Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour

Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However, this type of virus-induced manipulation of vector behaviour was not observed for the semi persistent crinivirus, ToCV, which is not specifically transmitted by B. tabaci and has a much less intimate virus-vector relationship.The authors would like to acknowledge the Brazilian Ministry of Education grant entitled: CAPES/Pesquisador Visitante Especial (Edital N º 61/2011, Proc. 130/2012 and 376/2013). This work was also supported by the National Institute of Science and Technology (INCT) Semiochemicals in Agriculture (CNPq Process 573761/2008-6 and FAPESP Process 2008/57701-2). We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour

Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However, this type of virus-induced manipulation of vector behaviour was not observed for the semi persistent crinivirus, ToCV, which is not specifically transmitted by B. tabaci and has a much less intimate virus-vector relationship

Socio-Economic Variations Determine the Clinical Presentation, Aetiology and Outcome of Infective Endocarditis: a Prospective Cohort Study from the ESC-EORP EURO-ENDO (European Infective Endocarditis) Registry

Background: Infective endocarditis (IE) is a life-threatening disease associated with high mortality and morbidity worldwide. We sought to determine how socio-economic factors might influence its epidemiology, clinical presentation, investigation and management, and outcome, in a large international multi-centre registry. Methods: The EurObservationalProgramme (EORP) of the European Society of Cardiology (ESC) EURO-ENDO registry comprises a prospective cohort of 3113 adult patients admitted for IE in 156 hospitals in 40 countries between January 2016 and March 2018. Patients were separated in 3 groups, according to World Bank economic stratification (Group 1 - high income [75.6%]; Group 2 - upper-middle income [15.4%]; Group 3 - lower-middle income [9.1%]). Results: Group 3 patients were younger (median age [IQR]: Group 1 - 66 [53-75] years; Group 2 - 57 [41-68] years; Group 3 - 33 [26-43] years; p<0.001) with a higher frequency of smokers, intravenous drug use and human immunodeficiency virus (HIV) infection (all p<0.001) and presented later (median [IQR) days since symptom onset: Group 1 - 12 [3-35]; Group 2 - 19 [6-54]; Group 3 - 31 [12-62]; p<0.001) with a higher likelihood of developing congestive heart failure (13.6%; 11.1%; and 22.6%, respectively; p<0.001) and persistent fever (9.8%; 14.2%; 27.9%; p<0.001). Among 2157 (69.3%) patients with theoretical indication for cardiac surgery, surgery was performed less frequently in Group 3 patients (75.5%, 76.8% and 51.3%, respectively p<0.001) who also demonstrated the highest mortality (15.0%, 23.0% and 23.7%, respectively; p<0.001). Conclusions: Socio-economic factors influence the clinical profile of patients presenting with IE across the world. Despite younger age, patients from the poorest countries presented with more frequent complications and higher mortality associated with delayed diagnosis and lower use of surgery

Socio-Economic Variations Determine the Clinical Presentation, Aetiology and Outcome of Infective Endocarditis: a Prospective Cohort Study from the ESC-EORP EURO-ENDO (European Infective Endocarditis) Registry

International audienceAbstract Background Infective endocarditis (IE) is a life-threatening disease associated with high mortality and morbidity worldwide. We sought to determine how socio-economic factors might influence its epidemiology, clinical presentation, investigation and management, and outcome, in a large international multi-centre registry. Methods The EurObservationalProgramme (EORP) of the European Society of Cardiology (ESC) EURO-ENDO registry comprises a prospective cohort of 3113 adult patients admitted for IE in 156 hospitals in 40 countries between January 2016 and March 2018. Patients were separated in 3 groups, according to World Bank economic stratification (Group 1 - high income [75.6%]; Group 2 - upper-middle income [15.4%]; Group 3 - lower-middle income [9.1%]). Results Group 3 patients were younger (median age [IQR]: Group 1 - 66 [53-75] years; Group 2 - 57 [41-68] years; Group 3 - 33 [26-43] years; p<0.001) with a higher frequency of smokers, intravenous drug use and human immunodeficiency virus (HIV) infection (all p<0.001) and presented later (median [IQR) days since symptom onset: Group 1 - 12 [3-35]; Group 2 - 19 [6-54]; Group 3 - 31 [12-62]; p<0.001) with a higher likelihood of developing congestive heart failure (13.6%; 11.1%; and 22.6%, respectively; p<0.001) and persistent fever (9.8%; 14.2%; 27.9%; p<0.001). Among 2157 (69.3%) patients with theoretical indication for cardiac surgery, surgery was performed less frequently in Group 3 patients (75.5%, 76.8% and 51.3%, respectively p<0.001) who also demonstrated the highest mortality (15.0%, 23.0% and 23.7%, respectively; p<0.001). Conclusions Socio-economic factors influence the clinical profile of patients presenting with IE across the world. Despite younger age, patients from the poorest countries presented with more frequent complications and higher mortality associated with delayed diagnosis and lower use of surgery