Occurrence of potato virus Y on potato crops in São Paulo state and effects of virus infection on tuber production and plant emergence

Potato is one of the world's most important food crops, and its production is susceptible to losses caused by viruses such as potato virus Y (PVY), one of the most significant phytopathogens affecting potato-growing regions globally. This study aimed to: determine the incidence of PVY in potato cultivation areas in the state of São Paulo over the years 2023 and 2024; identify the predominant PVY strain in the analyzed areas; evaluate the impact of PVY infection on potato plants of the Agata and Asterix cultivars; and assess the effect of PVY on plant emergence. Based on biological and molecular analyses, the strain used in this study in the biological assays was identified as PVYNTN. The field survey conducted in 2023 and 2024 revealed an average PVY incidence of 15.3% and 13.6%, respectively. The predominant strain in these areas was PVYNTN. The biological assays showed that infection by this strain caused a marked reduction in tuber yield and plant emergence in both Agata and Asterix cultivars. Tuber production was reduced by 34.4–68.1% in Agata and 42.8–53.7% in Asterix. Plant emergence from tubers produced by PVY-infected plants also declined significantly. On average across two experiments, plant emergence from PVY-infected tubers was significantly reduced, from 77.5–26.3% in Agata and from 76.7–37.1% in Asterix. These findings highlight the negative impact of PVY on potato production, emphasizing the need for management strategies to control virus spread, particularly in regions where PVY incidence is high.

Hamdan, R.S., I.D. Ismail and I. Akel. 2021. Effect of Tomato Yellow Leaf Curl Virus Infection on Some Growth Indicators of Pepper Hybrids Grown Under Plastic House Conditions in Lattakia Governorate, Syria. Arab Journal of Plant Protection, 39(4): 309-316. https://doi.org/10.22268/AJPP-39.4.309316 This study aimed to evaluate the effect of Tomato yellow leaf curl virus (TYLCV) infection on some growth parameters of several pepper hybrids grown under protected cultivation along the Syrian coast. Four pepper hybrids (Capsicum annum) were tested, two hot (Lahab, Sirad) and two sweet (Nevada, Dallas) peppers. The research was carried out during the 2020-2021 growing season in a plastic house at the Agriculture Scientific Research Center in Lattakia, using a randomized complete block design, with 8 treatments, three replicates and 5 plants per replicate. The results obtained showed that the sweet pepper hybrids (Nevada, Dallas) were more sensitive to infection with Tomato yellow leaf curl virus than the hot pepper hybrids (Lahab, Sirad), without significant differences among them. The pepper hybrid Nevada did not show any apparent symptoms, and the effect of the virus on some growth parameters (number flowers, flower setting, and the leaf surface area) was evident in comparison with other hybrids, but the differences were not significant. The Dallas, Sirad and Lahab pepper hybrids showed visible symptoms in response to infection with infection rate of 93.33%, 80% and 80%, respectively. The effect of virus infection on the growth parameters of these hybrids was variable. The reduction in the flowers number of Nevada, Dallas, Cirad and Lahab after 45 days of infection was 33%, 31.10%, 10.23% and 5.07%, respectively, and also with a reduction in the number of flowers setting of 77.39%, 20.87%, 23.33% and 66.68%, respectively. The same was true for the leaf surface area, where reduction rate for the Nevada, Dallas, Sirad and Lahab hybrids 30 days after infection was 48.17%, 53.06%, 16.45% and 36.6%, respectively. Keywords: Tomato yellow leaf curl virus, pepper hybrids, growth parameter, host resistance, protected agriculture.

