Plant Health and Environment Laboratory

Napier, New Zealand

Plant Health and Environment Laboratory

Napier, New Zealand
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Zhao Z.,Landcare Research | Li D.,Plant Health and Environment Laboratory | Davies K.A.,University of Adelaide | Ye W.,United Road Services
Nematology | Year: 2015

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.

Joharchi O.,Islamic Azad University at Yazd | Fan Q.-H.,Plant Health and Environment Laboratory | Arjomandi E.,Tarbiat Modares University
Systematic and Applied Acarology | Year: 2017

The mite family Laelapidae has been little studied in the Pacific Islands. This paper presents a new species and a new record of the genus Cosmolaelaps Berlese, 1903 from Fiji and Tonga. Cosmolaelaps dioscorea sp. nov. was collected from yam (Plantae: Dioscoreaceae: Dioscorea sp.) in Fiji and Cosmolaelaps paulista Freire & Moraes, 2007 from taro (Plantae: Araceae: Colocasia Schott) in Fiji and Tonga. The new species is described. © Systematic & Applied Acarology Society.

Tang J.,Plant Health and Environment Laboratory | Veerakone S.,Plant Health and Environment Laboratory | Ward L.I.,Plant Health and Environment Laboratory
Plant Disease | Year: 2016

Tradescantia mild mosaic virus (TraMMV) was named and characterized in 2006 in Italy (Ciuffo et al. 2006). A potyvirus with the name Tradescantia-Zebrina virus (TZV) was reported from the USA some years earlier in Tradescantia albiflora with leaf distortion and stunting (Lockhart et al. 1981), and could be the same virus. In July 2014, streaking and malformation of leaves were observed on several plants of T. spathacea in a public winter garden in Auckland, New Zealand. Electron microscopy of a crude sap preparation from the symptomatic leaf tissue revealed the presence of filamentous flexuous virus particles approximately 750 nm in length. When inoculated with sap of the viruliferous leaf tissue, Chenopodium amaranticolor, C. quinoa, Nicotiana clevelandii, and N. sylvestris developed chlorotic local spots 4 weeks post inoculation. Total nucleic acid was extracted from leaf tissue of each of the five infected species using a semiautomated nucleic acid extraction machine (ThermoFisher Scientific, Waltham, MA) with an InviMag Plant Kit (Stratec, Berkenfeld, Germany), as per the manufacturer’s instructions. The nucleic acid was used in reverse transcription-polymerase chain reaction (RT-PCR) with novel forward (5′-CGTGGGGTTATGATGATTTG-3′) and reverse (5′-CTCGGCTGAGTCACTAAAGT-3′) primers specific to a 700-bp fragment of the TraMMV polyprotein gene. A one-step RT-PCR kit form Invitrogen (Life Technologies) was used with the following cycling conditions: 50°C for 30 min, 94°C for 5 min, then 40 cycles of 94°C for 30 s, 56°C for 30 s and 72°C for 45 s; followed by a final extension at 72°C for 5 min. PCR products of the expected size were obtained from all five species tested, and the amplicon from T. spathacea was directly sequenced in both directions and the assembled sequence was deposited in GenBank (Accession No. KT633608). A BLASTn search showed 97% nucleotide sequence identity to an isolate of TraMMV from Italy (AY861351). From July to November 2014, a further 12 tradescantia plants (of which 8 plants were symptomatic) representing the following species, T. fluminensis, T. sillamontana, T. spathacea, and T. zebrine were collected from different locations in the Auckland region. All symptomatic plants tested positive for TraMMV using the method previously described. A phylogenetic analysis for the obtained TraMMV nucleotide sequences revealed that the New Zealand isolates from different Tradescantia species share over 98.7% identity to each other. To our knowledge, this is the first report of TraMMV in New Zealand. As a potyvirus, TraMMV may be transmitted by aphid, and if TraMMV and TZV are the same virus, it can be vectored by at least two species, Myzus persicae and Rhopalosiphon padi (Lockhart et al. 1981). Chenopodium amaranticolor and C. quinoa have been reported previously as experimental hosts of TraMMV (Ciuffo et al. 2006), and this study revealed that N. clevelandii and N. sylvestris can also be infected with TraMMV by mechanical inoculation. Although T. fluminensis is listed as a weed species in New Zealand and subject to active control, the other Tradescantia species are ornamentals common in public and domestic gardens in New Zealand, and their ornamental appearance and economic value could be potentially affected by the infection of TraMMV. © 2016, American Phytopathological Society. All rights reserved.

