Thrips palmi (from the order Thysanoptera) is a serious insect pest of various crops, including vegetables, fruits and ornamental plants, causing significant economic losses. Its presence constitutes a double threat; not only does T. palmi feed on the plants, it is also a vector for several plant viruses. T. palmi originated in Asia, but has spread to North and Central America, Africa, Oceania and the Caribbean in recent decades. This species has been sporadically noted in Europe and is under quarantine regulation in the European Union. For non-specialists its larval stages are indistinguishable morphologically from another widespread and serious insect pest Frankliniella occidentalis (a non-quarantine species in the European Union) as well as other frequently occurring thrips. In this study, we have developed a loop-mediated isothermal amplification protocol to amplify rDNA regions of T. palmi. The results were consistent whether isolated DNA or crushed insects were used as template, indicating that the DNA isolation step could be omitted. The described method is species-specific and sensitive and provides a rapid diagnostic tool to detect T. palmi in the field.

Temperature is an important environmental factor influencing plant development in natural and diseased conditions. The growth rate of plants grown at C27°C is more rapid than for plants grown at 21°C. Thus, temperature affects the rate of pathogenesis progression in individual plants. We have analyzed the effect of temperature conditions (either 21°C or 27°C during the day) on the accumulation rate of the virus and satellite RNA (satRNA) in Nicotiana benthamiana plants infected by peanut stunt virus (PSV) with and without its satRNA, at four time points. In addition, we extracted proteins from PSV and PSV plus satRNA-infected plants harvested at 21 dpi, when disease symptoms began to appear on plants grown at 21°C and were well developed on those grown at 27°C, to assess the proteome profile in infected plants compared to mock-inoculated plants grown at these two temperatures, using 2D-gel electrophoresis and mass spectrometry approaches. The accumulation rate of the viral RNAs and satRNA was more rapid at 27°C at the beginning of the infection and then rapidly decreased in PSV-infected plants. At 21 dpi, PSV and satRNA accumulation was higher at 21°C and had a tendency to increase further. In all studied plants grown at 27°C, we observed a significant drop in the identified proteins participating in photosynthesis and carbohydrate metabolism at the proteome level, in comparison to plants maintained at 21°C. On the other hand, the proteins involved in protein metabolic processes were all more abundant in plants grown at 27°C. This was especially evident when PSV-infected plants were analyzed, where increase in abundance of proteins involved in protein synthesis, degradation, and folding was revealed. In mock-inoculated and PSV-infected plants we found an increase in abundance of the majority of stress-related differently-regulated proteins and those associated with protein metabolism. In contrast, in PSV plus satRNA-infected plants the shift in the temperature barely increased the level of stress-related proteins.

No abstract

BackgroundTomato torrado virus (ToTV) infection manifests with burn-like symptoms on leaves, leaflets and upper stem parts of susceptible infected plants. The symptoms caused by ToTV may be considered as one of the most severe virus-induced forms of systemic necrosis, which spreads within the whole plant and leads to a lethal phenotype. However, to date there are no data revealing which viral genes encode for a specific pathogenicity determinant that triggers the plant necrotic response for any torradovirus. In this study we evaluated the influence of three coat protein subunits of ToTV: Vp23, Vp26 and Vp35, transiently expressed from a PVX-based vector, and checked their association with the induction of systemic necrosis in infected Solanum lycopersicum L. (cv. Beta Lux), a natural host of ToTV.MethodsTo estimate how ToTV coat protein subunits might contribute in plant response to virus infection we over-expressed the proteins from PVX-based vector in tomato and analyzed enzymatic activities related with plant defense response. By doing protein qualitative analysis performed by mass spectrometry we indicated the PR10 in protein fraction with induced ribonuclease activity.ResultsWe observed that only the Vp26 enhanced PVX pathogenicity causing severe necrosis of the infected plant. Moreover, we indicated increased RNase and oxidative activities in plants infected with PVX-Vp26 chimeras only. Importantly, we suspected that this increased RNase activity is associated with increased accumulation of PR10 mRNA and products of its translation.ConclusionsOn the basis of the obtained results, we indicated that Vp26 acts as the elicitor of hypersensitive response-like reactions of PVX-Vp26 manifesting with enhanced pathogenicity of the recombined PVX. This might be the first described suspected necrosis determinant of torradoviruses infecting tomatoes.Electronic supplementary materialThe online version of this article (10.1186/s12985-019-1117-9) contains supplementary material, which is available to authorized users.

