Taxonogenomic analysis of the complex leads to the descriptions of sp. nov. and sp. nov.

The pathovar-based taxonomy of the group is very confusing due to an overlap of plant host ranges and level of host specificity. Here, whole-genome sequence-based parameters (digital DNA-DNA hybridization and blast-based average nucleotide identity), phylogenomic, biochemical and phenotypical data were used to taxonomically analyse the 11 known pathovars of the complex. This polyphasic approach taxonomically assigned the 11 pathovars of complex into three distinct species, two of which are new: , sp.

Phenazines are involved in the antagonism of a novel subspecies of Pseudomonas chlororaphis strain S1Bt23 against Pythium ultimum.

Long-term use of chemical fungicides to control plant diseases caused by fungi and oomycetes has led to pathogen resistance and negative impacts on public health and environment. There is a global search for eco-friendly methods and antagonistic bacteria are emerging as alternatives. We isolated a potent antagonistic bacterial strain (S1Bt23) from woodland soil in Québec, Canada.

Draft genome sequences of sp. MHB01, MHB02, and MHB03 isolated from superabsorbent polymer granules inoculated with an arbuscular mycorrhizal fungus.

sp. MHB01, MHB02, and MHB03 were isolated from superabsorbent polymer granules cultured with an arbuscular mycorrhizal fungus. Whole-genome sequencing of these three strains revealed genome sizes of 4.

TaqMan Real-Time PCR Assay for Specific Detection and Differentiation of pv. from Other Pathovars Targeting a Recombination Mediator Gene, F.

Bacterial leaf streak and black chaff diseases of wheat caused by pv. is becoming a major constraint to growers and trade since it is seedborne. Molecular tools for specific detection/differentiation of pv.

sp. nov., a new nitrogen-fixing symbiovar isolated from root nodules of in Tunisia.

Three bacterial strains, 1AS11, 1AS12 and 1AS13, members of the new symbiovar salignae and isolated from root nodules of grown in Tunisia, were characterized using a polyphasic approach. All three strains were assigned to the complex on the basis of gene analysis. Phylogenetic analysis based on 1734 nucleotides of four concatenated housekeeping genes (, , and ) showed that the three strains were distinct from known rhizobia species of the complex and clustered as a separate clade within this complex.

Phylogenomic Insights on the Complex, and Development of a TaqMan Real-Time Assay for Specific Detection of pv. on Barley.

The reemergence and spread of , the causal agent of bacterial leaf streak in cereal crops and wilt in turfgrass and forage species, is a concern to growers in the United States and Canada. The pathogen is seedborne and listed as an A2 quarantine organism by EPPO, making it a major constraint to international trade and exchange of germplasm. The pathovar concept of the group is confusing due to overlapping of plant host ranges and specificity.

Goss's Wilt Resistance in Corn Is Mediated via Salicylic Acid and Programmed Cell Death but Not Jasmonic Acid Pathways.

A highly aggressive strain (CMN14-5-1) of bacteria, which causes Goss's wilt in corn, induced severe symptoms in a susceptible corn line (CO447), resulting in water-soaked lesions followed by necrosis within a few days. A tolerant line (CO450) inoculated with the same strain exhibited only mild symptoms such as chlorosis, freckling, and necrosis that did not progress after the first six days following infection. Both lesion length and disease severity were measured using the area under the disease progression curve (AUDPC), and significant differences were found between treatments.

First Report of Bacterial Leaf Streak of Barley () Caused by pv. in British Columbia, Canada.

Bacterial leaf streak (BLS) of barley is caused by the Gram-negative bacterial pathogen Xanthomonas translucens (Sapkota et al. 2020). In 2021, we observed multiple hill plots with BLS symptomatic plants in a barley stripe rust nursery in Vancouver, BC, Canada.

Genotypic and symbiotic diversity studies of rhizobia nodulating Acacia saligna in Tunisia reveal two novel symbiovars within the Rhizobium leguminosarum complex and Bradyrhizobium.

Acacia saligna is an invasive alien species that has the ability to establish symbiotic relationships with rhizobia. In the present study, genotypic and symbiotic diversity of native rhizobia associated with A. saligna in Tunisia were studied.

Corrigendum: Molecular Analysis of Bacterial Isolates From Necrotic Wheat Leaf Lesions Caused by , and Description of Three Putative Novel Species, sp. nov., sp. nov. and sp. nov.

[This corrects the article DOI: 10.3389/fmicb.2021.

Whole-Genome Resources and Species-Level Taxonomic Validation of 89 Plant-Pathogenic Strains Isolated from Various Host Plants.