HIV is a major health concern with over 37 million individuals worldwide living with HIV. The onset of combination antiretroviral therapy (cART) patients with HIV (PWH) live longer but exhibit accelerated development of cardiovascular disease. Clinical evidence indicates that 35% of PWH exhibit hypertension, however, the etiopathology is still ill-defined. We plan to take advantage of a transgenic mouse model (Tg26) that mimics patients with a repressed virus, to test the hypothesis that viral infection independent of cART induces endothelial dysfunction and hypertension via a TNF-α mediated mechanism. Vascular reactivity was analyzed via wire myography and blood pressure (BP) recorded via radio-telemetry. Results showed that viral infection impaired aorta endothelium-dependent relaxation as reflected by a decrease in acetylcholine-mediated relaxation in both Tg26 mice (P<0.05) which was ameliorated with the NOX 1/4 inhibitor GKT 137831. Smooth muscle cell-dependent relaxation (SNP) and contractility to phenylephrine and KCl remained intact in Tg26 mice. Viral infection increased systolic, diastolic, and mean arterial pressure (MAP: male: WT=112.3±1.3 vs Tg26=121.9±4.0 mmHg/ female: WT=110.6±3.01/ Tg26=120.3±6.9 mmHg) and elevated heart rate (HR) in both sexes (p<0.05). We used atropine, propranolol, and hexamethonium in WT and Tg26 mice to investigate the contribution of the autonomic nervous system to hypertension. HR responses to both atropine (Female: +5.07±2.8% vs. male +4.3±5.4% of baseline) and propranolol (Female: 19.9±6.1% vs. male 12.0±4.3%) revealed no significance or sex differences in WT mice and no effects of viral infection on autonomic control of heart rate in Tg26 mice. BP responses to hexamethonium revealed no effect of sex or viral infection, supporting a limited contribution of the autonomic nervous system to hypertension in Tg26 mice. However, we found that TNFα inhibition with etanercept reduced mean arterial pressure in Tg26 mice to the level of the WT mice (WT=112.3±1.3, Treated=110.1±0.185) and improved endothelial function. These data indicate that HIV infection contributes to cardiovascular disease via inducing endothelial dysfunction and hypertension via NOX and TNFα-dependent mechanisms respectively.

Effects of irrigation and straw mulch on water use and tuber yield of potato in eastern India

The effect of 100 separate viral infections of the respiratory tract on pulmonary function was evaluated prospectively over an eight-year period in 84 patients with chronic obstructive pulmonary diseases and in eight normal subjects. Some viral infections were associated with small acute declines in forced vital capacity and/or 1-sec forced expiratory volume of 25–300 ml. These declines were detectable only during the 90-day period after infection. The greatest abnormalities of pulmonary function followed infections with influenza virus, and the mean acute changes in I-sec forced expiratory volume (- 118.5 ml) were significantly greater than expected (- 15.2 ml; P = 0.03). Smaller, statistically insignificant declines followed infections with parainfluenza virus, rhinovirus, adenovirus, and respiratory syncytial virus, and no changes were detectable after infections with coronavirus, herpes simplex virus, Mycoplasma pneumoniae, and Haemophilus influenzae. Long-term effects of influenza or other viral infections on the course of chronic obstructive pulmonary disease were not detected in this study population.

Lenalidomide (LEN) Therapy In Combination with Dexamethasone (DEX) Is Associated with a Low Incidence of Viral Infections

195 Development of a fetal porcine model for congenital viral infections in the developing CNS

The study aims to investigate the performance of a metagenomic next-generation sequencing (NGS)-based diagnostic technique for the identification of potential bacterial and viral infections and effects of concomitant viral infection on the survival rate of intensive care unit (ICU) sepsis patients. A total of 74 ICU patients with sepsis who were admitted to our institution from February 1, 2018 to June 30, 2019 were enrolled. Separate blood samples were collected from patients for blood cultures and metagenomic NGS when the patients' body temperature was higher than 38 °C. Patients' demographic data, including gender, age, ICU duration, ICU scores, and laboratory results, were recorded. The correlations between pathogen types and sepsis severity and survival rate were evaluated. NGS produced higher positive results (105 of 118; 88.98%) than blood cultures (18 of 118; 15.25%) over the whole study period. Concomitant viral infection correlated closely with sepsis severity and had the negative effect on the survival of patients with sepsis. However, correlation analysis indicated that the bacterial variety did not correlate with the severity of sepsis. Concurrent viral load correlates closely with the severity of sepsis and the survival rate of the ICU sepsis patients. This suggests that prophylactic administration of antiviral drugs combined with antibiotics may be beneficial to ICU sepsis patients.