Background Root-knot nematodes (RKNs)-Meloidogyne spp.are a group of nematodes distributed worldwide that infect monocotyledonous and dicotyledonous crop species. Plant responses to RKNs have been described in many studies of various host plants. In the course of parasitism, RKNs induce the transcriptional reprogramming of host cells to establish giant cells. Nematode attack induces many mechanisms in host plants, including pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effectortriggered immunity (ETI). Research on plant-RKN interactions has shown the activation and suppression of the expression of genes encoding various defenserelated proteins. Scope and conclusions In this review, our goal is to critically summarize current knowledge on monocotyledonous and dicotyledonous plant-Meloidogyne interactions, including data on the role of RKN effectors and nematode PAMPs in host plant defense responses.

Thrips palmi and Frankliniella occidentalis (order Thysanoptera) are thrips species that represent major plant pests. They are polyphagous insects capable of adversely affecting crop production. As such, in the European Union, these thrips species should be regulated as quarantine organisms. T. palmi and F. occidentalis can cause considerable damage to susceptible plants by feeding on them and transmitting several viruses responsible for serious plant diseases. Successful pest control strategies are based on an early, fast, and reliable diagnosis, which precedes the selection of appropriate steps to limit the effects of harmful organisms. We herein describe a novel diagnostic approach that enables the sensitive and species-specific detection (and differentiation) of these pests in a duplex polymerase chain reaction assay, which was adapted for both standard and real-time quantitative assays. Our method is based on the amplification of a 5.8S-internal transcribed spacer 2 ribosomal DNA fragment that is conserved between T. palmi and F. occidentalis.

Abstract:Thrips from the genus Frankliniella (Thysanoptera, Thripidae) are phytophagous on crops and wild plants. Some of them cause slight economic damage, however, others including F. occidentalis and F. intonsa are responsible for considerable losses in crop production. Moreover, they constitute a double threat for host plants by not only feeding on them but also vectoring viruses, some of which are on the quarantined list of the European Plant Protection Organization. The rapid detection and differentiation between more and less harmful Frankliniella species is, therefore, important in order to combat the pests at the time of their appearance. In this study, we have undertaken to develop a method of detecting F. occidentalis, F. intonsa, F. pallida, and F. tenuicornis. The protocol is based on PCR amplification of ITS1 rDNA fragments of these insects using universal primers pair giving products of slightly distinct length for studied insects. Restriction enzymes digestion which is easy to interpret, allows for visible differentiation of all these Frankliniella species. The method was shown to be species-specific and sensitive. Even single specimens in either the larvae or adult stage could be distinguished.

The genus Ditylenchus consists of more than 60 species, some of which are plant parasites. In this paper we report on Ditylenchus laurae sp. n. from Poland, a new species associated with the aquatic plant, Potamogeton perfoliatus L. Ditylenchus laurae sp. n. is characterised by a long and slender body with L = 1881 (1523-2095) μm and 1875 (1690-2089) μm, a = 88.8 (72.5-102.5) and 89.7 (71.9-97.9), stylet length = 10.8 (9.6-12.1) μm and 8.3 (7.7-9.0) μm, tail length = 117.2 (103.5-126.7) μm and 102.4 (98.3-113.6) μm in females and males, respectively; four incisures, rounded stylet knobs, long basal bulb (about ten times as long as wide), post-vulval uterine sac from 4.3-5.6 vulval body diam. long, and mucronate tail. Characterisation using the ITS rRNA, COI and hsp90 gene sequences was conducted and a phylogenetic analyses revealed that D. laurae sp. n. belongs to the D. dipsaci complex.