue Li ◽

Yajuan Qian ◽

...

Keyword(s):

Sweet Potato ◽

Cell Lines ◽

Immunosorbent Assay ◽

Root Rot ◽

Enzyme Linked Immunosorbent Assay ◽

Dickeya Dadantii ◽

Crude Extracts ◽

Tissue Print ◽

Hybridoma Cell Lines ◽

Dot Elisa

Sweet potato stem and root rot is an important bacterial disease and often causes serious economic losses to sweet potato. Development of rapid and sensitive detection methods is crucial for diagnosis and management of this disease in field. Here, we report the production of four hybridoma cell lines (25C4, 16C10, 9B1, and 9H10) using Dickeya dadantii strain FY1710 as an immunogen. Monoclonal antibodies (MAbs) produced by these four hybridoma cell lines were highly specific and sensitive for D. dadantii detection. Indirect enzyme-linked immunosorbent assay (indirect-ELISA) results showed that the four MAbs 25C4, 16C10, 9B1, and 9H10 could detect D. dadantii in suspensions diluted to 4.89 × 104, 4.89 × 104, 9.78 × 104, and 9.78 × 104 CFU/ml, respectively. Furthermore, all four MAbs can react strongly and specifically with all four D. dadantii strains used in this study, not with the other seven tested bacterial strains. Using these four MAbs, three different serological approaches, triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA), dot-ELISA, and tissue-print-ELISA, were developed for detection of D. dadantii in crude extracts prepared from field-collected sweet potato plants. Among these three methods, TAS-ELISA and dot-ELISA were used to detect D. dadantii in suspensions diluted up to 1.23 × 104 and 1.17 × 106 CFU/ml, respectively, or in sweet potato crude extracts diluted up to 1:3,840 and 1:1,920 (wt/vol, grams per milliliter), respectively. Surprisingly, both TAS-ELISA and dot-ELISA serological approaches were more sensitive than the conventional PCR. Analyses using field-collected sweet potato samples showed that the newly developed TAS-ELISA, dot-ELISA, or tissue-print-ELISA were reliable in detecting D. dadantii in sweet potato tissues. Thus, the three serological approaches were highly valuable for diagnosis of stem and root rot in sweet potato production.

Download Full-text