Quantitative insights into grapevine anthracnose (Elsinoë ampelina) epidemiology: impact of temperature and leaf age on incubation, lesion development, and sporulation

Grapevine anthracnose, caused by Elsinoe ampelina, is one of the most devastating diseases for wine and table grapes, particularly in hot, humid regions. This study explores how temperature and leaf age affect incubation and how temperature affects lesion development and sporulation. The influence of temperature and leaf age on incubation period (days) was tested under controlled conditions. Leaves from 1 to 8 days old were inoculated and maintained at temperatures of 5, 10, 15, 20, 25, and 30°C. The time elapsed between inoculation and the emergence of initial lesions was recorded. The effect of temperature on lesion development and sporulation was investigated under vineyard conditions. This was achieved through artificial inoculations, with 17, 11, and 11 inoculations conducted in 2016, 2017, and 2018, respectively. The average incubation period, considering all leaf ages, was 27.50 days at 5°C, 15.10 days at 10°C, 9.70 days at 15°C, 5.90 days at 20°C, 3.70 days at 25°C, and 2.26 days at 30°C. Regardless of temperature, the average incubation period was 3.6, 5.9, 8.3, 9.8, 11.9, 13.4, 15.6, and 17.1 days for leaves 1, 2, 3, 4, 5, 6, 7, and 8 days old respectively. The exponential decay model accurately describes the incubation period as a function of both temperature and leaf age. On average, the relative lesion development (RLD) were 0.00, 0.00, 0.23, 0.47, 0.72, 0.93 0.92, 0.90, 0.94, and 1.0 at 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 days after inoculation, respectively. The average relative sporulation (RSPO) was 0.03, 0.36, 0.82, 0.96, and 1.0 at 5, 10, 15, 20, and 25 days after inoculation, respectively. Both RDL and RSPO as a function of degree-days (Tbase= 0°C) since inoculation were well described by the logistic function. The rates of change in relative lesion development and relative sporulation were 0.055 and 0.032, respectively. The results of this study provide new quantitative insights into three important stages (monocyclic processes) in the development of grapevine anthracnose caused by E. ampelina.

A Decade of Hidden Phytoplasmas Unveiled Through Citizen Science

Climate change is impacting agriculture in many ways, and a contribution from all is required to reduce the imminent losses related to it. Recently, it has been shown that citizen science could be a way to trace the impact of climate change. However, how can citizen science be applied in plant pathology? Here, using as an example a decade of phytoplasma-related diseases reported by growers, agronomists, and citizens in general, and confirmed by a government laboratory, we explored how to better value plant pathogen monitoring data. Through this collaboration, we found that in the last decade, 34 hosts have been affected by phytoplasmas; 9, 13, and 5 of these plants were, for the first time, reported phytoplasma hosts in eastern Canada, all of Canada, and worldwide, respectively. Another finding of great impact is the first report of a 'Candidatus Phytoplasma phoenicium'-related strain in Canada, while 'Ca. P. pruni' and 'Ca. P. pyri' were reported for the first time in eastern Canada. These findings will have a great impact on the management of phytoplasmas and their insect vectors. Using these insect-vectored bacterial pathogens, we show the need for new strategies that can allow fast and accurate communication between concerned citizens and those institutions confirming their observations.[Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Grapevine Virology in the Third-Generation Sequencing Era: From Virus Detection to Viral Epitranscriptomics

Among all economically important plant species in the world, grapevine (Vitis vinifera L.) is the most cultivated fruit plant. It has a significant impact on the economies of many countries through wine and fresh and dried fruit production. In recent years, the grape and wine industry has been facing outbreaks of known and emerging viral diseases across the world. Although high-throughput sequencing (HTS) has been used extensively in grapevine virology, the application and potential of third-generation sequencing have not been explored in understanding grapevine viruses and their impact on the grapevine. Nanopore sequencing, a third-generation technology, can be used for the direct sequencing of both RNA and DNA with minimal infrastructure. Compared to other HTS methods, the MinION nanopore platform is faster and more cost-effective and allows for long-read sequencing. Due to the size of the MinION device, it can be easily carried for field viral disease surveillance. This review article discusses grapevine viruses, the principle of third-generation sequencing platforms, and the application of nanopore sequencing technology in grapevine virus detection, virus-plant interactions, as well as the characterization of viral RNA modifications.

