Studies on pathogenicity and host resistance of Exserohilum turcicum and Fusarium spp. on maize (Zea mays L.) cultivated in tropical and temperate climate zones

In the last 60 years, maize production has increased worldwide, reaching 1.14 billion tons in 2018. Maize production in Europe and South America was about 110 and 130 million tons in 2018, respectively. The demand for highly productive maize is observed in both tropical and temperate zones. Thus, the selection of plants from different maturity groups and high yield production are required from breeding programs. Besides highly productive plants, other agronomical traits such as resistance to pest and diseases needs to be considered during selection. Globally, some of the most important diseases affecting maize are northern corn leaf blight (NCLB), and Gibberella and Fusarium ear rot (GER and FER, respectively). Host resistance to E. turcicum is based on qualitative or quantitative sources, while for GER and FER only quantitative resistance is available in commercial hybrids. The quantitative resistance is more durable; however, it is more laborious to introgress into breeding lines. Northern corn leaf blight (NCLB) is an important disease in maize-producing areas worldwide. The symptoms of NCLB, whose causal agent is the ascomycete Exserohilum turcicum (teleomorph Setosphaeria turcica), are characterized by elliptical grey-green lesions. High disease severity can cause yield losses up to 40% (Levy und Pataky 1992). The main control methods applied for NCLB control are fungicide applications and the cultivation of resistant hybrids. Qualitative resistance has been widely used to control NCLB in many countries through the deployment of Ht genes. The race assessment from isolates collected in Argentina and Brazil during 2017, 2018 and 2019 revealed a high frequency of race 0 isolates (83% and 65% in Argentina and Brazil, respectively). In those countries, Ht genes are not being used extensively to control NCLB. This information is important for breeding programs and may help with disease management. Favorable weather conditions for NCLB development are long dewy periods and moderate temperatures. These optimum conditions for disease development can be observed in temperate regions as well as in mid-altitude regions in the tropics. The comparison of E. turcicum isolates in response to temperatures varied in vitro and in vivo between 15 and 30°C demonstrating that the aggressiveness of South American isolates was higher than that of European isolates. The multivariate analysis confirmed that South American isolates are better adapted to higher temperatures by grouping them separately. In conclusion, E. turcicum populations may adapt quickly to environmental changes. The plasticity in adapting to environmental conditions of E. turcicum may decrease the durability of resistance. Studies on the pathogenesis of E. turcicum in the differential maize line B37 with and without the resistance genes Ht1, Ht2, Ht3 and Htn1 were conducted for different stages of infection and disease development from penetration (0-1 dpi), until full symptom expression (14-18 dpi). Symptomological analysis demonstrated that Ht1 expressed necrotic lesions with chlorosis, Ht2 displayed chlorosis and small lesions, Ht3 resulted in chlorotic spots and Htn1 express wilt-type lesions. Histological studies conducted with Chlorazol Black E staining indicated that the pathogen was able to penetrate xylem vessels at 6 dpi in compatible interactions and strongly colonized the mesophyll at 12 dpi, which is considered the crucial process differentiating susceptibility from resistance. Additionally, lower disease levels, low fungal DNA content at 10 and 14 dpi, and the delayed progress of infection in compatible interactions with resistant lines imply that the Ht genes are associated with or confer additional quantitative resistance. Physiological studies showed a reduction in the photosynthetic rate, transpiration, stomatal conductance and instantaneous carboxylation efficiency in the incompatible interaction at 5 dpi. At 14 dpi, the strong necrosis displayed in the resistance reaction by B37Ht1 resulted in the reduction of photosynthesis as observed for B37. However, leaf area, aerial and root dry biomass were not reduced in inoculated plants at 28 dpi. Additionally, high rates of peroxide localization were observed in inoculated plants at 3 and 6 dpi, corroborating data on peroxidase activity. In fact, Ht1, Ht3 and Htn1 reduced pathogen sporulation whereas Ht2 reduced the number and size of lesions. All phenotypical studies demonstrated that Ht genes confer distinct resistance mechanisms. The resistance phenotype expressed by Ht2 may change according to environmental conditions. There are reports on the influence of low post-inoculation temperature (22/18°C) and low light intensity (324 and 162 µmol m-2 s-1) on resistance expressed by this gene. Our objective was to prove that temperature has no influence on the resistance conferred by the Ht2-gene against E. turcicum. Therefore, maize plants were pre-exposed to warm (30/25°C) and moderate (20/15°C) temperature regimes for 10 days before inoculation. There was no influence of pre-inoculation temperature on the expression of resistance by Ht2. The resistance conferred by the Ht2 gene was confirmed by quantifying the fungal DNA in planta at 21 dpi. Changes in resistance phenotypes may be related to pathogen aggressiveness factors. GER and FER can cause qualitative yield losses due to mycotoxin production. GER is mainly caused by Fusarium graminearum and FER by F. verticillioides. GER is more frequent in regions with colder temperatures and high precipitation, and is more prevalent in Germany, while FER occurrence is favored by warm and dry weather conditions and is more prevalent in Brazil. In general, F. graminearum was more aggressive than F. verticillioides, which support affirmations about systemic colonization by F. verticillioides. With regard to tropical and temperate hosts, the German isolates were more aggressive than the Brazilian isolates when inoculated in the tropical lines. Additionally, tropical lines pre-exposed to higher temperatures presented higher disease severity when compared to plants exposed to mild temperatures. In general, the cultivation of resistant hybrids remains a successful strategy for controlling NCLB, GER and FER. The optimization of resistance resources is fundamental for maintaining the durability of resistance.2021-11-1

