Efeito da fertilização nitrogenada e fungicida no manejo de doenças e na qualidade da farinha de cultivares precoces do trigo.

No Brasil, a região Sul é a principal produtora de trigo e o estado do Rio Grande do Sul representa 36% da produção nacional. Nesta região, as condições climáticas são favoráveis a doenças durante todo o período de desenvolvimento das plantas de trigo. Com a finalidade de reduzir os danos, o manejo das doenças é realizado com diferentes estratégias, tais como rotação de culturas, cultivares resistentes, sementes sadias, ajustes na fertilização e aplicação de fungicidas. A fertilização nitrogenada influencia a intensidade de doenças, porém são escassos os estudos investigando o seu impacto dentro de um programa de manejo integrado de doenças em trigo. Portanto, neste trabalho foi avaliado o efeito da fertilização nitrogenada e da aplicação de fungicida, em duas cultivares precoces de trigo, na intensidade de doenças, no rendimento, e na qualidade do grão e da farinha. O experimento foi realizado no Centro Agropecuário da Palma, Universidade Federal de Pelotas-Brasil, durante as safras 2019 e 2020. O delineamento experimental usado foi parcelas subdivididas com quatro repetições, sendo a parcela principal o tratamento sem ou com a aplicação de fungicida (bixafem+protioconazol+trifloxistrobina). As subparcelas foram as cultivares de trigo TbioAudaz (moderada resistência a doenças e trigo melhorador) e TbioTibagi (suscetível a doenças e trigo pão). As sub - subparcelas foram três doses de nitrogênio: baixo N: 70 kg ha-1, N recomendado: 130 kg ha-1 e alto N: 200 kg ha-1. A análise estatística empregou modelo linear de efeitos mistos. As doenças, que ocorreram, devido ao inóculo presente no ambiente, fora m quantificadas (severidade) desde a emergência das plântulas até a maturação fisiológica. Com estes dados, a área abaixo da curva de progresso da doença (AACPD) foi calculada para a mancha amarela, oídio, ferrugem da folha e giberela. Durante a fase de desenvolvimento do grão (ZGS80) foi determinada a eficiência do fotossistema II (Fv/Fm) associada aos processos fotossintéticos. Além disso, foi determinado a produtividade, peso hectolítrico (PH), proteína em base seca (PS), número de q ueda do grão (NQG) e glúten seco (GS). Os resultados mostraram que a cultivar moderadamente resistente e o aumento da fertilização nitrogenada reduziram significativamente (p<0,05) a AACPD da mancha amarela. No entanto, maior AACPD de oídio foi observada com altas doses de nitrogênio. Para ferrugem da folha e giberela, a cultivar moderadamente resistente e a aplicação de fungicida reduziram significativamente (p<0,05) a AACPD. O efeito fungicida foi menor para a TbioAudaz, em comparação com a TbioTibagi,devido à maior resistência da primeira cultivar. Houve efeito significativo das interações cultivar×nitrogênio e cultivar×fungicida para o rendimento de grãos, PH, PS, NQG e GS. A Fv/Fm foi menor para a cultivar TbioTibagi sem aplicação de fungicida, o que está diretamente relacionado às disfunções fotossintéticas decorrentes das doenças e, consequentemente,impactando a produtividade e a qualidade do grão e da farinha. Neste estudo verificou-se que a dose recomendada de 130 kg ha-1 tem efeito similar à dose de 200 kg ha-1 na redução da mancha amarela e na produtividade para ambas as cultivares, mantendo parâmetros adequados de qualidade da farinh

Silicon uptake by a pasture grass experiencing simulated grazing is greatest under elevated precipitation

Background Grasses are hyper-accumulators of silicon (Si) and often up-regulate Si following herbivory. Positive correlations exist between Si and plant water content, yet the extent to which Si uptake responses can be mediated by changes in soil water availability has rarely been studied and never, to our knowledge, under field conditions. We used field-based rain-exclusion shelters to investigate how simulated grazing (shoot clipping) and altered rainfall patterns (drought and elevated precipitation, representing 50% and 150% of ambient precipitation levels, respectively) affected initial patterns of root- and shoot-Si uptake in a native Australian grass (Microlaena stipoides) in Si-supplemented and untreated soils. Results Si supplementation increased soil water retention under ambient and elevated precipitation but not under drought, although this had little effect on Si uptake and growth (tiller numbers or root biomass) of M. stipoides. Changes in rainfall patterns and clipping had strong individual effects on plant growth and Si uptake and storage, whereby clipping increased Si uptake by M. stipoides under all rainfall treatments but to the greatest extent under elevated precipitation. Moreover, above-ground–below-ground Si distribution only changed following elevated precipitation by decreasing the ratio of root:shoot Si concentrations. Conclusions Results highlight the importance of soil water availability for Si uptake and suggest a role for both active and passive Si transport mechanisms. Such manipulative field studies may provide a more realistic insight into how grasses initially respond to herbivory in terms of Si-based defence under different environmental conditions