Bacterial spot disease caused by s spp. is a global threat to tomato and pepper plants. A recent classification of these pathogens indicated the need for a diverse dataset of whole-genome resources.

Phylogenetic study of rhizobia nodulating pea (Pisum sativum) isolated from different geographic locations in Tunisia.

Nodulated Pisum sativum plants showed the presence of native rhizobia in 16 out of 23 soil samples collected especially in northern and central Tunisia. A total of 130 bacterial strains were selected and three different ribotypes were revealed after PCR-RFLP analysis. Sequence analyses of rrs and four housekeeping genes (recA, atpD, dnaK and glnII) assigned 35 isolates to Rhizobium laguerreae, R.

MinION Nanopore-based detection of Clavibacter nebraskensis, the corn Goss's wilt pathogen, and bacteriomic profiling of necrotic lesions of naturally-infected leaf samples.

The Goss's bacterial wilt pathogen, Clavibacter nebraskensis, of corn is a candidate A1 quarantine organism; and its recent re-emergence and spread in the USA and Canada is a potential biothreat to the crop. We developed and tested an amplicon-based Nanopore detection system for C. nebraskensis (Cn), targeting a purine permease gene.

Secretome Analysis of Strains Treated with Natural Xylem Sap In Vitro Predicts Involvement of Glycosyl Hydrolases and Proteases in Bacterial Aggressiveness.

The Gram-positive bacterium (Cn) causes Goss's wilt and leaf blight on corn in the North American Central Plains with yield losses as high as 30%. Cn strains vary in aggressiveness on corn, with highly aggressive strains causing much more serious symptoms and damage to crops. Since Cn inhabits the host xylem, we investigated differences in the secreted proteomes of Cn strains to determine whether these could account for phenotypic differences in aggressiveness.

Draft Genome Sequences of Hazelnut-Associated Strains Isolated in Ontario, Canada.

Two strains (H346-M and H346-S) were isolated from hazelnut trees showing symptoms of shoot dieback and necrosis. The draft genome sequences of H346-M and H346-S consist of 66 and 51 contigs, respectively, with total sizes of 5,693,988 and 5,889,925 bp and 4,885 and 5,045 protein-coding sequences, respectively.

Analysis of Draft Genome Sequences of Two New Strains Associated with Wheat Leaf Necrotic Tissues Caused by Xanthomonas translucens Reveals Distinct Species.

We report whole-genome sequences of two new strains (DOAB1048 and DOAB1050) isolated from necrotic wheat leaves caused by The draft genome sequences of DOAB1048 and DOAB1050 consist of 52 and 57 scaffolds and have sizes of 4,795,525 bp and 4,962,883 bp with 4,418 and 4,517 coding sequences, respectively.

Taxogenomics and Systematics of the Genus .

Members of the genus are Gram-negative bacteria isolated from various environments. Taxonomic affiliation based on multilocus sequence analysis (MLSA) is used routinely for inferring accurate phylogeny and identification of bacterial species and genera. Partial sequences of five housekeeping genes (A, B, S, B, and G) were extracted from 206 draft or complete genomes of strains publicly available in databases and analyzed together with the representative sequences of the 25 validly published type strains to verify and assess their phylogenetic assignations.

Pathogenicity and a TaqMan Real-Time PCR for Specific Detection of , a Bacterial Pathogen of Onions.

Bacterial diseases of onion are reported to cause significant economic losses. Brady, one of the pathogens causing the center rot on onions, has not yet been reported in Canada. We report the pathogenicity of on commercially available Canadian green onions (scallions).

Diversity of bacteria associated with corn roots inoculated with Canadian woodland soils, and description of sp. nov.

Bacteria associated with corn roots inoculated with soils collected from the Canadian woodlands were isolated and characterized. Genus-level identification based on 16S rRNA sequence analysis classified the 161 isolates in 19 genera. The majority (64%) of the isolates were affiliated with the genus .

Genome analysis of two novel Pseudomonas strains exhibiting differential hypersensitivity reactions on tobacco seedlings reveals differences in nonflagellar T3SS organization and predicted effector proteins.

Multilocus sequence analysis (MLSA) of two new biological control strains (S1E40 and S3E12) of Pseudomonas was performed to assess their taxonomic position relative to close lineages, and comparative genomics employed to investigate whether these strains differ in key genetic features involved in hypersensitivity responses (HRs). Strain S3E12, at high concentration, incites HRs on tobacco and corn plantlets while S1E40 does not. Phylogenies based on individual genes and 16S rRNA-gyrB-rpoB-rpoD concatenated sequence data show strains S1E40 and S3E12 clustering in distinct groups.