Cardiac damage biomarkers and heart rate variability following a 118-km mountain race: relationship with performance and recovery

This study aimed to assess the release of cardiac damage biomarkers jointly with cardiac autonomic modulation after a mountain ultramarathon. Such knowledge and the possible relationship of these markers with race time is of primary interest to establish possible recommendations upon athletes’ recovery and return to training following these competitions. Forty six athletes enrolled in the Penyagolosa Trails CSP115 race (118 km and a total positive elevation of 5439 m) took part in the study. N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitive cardiac troponin T (hs-TNT) concentrations as well as linear and nonlinear heart rate variability (HRV) were evaluated before and after the race. NT-proBNP and hs-TNT significantly increased post-race; fifty percent of the finishers surpassed the Upper Reference Limit (URL) for hs-TNT while 87% exceeded the URL for NT-proBNP. Overall and vagally-mediated HRV were diminished and cardiac autonomic modulation became less complex and more predictable following the race. More pronounced vagal modulation decreases were associated with higher levels of postexertional NT-proBNP. Moreover, rise in hs-TNT and NT-proBNP was greater among faster runners, while pre-race overall and vagally-mediated HRV were correlated with finishing time. Participation in a 118-km ultratrail induces an acute release of cardiac damage biomarkers and a large alteration of cardiac autonomic modulation. Furthermore, faster runners were those who exhibited a greater rise in those cardiac damage biomarkers. In light of these findings, an appropriate recovery period after ultraendurance races appears prudent and particularly important among better performing athletes. At the same time, HRV analysis is shown as a promising tool to assess athletes’ readiness to perform at their maximum level in an ultraendurance race

First Results from the rapid-response spectrophotometric characterization of Near-Earth Objects

As part of our multi-observatory, multi-filter campaign, we present \rmi color observations of 82 Near-Earth Objects (NEOs) obtained with the RATIR instrument on the 1.5m robotic telescope at the San Pedro Martir's National Observatory in Mexico. Our project is particularly focused on rapid response observations of small ($\lesssim 850$ m) NEOs. The rapid response and the use of spectrophotometry allows us to constrain the taxonomic classification of NEOs with high efficiency. Here we present the methodology of our observations and our result, suggesting that the ratio of C-type to S-type asteroids in a size range of $\sim$30-850m is 1.1, which is in accordance with our previous results. We also find that 10$\%$ of all NEOs in our sample are neither C- nor S-type asteroidsComment: 31 pages, 4 tables, 10 figure

