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We aimed to evaluate the facilitation effects of an aluminum (Al) hyperaccumulator species bearing cluster roots, Gevuina avellana, on the seedling growth and performance of an Al-intolerant and phosphorus (P)- deficient-sensitive plant, Vaccinium corymbosum. For this, seedlings of G. avellana and V. corymbosum were grown alone or together as follows: i) two G. avellana seedlings, ii) one G. avellana + one V. corymbosum and iii) two V. corymbosum, in soil supplemented with Al (as Al2(SO4)3) and in the control (without Al supplementation). We determined relative growth rate (RGR), photosynthetic rate, chlorophyll concentration, lipid peroxidation and Al and nutrient concentration [Nitrogen (N), P, potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), and sulfur (S)] in leaves and roots of both species. The results showed that, in general, G. avellana did not assist V. corymbosum to enhance its RGR nor reduce its Al uptake. However, G. avellana assisted V. corymbosum in enhanced N acquisition and, consequently, to increase its chlorophyll concentration and photosynthetic rate. Besides, V. corymbosum had lower lipid peroxidation in leaves when grown in the soil with high Al supplementation in association with G. avellana. Our results suggest a facilitating effect of G. avellana to V. corymbosum when grown in soils with high Al concentration, by enhancing chlorophyll concentrations and photosynthetic rate, and decreasing the oxidative damage to lipids. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this paper is to evaluate to the safety, feasibility and efficacy of a novel treatment for transsphincteric cryptoglandular fistula: injection of autologous plasma rich in growth factors (PRGF) into the fistula tract accompanied by sealing using a fibrin plug created from the activated platelet-poor fraction of the same plasma. Method: This article is a prospective, phase II clinical trial. The procedure was externally audited. Thirty-six patients diagnosed with transsphincteric fistula-in-ano were included. All patients underwent follow-up examinations at 1 week and again at 3, 6 and 12 months after discharge. Main outcome measures safety (number of adverse events), feasibility and effectiveness of the treatment. Results: A total of 36 patients received the study treatment, with the procedure found to be feasible in all patients. A total of seven adverse events (AE) related to the injected product or surgical procedure were identified in 4 of 36 patients. At the end of the follow-up period (12 months), 33.3% of patients (12/36) had achieved complete fistula healing and 11.1% of patients (4/36) had achieved partial healing. In total, this amounted to 44.4% of patients (16/36) being asymptomatic at final follow-up. In successfully healed patients, a gradual reduction in pain was observed, as measured using a Visual Analog Scale (VAS) (p = 0.0278). Compared to baseline, a significant improvement in Wexner score was seen in patients achieving total or partial healing of the fistula (p = 0.0195). Conclusions: The study treatment was safe and feasible, with apparently modest efficacy rates. Continence and pain improvement following treatment may be considered predictive factors for healing. [ABSTRACT FROM AUTHOR]

