Publications

4369

Specific scopeThis Standard describes a national regulatory control system for the bacterial pathogen ‘Candidatus Liberibacter solanacearum’ and its vector Bactericera cockerelli when regulated as quarantine pests. It also covers measures to reduce the risk of ‘Ca. L. solanacearum’ spreading to potato production systems when listed as a regulated nonquarantine pest (RNQP) on seed potatoFor the EPPO A1 listed pests recommended for regulation as quarantine pests B. cockerelli and ‘Ca. L. solanacearum’ (Solanaceae haplotypes, i.e. non‐European haplotypes, such as haplotypes A and B), the Standard describes measures to achieve: Exclusion from the EPPO region of B. cockerelli, which is an efficient vector of ‘Ca. L. solanacearum’ within solanaceous crops (e.g. potato, tomato) Eradication of incursions of B. cockerelli Exclusion from the EPPO region of non‐European haplotypes of ‘Ca. L. solanacearum’ Eradication of incursions of non‐European haplotypes of ‘Ca. L. solanacearum’. Although reference will only be made to the non‐European haplotypes A and B, the Standard would also apply to new non‐European haplotypes of ‘Ca. L. solanacearum’ which may have different host ranges or which may be vectored more efficiently by psyllids which are widespread in the region.For the haplotypes which are not recommended for regulation as quarantine pests but are recommended for regulation as RNQPs on seed potato (i.e. European haplotypes, such as C, D and E), the Standard describes measures (specified in Appendix 4) to reduce the risk of spread to potato production systems to achieve: Exclusion of European haplotypes of ‘Ca. L. solanacearum’ from the potato production system Suppression of European haplotypes of ‘Ca. L. solanacearum’ in potato production systems where they are present. Although reference will only be made to haplotypes C, D and E, Appendix 4 would also apply to new European haplotypes of ‘Ca. L. solanacearum’.SpecificapprovalFirst approved in 2017‐09. Revised in 2020‐09.

Abstract Background Anaerobic ammonium oxidizing bacteria (anammox bacteria) are contributing significantly to the nitrogen cycle and are successfully used in wastewater treatment. Due to the lack of complete genomes in the databases, little is known about the stability and variability of their genomes and how the genomes evolve in response to changing environments. Results Here we report the complete genome of the anammox bacterium “Candidatus Kuenenia stuttgartiensis” strain CSTR1 which was enriched planktonically in a semi-continuous stirred-tank reactor. A comparison of the genome of strain CSTR1 with the genome of “Ca. Kuenenia stuttgartiensis” MBR1 and the draft genome of KUST showed > 99% average nucleotide identity among all. Rearrangements of large genomic regions were observed, most of which were associated with transposase genes. Phylogenetic analysis suggests that strain MBR1 is more distantly related to the other two strains. Proteomic analysis of actively growing cells of strain CSTR1 (growth rate ~ 0.33 d− 1) failed to detect the annotated cytochrome cd1-type nitrite reductase (NirS) although in total 1189 proteins were found in the proteome. Yet, this NirS was expressed when strain CSTR1 was under stress or starvation (growth rate < 0.06 d− 1). We also observed large sequence shifts in the strongly expressed S-layer protein compared to other “Ca. Kuenenia” strains, indicating the formation of hybrids of genes encoding the surface proteins. Conclusions “Ca. Kuenenia” strains appear to be relatively stable in their basic physiological traits, but show high variability in overall genome structure and surface proteins.

Abstract Rickettsia are obligate intracellular pathogens transmitted by arthropod vectors. The re‐emergence of several rickettsioses imposes severe global health burden. In addition to the well‐established rickettsial pathogens, newer rickettsial species and their pathogenic potentials are being uncovered. There are many reports of spotted and typhus fever caused by rickettsiae in India. Hence, in this study we screened the ectoparasites of pet and domestic animals for the presence of rickettsia using polymerase chain reaction. Nine cat flea samples ( Ctenocephalides felis felis ), that tested positive for the presence of rickettsia were subjected to Multi Locus Sequence Typing. Nucleotide sequencing and Phylogenetic analysis of gltA, ompB and 16rrs genes revealed that the rickettsiae detected in cat fleas was Rickettsia asembonensis . Further studies are required to assess Rickettsia asembonensis pathogenic potential to human and its enzootic maintenance of in various hosts and vectors.