Pulmonary and Inspiratory Muscle Function Response to a Mountain Ultramarathon

The study aimed to provide within-race data on the time course of pulmonary function during a mountain ultramarathon (MUM). Additionally, we wanted to assess possible sex differences regarding pre- to post-race change in pulmonary and inspiratory muscle function. Lastly, we were interested in evaluating whether changes in respiratory function were associated with relative running speed and due to general or specific fatigue. 47 athletes (29 males and 18 females; 41 ± 5 years) were submitted to a cardiopulmonary exercise test (CPET) before a 107-km MUM. Spirometric variables: forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC and peak expiratory flow (PEF); maximal inspiratory pressure (MIP); squat jump (SJ) and handgrip strength (HG) were assessed before and after the race. Additionally PEF was measured at three aid stations (33rd, 66th and 84th km) during the race. PEF declined from the 33rd to the 66th km (p = 0.004; d = 0.72) and from the 84th km to the finish line (p = 0.003; d = 0.90), while relative running speed dropped from the first (0-33 km) to the second (33-66 km) race section (p < 0.001; d = 1.81) and from the third (66-84 km) to the last race section (p < 0.001; d = 1.61). Post-race, a moderate reduction was noted in FVC (-13%; p < 0.001; d = 0.52), FEV1 (-19.5%; p < 0.001; d = 0.65), FEV1/FVC (-8.4%; p = 0.030; d = 0.59), PEF (- 20.3%; p < 0.001; d = 0.58), MIP (-25.3%; p < 0.001; d = 0.79) and SJ (-31.6%; p < 0.001; d = 1.42). Conversely, HG did not change from pre- to post-race (-1.4%; p = 0.56; d = 0.05). PEF declined during the race in parallel with running speed drop. No sex differences were noted regarding post-race respiratory function, except that FEV1/FVC decay was significantly greater among women. The magnitude of pre- to post-race respiratory function decline was uncorrelated with relative running speed

Olefin Dimerization and Isomerization Catalyzed by Pyridylidene Amide Palladium Complexes

A series of cationic palladium complexes [Pd(N^N')Me(NCMe)]+ was synthesized, comprising three different N^N'-bidentate coordinating pyridyl-pyridylidene amide (PYA) ligands with different electronic and structural properties depending on the PYA position (ortho-, meta-, and para-PYA). Structural investigation in solution revealed cis/trans isomeric ratios that correlate with the donor properties of the PYA ligand, with highest cis ratios for the complex having the most donating ortho-PYA ligand and lowest ratios for that with the weakest donor para-PYA system. The catalytic activity of the cationic complexes [Pd(N^N')Me(NCMe)]+ in alkene insertion and dimerization showed a strong correlation with the ligand setting. While complexes bearing more electron-donating meta- and ortho-PYA ligands produced butenes within 60 and 30 min respectively, the para-PYA complex was much slower and only reached 50% conversion of ethylene within 2 h. Likewise, insertion of methyl acrylate as polar monomer was more efficient with stronger donor PYA units, reaching a 32% ratio of methyl acrylate vs ethylene insertion. Mechanistic investigations about the ethylene insertion allowed to detect, for the first time, by NMR spectroscopy both cis- and trans-Pd-ethyl intermediates and, furthermore, revealed a trans-to-cis isomerization of the Pd\u2013ethyl resting state as the rate-limiting step for inducing ethylene conversion. These PYA palladium complexes induce rapid double bond isomerization of terminal to internal alkenes through a chain walking process, which prevents both polymerization and also the conversion of higher olefins, leading selectively to ethylene dimerization

Penetration by Botryosphaeriaceae species in avocado, guava and persimmon fruit during postharvest