Nothofagus dombeyi (Mirb.) Blume and Nothofagus nitida (Phil.) Krasser are closely related evergreen trees native to south central Chile. Nothofagus dombeyi is a pioneer in habitats subject to high daytime irradiances and nighttime freezing temperatures and has a wider altitudinal and latitudinal distribution than N. nitida, which is restricted to more oceanic climates. We postulated that N. dombeyi has a greater cold-acclimation capacity, expressed as a greater capacity to maintain a functional photosynthetic apparatus at low temperatures, than N. nitida. Because cold-acclimation may be related to the accumulation of cryoprotective substances, we investigated relationships between ice nucleation temperature (IN), freezing temperature (FT), and the temperature causing injury to 50% of the leaf tissues (LT50) on the one hand, and concentrations of total soluble carbohydrates (TSC), starch and proline on the other hand. Observations were made throughout a seasonal cycle in adults and seedlings in the field and in seedlings in the laboratory under cold-acclimation inductive and non-inductive conditions. In adults, LT50 values were lower in N. dombeyi than in N. nitida, suggesting that N. dombeyi is the more frost tolerant species. Adults of both species tolerated freezing in autumn and winter but not in spring and summer. In the fall and winter, seedlings of N. dombeyi had a much lower LT50 than those of N. nitida. Nothofagus nitida seedlings, in autumn and winter, exhibited freezing avoidance mechanisms. Although elevated TSC and proline concentrations may contribute to freezing tolerance in adults of both species, an increase in proline concentration is unlikely to be the dominant frost tolerance response in adults because proline concentrations were higher in N. nitida than in N. dombeyi. In seedlings, however, there were large differences in proline accumulation between species that may account for the difference between them in freezing tolerance. Starch concentration in both species decreased during winter. Chlorophyll fluorescence indicated that maximal photochemical efficiency (Fv/Fm) remained at optimal values (∼0.8) throughout the year. The effective photochemical efficiency of PSII (ΦPSII) and relative electron transport rates (ETRr) decreased in winter in both species. In seedlings, fluorescence parameters were more affected in winter in N. nitida than in N. dombeyi. We concluded that adults and seedlings of N. dombeyi are hardier than adults and seedlings of N. nitida, which is consistent with its wider latitudinal and altitudinal distribution. [ABSTRACT FROM AUTHOR]

Ascorbic acid (ASC) is an important antioxidant in plant cells, being the main biosynthesis pathway is L-galactose or Smirnoff-Wheeler. ASC is involved in plant growth and development processes, being a cofactor and regulator of multiple signaling pathways in response to abiotic stresses. Aluminum toxicity is an important stressor under acidic conditions, affecting plant root elongation, triggering ROS induction and accumulation of hydrogen peroxide (H 2 O 2 ). To mitigate damage from Al-toxicity, plants have evolved mechanisms to resist stress conditions, such as Al-tolerance and Al-exclusion or avoidance, both strategies related to the forming of non-phytotoxic complexes or bind-chelates among Al and organic molecules like oxalate. Dehydroascorbate (DHA) degradation generates oxalate when ASC is recycled, and dehydroascorbate reductase (DHAR) expression is inhibited. An alternative strategy is ASC regeneration, mainly due to a higher level of DHAR gene expression and low monodehydroascorbate reductase (MDHAR) gene expression. Therefore, studies performed on Fagopyrum esculentum, Nicotiana tabacum, Poncirus trifoliate, and V. corymbosum suggest that ASC is associated with the Al-resistant mechanism, given the observed enhancements in defense mechanisms, including elevated antioxidant capacity and oxalate production. This review examines the potential involvement of ASC metabolism in Al-resistant mechanisms., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier Masson SAS.)

Plastic covers have been used to prevent environmental constraints negatively affecting sweet cherry production in Southern Chile. However, less information is available on agronomic practices and their effects on fruit quality in sweet cherry covered orchards. Thus, in this study, we evaluated the impact of fruit load regulation on cherries' antioxidant-related parameters and the quality and condition at harvest and postharvest in sweet cherry ( Prunus avium ) cv. Regina that was cultivated under a plastic cover in Southern Chile. For this, four fruit load treatments were manually applied-(i) 100% fruit load (the control), (ii) 80% fruit load, (iii) 60% fruit load, and (iv) 40% fruit load-in a commercial sweet cherry orchard for two seasons (2021/2022 and 2022/2023). The results revealed that the yield and fruit load were not significantly different between the treatments. Interestingly, the 60% and 40% fruit loads increased the fresh weight, fruit size, and firmness (20.3%) compared to the control (the 100% fruit load) during both seasons. Likewise, the 60% and 40% fruit load treatments exhibited the highest fruit size distribution of 30 mm, while the 100 and 80% fruit load treatments showed the highest fruit distribution with fruit sizes between 28 mm and 24 mm. The total soluble solids (TSSs) did not vary among the fruit load treatments, while a significant increase was found in the titratable acidity (TA) in the 60 and 40% fruit load treatments during both seasons. No significant differences in antioxidant activity (AA) and total phenols (TPHs) among the treatments were observed during both seasons. Overall, the results revealed that the fruit load treatments, mainly 40%, increased the fruit weight and firmness and reduced pitting in fruits by 39.4% at postharvest. Thus, fruit thinning might be an important agronomical practice to regulate fruit load, positively affecting fruit quality at harvest and during postharvest storage in sweet cherry cv. Regina cultivated under a plastic cover. However, more biochemical and molecular studies are needed to elucidate the mechanism involved in this improvement.

