Mycosphaerella fijiensis Morelet (anamorph Pseudocercospora fijiensis Morelet), the causal agent of black Sigatoka disease of banana, is considered to be the greatest economical threat for ...export-banana cultivation throughout the world because most cultivars are highly susceptible. The disease has a worldwide distribution throughout the humid tropical regions, but was still absent in some Caribbean islands hitherto. In Martinique Island, an intensive survey has been conducted by the plant protection service and the Fédération Régionale de Défense Contre les Organismes Nuisibles (FREDON) since April 2008 to detect as early as possible any outbreak of infection by M. fijiensis. In September 2010, typical symptoms of black Sigatoka were observed in a plantain crop located in Ducos Municipality (14°35.702'N, 60°58.221'W) in the west-central area of the island. Typical early symptoms were 1- to 4-mm long brown streaks on the abaxial leaf surface. The presence of the disease was further confirmed by the in situ observation of microscopic features of the anamorphic form of the pathogen (3). Typical pale brown, straight or slightly geniculate conidiophores were observed occurring singly or in little groups without any stroma, with a thickened wall at the conidial scars. Conidia were hyaline to pale olive, straight or slightly curved, with one to eight septa, and a conspicuous scar at the basal cell. The diagnosis was confirmed by real-time PCR targeting M. fijiensis-specific regions within the β-tubulin gene (1). Positive results were consistently obtained with DNA extracted from infected banana tissue samples, and the identity of the amplicon was confirmed by sequencing (Accession No. HQ412771) and comparison with reference sequences deposited on GenBank. After this first finding, the survey was intensified and black Sigatoka symptoms were also observed in several other locations on the island, affecting a large range of susceptible cultivars (Grande Naine, French, and Figue Sucrée), and in plantations, backyards, and private gardens. The presence of the fungus in the samples was confirmed by PCR analysis of DNA extracted from symptomatic leaves with a M. fijiensis-specific ITS-based primer pair (2). The pathogen may have been introduced into Martinique by ascospores, from islands where black Sigatoka is present, that were blown by continuous southerly winds over a 2-week period in August 2010 that was immediately followed by heavy rains that favor disease development. To our knowledge, this is the first report of M. fijiensis on Martinique Island, showing that the disease is still spreading northward in this region of the Caribbean. References: (1) M. Arzanlou et al. Phytopathology 97:1112, 2007. (2) J. Henderson et al. Page 59 in: Mycosphaerella Leaf Spot Disease of Bananas: Present Status and Outlook. L. Jacome et al., eds. International Network for the Improvement of Banana and Plantain (INIBAP), Montpellier, France. 2003. (3) M. F. Zapater et al. Fruits 63:389, 2008.
Bananas are usually harvested at a green preclimacteric stage prior to sale. The preclimacteric phase is called green life (GL), which is defined as the number of days between harvesting and ...initiation of the natural ripening process. Sigatoka disease (SD) has previously been shown to influence the postharvest behaviour of banana fruit. This work was set out to determine whether there is a relationship between the level of SD severity and the extent of the effects on banana quality as characterized by several pomological traits, especially pulp colour. In an experiment conducted with fruits harvested at a constant physiological age, our results showed that SD had a major effect on the percentage of fruit ripening in the field and on fruit weight, but not on fruit diameter. We showed too that pulp colour was greatly affected by SD; when severity increased, pulp colour parameters were modified – L* (lightness) decreased, a* (axis red to green) and b* (axis yellow to blue) increased, giving a more greyish pulp colour, with less green and more yellow and red. These results may enable the development of a method for controlling fruit quality, by measuring pulp colour in the field, in order to reduce post-harvest losses.
