Identification of microsatellite markers linked to the blast resistance gene <Emphasis Type="Italic">Pi-1(t)</Emphasis> in rice

The present work was conducted to identify microsatellite markers linked to the rice blast resistance gene Pi-1(t) for a marker-assisted selection program. Twenty-four primer pairs corresponding to 19 microsatellite loci were selected from the Gramene database (www. gramene.org) considering their relative proximity to Pi-1(t) gene in the current rice genetic map. Progenitors and DNA bulks of resistant and susceptible families from F₃ segregating populations of a cross between the near-isogenic lines C101LAC (resistant) and C101A51 (susceptible) were used to identify polymorphic microsatellite markers associated to this gene through bulked segregant analysis. Putative molecular markers linked to the blast resistance gene Pi-1(t) were then used on the whole progeny for linkage analysis. Additionally, the diagnostic potential of the microsatellite markers associated to the resistance gene was also evaluated on 17 rice varieties planted in Latin America by amplification of the specific resistant alleles for the gene in each genotype. Comparing with greenhouse phenotypic evaluations for blast resistance, the usefulness of the highly linked microsatellite markers to identify resistant rice genotypes was evaluated. As expected, the phenotypic segregation in the F₃ generation agreed to the expected segregation ratio for a single gene model. Of the 24 microsatellite sequences tested, six resulted polymorphic and linked to the gene. Two markers (RM1233*I and RM224) mapped in the same position (0.0 cM) with the Pi-1(t) gene. Other three markers corresponding to the same genetic locus were located at 18.5 cM above the resistance gene, while another marker was positioned at 23.8 cM below the gene. Microsatellite analysis on elite rice varieties with different genetic background showed that all known sources of blast resistance included in this study carry the specific Pi-1(t) allele. Results are discussed considering the potential utility of the microsatellite markers found, for MAS in rice breeding programs aiming at developing rice varieties with durable blast resistance based on a combination of resistance genes. Centro Internactional de Agricultura Tropical (CIAT) institute where the research was carried out     

Utilizing benthic habitat maps to inform biodiversity monitoring in marine protected areas

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First Characterization of Ostreopsis cf. ovata (Dinophyceae) and Detection of Ovatoxins during a Multispecific and Toxic Ostreopsis Bloom on French Atlantic Coast

Blooms of the benthic toxic dinoflagellate genus Ostreopsis have been recorded more frequently during the last two decades, particularly in warm temperate areas such as the Mediterranean Sea. The proliferation of Ostreopsis species may cause deleterious effects on ecosystems and can impact human health through skin contact or aerosol inhalation. In the eastern Atlantic Ocean, the toxic O. cf. ovata has not yet been reported to the north of Portugal, and the only species present further north was O. cf. siamensis, for which the toxic risk is considered low. During summer blooms of unidentified Ostreopsis species on the French Basque coast (Atlantic) in 2020 and 2021, people suffered from irritations and respiratory disorders, and the number of analyzed cases reached 674 in 2021. In order to investigate the causes, sampling was carried out during summer 2021 to (i) taxonomically identify Ostreopsis species present using a molecular approach, (ii) isolate strains from the bloom and culture them, and (iii) characterize the presence of known toxins which may be involved. For the first time, this study reports the presence of both O. cf. siamensis and O. cf. ovata, for which the French Basque coast is a new upper distribution limit. Furthermore, the presence of ovatoxins a, b, c, and d in the environmental sample and in a cultivated strain in culture confirmed the toxic nature of the bloom and allowed identifying O. cf. ovata as the producer. The present data identify a new health risk in the area and highlight the extended distribution of some harmful dinoflagellates, presumably in relation to climate change.     

Impact of proximal cytoplasmic droplets on quality traits and in-vitro embryo production efficiency of cryopreserved bull spermatozoa

Background

Proximal cytoplasmic droplets (PCDs), a remnant of germ cell cytoplasm, are common non-specific morphological defects in bovine semen. This study evaluated the effect of higher percentages of PCDs on the quality of frozen-thawed bovine semen, embryo production and early embryo development.

Methods

Three ejaculates from each of five (group 1: PCD ≤ 1%, control) and eight adult Bos indicus bulls (group 2: PCD ≥ 24%) were analysed. Semen samples were examined for: post-thaw motility, vigour of movement, concentration, sperm morphology, slow thermoresistance test (STT), membrane integrity, acrosome status, mitochondrial function using fluorescent probes association (FITC-PSA, PI and JC-1) and sperm chromatin integrity using acridine orange assay. Two bulls from group 2, with 28.5% and 48.5% PCD, respectively, and three bulls from the control group, each with 0% PCD, were selected for IVF (in vitro fertilisation).