Main Conclusions: In contrast to Neltuma species, S. tamarugo exhibited higher stress tolerance, maintaining photosynthetic performance through enhanced gene expression and metabolites. Differentially accumulated metabolites include chlorophyll and carotenoids and accumulation of non-nitrogen osmoprotectants. Plant species have developed different adaptive strategies to live under extreme environmental conditions. Hypothetically, extremophyte species present a unique configuration of physiological functions that prioritize stress-tolerance mechanisms while carefully managing resource allocation for photosynthesis. This could be particularly challenging under a multi-stress environment, where the synthesis of multiple and sequential molecular mechanisms is induced. We explored this hypothesis in three phylogenetically related woody species co-occurring in the Atacama Desert, Strombocarpa tamarugo, Neltuma alba, and Neltuma chilensis, by analyzing their leaf dehydration and freezing tolerance and by characterizing their photosynthetic performance under natural growth conditions. Besides, the transcriptomic profiling, biochemical analyses of leaf pigments, and metabolite analysis by untargeted metabolomics were conducted to study gene expression and metabolomic landscape within this challenging multi-stress environment. S. tamarugo showed a higher photosynthetic capacity and leaf stress tolerance than the other species. In this species, a multifactorial response was observed, which involves high photochemical activity associated with a higher content of chlorophylls and β-carotene. The oxidative damage of the photosynthetic apparatus is probably attenuated by the synthesis of complex antioxidant molecules in the three species, but S. tamarugo showed the highest antioxidant capacity. Comparative transcriptomic and metabolomic analyses among the species showed the differential expression of genes involved in the biosynthetic pathways of key stress-related metabolites. Moreover, the synthesis of non-nitrogen osmoprotectant molecules, such as ciceritol and mannitol in S. tamarugo, would allow the nitrogen allocation to support its high photosynthetic capacity without compromising leaf dehydration tolerance and freezing stress avoidance., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Boron (B) is a micronutrient crucial for the growth, development, productivity, and quality of crops. However, in areas characterized by acid soil (pH water < 5.0) and high rainfall, soil B concentration tends to decrease, leading to insufficient supply to crops. This study was aimed at determining the optimal rate of B fertilization to enhance Vaccinium corymbosum L. performance in acid conditions. One-year-old cultivars with contrasting Al resistance (Al-sensitive Star and Al-resistant Cargo) were used. Plants were conditioned in plastic pots containing 18 L of half-ionic-strength Hoagland solution (pH 4.5) for 2 weeks. Thereafter, the following B treatments were applied foliarly: control, without B application (distilled water), 200, 400, and 800 mg L -1 of B as Solubor ® for up to 72 h. Photosynthetic performance, root and shoot B levels, antioxidants, and oxidative stress were evaluated. Root and shoot B concentrations increased with the increasing B application, being higher in leaves than in roots of both cultivars. Net photosynthesis decreased at 800 mg L -1 B supply and effective quantum yield of PSII at 72 h in all B treatments. Lipid peroxidation increased in both cultivars at 800 mg L -1 B treatment. Antioxidant activity increased in all B treatments in both cultivars; while, at 400 and 800 mg L -1 B, total phenols increased in leaves of cultivar Star and decreased in cultivar Cargo. In conclusion, optimal B foliar application for highbush blueberry appears to be around 400 mg L -1 B. The appropriate B foliar application could help mitigate potential stress-induced problems in highbush blueberry cultivation. However, the optimal foliar B application should be confirmed in field experiments to help the farmers manage B nutrition.