L'Italia come modello per l'Europa e per il mondo nelle politiche sanitarie per il trattamento dell'epatite cronica da HCV

The World Health Organization foresees the elimination of HCV infection by 2030. In light of this and the curre nt, nearly worldwide, restriction in direct-acting agents (DAA) accessibility due to their high price, we aimed to evaluate the cost-effectiveness of two alternative DAA treatment policies: Policy 1 (universal): treat all patients, regardless of the fibrosis stage; Policy 2 (prioritized): treat only priori tized patients and delay treatment of the remaining patients until reaching stage F3. T he model was based on patient’s data from the PITER cohort. We demonstrated that extending HC V treatment of patients in any fibrosis stage improves health outcomes and is cost-effective

Economic consequences of investing in anti-HCV antiviral treatment from the Italian NHS perspective : a real-world-based analysis of PITER data

OBJECTIVE: We estimated the cost consequence of Italian National Health System (NHS) investment in direct-acting antiviral (DAA) therapy according to hepatitis C virus (HCV) treatment access policies in Italy. METHODS: A multistate, 20-year time horizon Markov model of HCV liver disease progression was developed. Fibrosis stage, age and genotype distributions were derived from the Italian Platform for the Study of Viral Hepatitis Therapies (PITER) cohort. The treatment efficacy, disease progression probabilities and direct costs in each health state were obtained from the literature. The break-even point in time (BPT) was defined as the period of time required for the cumulative costs saved to recover the Italian NHS investment in DAA treatment. Three different PITER enrolment periods, which covered the full DAA access evolution in Italy, were considered. RESULTS: The disease stages of 2657 patients who consecutively underwent DAA therapy from January 2015 to December 2017 at 30 PITER clinical centres were standardized for 1000 patients. The investment in DAAs was considered to equal €25 million, €15 million, and €9 million in 2015, 2016, and 2017, respectively. For patients treated in 2015, the BPT was not achieved, because of the disease severity of the treated patients and high DAA prices. For 2016 and 2017, the estimated BPTs were 6.6 and 6.2 years, respectively. The total cost savings after 20 years were €50.13 and €55.50 million for 1000 patients treated in 2016 and 2017, respectively. CONCLUSIONS: This study may be a useful tool for public decision makers to understand how HCV clinical and epidemiological profiles influence the economic burden of HCV

Oxalic acid-mediated biochemical and physiological changes in the common bean-Sclerotinia sclerotiorum interaction

The success of Sclerotinia sclerotiorum infection relies mainly on the production of the non-host selective toxin named oxalic acid (OA). This toxin is known to play multiple roles in a host infected by the fungus, but its effect on photosynthesis and the antioxidant system of common bean plants remain elusive. Therefore, we performed detailed analysis of leaf gas exchange, chlorophyll a fluorescence, activities of antioxidant enzymes, concentrations of reactive oxygen species and photosynthetic pigments to investigate the OA's role during the S. sclerotiorum pathogenesis. To achieve this goal, common bean plants were sprayed with water or with oxalic acid (referred to as –OA and +OA plants, respectively) and either non-challenged or challenged with a wild-type (WT) or an OA-defective mutant (A4) of S. sclerotiorum. Irrespective of OA spray, the WT isolate was more aggressive than the A4 isolate and spraying OA increased OA concentration in the leaflets as well as the aggressiveness of both isolates. Biochemical limitations were behind S. sclerotiorum-induced photosynthetic impairments notably for the +OA plants inoculated with the WT isolate. Inoculated plants were not able to fully capture and exploit the collected energy due to the degradation of photosynthetic pigments. Photoinhibition of photosynthesis and photochemical dysfunctions were potentiated by OA. Higher activities of superoxide dismutase, peroxidase and ascorbate peroxidase besides reductions on catalase activity were noticed for plants inoculated with the WT isolate. OA was able to counteract most of the increases in the activities of antioxidant enzymes thereby increasing the generation of superoxide and hydrogen peroxide and the concurrent damage to the membranes of host cells as evidenced by the high malondialdehyde concentration. In conclusion, OA was found to enhance biochemical limitations to photosynthesis, photochemical dysfunctions and oxidative stress in the leaflets of common bean plants infected by S. sclerotiorum