Botryosphaeriaceae species have a wide host range and a worldwide distribution. These fungal species can colonize several plant organs, such as the trunk, leaves and fruit. Some Botryosphaeriaceae species cause important diseases on persimmon, avocado and guava fruit. However, there is a lack of information regarding the mechanisms of penetration by Botryosphaeriaceae species on these tropical and subtropical fruits. This study aimed to better understand the mechanisms involved in fungal penetration, host specificity and aggressiveness of Botryosphaeria dothidea, Lasiodiplodia pseudotheobromae and Neofusicoccum parvum on avocado (Persea americana), guava (Psidium guajava) and persimmon (Diospyros kaki) fruit. Scanning electron microscopy (SEM) image analysis showed that in avocado fruit, the three studied Botryosphaeriaceae species penetrated through lenticels. In guava fruit, penetration through stomata was verified for Botryosphaeria dothidea and Neofusicoccum parvum. In persimmon fruit, an appressoria-like structure was observed for B. dothidea, which suggests direct penetration. Disease incidence in wounded fruit was 24% higher than in non-wounded fruit. L. pseudotheobromae and N. parvum showed differences in aggressiveness in guava fruit. The longest incubation period was observed for N. parvum inoculated on guava, with an average of 4.5 days, and the shortest incubation period was verified for B. dothidea inoculated on avocado, with an average of 2.8 days. The area under the disease progress curve (AUDPC) did not differ between Botryosphaeriaceae species on avocado, whereas on guava and persimmon fruit, the AUDPC was lower for B. dothidea. The information regarding penetration mechanisms and aggressiveness is important to improve postharvest disease control strategies.EEA BalcarceFil: Ludwig Navarro, Barbara. University of São Paulo. Luiz de Queiroz Agriculture College. Department of Plant Pathology and Nematology; Brasil.Fil: Edwards Molina, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Edwards Molina, Juan Pablo. University of São Paulo. Luiz de Queiroz Agriculture College. Department of Plant Pathology and Nematology; Brasil.Fil: Nogueira Júnior, Antonio F. University of São Paulo. Luiz de Queiroz Agriculture College. Department of Plant Pathology and Nematology; Brasil

Comparative digital study of two cranial rotation methods of the proximal fragment on the center of rotation of angulation-based leveling osteotomy planning with different tibial distal anatomical axes