Background: Titanium dioxide nanoparticles (TiO 2 NPs) have been reported to have contrasting effects on plant physiology, while their effects on sugar, protein, and amino acid metabolism are poorly understood. In this work, we evaluated the effects of TiO 2 NPs on physiological and agronomical traits of tomato (Solanum lycopersicum L.) seedlings. Tomato seeds were treated with TiO 2 NPs (1000 and 2000 mg L - 1 ), TiO 2 microparticles (µPs, 2000 mg L - 1 ) as the size control, and ultrapure water as negative control., Results: The dry matter of stems (DMs), leaves (DMl) and total dry matter (DMt) decreased as particle concentration increased. This trend was also observed in the maximum quantum yield of light-adapted photosystem II (PSII) (F v ´/F m ´), the effective quantum yield of PSII (ΦPSII), and net photosynthesis (P n ). The concentrations of sugars, total soluble proteins, and total free amino acids were unaffected, but there were differences in the daily dynamics of these compounds among the treatments., Conclusion: Our results suggest that treating tomato seeds with TiO 2 might affect PSII performance, net photosynthesis and decrease biomass production, associated with a concentration- and size-related effect of TiO 2 particles., (© 2024. The Author(s).)

Boron (B) is an essential microelement for plants, and its deficiency can lead to impaired development and function. Around 50% of arable land in the world is acidic, and low pH in the soil solution decreases availability of several essential mineral elements, including B, magnesium (Mg), calcium (Ca), and potassium (K). Plants take up soil B in the form of boric acid (H 3 BO 3 ) in acidic soil or tetrahydroxy borate [B(OH) 4 ] - at neutral or alkaline pH. Boron can participate directly or indirectly in plant metabolism, including in the synthesis of the cell wall and plasma membrane, in carbohydrate and protein metabolism, and in the formation of ribonucleic acid (RNA). In addition, B interacts with other nutrients such as Ca, nitrogen (N), phosphorus (P), K, and zinc (Zn). In this review, we discuss the mechanisms of B uptake, absorption, and accumulation and its interactions with other elements, and how it contributes to the adaptation of plants to different environmental conditions. We also discuss potential B-mediated networks at the physiological and molecular levels involved in plant growth and development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Vera-Maldonado, Aquea, Reyes-Díaz, Cárcamo-Fincheira, Soto-Cerda, Nunes-Nesi and Inostroza-Blancheteau.)

Salicylic acid (SA) application is a promising agronomic tool. However, studies under field conditions are required, to confirm the potential benefits of SA. Thus, SA application was evaluated under field conditions for its effect on abscisic acid levels, antioxidant related-parameters, fruit quality, and yield in Aristotelia chilensis subjected to different levels of irrigation. During two growing seasons, three-year-old plants under field conditions were subjected to full irrigation (FI: 100% of reference evapotranspiration (ETo), and deficit irrigation (DI: 60% ETo). During each growth season, a single application of 0.5 mM SA was performed at fruit color change by spraying fruits and leaves of both irrigation treatments. The results showed that DI plants experienced moderate water stress (-1.3 MPa), which increased ABA levels and oxidative stress in the leaves. The SA application facilitated the recovery of all physiological parameters under the DI condition, increasing fruit fresh weight by 44%, with a 27% increase in fruit dry weight, a 1 mm increase in equatorial diameter, a 27% improvement in yield per plant and a 27% increase in total yield, with lesser oxidative stress and tissue ABA levels in leaves. Also, SA application significantly increased (by about 10%) the values of fruit trait variables such as soluble solids, total phenols, and antioxidant activity, with the exceptions of titratable acidity and total anthocyanins, which did not vary. The results demonstrated that SA application might be used as an agronomic strategy to improve fruit yield and quality, representing a saving of 40% regarding water use.

