Control cultural de la podredumbre radical causada por Phytophthora cinnamomi en dehesas de encina

Parte de esta tesis está escrita en inglés.En este trabajo se ha estudiado el efecto in vitro de varios productos de Ca2+ y K+ (CaO, CaCO3, CaCl2, Ca(NO3)2, CaSO4, KOH, KNO3, KCl, KIO3 y K2SO4) sobre el crecimiento micelial, producción de esporangios y clamidosporas (esporas de resistencia) y germinación de esporangios (producción de zoosporas infectivas) de P. cinnamomi. Aunque ninguno de los productos testados a pH~6 inhibió el crecimiento micelial del patógeno, el CaO, CaCO3, CaSO4, KOH y KIO3 inhibieron de forma eficaz la producción de esporangios, y por lo tanto, la producción de zoosporas de P. cinnamomi, si bien no resultan tan efectivos en la inhibición de la germinación de los esporangios ya formados. El CaO, CaCO3, K2SO4 y CaCl2 inhibieron eficazmente la producción de clamidosporas. También se ha testado el efecto de los compuestos más eficaces en los ensayos in vitro (CaO, CaCO3, CaSO4, KOH y KIO3) sobre la densidad de inóculo en suelo y la infectividad de P. cinnamomi. Cada producto se añadió a las dosis habitualmente empleadas en las dehesas a suelo infestado con clamidosporas del patógeno. Dos semanas después de la adición de los productos, sólo los compuestos de K+ dieron lugar a una disminución significativa de la densidad de clamidosporas viables. En ese momento, los suelos fueron transferidos a macetas donde se plantaron encinas. Las plantas que crecieron en suelo infestado y no tratado mostraron niveles altos de síntomas foliares y radicales, mientras que las plantas que crecieron en suelos infestados tratados con los fertilizantes (excepto el KIO3), mostraron una reducción significativa de la severidad de síntomas. Estos resultados indican que la aplicación de enmiendas calizas, CaO y CaCO3 fundamentalmente, aunque también CaSO4, y KOH a los suelos de dehesa infestados por el patógeno podría constituir un tratamiento efectivo contra la podredumbre radical, reduciendo la incidencia de esta grave enfermedad...In this work the in vitro effectiveness of different Ca2+ and K+ products (CaO, CaCO3, CaCl2, Ca(NO3)2, CaSO4, KOH, KNO3, KCl, KIO3 and K2SO4) on mycelial growth, sporangial and chlamydospore (resistant spores) production and sporangial germination (production of infective zoospores) of P. cinnamomi has been tested. Although none of the products inhibited mycelial growth at pH ~ 6, CaO, CaCO3, CaSO4, KOH and KIO3 effectively inhibited the sporangial production of the pathogen and therefore, its zoospore production, although none of them were as effective in inhibiting the germination of already formed sporangia. CaO, CaCO3, K2SO4 and CaCl2 effectively inhibited the production of chlamydospores. The effect of the more effective compounds in the in vitro experiments (CaO, CaCO3, CaSO4, KOH and KIO3) was also tested for their effect on the inoculum density in the soil and the infectivity of P. cinnamomi. Each product was added at the doses commonly used in rangelands to soil infested with chlamydospores of the pathogen. Two weeks after, only K+ compounds resulted in a significant decrease of the density of viable chlamydospores. At that time, soils were transferred to pots where Holm oak seedlings were planted. Plants grown in infested and untreated soil showed high levels of foliar and root symptoms, while plants grown in infested and fertilized soils showed a significant reduction in the severity of symptoms, except KIO3. These results suggest that the application of Ca2+ amendments, mainly CaO and CaCO3, but also CaSO4 and KOH, to the soil in rangelands affected by the pathogen could be an effective treatment against the root rot, decreasing the incidence of this serious disease

Trunk injection of fosetyl-aluminium controls the root disease caused by Phytophthora cinnamomi on Quercus ilex woodlands