The center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) technique was developed for cranial cruciate ligament (CrCL) rupture treatment, aiming to modify the mechanical-anatomical angle (AMA), which is described as a predictive risk factor for the disease and is recommended to be taken into consideration when one is choosing a surgical procedure for tibial plateau slope alteration. Identifying a tibial distal anatomical axis (DAA) is essential in CBLO surgical planning and measuring AMA amplitude. The aim of this study was: to evaluate two methods of cranial rotation of the proximal fragment using four different tibial distal anatomical axes for digital planning on the CBLO technique, comparing its effectiveness in achieving the desired tibial plateau angle (TPAd) and closing the AMA angle. Tibial measurements were made with the vPOP pro software using 30 mediolateral radiographs of canine stifles. The DAA described by four authors was used based on the amount of Rotation completed (Rc) for each. The rotation methods evaluated were: 1) commercial CBLO table (RT) and 2) overlapping the tip of the intercondylar eminence with the corresponding DAA line (RE). The TPAd to be obtained was fixed at 10°, and the final AMA to be achieved at 0°. The mean values and standard deviations of the final TPA and final AMA with the rotation method were TPA(RT)f(%TPAd), TPA(RE)f(%TPAd), AMA(RT)f(%AMAzero), AMA(RE)f(%AMAzero). The results of each author were Hulse 10.0 ± 0.3(46.6%), 9.9 ± 0.1(60%), 0.3 ± 0.3(33.3%), 0.3 ± 0.3(13.3%), Osmond 10.1 ± 0.2(75%), 10,1 ± 0.2(83.3%), 0.4 ± 0.4(33.3%), 0.4 ± 0.3(8,3%), Miles 10.0 ± 0.1(66.6%), 10.0 ± 0.1(75%), 0.2 ± 0.1(16.6%), 0.2 ± 0.1(8.3%), Tudury 9.6 ± 0.6(31.2%), 9.5 ± 0.2(31.2%), 1.0 ± 0.7(18.7%), 1.0 ± 0.6(12.5%), respectively. The initially described RT obtained a higher percentage of AMA at zero degrees. Therefore, the RE method is discarded for use as an alternative to CBLO planning.A técnica da osteotomia de nivelamento baseada no centro de rotação de angulação (CORA) chamada CBLO foi desenvolvida para o tratamento da ruptura do ligamento cruzado cranial (RLCCr), visando modificar o ângulo mecânico-anatômico (AMA), o qual é descrito como fator de risco preditivo para a doença e é recomendado que seja levado em consideração na escolha do procedimento cirúrgico para alteração da inclinação do platô tibial. A identificação de um eixo anatômico distal da tíbia (EAD) é um passo fundamental no planejamento cirúrgico da CBLO e para avaliar a amplitude do AMA. O objetivo deste estudo foi: avaliar dois métodos de rotação craniana do fragmento proximal utilizando quatro eixos anatômicos distais tibiais diferentes para o planejamento digital da técnica CBLO, comparando sua eficácia para atingir o ângulo do platô tibial desejado (TPAd) e no fechamento do AMA. As medidas tibiais foram feitas no software vPOP pro usando 30 radiografias medio-laterais de joelhos caninos. Foi utilizado o EAD descrito por quatro autores diferentes, baseada na quantidade de Rotação concluída (Rc) para cada um deles. Os métodos de rotação avaliados foram: 1) tabela comercial de CBLO (RT) e 2) sobreposição da ponta da eminência intercondilar com a linha EAD correspondente (RE). O TPAd a ser obtido foi fixado em 10° e o AMA final a ser alcançado em 0º. A média e o desvio padrão do TPA final e AMA final com o método de rotação: TPA(RT)f(%TPAd), TPA(RE)f(%TPAd), AMA(RT)f(%AMAzero), AMA(RE)f(%AMAzero) e o resultado de cada autor foram Hulse 10,0 ± 0,3(46,6%), 9,9 ± 0,1(60%), 0,3 ± 0,3(33,3%), 0,3 ± 0,3(13,3%), Osmond 10,1 ± 0,2(75%), 10,1 ± 0,2(83,3%), 0,4 ± 0,4(33,3%), 0,4 ± 0,3(8,3%), Miles 10,0 ± 0,1(66,6%), 10,0 ± 0,1(75%), 0,2 ± 0,1(16,6%), 0,2 ± 0,1(8,3%), Tudury 9,6 ± 0,6(31,2%), 9,5 ± 0,2(31,2%), 1,0 ± 0,7(18,7%), 1,0 ± 0,6(12,5%) respectivamente. O RT inicialmente descrito obteve um percentual maior de AMA em zero graus, portanto, o método RE é descartado para utilizá-lo como alternativa no planejamento CBLO

Ultra Trail Performance is Differently Predicted by Endurance Variables in Men and Women

The study aimed to assess the relationship between peak oxygen uptake, ventilatory thresholds and maximal fat oxidation with ultra trail male and female performance. 47 athletes (29 men and 18 women) completed a cardiopulmonary exercise test between 2 to 4 weeks before a 107-km ultra trail. Body composition was also analyzed using a bioelectrical impedance weight scale. Exploratory correlation analyses showed that peak oxygen uptake (men: r=–0.63, p=0.004; women: r=–0.85, p < 0.001), peak speed (men: r=–0.74, p < 0.001; women: r=–0.69, p=0.009), speed at first (men: r=–0.49, p=0.035; women: r=–0.76, p=0.003) and second (men: r=–0.73, p < 0.001; women: r=–0.76, p=0.003) ventilatory threshold, and maximal fat oxidation (men: r=–0.53, p=0.019; women: r=–0.59, p=0.033) were linked to race time in male and female athletes. Percentage of fat mass (men: r=0.58, p=0.010; women: r=0.62, p= 0.024) and lean body mass (men: r=–0.61, p=0.006; women: r=–0.61, p=0.026) were also associated with performance in both sexes. Subsequent multiple regression analyses revealed that peak speed and maximal fat oxidation together were able to predict 66% of male performance; while peak oxygen uptake was the only statistically significant variable explaining 69% of the variation in women’s race time. These results, although exploratory in nature, suggest that ultra trail performance is differently predicted by endurance variables in men and women