The potato ( Solanum tuberosum L) is one of the four most important crops worldwide in production and consumption. It originated from South America along the Andes, where six hotspots of diversity known as subcenters of origin are described from Venezuela to Chiloe Island in Chile, and where the greatest diversity of potatoes in the world is found. Today, the use of ancestral genetic resources has gained significant relevance, recovering and producing foods with a greater nutrient content and beneficial to human health. Therefore, native potatoes possess a set of characteristics with great potential for use in potato breeding guided primarily to produce better feed, especially potatoes of the Chilotanum Group that are easily crossed with conventional varieties. The primary objective of this study was to evaluate 290 accessions of S. tuberosum subsp tuberosum belonging to the Chilotanum Group using a set of molecular markers and correlate them to its phenotypic traits for future use in breeding programs. For this purpose, 290 accessions were analysed through 22 specific microsatellites described previously, correlating them with flesh and skin colour, total phenolic content, and anthocyanin content. A division into groups considering all the 290 accessions resulted in two clusters using STRUCTURE analysis and seven different genetic clusters using UPGMA. The latter exhibited common phenotypic characteristics as well as anthocyanin content, strongly supporting a correlation between phenotypic traits and the genetic fingerprint. These results will enable breeders to focus on the development of potatoes with high polyphenol and anthocyanin content., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Behn, Lizana, Zapata, Gonzalez, Reyes-Díaz and Fuentes.)

In rainy areas, sweet cherries are cultivated under plastic covers, preventing the cracking of the fruit but decreasing the firmness and acidity of the cherries. We evaluated the impact of plastic cover and pre-harvest K foliar application on quality parameters, antioxidant properties, and phenolic and organic acid compositions in fruits of sweet cherry cv. Regina of Southern Chile. Our results showed that K+ increased firmness, total soluble content, size, fruit weight, and titratable acidity at harvest, independent of the cover factor. The positive impacts of foliar K fertilization on anthocyanins, flavonoids, and phenolic acids could explain the higher antioxidant capacity of fruits. Our study revealed that the additional K doses applied increased malic acid, the main organic acid in cherry fruits, but only in fruits from uncovered trees. In covered trees, the effect was reversed. Citric acid was higher in fruit from covered trees. Our results indicated that tartaric acid also increased with the application of higher K doses; however, this acid was detectable only in uncovered tree fruit. Interestingly, all organic acids were lower in fruits produced in the lower canopy than those detected in fruits harvested from the upper canopy. This showed the positive impact of canopy light exposure on maintaining suitable acidity levels in sweet cherry fruits.

Despite men-who-have-sex-with-men (MSM) from Latin America (LA) are still a vulnerable population for known health-related conditions and social problems, availability of comparable data across LA countries for assessment and monitoring purposes is limited. The objective of this article is to present the study design and the questionnaire of LAMIS-2018 (Latin America MSM Internet Survey), its recruitment strategy, rates and sources by country, and the lessons learned from its implementation. LAMIS-2018 was a cross-sectional, internet-based survey targeting MSM living in 18 LA countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela) that gathered data about sexual behaviors, HIV/STI and viral hepatitis knowledge, prophylactic use of antiretrovirals, psychosocial health, and access to sexual health services. The survey went online for four months and was available in three languages (Spanish, Portuguese, and Dutch). Promotion was carried out using dating apps, websites, social networks, and by community-based and academic organizations of each participating country directly in gay venues and in their own premises. Overall, 64,655 MSM participated in LAMIS-2018. Dating apps and websites were the most important recruitment source in most countries, except for Honduras, Nicaragua, and Suriname, where community-based organizations recruited most of the participants. Beyond the LAMIS-2018 implementation description, we highlight the feasibility of such a study in this context, based on the collaboration between community-based and academic organizations to obtain a large sample of MSM in the region. LAMIS-2018 data will contribute to identify determinants of risk behaviors and prevention needs of vulnerable MSM populations in each country of the region., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Reyes-Díaz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