Chapman J.R.,Plant Health and Environment Laboratory | Chapman J.R.,Linnaeus University | Taylor R.K.,Plant Health and Environment Laboratory | Weir B.S.,Landcare Research | And 5 more authors.
Phytopathology | Year: 2012

Pseudomonas syringae pv. actinidiae, the causal agent of canker in kiwifruit (Actinidia spp.) vines, was first detected in Japan in 1984, followed by detections in Korea and Italy in the early 1990s. Isolates causing more severe disease symptoms have recently been detected in several countries with a wide global distribution, including Italy, New Zealand, and China. In order to characterize P. syringae pv. actinidiae populations globally, a representative set of 40 isolates from New Zealand, Italy, Japan, South Korea, Australia, and Chile were selected for extensive genetic analysis. Multilocus sequence analysis (MLSA) of housekeeping, type III effector and phytotoxin genes was used to elucidate the phylogenetic relationships between P. syringae pv. actinidiae isolates worldwide. Four additional isolates, including one from China, for which shotgun sequence of the whole genome was available, were included in phylogenetic analyses. It is shown that at least four P. syringae pv. actinidiae MLSA groups are present globally, and that marker sets with differing evolutionary trajectories (conserved housekeeping and rapidly evolving effector genes) readily differentiate all four groups. The MLSA group designated here as Psa3 is the strain causing secondary symptoms such as formation of cankers, production of exudates, and cane and shoot dieback on some kiwifruit orchards in Italy and New Zealand. It is shown that isolates from Chile also belong to this MLSA group. MLSA group Psa4, detected in isolates collected in New Zealand and Australia, has not been previously described. P. syringae pv. actinidiae has an extensive global distribution yet the isolates causing widespread losses to the kiwifruit industry can all be traced to a single MLSA group, Psa3. © 2012 The American Phytopathological Society.

Chomnunti P.,CAS Kunming Institute of Botany | Chomnunti P.,Mae Fah Luang University | Hongsanan S.,Mae Fah Luang University | Aguirre-Hudson B.,Jodrell Laboratory | And 10 more authors.
Fungal Diversity | Year: 2014

Sooty moulds are a remarkable, but poorly understood group of fungi. They coat fruits and leaves superficially with black mycelia, which reduces photosynthesis rates of host plants. Few researchers have, however, tried to quantify their economic importance. Sooty moulds have been well-studied at the morphological level, but they are poorly represented in a natural classification based on phylogeny. Representatives are presently known in Antennulariellaceae, Capnodiaceae, Chaetothyriaceae, Coccodiniaceae, Euantennariaceae, Metacapnodiaceae and Trichomeriaceae and several miscellaneous genera. However, molecular data is available for only five families. Most sooty mould colonies comprise numerous species and thus it is hard to confirm relationships between genera or sexual and asexual states. Future studies need to obtain single spore isolates of species to test their phylogenetic affinities and linkages between morphs. Next generation sequencing has shown sooty mould colonies to contain many more fungal species than expected, but it is not clear which species are dominant or active in the communities. They are more common in tropical, subtropical and warm temperate regions and thus their prevalence in temperate regions is likely to increase with global warming. Sooty moulds are rarely parasitized by fungicolous taxa and these may have biocontrol potential. They apparently grow in extreme environments and may be xerophilic. This needs testing as xerophilic taxa may be of interest for industrial applications. Sooty moulds grow on sugars and appear to out-compete typical "weed" fungi and bacteria. They may produce antibiotics for this purpose and their biochemical potential for obtaining novel bioactive compounds for medical application is underexplored. © 2014 Mushroom Research Foundation.

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 | Year: 2013

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.