Profile of Patients with Gallstone Disease in a Sub-Saharan African General Surgery Department: A Retrospective Cohort Study Protocol

Introduction:

Gallstone disease is a disorder characterised by the formation of stones in the biliary tract. It is the most common biliary condition accounting for more than 98% of all gallbladder and biliary tract disorders. In Africa, previous studies have shown a relative rarity of this condition with a prevalence less than 5%; since it is between 2 and 5 times higher in other continents. A good knowledge of the profile of patient with gallstone disease in a surgical setting could allow to reduce gallstone disease complications and to tailor better the treatment. To our knowledge, there was no previous study about gallstone disease in this region even if there is a high prevalence of metabolic factors of gallstone disease.

Methods:

This study objective is to describe the epidemiological, diagnostic and therapeutic profile of patients with gallstone disease at the Department of General Surgery of Saint-Louis Hospital (Senegal). It will be a single-centre retrospective cohort study in a period of 5 years (January 2015 – December 2020). The patients’ record of the department of general surgery will be consulted and the patient contacted if there are missing data. Patients with gallstone disease diagnosed with imaging (ultrasonography and/or CT scan) regardless the presentation (asymptomatic, biliary colic, cholecystitis, common bile duct lithiasis, angio-cholitis, pancreatitis) will be included. Adults and paediatric patients will be enrolled. Patient records lacking sufficient data will be excluded. Studied parameters will be epidemiological, clinical, paraclinical and therapeutic aspects.

Ethics and dissemination:

Anonymity and confidentiality of information collected in patients will be respected. This research protocol will be submitted to the Ethics Committee of our institution for approval. The knowledge of the profile of patients with gallstone disease in a surgical setting could allow to reduce gallstone disease complications and to tailor better the treatment. Finally, it will help to reduce the burden of gallstone disease.

Highlights

Factors Associated with Foot Lesions in Diabetic Patients at Saint-Louis Hospital (Senegal): A Case-Control Study Protocol

Introduction:

Diabetes prevalence has increased over the past years. In Senegal, this prevalence is 4% in the general population. However, the region of Saint-Louis (in the north of the country) has the highest rate with 10.4%. The main prognosis problem is the occurrence foot lesions that can lead to lower-limbs amputation. Diabetic foot is a real public health issue, due to its economic burden and its serious repercussions on patients, leading to poor quality of life. The objective of this case-control study is to identify factors associated with foot lesions in diabetic patients.

Methods and analysis:

It will be a case-control study from January to December 2021. The patients will be recruited from the departments of general surgery, internal medicine, and emergency. An univariate then multivariate analysis (logistic regression) will allow us to select the variables associated with foot lesions in our study population. The parameters included in the logistic regression will be those with a p < 0.20 in the univariate analysis. Finally, a binary logistic regression analysis (with the calculation of Odds Ratios (OR) with confidence intervals (CI)) according to the backward stepwise method will identify the factors independently associated to foot lesions in diabetic patients.

Ethics and dissemination:

This research protocol will be submitted to the Ethics Committee of our institution for approval. The knowledge of factors causing diabetic foot will help to communicate with policymakers to raise the awareness in our community. Finally, it will help to prevent lower limb amputations.

Highlights

[Intra-anesthetic arterial hypotension in elderly patients during emergency surgery: what are the risk factors?]

L'anesthésie des personnes âgées de 65 ans et plus en urgence reste complexe. La survenue d'incidents peropératoires et en l'occurrence l'hypotension artérielle est conditionnée par leur état de santé initial et par la qualité de la prise en charge péri-opératoire. L'étude a pour but de déterminer l'incidence de l'hypotension artérielle per-anesthésique du sujet âgé pour une chirurgie urgente et évaluer l'implication de certains facteurs dans sa survenue: âge, sexe, terrain, classe ASA, technique anesthésique. Une étude rétrospective descriptive et analytique a été réalisée aux blocs des urgences chirurgicales du CHU Aristide LE DANTEC allant du 1er mars 2014 au 28 février 2015. Nous avons colligé 210 patients sur 224 anesthésies en urgence du sujet âgé de 65 ans et plus, soit 10,93%. On notait 101 hommes et 109 femmes dont les 64,3% présentaient au moins une tare. L'évaluation de l'état préopératoire des patients a été faite avec la classification de l'American Society of Anesthesiology (ASA), avec 71% pour les classes ASA 1 et 2 et 29% pour les classes ASA 3 et 4. L'anesthésie locorégionale était la technique anesthésique la plus pratiquée (56,7%). L'hypotension artérielle peropératoire a été objectivée chez 28 patients soit 13,33%, dont 16 cas sous anesthésie générale et 12 cas sous anesthésie locorégionale. Elle était plus fréquente chez les patients de classe ASA élevée et un peu moins sur terrain d'HTA et de cardiopathie sous-jacente. L'anesthésie du sujet âgé en urgence expose à un risque d'hypotension artérielle peropératoire non négligeable notamment chez les patients de classes ASA élevée. Sa prévention repose sur une bonne évaluation préopératoire et une prise en charge anesthésique adéquate.