In Spain, Quercus open woodlands are animal ranching systems of organic production seriously threatened by the exotic pathogen Phytophthora cinnamomi. The root disease it causes kills thousands of oaks annually. Effective disease management needs to integrate different techniques, and the use of a resistance inducer such as fosetyl‐Al can play a key role, because the use of potassium phosphite is prohibited in Spain. In a woodland where the pathogen recently arrived, 60 holm oaks in three different defoliation classes (asymptomatic, slight and moderate defoliation) were selected for trunk injection with pressurised capsules containing 4% of commercial fosetyl‐Al or water (controls). Holm oaks were checked periodically for defoliation and presence of the pathogen in roots and rhizosphere soil. Three years after treatments, defoliation was significantly lower in oaks treated with fosetyl‐Al, which even increased canopy cover, in comparison with control oaks, independent of the initial defoliation class considered. Chlamydospore density in rhizosphere soil, as well as the presence of the pathogen into the roots, was not significantly influenced by fosetyl‐Al treatments, although a trend to a lower presence of P. cinnamomi in roots was observed in treated oaks at every soil inoculum density detected. This study has shown that fosetyl‐Al, a phosphonate registered as a fungicide in the European Union, provides protection to holm oaks against P. cinnamomi, even exhibiting a therapeutic effect on pre‐existing infections. Consequently, this effective measure should be considered as part of the integrated approach to control this highly destructive pathogen in holm oak woodlands

Influencia del cultivo de Lupinus luteus L. en la densidad de inóculo de Phytophthora cinnamomi en suelos de dehesa

Phytophthora cinnamomi es un patógeno que causa podredumbre radical en el arbolado de la dehesa y también en Lupinus luteus, cultivo frecuente en dehesas de Andalucía occidental. En dehesas que mostraban distintas situaciones en cuanto a decaimiento del arbolado y severidad de la enfermedad en el altramuz, el aislamiento y conteo de colonias de P. cinnamomi a partir de muestras de suelo ha mostrado la capacidad del cultivo herbáceo para mantener o incrementar la densidad de inóculo y así potenciar la infección de las encinas. Los resultados obtenidos desaconsejan el cultivo de esta leguminosa en dehesas con presencia del patógeno en el suelo, tanto si el arbolado sufre la enfermedad radical o no

La tremosilla (Lupinus luteus): un nuevo huésped de Phytophthora cinnamomi en las dehesas de Andalucía occidental

Phytophthora cinnamomi es un patógeno agresivo que causa podredumbre radical, marchitez y muerte de Lupinus luteus (altramuz amarillo, tremosilla) en dehesas de Andalucía occidental. Este oomiceto, principal responsable de la podredumbre radical de los Quercus en Andalucía, ha sido aislado de raíces de plantas de altramuz sintomáticas en todas las dehesas prospectadas. Las inoculaciones artificiales en distintas variedades de altramuz amarillo han reproducido los síntomas de la enfermedad, tanto en fase de pre-emergencia como de post-emergencia, habiéndose reaislado al patógeno de las raíces necróticas. La susceptibilidad del altramuz amarillo a la infección radical por P. cinnamomi ha resultado muy alta, incluso mayor que la exhibida por el altramuz azul (Lupinus angustifolius), si bien no se han observado diferencias significativas entre las distintas variedades de L. luteus ensayadas. Estos resultados sugieren que se deben reconsiderar el cultivo de la tremosilla en dehesas afectadas por el decaimiento de los Quercus causado por P. cinnamomi. Este trabajo constituye la primera descripción de P. cinnamomi como patógeno radical del altramuz amarillo

Nuevas especies de Pythium que causan podredumbre radical de Quercus en España y Portugal

Pythium spiculum, una nueva especie recientemente descrita, se viene aislando desde 2003 de raíces y rizosfera de Quercus rotundifolia y Q. suber que sufren decaimiento en el sur de España y Portugal. En los suelos donde crecen formaciones de Quercus, esta especie ha sido aislada con frecuencias similares a las encontradas para Phytophthora cinnamomi, especie que, hasta el momento, ha sido el único oomiceto descrito como patógeno radical de Quercus en esta región. Las inoculaciones artificiales llevadas a cabo en plántulas de Q. rotundifolia mostraron que Py. spiculum es un patógeno agresivo de las raíces de Quercus, aunque produce severidades de síntomas significativamente menores que P. cinnamomi. Este nuevo patógeno puede jugar un papel decisivo en el decaimiento de Quercus en la Península Ibérica. Otra especie recientemente descrita, Py. sterilum, también es patógena de raíces de Quercus, pero se ha encontrado únicamente en rizosfera de encinas enfermas en el centro de España, por lo que más que un factor activo de decaimiento, debe ser considerado como un riesgo potencial para las masas de Quercus

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London