Results

Semen analyses revealed a significant correlation (P < 0.01) between increased rates of PCD and sperm quality traits. Nevertheless, no differences were observed in sperm motility and vigour either before or after the STT or in the percentage of intact acrosomes (analysed by differential interference contrast microscopy (DIC) after STT), but membrane integrity, acrosome status (evaluated with FITC-PSA staining method after thawing) and mitochondrial function were reduced, when compared with group 1 (P < 0.05). The higher incidence of PCD was positively correlated to chromatin damage, especially after three hours of incubation at 37°C. IVF showed similar results for bull C2 (group 1, control) and bull P2 (group 2, group with higher PCDs).

Conclusion

Higher PCD levels influenced spermatozoa quality traits. IVF and embryo development data showed that cleavage, blastocyst formation and blastocyst hatching may have been influenced by the interaction of morphology traits and individual bull effects.     

Evaluation of dry ashing in conjunction with ion chromatographic determination of transition metal ions in pig feed samples

The contents of transition metal ions iron, copper, zinc, and manganese were simultaneously determined in pig feed using an ion chromatographic technique (IC) preceded by dry ashing. Employing ion exchange, the ions were separated on an IonPac CS5A column used in combination with a pyridine-2,6-dicarboxylic acid based eluent. The separation was followed by spectrophotometric detection after postcolumn reaction with 4-(2-pyridylazo)resorcinol. Dry ashing parameters were varied to assess their role in potential analyte loss. Quantitative recoveries (>95%) were obtained for all analytes with a dry ashing method that included a moderate temperature-time regime and ash leaching support in the form of sonication and heat treatment. The use of HCl as leaching acid and the presence of alkaline earths in the matrix solution did not interfere with the chromatographic separation.     

Contribution of dimethyl sulfide to the aroma of Syrah and Grenache Noir wines and estimation of its potential in grapes of these varieties

The contribution of dimethyl sulfide (DMS) to the aroma of Syrah and Grenache Noir wines from the Rhone Valley of France was investigated by sensory analysis, and its levels in these wines were measured. The potential DMS in the corresponding grapes and wines, susceptible to release during wine aging, was evaluated. Free DMS and potential DMS assessed by a heat-alkaline treatment were measured in grape juices and wines by SPME-GC-MS using methods previously reported and slightly modified. A relationship between potential DMS from grapes and the total DMS levels in wine was demonstrated. Furthermore, a linear regression between the ratio of free DMS levels to these total DMS levels in wine and time of storage was found. Free and potential DMS levels in grapes and wines depended on grape variety, vintage, and vine location. DMS imparted a noticeable and complex contribution to the aroma of the wines investigated, depending on the mode of sensory perception used, either before or after glass swirling. It significantly enhanced the fruity notes of the wines, and additional truffle and black olive notes.     

How successful are plant species reintroductions?

Reintroduction of native species has become increasingly important in conservation worldwide for recovery of rare species and restoration purposes. However, few studies have reported the outcome of reintroduction efforts in plant species. Using data from the literature combined with a questionnaire survey, this paper analyses 249 plant species reintroductions worldwide by assessing the methods used and the results obtained from these reintroduction experiments. The objectives were: (1) to examine how successful plant species reintroductions have been so far in establishing or significantly augmenting viable, self-sustaining populations in nature; (2) to determine the conditions under which we might expect plant species reintroductions to be most successful; (3) to make the results of this survey available for future plant reintroduction trials. Results indicate that survival, flowering and fruiting rates of reintroduced plants are generally quite low (on average 52%, 19% and 16%, respectively). Furthermore, our results show a success rate decline in individual experiments with time. Survival rates reported in the literature are also much higher (78% on average) than those mentioned by survey participants (33% on average). We identified various parameters that positively influence plant reintroduction outcomes, e.g., working in protected sites, using seedlings, increasing the number of reintroduced individuals, mixing material from diverse populations, using transplants from stable source populations, site preparation or management effort and knowledge of the genetic variation of the target species. This study also revealed shortcomings of common experimental designs that greatly limit the interpretation of plant reintroduction studies: (1) insufficient monitoring following reintroduction (usually ceasing after 4 years); (2) inadequate documentation, which is especially acute for reintroductions that are regarded as failures; (3) lack of understanding of the underlying reasons for decline in existing plant populations; (4) overly optimistic evaluation of success based on short-term results; and (5) poorly defined success criteria for reintroduction projects. We therefore conclude that the value of plant reintroductions as a conservation tool could be improved by: (1) an increased focus on species biology; (2) using a higher number of transplants (preferring seedlings rather than seeds); (3) taking better account of seed production and recruitment when assessing the success of reintroductions; (4) a consistent long-term monitoring after reintroduction.     