Tang J.,Plant Health and Environment Laboratory | Khan S.,Plant Health and Environment Laboratory | Delmiglio C.,Plant Health and Environment Laboratory | Ward L.I.,Plant Health and Environment Laboratory
Journal of Virological Methods | Year: 2014

A real-time TaqMan RT-PCR assay was developed for the rapid and sensitive detection of Tomato ringspot virus (ToRSV), an important plant virus which infects a wide range of fruit and ornamental crops. Primers and a probe were designed based on the highly conserved 3'-untranslated region (UTR) sequences of ToRSV, to amplify a 182. bp fragment of this region of RNA-1 and RNA-2. The assay was demonstrated to reliably amplify all ToRSV isolates tested. The detection limit was estimated to be about 12 copies of the ToRSV target region. No amplification was observed from the RNA of other nepoviruses or healthy host species. A comparison with a published conventional RT-PCR and a SYBR-based qRT-PCR indicated that both of the published assays lacked reliability and sensitivity, as neither were able to amplify all ToRSV isolates tested, and both were approximately 1000 times less sensitive than the novel TaqMan real-time assay. This TaqMan real-time assay was tested using four different reagent kits and was shown to be robust and stable, with no significant differences in sensitivity between kits. It is expected that the implementation of this TaqMan real-time RT-PCR assay will facilitate efficient phytosanitary certification of nursery stock requiring testing for ToRSV by regulatory agencies, and will also have wider uses for the general detection of ToRSV in a range of hosts. © 2014 Elsevier B.V.

Fan Q.-H.,Plant Health and Environment Laboratory
Systematic and Applied Acarology | Year: 2015

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.

Dhami M.K.,Plant Health and Environment Laboratory | Kumarasinghe L.,Plant Health and Environment Laboratory
PLoS ONE | Year: 2014

Spotted wing drosophila (Drosophila suzukii) is an emerging pest that began spreading in 2008 and its distribution now includes 13 countries across two continents. Countries where it is established have reported significant economic losses of fresh produce, such as cherries due to this species of fly. At larval stages, it is impossible to identify due to its striking similarities with other cosmopolitan and harmless drosophilids. Molecular methods allow identification but the current technique of DNA barcoding is time consuming. We developed and validated a rapid, highly sensitive and specific assay based on real-time PCR and high resolution melt (HRM) analysis using EvaGreen DNA intercalating dye chemistry. Performance characteristics of this qualitative assay, validation and applicability in a New Zealand quarantine framework are discussed. Application of this robust and independently validated assay across the spectrum of key food production and border protection industries will allow us to reduce the further spread of this damaging species worldwide. © 2014 Dhami, Kumarasinghe.

Tang J.,Plant Health and Environment Laboratory | Ward L.I.,Plant Health and Environment Laboratory | Clover G.R.G.,Plant Health and Environment Laboratory
Plant Disease | Year: 2013

Strawberry latent ringspot virus (SLRSV) is widespread in many countries, especially in Europe. The virus was thought to be uncommon in New Zealand, having only been recorded in Prunus spp. However, this study revealed that SLRSV infects a much wider range of hosts. From 1999 to 2009, SLRSV was isolated from anemone (Anemone × hybrida), blackberry (Rubus spp.), impatiens (Impatiens walleriana), pepino (Solanum muricatum), and tibouchina (Tibouchina sp.) in the North Island of New Zealand. These SLRSV isolates were identified using electron microscopy, mechanical inoculation, enzyme-linked immunosorbent assay, and reverse-transcription polymerase chain reaction techniques. This is thought to be the first report of anemone, impatiens, pepino, and tibouchina as hosts of SLRSV. Phylogenetic analysis and host range suggest that the five newly identified New Zealand isolates belong to two distinct strains: blackberry and impatiens isolates represent one strain and the other three isolates, plus the flowering cherry isolate reported previously in New Zealand, represent another strain. Both these strains are distinct from isolates reported elsewhere in the world. The strain infecting blackberry and impatiens is especially different and produced an unusual reaction in mechanical inoculation tests on herbaceous indicators. It is postulated that SLRSV may have gone undetected on its wider host range in New Zealand due to the latent infection in some hosts. The relationship of SLRSV isolates between New Zealand and overseas and the transmission modes of this virus are also discussed. © 2013 The American Phytopathological Society.

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