Pacing and Body Weight Changes During a Mountain Ultramarathon: Sex Differences and Performance

The study was aimed at comparing pacing adopted by males and females in a 107-km mountain ultramarathon and assessing whether pacing-related variables were associated with intracompetition body weight changes and performance. Forty-seven athletes (29 males; 18 females) were submitted to a cardiopulmonary exercise test before the race. Athletes were also weighted before the start of the race, at three midpoints (33 km, 66 km and 84 km) and after the race. Pacing was analyzed using absolute and relative speeds and accelerometry-derived sedentary time spent during the race. Results showed that females spent less sedentary time (4.72 ± 2.91 vs. 2.62 ± 2.14%; p = 0.035; d = 0.83) and displayed a smaller body weight loss (3.01 ± 1.96 vs. 4.37 ± 1.77%; p = 0.048; d = 0.77) than males. No significant sex differences were revealed for speed variability, absolute and relative speed. In addition, finishing time was correlated with: speed variability (r = 0.45; p = 0.010), index of pacing (r = -0.63; p < 0.001) and sedentary time (r = 0.64; p < 0.001). Meanwhile, intracompetition body weight changes were related with both the absolute and relative speed in the first and the last race section. These results suggest that females, as compared with males, take advantage of shorter time breaks at aid stations. Moreover, performing a more even pacing pattern may be positively associated with performance in mountain ultramarathons. Finally, intracompetition body weight changes in those races should be considered in conjunction with running speed fluctuations

Inspiratory and Lower-Limb Strength Importance in Mountain Ultramarathon Running. Sex Differences and Relationship with Performance

The study was aimed at comparing lower-limb strength and respiratory parameters between male and female athletes and their interaction with performance in a 107 km mountain ultramarathon. Forty seven runners (29 males and 18 females; mean ± SD age: 41 ± 5 years) were enrolled. Lower-limb strength assessment comprised a squat jump test, an ankle rebound test, and an isometric strength test. Respiratory assessment included pulmonary function testing and the measurement of maximal inspiratory pressure. Male athletes performed largely better in the squat jump (26 ± 4 vs. 21 ± 3 cm; p < 0.001; d = 1.48), while no sex differences were found in the other two lower-limb tests. Concerning the respiratory parameters, male athletes showed largely greater values in pulmonary expiratory variables: forced vital capacity (5.19 ± 0.68 vs. 3.65 ± 0.52 L; p < 0.001; d = 2.53), forced expiratory volume in 1 s (4.24 ± 0.54 vs. 2.97 ± 0.39 L; p < 0.001; d = 2.69), peak expiratory flow (9.9 ± 1.56 vs. 5.89 ± 1.39 L/min; p < 0.001; d = 2.77) and maximum voluntary ventilation in 12 s (171 ± 39 vs. 108 ± 23 L/min; p < 0.001; d = 1.93); while no sex differences were identified in maximal inspiratory pressure. Race time was associated with ankle rebound test performance (r = −0.390; p = 0.027), isometric strength test performance (r = −0.349; p = 0.049) and maximal inspiratory pressure (r = −0.544; p < 0.001). Consequently, it seems that athletes competing in mountain ultramarathons may benefit from improving lower-limb isometric strength, ankle reactive strength and inspiratory muscle strength. Nevertheless, further interventional studies are required to confirm these exploratory results. In addition, the fact that the magnitude of the sex difference for isometric strength was minor, as compared with the other strength tests, could represent one of the factors explaining why the performance gap between males and females is reduced in ultramarathons