Universal criteria for species conservation priorities? Findings from a survey of public views across Europe

Decisions on biodiversity management and conservation are increasingly based on indicators. These imply, explicitly or implicitly, a number of criteria such as nativeness, rarity, endangeredness and (economic) value. We investigated to which degree such criteria matter to members of the general public and conducted a survey in eight sites across Europe (n = 2378). We explored the relationships between perceived desirability of a species’ population increase and six species-related attributes, including previous population change, rarity, vulnerability, harmfulness, value, attractiveness, and nativeness.For all three species types investigated, previous population change, followed by perceived harmfulness and value, had the strongest relationship with desirability of future increase. Perceived nativeness played only a minor role in informing a species’ desirability. A strong relationship between previous change and desirability of future increase could also be found in a number of additional species and six different habitat types, suggesting that previous change is a key criterion that the general public draws on to inform their attitudes towards biodiversity management.We compare the roles of such criteria for the general public to those used in the scientific and political discourse, and draw conclusions for the use of indicators in the conservation debate, arguing that biodiversity management that is strongly focused on nativeness might fall short of the interests of the citizenship, whereas other criteria, such as population trends, harmfulness and role and value of a species in the ecosystem strongly resonate with the views of the general public.     

Isolation of microsatellites from an enriched genomic library of the plant-parasitic nematode <Emphasis Type="Italic">Meloidogyne incognita</Emphasis> and their detection in other root-knot nematode species

The root-knot nematode Meloidogyne incognita is a polyphagous pest distributed from temperate to tropical regions. However, the lack of suitable markers leads to a poor knowledge of its population genetic structure and colonization process. Here we describe the first characterization of 15 microsatellite loci from this nematode, that were developed from an enriched genomic library. Although the variability of these microsatellites was generally low, three of them exhibited a significant level of intrapopulation polymorphism, with three to seven alleles detected. The observed and expected heterozygosities ranged from 0.025 to 0.385 and from 0.024 to 0.779, respectively. Thus, these new microsatellite markers have potential value for the implementation of genotyping experiments in this nematode. Furthermore, successful cross-amplification of the variable microsatellite loci in seven other Meloidogyne species provides the opportunity of using these markers for population genetic studies in these damaging plant-parasitic nematodes.     

Dynamic of nasal colonization by methicillin-resistant Staphylococcus aureus ST398 and ST1 after mupirocin treatment in a family in close contact with pigs

Nasal colonization by methicillin-resistant Staphylococcus aureus (MRSA) was evaluated after a mupirocin treatment in a family previously colonized by MRSA sequence type ST398 and ST1, who lived close to a pig farm. Eight nasal samples were swabbed from each of the four family members on different moments after mupirocin treatment. The efficacy of treatment was low in those family members who worked in the farm, and higher in the remaining two family members with sporadic contact with pigs. In addition, nasal and skin swabs from randomly selected pigs of the farm were taken. MRSA were detected in 33% of pigs tested. All MRSA isolates obtained were characterized by Staphylococcal-Cassette-Chromosome mec (SCCmec) determination, Multilocus-Sequence-Typing (MLST), spa- and agr-typing, Pulsed-field-gel-electrophoresis (PFGE), antimicrobial susceptibility, detection of antimicrobial resistance genes, and toxin gene profiling. Spa-types t011, t1255 and t1197 were detected in humans and animals, with indistinguishable PFGE patterns, suggesting animal to human MRSA transmission. Each spa-type was ascribed to a specific pulsotype. Spa-types t127 and t108 were only detected in MRSA isolates obtained from humans, and t012 only in those from animals. MRSA ST1-t127 isolates and some ST398-t011 and ST398-t1197 isolates presented a multiantimicrobial-resistance phenotype. None of them harbored lukF/lukS, tst, eta and etb virulence genes. This study showed that the efficacy of nasal MRSA decolonization in healthy people with very close contact with pigs is especially low.