Phytoplasmas have been associated with a disease that affects trees of at least 11 species from different botanic families in Bogotá, Colombia. ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ are the major groups of phytoplasma in the area of Bogotá. In this study, the genetic diversity within ‘Ca. P. asteris’ and ‘Ca. P. fraxini’ was studied in five urban tree species: Croton species (Euphorbiaceae), Fraxinus uhdei (Oleaceae), Magnolia grandiflora (Magnoliaceae), Populus nigra (Salicaceae) and Quercus humboldtii (Fagaceae). Analyses of the 16S rRNA gene using nested PCR, RFLP and sequencing showed that phytoplasmas of ‘Ca. P. asteris’ could be assigned to: subgroup 16SrI-B; a new subgroup named 16SrI-AF, with a restriction pattern similar to that of 16SrI-B; and a new subgroup named 16SrI-AG, with a restriction pattern similar to that of 16SrI-K and 16SrI-AH with a restriction pattern similar to that of 16SrI-AC. ‘Ca. P. fraxini’ isolates belonged to a new subgroup named 16SrVII-G, with a restriction pattern similar to that of 16SrVII-A. To complement the identification of the phytoplasma strains, we amplified nonribosomal genes such as leuS and secA. Unexpectedly, it was observed that in 16 trees in which 16S rRNA gene analysis showed the presence of ‘Ca. P. fraxini’ only, the leuS or secA primers amplified sequences exclusively affiliated to ‘Ca. P. asteris. In those plants, sequences belonging to ‘Ca. P. fraxini’ leuS or secA genes were not amplified. The present work contributes to the identification of novel strains of both species in Colombia, and supports previous suggestions that phytoplasmas in South America are highly variable.

Abstract Background Marine sponges and their microbiomes contribute significantly to carbon and nutrient cycling in global reefs, processing and remineralizing dissolved and particulate organic matter. Lamellodysidea herbacea sponges obtain additional energy from abundant photosynthetic Hormoscilla cyanobacterial symbionts, which also produce polybrominated diphenyl ethers (PBDEs) chemically similar to anthropogenic pollutants of environmental concern. Potential contributions of non-Hormoscilla bacteria to Lamellodysidea microbiome metabolism and the synthesis and degradation of additional secondary metabolites are currently unknown. Results This study has determined relative abundance, taxonomic novelty, metabolic capacities, and secondary metabolite potential in 21 previously uncharacterized, uncultured Lamellodysidea-associated microbial populations by reconstructing near-complete metagenome-assembled genomes (MAGs) to complement 16S rRNA gene amplicon studies. Microbial community compositions aligned with sponge host subgroup phylogeny in 16 samples from four host clades collected from multiple sites in Guam over a 3-year period, including representatives of Alphaproteobacteria, Gammaproteobacteria, Oligoflexia, and Bacteroidetes as well as Cyanobacteria (Hormoscilla). Unexpectedly, microbiomes from one host clade also included Cyanobacteria from the prolific secondary metabolite-producer genus Prochloron, a common tunicate symbiont. Two novel Alphaproteobacteria MAGs encoded pathways diagnostic for methylotrophic metabolism as well as type III secretion systems, and have been provisionally assigned to a new order, designated Candidatus Methylospongiales. MAGs from other taxonomic groups encoded light-driven energy production pathways using not only chlorophyll, but also bacteriochlorophyll and proteorhodopsin. Diverse heterotrophic capabilities favoring aerobic versus anaerobic conditions included pathways for degrading chitin, eukaryotic extracellular matrix polymers, phosphonates, dimethylsulfoniopropionate, trimethylamine, and benzoate. Genetic evidence identified an aerobic catabolic pathway for halogenated aromatics that may enable endogenous PBDEs to be used as a carbon and energy source. Conclusions The reconstruction of high-quality MAGs from all microbial taxa comprising greater than 0.1% of the sponge microbiome enabled species-specific assignment of unique metabolic features that could not have been predicted from taxonomic data alone. This information will promote more representative models of marine invertebrate microbiome contributions to host bioenergetics, the identification of potential new sponge parasites and pathogens based on conserved metabolic and physiological markers, and a better understanding of biosynthetic and degradative pathways for secondary metabolites and halogenated compounds in sponge-associated microbiota.