Time filter

Source Type

Andersen M.T.,The New Zealand Institute for Plant and Food Research Ltd | Liefting L.W.,AgriGenesis Biosciences Ltd | Liefting L.W.,Plant Health and Environment Laboratory | Havukkala I.,AgriGenesis Biosciences Ltd | Beever R.E.,Landcare Research
BMC Genomics

Background: 'Candidatus Phytoplasma australiense' is associated with at least nine diseases in Australia and New Zealand. The impact of this phytoplasma is considerable, both economically and environmentally. The genome of a NZ isolate was sequenced in an effort to understand its pathogenicity and ecology. Comparison with a closely related Australian isolate enabled us to examine mechanisms of genomic rearrangement.Results: The complete genome sequence of a strawberry lethal yellows (SLY) isolate of 'Candidatus Phytoplasma australiense' was determined. It is a circular genome of 959,779 base pairs with 1126 predicted open reading frames. Despite being 80 kbp larger than another 'Ca. Phytoplasma australiense' isolate PAa, the variation between housekeeping genes was generally less than 1% at a nucleotide level. The difference in size between the two isolates was largely due to the number and size of potential mobile units (PMUs), which contributed to some changes in gene order. Comparison of the genomes of the two isolates revealed that the highly conserved 5′ UTR of a putative DNA-directed RNA polymerase seems to be associated with insertion and rearrangement events. Two types of PMUs have been identified on the basis of the order of three to four conserved genes, with both PMUs appearing to have been present in the last common ancestor of 'Ca. Phytoplasma asteris' and 'Ca. Phytoplasma australiense'. Comparison with other phytoplasma genomes showed that modification methylases were, in general, species-specific. A putative methylase (xorIIM) found in 'Ca. Phytoplasma australiense' appeared to have no analogue in any other firmicute, and we believe has been introduced by way of lateral gene transfer. A putative retrostransposon (ltrA) analogous to that found in OY-M was present in both isolates, although all examples in PAa appear to be fragments. Comparative analysis identified highly conserved 5′ and 3′ UTR regions of ltrA, which may indicate how the gene is excised and inserted.Conclusions: Comparison of two assembled 'Ca. Phytoplasma australiense' genomes has shown they possess a high level of plasticity. This comparative analysis has yielded clues as to how rearrangements occur, and the identification of sets of genes that appear to be associated with these events. © 2013 Andersen et al.; licensee BioMed Central Ltd. Source

Zhao Z.,Landcare Research | Li D.,Plant Health and Environment Laboratory | Davies K.A.,University of Adelaide | Ye W.,United Road Services

Schistonchus zealandicus n. Sp. was recovered from the sycones of Ficus macrophylla from St Helier's Bay,MtWellington, and St Johns, suburbs of Auckland, New Zealand. It is characterised by having the opening of the excretory pore located just posterior to the anterior end of the nematode but anterior to the conus level of the stylet, a short post-vulval uterine sac (10-18 μm or 0.4-0.7 vulval body diam. long), presence of two incisures in the lateral field with many broken, non-defined lines between them, rose-thorn-shaped spicule, three pairs of subventral papillae on the male tail (one pair adcloacal on the anterior lip, one pair slightly posterior to mid-tail length, and one pair close to tail tip), a distinctive mucron on the male tail, apparent biogeographical range, and its association with F. macrophylla. The absence of a lip sector disc suggests that it is close to S. altermacrophylla, S. aureus and S. laevigatus. Molecular phylogeny of near full length small subunit and D2-D3 expansion segments of the large subunit rRNA genes supports the proposal of S. zealandicus n. Sp. as a new species. © 2015 Koninklijke Brill NV, Leiden. Source

Holder P.,Plant Health and Environment Laboratory | Disbury M.,Wellington Mail Center | Singe M.,Southern Monitoring Services New Zealand BioSecure | Kean J.M.,Agresearch Ltd. | McFadden A.,Investigation and Diagnostic Center
Journal of Medical Entomology

A biosecurity response was triggered by the detection of Aedes albopictus (Skuse) (Diptera: Culicidae) at the Port of Auckland, New Zealand, Ae. albopictus does not occur in New Zealand and is the most significant mosquito threat to this country, The possibility that a founding population had established, resulted in a large-scale biosecurity surveillance and control program. The response was initiated in early March 2007 and completed by mid-May 2007. No further exotic mosquitoes were detected, The response surveillance program consisted of larval habitat surveys and high density ovi- and light trapping. It was coordinated with a habitat modification and S-methoprene treatment control program, The response policies were guided by analysis of surveillance and quality assurance data, population modeling, and trace-back activities. Mosquito habitat and activity close to port were both more abundant than expected, particularly in storm water drain sumps, Sumps are difficult to treat, and during the response some modification was required to the surveillance program and the control regime. We were assured of the absence or eradication of any Ae. albopictus population, as a result of nil detection from surveillance, backed up by four overlapping rounds of insecticide treatment of habitat. This work highlights the importance of port surveillance and may serve as a guide for responses for future urban mosquito incursions. © 2010 Entomological Society of America. Source

Vanneste J.L.,The New Zealand Institute for Plant and Food Research Ltd | Yu J.,The New Zealand Institute for Plant and Food Research Ltd | Cornish D.A.,The New Zealand Institute for Plant and Food Research Ltd | Tanner D.J.,Zespri International Ltd | And 5 more authors.
Plant Disease

Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker of kiwifruit, was detected for the first time in New Zealand in November 2010. Only in Bay of Plenty, one of the four regions where this pathogen had been detected, did symptoms evolve beyond leaf spots, resulting in cane die-back, wilting of canes, and canker, sometimes leading to death of the vine. Molecular analysis (cts haplotype and BOX-polymerase chain reaction [PCR] electrophoretic pattern) of strains isolated from different regions of New Zealand revealed that two biovars could be distinguished. They have been called biovar 3 and biovar 4 to differentiate them from strains from Japan (biovar 1) or Korea (biovar 2), which have a different cts haplotype or a different BOX-PCR pattern. Biovars 3 and 4 displayed different degrees of virulence, as measured by their ability to cause leaf spots on young, potted kiwifruit plants. Biovar 3, which has also been present in Italy since 2008 and in France, was found in the Bay of Plenty, where cane die-backs were observed. In contrast, no symptoms other than leaf spots have been observed in orchards where strains of biovar 4 have been isolated. We report the distribution and the disease progression of biovars 3 and 4 in New Zealand. © 2013 The American Phytopathological Society. Source

Fan Q.-H.,Plant Health and Environment Laboratory
Systematic and Applied Acarology

A new species Krugeria fuzhouensis Xu & Fan sp. nov. (Acari: Tenuipalpidae) on Pterospermum heterophyllum (Sterculiaceae) from China is described and illustrated. The ontogenetic changes in idiosoma and leg chaetotaxy on the female, male, deutonymph, protonymph and larva are presented. A key to the world species is provided. © Systematic & Applied Acarology Society. Source

Discover hidden collaborations