Induced resistance during the interaction pathogen x plant and the use of resistance inducers

Plants react to aggressions through different defence responses. Mechanical barriers consist in the increase of production and deposition of substances capable of containing pathogen invasion. Chemical barriers consist in the increase of concentration or activity of defence proteins and synthesis of phenolic compounds and phytoalexins. Elicitor substances have been widely used in plant disease control showing impressive results and a low impact to the environment and man. This review contains information about plant defence mechanisms and shows the use of inducers of resistance in the control of pathogens and prospects of advance towards sustainable agriculture

INTREPID Futures Initiative: Universities and Knowledge for Sustainable Urban Futures: as if inter and trans-disciplinarity mattered. 4th INTREPID REPORT

This London Workshop is meant to advance the agenda of “Universities and Knowledge for Sustainable Urban Futures: as if ID and TD mattered”, by helping to define the scope of the EU COST Action INTREPID contribution, and of the activities to be funded for 2017-2019. Intention statement: ‘To contribute to the shaping of tomorrow’s universities & their urban curricula: as if inter and transdisciplinary ways of knowing actually mattered’. For this purpose, the Workshop was a one-day gathering of experts and practitioners with diverse experience and disciplinary backgrounds. The report outlines the results obtained

Biology and molecular characterization of necroviruses

Three necroviruses, family Tombusviridae, are known to infect Olea europaea L., Olive latent virus 1 (OLV-1), Olive mild mosaic virus (OMMV) and Tobacco necrosis virus D (TNV-D), often asymptomatically. OLV-1 has a wide geographical distribution whereas that of OMMVand TNV-D is not known as their discovery is recent, dating from 2005 and 2009, respectively. OMMV has received special attention because of its origin, likely to have resulted from a recombination event between TNV-D, with which it shares a coat protein (CP) amino acid identity of 86% and OLV-1 sharing an RNA-dependent RNA polymerase amino acid identity of 91%. Due to these properties OMMV and TNV-D are indistinguishable by serology or Reverse Transcription – Polymerase Chain Reaction assays that use primers hybridizing in the CP gene region, rendering ambiguous earlier TNV-D identifications based on such tests. OLV-1 and OMMV are transmitted through the soil to roots of host plants in the absence of any vectors but the transmission rate of OMMV increases to more than double in the presence of Olpidium brassicae zoospores that vector this virus in an in vitro manner. A point mutation leading to an amino acid substitution located in an inner region of the virion is responsible for the loss of biologically assisted transmission, probably by altering the particle conformation rendering the binding site inaccessible to the zoospore receptors. The field occurrences of necrovirus multiple infections are common and increase the chances for recombination events, the epidemiological implications of which are still uncertain. The biological and molecular properties of the necroviruses identified in olive trees are the main focus of this review

Envisioning innovative groundwater management policies through scenario workshops in France and Portugal

International audienceIn the Mediterranean basin, climate change is expected to result in reduced available water resources and increased water demand. This will lead to growing competition for the access to scarce water resources. And it will increase environmental pressures exerted on aquatic ecosystems and problems of water resources overexploitation. Groundwater resources could be significantly affected (drop in water tables, sea water intrusion) in particular because their exploitation is often weakly regulated. In this context, policy makers are increasingly enjoined to explore how current groundwater management rules can be adapted. Given the magnitude of predicted hydro-climatic changes, deep institutional, economic and legal changes will be required to take up the challenge of climate change. Policy makers and stakeholders will have to invent a new water management paradigm, calling into question some of the established assumptions, social values and even ideologies. In particular, the role of the State, market forces and collective action in water management will need to be re-examined. In this paper, we argue that the exploration of possible futures should not be conducted by policy makers and experts alone but that it should also involve grass root water users, farmers in particular. We present a participatory foresight methodology which was implemented in two case studies in southern France (Roussillon) and Portugal (Algarve). After describing the methodology, the paper focuses on three contrasted water management scenarios which were discussed with five groups of farmers. It then describes the results obtained, both in terms of ideas related to future water management scenarios and in terms of participatory process

Envisioning innovative groundwater regulation policies through scenario workshops in France and Portugal

Groundwater management policies will need to be revised in many Mediterranean countries, in light of the impact of climate change and the increasing demand for water. In this paper, we analyse stakeholder perceptions of three groundwater policy scenarios which respectively assume a strengthening of state intervention, the introduction of market regulation mechanisms, and the transfer of regulation responsibility to farmers. The method consists of organizing scenario workshops with experts, institutional representatives and farmers. It is applied in two case studies in France and Portugal. From a methodological viewpoint, the research demonstrates farmers’ ability to contribute to an exploratory assessment of possible future water management scenarios. From a policy viewpoint, it clarifies expectations concerning state intervention and self-regulation by farmers. It also provides some insights regarding the acceptability of tradable groundwater permits in two European contexts

D etection of sweet potato virus C, sweet potato virus 2 and sweet potato feathery mottle virus in Portugal

Field sweet potato plants showing virus-like symptoms, as stunting, leaf distortion, mosaic and chlorosis, were collected in southwest Portugal and tested for the presence of four potyviruses, sweet potato virus C (SPVC), sweet potato virus 2 (SPV2), sweet potato feathery mottle virus (SPFMV), sweet potato virus G (SPVG), and the crinivirus sweet potato chlorotic stunt virus (SPCSV). DsRNA fractions were extracted from symptomatic leaves and used as templates in single and multiplex RT-PCR assays using previously described specific primers for each analyzed virus. The amplified reaction products for SPVC, SPV2 and SPFMV were of expected size, and direct sequencing of PCR products revealed that they correspond to the coat protein gene (CP) and showed 98%, 99% and 99% identity, respectively, to those viruses. Comparison of the CP genomic and amino acid sequences of the Portuguese viral isolates recovered here with those of ten other sequences of isolates obtained in different countries retrieved from the GenBank showed very few differences. The application of the RT-PCR assays revealed for the first time the presence of SPVC and SPFMV in the sweet potato crop in Portugal, the absence of SPVG and SPCSV in tested plants, as well as the occurrence of triple virus infections under field conditions