A Quantitative Dynamic Simulation of Bremia lactucae Airborne Conidia Concentration above a Lettuce Canopy

Lettuce downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for B. lactucae airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing disease subprocesses (e.g., sporulation) and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of independent data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results show an accurate simulation of the trend and shape of B. lactucae temporal dynamics of airborne spore concentration. The model simulated hourly and daily peaks in airborne spore concentrations. More than 95% of the simulation runs, the daily-simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 94% of the simulation runs, the proportion of the linear variation in the hourly-observed values explained by the variation in the hourly-simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is the only dynamic model developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew understanding, forecasting and management.

Infection Efficiency of Four Phytophthora infestans Clonal Lineages and DNA-Based Quantification of Sporangia

The presence and abundance of pathogen inoculum is with host resistance and environmental conditions a key factor in epidemic development. Therefore, several spore-sampling devices have been proposed to monitor pathogen inoculum above fields. However, to make spore sampling more reliable as a management tool and to facilitate its adoption, information on infection efficiency and molecular tools for estimating airborne sporangia concentration are needed. Experiments were thus undertaken in a growth chamber to study the infection efficiency of four clonal lineages of P. infestans (US-8, US-11, US-23, and US-24) by measuring the airborne sporangia concentration and resulting disease intensity. The relationship between the airborne sporangia concentration and the number of lesions per leaf was exponential. For the same concentration, the sporangia of US-23 caused significantly more lesions than the sporangia of the other clonal lineages did. Under optimal conditions, an airborne sporangia concentration of 10 sporangia m⁻³ for US-23 was sufficient to cause one lesion per leaf, whereas for the other clonal lineages, it took 15 to 25 sporangia m⁻³ to reach the same disease intensity. However, in terms of diseased leaf area, there was no difference between clonal lineages US-8, US-23 and US-24. Also, a sensitive quantitative real-time polymerase chain reaction (qPCR) tool was developed to quantify P. infestans airborne sporangia with detection sensitivity of one sporangium. The specificity of the qPCR assay was rigorously tested for airborne inoculum and was either similar to, or an improvement on, other published PCR assays. This assay allows rapid and reliable detection and quantification of P. infestans airborne sporangia and thereby, facilitates the implementation of spores-sampling network.

Bremia lactucae Infection Efficiency in Lettuce is Modulated by Temperature and Leaf Wetness Duration Under Quebec Field Conditions

More than 80% of Canadian lettuce production is located in the province of Quebec. Yet most of our knowledge on the epidemiology of lettuce downy mildew (Bremia lactucae) is derived from controlled-condition experiments or field experiments conducted in subtropical climates and, thus, cannot readily be applied to Quebec lettuce production. The influence of temperature and leaf wetness duration on the infection efficiency (IE) of B. lactucae was studied for 4 years (2003, 2004, 2012, and 2013) under field and growth-chamber conditions. IE was defined as the ratio of the number of lesions/leaf to the airborne conidia concentration (ACC). B. lactucae ACC was measured with rotating-arm samplers three times/week. In addition, 72 lettuce trap plants/sampling day were exposed to the potential airborne B. lactucae inoculum and disease intensity was assessed after 7 days of incubation in greenhouse. Under growth-chamber conditions, an ACC of 1 conidium/m³ was sufficient to cause 1 lesion/leaf, and IE ranged from 0.25 to 1.00. Under field conditions, an ACC of 10 to 14 conidia/m³ was required to cause 1 lesion/leaf, and IE ranged from 0.02 to 0.10, except in 2004, when IE ranged from 0.03 to 1.00. IE increased with increasing leaf wetness duration but decreased with increasing temperature. Also, considering an observed average temperature range from 10 to 20°C in the area of Quebec, 2 h of leaf wetness was sufficient for infection by B. lactucae. Therefore, under Quebec lettuce production conditions, a leaf wetness period of 2 h and an ACC of 10 to 14 conidia/m³ can be used as risk indicators to facilitate disease management decisions. Also, under typical Quebec weather conditions, measuring both morning and evening leaf wetness events could be used to improve the reliability of leaf wetness duration as a downy mildew risk indicator. Further research is needed to validate these risk indicators for integration into management strategies.