In the Antarctic Peninsula, increases in mean annual temperature are associated with the coverage and population density of the two Antarctic vascular plant species-Deschampsia antarctica and Colobanthus quitensis-potentially modifying critical soil processes. In this study, we characterized the diversity and community composition of active microorganisms inhabiting the vascular plant rhizosphere in two sites with contrasting vegetation cover in King George Island, Western Antarctic Peninsula. We assessed the interplay between soil physicochemical properties and microbial diversity and composition, evaluating the effect of an in situ experimental warming on the microbial communities of the rhizosphere from D. antarctica and C. quitensis. Bacteria and Eukarya showed different responses to warming in both sites, and the effect was more noticeable in microbial eukaryotes from the low vegetation site. Furthermore, important changes were found in the relative abundance of Tepidisphaerales (Bacteria) and Ciliophora (Eukarya) between warming and control treatments. Our results showed that rhizosphere eukaryal communities are more sensitive to in situ warming than bacterial communities. Overall, our results indicate that vegetation drives the response of the active fraction of the microbial communities from the rhizosphere of Antarctic vascular plants to soil warming., (© The Author(s) 2022. Published by Oxford University Press on behalf of FEMS.)

Salinization of soils and freshwater resources by natural processes and/or human activities has become an increasing issue that affects environmental services and socioeconomic relations. In addition, salinization jeopardizes agroecosystems, inducing salt stress in most cultivated plants (nutrient deficiency, pH and oxidative stress, biomass reduction), and directly affects the quality and quantity of food production. Depending on the type of salt/stress (alkaline or pH-neutral), specific approaches and solutions should be applied to ameliorate the situation on-site. Various agro-hydrotechnical (soil and water conservation, reduced tillage, mulching, rainwater harvesting, irrigation and drainage, control of seawater intrusion), biological (agroforestry, multi-cropping, cultivation of salt-resistant species, bacterial inoculation, promotion of mycorrhiza, grafting with salt-resistant rootstocks), chemical (application of organic and mineral amendments, phytohormones), bio-ecological (breeding, desalination, application of nano-based products, seed biopriming), and/or institutional solutions (salinity monitoring, integrated national and regional strategies) are very effective against salinity/salt stress and numerous other constraints. Advances in computer science (artificial intelligence, machine learning) provide rapid predictions of salinization processes from the field to the global scale, under numerous scenarios, including climate change. Thus, these results represent a comprehensive outcome and tool for a multidisciplinary approach to protect and control salinization, minimizing damages caused by salt stress.

In rainy locations, sweet cherry is cultivated under plastic covers, which are useful to prevent fruit cracking but decrease cherry quality such as firmness and acidity. Here we evaluate the impact of pre-harvest K foliar applications on harvest and post-harvest fruit quality and condition of sweet cherry cultivated under plastic covers in southern Chile orchards. The study was performed on two commercial orchards (cv. Regina), located in different regions, during two consecutive seasons. In all cases, a conventional K regime (four sprays) was compared to an intensive K regimen (seven sprays). Results showed that cherries from the most southern region revealed lower acidity but higher soluble solids content weight and size. The intensive K regime improved the firmness and acidity of fruits of covered trees at harvest and post-harvest. Moreover, we found that condition defects were higher in fruits from un-covered trees and that trees grown under intensive K regime showed lower levels of cracking at harvest and pitting at post-harvest compared to trees treated with the conventional K regime. Otherwise, pedicel browning was inconsistently affected by K sprays. Our results revealed that an intensive K regime could improve the quality and condition of fruits at harvest and post-harvest in covered orchards of sweet cherry cv. Regina; however, the impacts can significantly vary depending on season and locality.