Role of the "other Babinski sign" in hyperkinetic facial disorders

BACKGROUND: The "other Babinski sign" consists in the co-contraction of the orbicularis and frontalis muscles, causing an eyebrow elevation during ipsilateral eye closure. It cannot be voluntarily reproduced. AIMS OF THE STUDY: To determine the utility of this sign in the differential diagnosis of hyperkinetic facial disorders. METHODS: The presence of the sign was assessed in consecutive patients with blepharospasm, primary hemifacial spasm or post-paralytic facial syndrome treated in a botulinum toxin outpatient clinic. RESULTS: Of the 99 patients identified, 86 were included, 41 with blepharospasm (32 female, mean age 71±11years), 28 with hemifacial spasm (16 female, mean age 65±12years) and 17 with post-paralytic facial syndrome (14 female, mean age 50±17years). The sign was detected in 67.9% of the patients with hemifacial spasm, in 23.5% of the post-paralytic facial syndrome group and in none of the patients with blepharospasm, exhibiting a sensitivity of 51% and a specificity of 100% for the diagnosis of hemifacial spasm/post-paralytic facial syndrome and a specificity of 76% for hemifacial spasm, compared to post-paralytic facial syndrome. CONCLUSIONS: This sign is highly specific for the diagnosis of peripherally induced hyperkinetic facial disorders. Its assessment should integrate the routine examination of patients with abnormal facial movements.info:eu-repo/semantics/publishedVersio

Evidence of olive mild mosaic virus transmission by Olpidium brassicae

Transmission of three strains of OMMV by an Olpidium sp. was evaluated and compared. The three strains were 1) an OMMV wild type (WT) recovered from olive trees, 2) an OMMV variant (L11) obtained after 15 serial passages of single local lesions induced in Chenopodium murale plants, and 3) a construct OMMV/OMMVL11 in which the coat protein (CP) gene replaced that of the wild type. A single-sporangial culture derived from Chinese cabbage (Brassica pekinensis) used as a bait plant grown in soil of an olive orchard, was identified as Olpidium brassicae based on the size and sequence of the generated amplicon in PCR specific tests. Each of the three virus strains was soil transmitted to cabbage roots in the absence of the fungus at similar rates of 30 to 40%. Separate plant inoculation by O. brassicae zoospores incubated with each viral strain resulted in enhanced transmission of OMMV, reaching 86% of infection whereas that of the other two strains remained practically unaffected at ca. 34%. Binding assays showed that the amount of virus bound to zoospores, estimated spectrophotometrically, was 7% in the case of OMMV, and practically nil in the case of the other two viral strains. Substitution of the coat protein (CP) gene of OMMV by that of the OMMV L11 strain, drastically reduced viral transmissibility in the presence of zoospores to the level of that observed in their absence. Our data shows that OMMV soil transmission is greatly enhanced by O. brassicae zoospores and that the viral CP plays a significant role in this process, most likely by facilitating virus binding and later entrance into the host plant roots

Specific amino acids of Olive mild mosaic virus coat protein are involved in transmission by Olpidium brassicae

Abstract: Transmission of Olive mild mosaic virus (OMMV) is facilitated by Olpidium brassicae (Wor.) Dang. An OMMV mutant (OMMVL11) containing two changes in the coat protein (CP), asparagine to tyrosine at position 189 and alanine to threonine at position 216, has been shown not to be Olpidium brassicae-transmissible owing to inefficient attachment of virions to zoospores. In this study, these amino acid changes were separately introduced into the OMMV genome through site-directed mutagenesis, and the asparagine-to-tyrosine change was shown to be largely responsible for the loss of transmission. Analysis of the structure of OMMV CP by comparative modelling approaches showed that this change is located in the interior of the virus particle and the alanine-to-threonine change is exposed on the surface. The asparagine-to-tyrosine change may indirectly affect attachment via changes in the conformation of viral CP subunits, altering the receptor binding site and thus preventing binding to the fungal zoospore

Multiplex RT-PCR for detection and identification of three necroviruses that infect olive trees

An optimized multiplex RT-PCR assay was developed to discriminate three necrovirus (Olive latent virus 1 (OLV-1), Tobacco necrosis virus D (TNV-D) and Olive mild mosaic virus (OMMV)) that infect olive trees. An olive orchard consisting of 54 trees of cv. "Galega vulgar" in the south of Portugal was surveyed. dsRNA fraction was used as template and revealed the 3 viruses, singly or in multiple infections, present in 17 out of 54 trees in the orchard. OMMV was the most frequent occurring in 15 trees, followed by OLV-1 in 12 and TNV-D in 4 plants. The results obtained showed that necrovirus- specific dsRNAs do exist in infected tissues in amounts below the resolution permitted by gel electrophoresis analysis and that the developed multiplex PCR based assay is of much higher sensitivity. The design of the specific primers described enabled, for the first time, to discriminate between OMMV and TNV-D by means of RT-PCR assays, an indispensable tool in identification, epidemiology and survey studie