Sigatoka disease (SD) of bananas is caused by the pathogenic fungus
Mycosphaerella musicola Leach. This disease provokes necrotic lesions on leaves and serious infestations can lead to a substantial ...reduction in the leaf area of infected plants and thus to yield losses. In addition to these effects on yield, SD was found to have an impact on fruit quality, especially because exported bananas ripen prematurely. In the present work, a plantation survey and experiments have been conducted in Guadeloupe (FWI) to assess the effect of this disease on the greenlife of bananas harvested at a constant physiological age, as measured in degree-days (dd). Our results revealed that bananas harvested at 900
dd from plants with high Sigatoka disease severity had normal diameter growth, but a shorter greenlife (GL) than bananas harvested from uninfected plants. These results indicate that SD is directly responsible for the reduction of banana greenlife since the reduction of GL could not be attributed to the harvest of fruits at a more advanced physiological age (dd). Furthermore, a correlation was noted between SD severity and GL. The potential physiological mechanisms involved are also discussed.
The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases convened a task force of experts in rheumatoid arthritis (RA) and clinical trial ...methodology to comment on the new draft ‘Guideline on clinical investigation of medicinal products for the treatment of RA’ released by the European Medicines Agency (EMA). Special emphasis was placed by the group on the development of new drugs for the treatment of early RA. In the absence of a clear definition of early RA, it was suggested that clinical investigations in this condition were conducted in disease-modifying antirheumatic drugs naïve patients with no more than 1 year disease duration. The expert group recommended using an appropriate improvement in disease activity (American College of Rheumatology (ACR) or Simplified/Clinical Disease Activity Index (SDAI/CDAI) response criteria) or low disease activity (by any score) as primary endpoints, with ACR/European League Against Rheumatism remission as a secondary endpoint. Finally, as compelling evidence showed that the Disease Acrivity Score using 28-joint counts (DAS28) might not provide a reliable definition of remission, or sometimes even low disease activity, the group suggested replacing DAS28 as a measurement instrument to evaluate disease activity in RA clinical trials. Proposed alternatives included SDAI, CDAI and Boolean criteria.
Carbonyl sulfide (COS), a trace gas showing striking similarity to CO2 in terms of biochemical diffusion pathway into leaves, has been recognized as a promising indicator of the plant gross primary ...production (GPP), the amount of carbon dioxide that is absorbed through photosynthesis by terrestrial ecosystems. However, large uncertainties about the other components of its atmospheric budget prevent us from directly relating the atmospheric COS measurements to GPP. The largest uncertainty comes from the closure of its atmospheric budget, with a source component missing. Here, we explore the benefit of assimilating both COS and CO2 measurements into the LMDz atmospheric transport model to obtain consistent information on GPP, plant respiration and COS budget. To this end, we develop an analytical inverse system that optimizes biospheric fluxes for the 15 plant functional types (PFTs) defined in the ORCHIDEE global land surface model. Plant uptake of COS is parameterized as a linear function of GPP and of the leaf relative uptake (LRU), which is the ratio of COS to CO2 deposition velocities in plants. A possible scenario for the period 2008–2019 leads to a global biospheric sink of 800 GgS yr−1, with higher absorption in the high latitudes and higher oceanic emissions between 400 and 600 GgS yr−1 most of which is located in the tropics. As for the CO2 budget, the inverse system increases GPP in the high latitudes by a few GtC yr−1 without modifying the respiration compared to the ORCHIDEE fluxes used as a prior. In contrast, in the tropics the system tends to weaken both respiration and GPP. The optimized components of the COS and CO2 budgets have been evaluated against independent measurements over North America, the Pacific Ocean, at three sites in Japan and at one site in France. Overall, the posterior COS concentrations are in better agreement with the COS retrievals at 250 hPa from the MIPAS satellite and with airborne measurements made over North America and the Pacific Ocean. The system seems to have rightly corrected the underestimated GPP over the high latitudes. However, the change in seasonality of GPP in the tropics disagrees with solar-induced fluorescence (SIF) data. The decline in biospheric sink in the Amazon driven by the inversion also disagrees with MIPAS COS retrievals at 250 hPa, highlighting the lack of observational constraints in this region. Moreover, the comparison with the surface measurements in Japan and France suggests misplaced sources in the prior anthropogenic inventory, emphasizing the need for an improved inventory to better partition oceanic and continental sources in Asia and Europe.
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