Detection of the root-knot nematode Meloidogyne ethiopica in Greece

Root-knot nematodes (RKN), Meloidogyne spp., are very significant in agriculture because they can be found almost everywhere and have a wide host range. In summer 2009, two soil samples from maize and kiwi crops, from the area of Kavalla in North Greece, were analyzed for the presence of nematodes. RKN were detected in both samples and identified as M. ethiopica on the basis of biochemical (esterases) and sequence data (18S rDNA). Meloidogyne ethiopica poses a significant threat to farmers in Greece and the establishment and spread of this species has to be controlled. This is the first report of M. ethiopica in Greece and the second report of this species for Europe.     

Assessment of the toxicity of ash-loaded runoff from a recently burnt eucalypt plantation

Although wildfires are identified as an important source of polycyclic aromatic hydrocarbons (PAHs) and PAHs are well-known for their pernicious properties, the toxicity of runoff from recently burnt areas has received little research attention. This knowledge gap was addressed here through laboratory assays in which four aquatic species from distinct trophic levels were exposed to different dilutions of ash-loaded runoff. The runoff was collected in a recently burnt eucalypt stand in north-central Portugal on two occasions, immediately after the wildfire and about 1?year later. The total PAH load was about four times higher at the first than second sampling occasion (1194 vs. 352?ng?l^?1) but even the latter value was considerably higher than those reported by prior studies on burnt areas. In addition, the two runoff samples differed noticeably in PAH composition, with a clear predominance of naphthalene in the second sample. Both runoff samples produced significant inhibitory effects on the three species representing the lower trophic levels, that is, the bacteria Vibrio fischeri, the algae Pseudokirchneriella subcapitata and the macrophyte Lemna minor. The invertebrate Daphnia magna was not significantly affected but chronic tests are needed to discard the probable propagation of toxic effects from the lower trophic levels. Surprisingly, the runoff collected 1?year after the wildfire was the most toxic to V. fischeri, P. subcapitata and L. minor. Possibly, this was due to predominance of naphthalene in this sample. Surely, however, this demonstrated that detrimental off-site effects of wildfires are not necessarily limited to the immediate post-fire situation.     

The quarantine root-knot nematode Meloidogyne enterolobii – a potential threat to Portugal and Europe

In 2017, during a survey on subsistence farms and gardens in Coimbra region, Portugal, 40 infected root samples were collected and 47 root-knot nematode (RKN) isolates identified, based on esterase phenotype. The phenotypes A2, H1, Hi2/Hi4, I1/I2/I3 and J3 associated to five Meloidogyne species (M. arenaria, M. hapla, M. hispanica, M. incognita and M. javanica) were found in 43 RKN isolates. The esterase phenotype En2/En4/En5, corresponding to M. enterolobii (=M. mayaguensis), was detected in four RKN isolates from Cereus hildmannianus (Cactaceae), Lampranthus sp. (Aizoaceae), Physalis peruviana (Solanaceae) and Callistemon sp. (Myrtaceae) infected roots. In order to validate the biochemical identification of the M. enterolobii isolates, molecular studies performed with species-specific primers yielded the expected fragment of c.520 bp, and the amplification of cytochrome oxidase subunits I and II regions of 800 bp. The DNA sequences of one of the isolates were compared with available Meloidogyne species sequences in databases. The Portuguese isolate grouped with 99–100% bootstrap support with all M. enterolobii sequences included for comparison, confirming the presence of this RKN species in Portugal. In the EPPO region, M. enterolobii has been reported in France and Switzerland and intercepted in the Netherlands, Germany and the UK associated with plant material from Asia, South America and Africa. Taking into account the pathogen aggressiveness and its distribution, there is a high probability of its spread not only in the Mediterranean region but also in Europe, and of it becoming a threat to the agricultural economy, where there are no effective strategies for its control.     

Seed germination and seedling vigour of transgenic tobacco (Nicotiana tabacum L.) with increased proline accumulation under osmotic stress

Proline plays important roles in various stages and processes of plant development. However, there are few reports on the effect of endogenous proline accumulation on germination and seedling vigour under suitable conditions of germination and development. The aim of this work was to evaluate the effect of endogenous proline in transgenic tobacco (Nicotiana tabacum L.) constitutively expressing the VaP5CSF129A gene in germination and seedling vigour. Under optimal conditions of germination, the transgenic seeds had high proline content when compared to the non-transgenic plants. However, this higher accumulation did not result in better germination or seedling vigour, contrasting to reported results for exogenous proline application. The pre-treatment by water submersion indicated that the lowest initial seed germination with the highest proline concentration may be due to their greater post-harvest dormancy. When newly germinated seedlings were subjected to osmotic stress (?0.9 MPa), the free proline content increased proportionally in all genotypes and the transgenic events seedlings showed greater root length compared to those of the non-transformed control. This can be advantageous as, in theory, seedlings with longer roots may have a better chance of growing and exploring the different soil layers, allowing the transgenic events to be more tolerant to edaphic constraints.     

Differences in constitutive and inducible defences in pine species determining susceptibility to pinewood nematode

The pinewood nematode, Bursaphelenchus xylophilus, originating from North America (NA), is a major invasive pine pest in Eurasia. It was first detected in Portugal in 1999 associated with maritime pine, Pinus pinaster, and has been differently affecting the main local pine species, P. pinaster and P. pinea. Field studies and direct inoculation experiments in Pinus spp. seedlings, under controlled conditions, were performed to assess whether the differences in constitutive and inducible defences are determining the different susceptibility of pine host species to B. xylophilus. Host co‐evolution with the pathogen was also assessed, including the NA P. radiata, widely used in forestry in the northeast of the Iberian peninsula. Pine mortality in the field was positively related with the abundance of B. xylophilus, and concentration of phenolics and condensed tannins in pines. In the greenhouse assay, seedling tissues were analysed for constitutive investment in defences, as well as the potential inducibility of those defences as driven by B. xylophilus inoculation. Slower growing P. pinea presented higher levels of constitutive defences than faster growing P. pinaster, with only P. pinaster being affected by B. xylophilus. Furthermore, co‐evolution with the pathogen is important, with the fast‐growing NA P. radiata presenting an inducible and effective response to B. xylophilus. Results point to the importance of integrating data on pine life history traits, including growth rate, and production of constitutive and inducible defences, into predictive models for this invasive forest pest.     

Identification of essential habitats: Including chimaeras into current shark protected areas

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