Effect of a systemic virus infection on chloroplast function and structure

ABSTRACTPotato is a vital food source worldwide, but its production is frequently threatened by viral diseases. Tomato chlorosis virus (ToCV) primarily affects solanaceous crops, especially tomatoes. Although ToCV has been reported in potatoes, its relevance in this crop remains understudied in Brazil. This study evaluated the incidence of ToCV in major potato‐producing regions of São Paulo state and identified the predominant whitefly species. Transmission efficiency of ToCV by Bemisia tabaci MEAM1 and MED, vertical transmission via tubers, and the latent and incubation periods in potato plants were also investigated. Field surveys (2022–2024) showed a low ToCV incidence in potato crops. MEAM1 was the predominant whitefly species, whereas MED was detected at a single location. MED transmitted ToCV to potato plants of cv. Agata with higher efficiency (36.6%) than MEAM1 (10%), but no significant difference was observed for plants of cv. Asterix. Vertical transmission rates via tubers were high, reaching 76.7% for cv. Agata and 88.1% for cv. Asterix. The mean latent period was 8 days, with symptom expression approximately 35 days post‐inoculation. These findings suggest that ToCV is currently not widely distributed in potato crops in São Paulo state. However, the high vertical transmission rates and the demonstrated transmissibility by both MEAM1 and MED highlight the potential risks for future spread. Continued monitoring of potato fields and whitefly populations is crucial to mitigate the potential risk posed by ToCV in the region.

Teratogenic Effects of Neonatal Arenavirus Infection on the Developing Rat Cerebellum Are Abrogated by Passive Immunotherapy

In order to assess the effect of Pseudorabies virus (PRV) infection on the function of swine alveolar macrophages (AM), lung lavage cells were cultured, infected with one of six strains of PRV, and various activities were measured. Activity measurement included viability, phagocytosis of yeast, phagosome‐lysosome fusion, phagocytosis of opsonized particles, and superoxide release. AM were infected with 5 × 10‐3 PFU/cell, and the comparative assessment of functions was performed at 18‐20 h postinfection. Cell viability in PRV‐infected cultures ranged from 79 to 94% of the viability in noninfected cultures. Phagocytosis of yeast was significantly reduced only in the AM cultures infected with the strain S‐62. Phagosome‐lysosome fusion was depressed in cultures infected with the strains S‐62, 4892, 3816, and BUK. The phagocytosis of opsonized sheep red blood cells showed significant differences between noninfected and PRV‐infected cultures in all cases except cultures infected with the strain PRV‐C. The O2 release after stimulation with opsonized zymosan was significantly reduced in all the PRV‐infected cultures. The effect of PRV infection on AM functions that are related to the bacterial activity of such cells suggests that PRV‐induced AM dysfunction might have a role in the increased susceptibility of PRV‐infected pigs to bacterial pneumonia.

Management of nitrogen (N) use is necessary to promote maximum development and production of tubers. For this reason, chlorophyll meters have been used to make N-fertilizer recommendations in potato. An assay was carried out with increasing doses of N. To define the thresholds IV for potato crops, correlations among IV, ISN, RR, and N content had been established. IV is the green index of the leaf measured by the chlorophyll meter. This index estimates the chlorophyll content in the leaf and through this the N concentration in vegetal tissue, based on the assumption that N and chlorophyll content have a strong correlation. ISN is the sufficiency nitrogen index. It was determined as the relation between the green index reading of each experimental unit and the highest average green index reading of the assay. RR is the relative yield. It was calculated as the ratio between the yield of each treatment and the highest average yield of the assay. The results had shown that varieties did not present N deficiencies during the vegetative growth phase, with IV and ISN values respectively equal to 41 SPAD units and 93 percent. During the tuber bulking phase, the necessary IV and ISN thresholds to reach maximum yields, for N content equal to 3 percent, were, respectively, between 38.5 and 40.5 SPAD units and between 84 and 94.8 at 70 and 89 days after planting. We concluded that the chlorophyll meter is an appropriate tool to determine the nutritional status in potato crops.

Potato production through bio-resources: Long-term effects on tuber productivity, quality, carbon sequestration and soil health in temperate Himalayas

A cultura da batata (Solanum tuberosum tuberosum L.) é para o Brasil, de grande relevância econômica, particularmente para os Estados do Paraná, Rio Grande do Sul, Minas Gerais, São Paulo e Santa Catarina, os quais abrigam 95% dos 182.000 ha atualmente cultivados em três safras anuais (águas, secas e inverno). Dentre estes, o Paraná, apesar de não apresentar as maiores produtividades médias, possui, ao lado do Rio Grande do Sul, uma das maiores áreas cultivadas (aproximadamente 40.700 ha, em 1999). Neste contexto, a região Centro-Oeste Paranaense (Campos de Guarapuava), tem se destacado pela qualidade e produtividade dos tubérculos produzidos para consumo direto, industrialização e multiplicação em seus 7.000 ha cultivados. Tal fato é creditado às características edafoclimáticas regionais favoráveis à cultura, aliadas a introdução de novos cultivares, materiais de propagação de origem controlada, épocas de plantio adequadas, controle de pragas e doenças, altas dosagens de adubações, irrigação suplementar, manejo do solo e a interação destes. No entanto, face aos crescentes custos de produção, problemas ambientais e potenciais ganhos de produtividade e qualidade, se faz necessária a geração de informações que melhor subsidiem as decisões técnicas tomadas, no intuito de se promover esta cultura, particularmente no que concerne ao manejo da fertilidade do solo. Neste particular, a adubação da batata vem sendo efetuada de maneira indiscriminada através da aplicação de 3 a 4 Mg.ha-1 das formulações 40-140-80 e 40-160-80 (g.kg-1 de N-P2O5-K2O) não calibradas para as distintas situações encontradas, o que justifica a presente pesquisa. Desta forma, o objetivo deste trabalho foi avaliar o efeito de doses e do parcelamento de fertilizantes. Aplicação de doses de nitrogênio e de dois parcelamentos (Uréia), de doses de fósforo (Super fosfato triplo), de doses e fontes de potássio (KCl e K2SO4) sobre a produtividade e a qualidade de tubérculos, bem como sobre a sanidade da variedade Monalisa cultivadas na safra das águas (de novembro/98 a fevereiro/99). Para tanto foi conduzido um experimento sobre um Latossolo Bruno Distrófico, representativo da região, constituído por 18 tratamentos e quatro repetições, totalizando 72 parcelas de15 m2, constituídas por 4 linhas de 14 tubérculos e 5 m de comprimento, espaçadas por 0,75 m. Alcançou-se iguais produtividades e qualidade com dosagens de P2O5 inferiores às convencionalmente utilizadas pelos agricultores. O parcelamento da adubação nitrogenada favoreceu alguns dos parâmetros avaliados. A utilização de maiores doses de K2O e da fonte com enxofre favoreceu tanto a produtividade de tubérculos, quanto a qualidade e a sanidade da lavoura, o que poderia traduzirse em significativa contribuição à produção regional. Altas doses de K tenderam a aumentar a produtividade e reduzir os sintomas de sarna (Streptomyces scabies), canela preta (Erwinia carotovora carotovora), requeima (Phytophthora infestans), podridão seca (Fusarium solani) e pinta preta (Alternaria solani).