Use of Phosphorus-Solubilizing Microorganisms as a Biotechnological Alternative: A Review.

Microorganisms with the ability to dissolve phosphorus have the potential to release this essential nutrient into the soil through natural solubilization processes, which allows for boosting plant growth and development. While literature reviews acknowledge their potential, unexplored territories concerning accessibility, application, and effective integration into sustainable agriculture necessitate further research. This manuscript employed distinct methodologies to execute a bibliometric analysis and a literature review. The combined application of both methodologies enables a holistic understanding of the domain landscape and its innovative facets. For the bibliometric analysis, the propositions of Donthu and Jia were utilized, supplemented by tools, such as Bibliometrix. The literature review adhered to a systematic methodology predicated on Petersen's guidelines to represent the domain accurately, pinpointing trends and gaps that could steer future, more detailed research. This investigation uncovers an escalating interest in studying these microorganisms since the 2000s, emphasizing their significance in sustainable agriculture and the context of phosphorus scarcity. It was also discerned that India and China, nations with notable agricultural sectors and a high demand for phosphorus fertilizers, spearheaded research output on this subject. This signifies their substantial contribution to the progression of this scientific field. Furthermore, according to the research consulted, phosphorus-solubilizing microorganisms play a pivotal role in the symbiotic interaction of soil with plant roots and represent an efficacious strategy to counteract the low availability of phosphorus in the soil and sustainably enhance agricultural systems. Finally, this review contributes to the relevant domain by examining existing empirical evidence with special emphasis on sustainable agriculture, improved understanding of phosphorus solubilization mechanisms, and recognition of various microbial entities.

Raman spectroscopy - a visit to the literature on plant, food, and agricultural studies.

Raman spectroscopy, a fast, non-invasive, and label-free optical technique, has significantly advanced plant and food studies and precision agriculture by providing detailed molecular insights into biological tissues. Utilizing the Raman scattering effect generates unique spectral fingerprints that comprehensively analyze tissue composition, concentration, and molecular structure. These fingerprints are obtained without chemical additives or extensive sample preparation, making Raman spectroscopy particularly suitable for in-field applications. Technological enhancements such as surface-enhanced Raman scattering, Fourier-transform-Raman spectroscopy, and chemometrics have increased Raman spectroscopy sensitivity and precision. These and other advancements enable real-time monitoring of compound translocation within plants and improve the detection of chemical and biological contaminants, essential for food safety and crop optimization. Integrating Raman spectroscopy into agronomic practices is transformative and marks a shift toward more sustainable farming activities. It assesses crop quality - as well as the quality of the food that originated from crop production - early plant stress detection and supports targeted breeding programs. Advanced data processing techniques and machine learning integration efficiently handle complex spectral data, providing a dynamic and detailed view of food conditions and plant health under varying environmental and biological stresses. As global agriculture faces the dual challenges of increasing productivity and sustainability, Raman spectroscopy stands out as an indispensable tool, enhancing farming practices' precision, food safety, and environmental compatibility. This review is intended to select and briefly comment on outstanding literature to give researchers, students, and consultants a reference for works of literature in Raman spectroscopy mainly focused on plant, food, and agronomic sciences. © 2024 Society of Chemical Industry.

Polysaccharide-based sustainable hydrogel spheres for controlled release of agricultural inputs.

Producing food in quantity and quality to meet the growing population demand is a challenge for the coming years. In addition to the need to improve the use and efficiency of conventional agricultural inputs, we face climate change and disparity in access to food. In this context, creating innovative, efficient, and ecologically approaches is necessary to transform this global scenario. Several delivery systems are being developed to encapsulate agrochemicals, aiming to improve the controlled release of active ingredients and protect them against environmental biotic and abiotic factors. Among these systems, hydrogel spheres are particularly notable for their ability to be fabricated from biodegradable materials, allowing the encapsulation of molecules, nanomaterials, and even organisms (e.g., bacteria and fungi). This review provides an overview of the latest progress in developing polysaccharide-based hydrogel spheres for agriculture. In addition, we describe methods for preparing hydrogel spheres and discuss the encapsulation and release of agricultural inputs in the field. Finally, we put hydrogel spheres into perspective and seek to highlight some current challenges in the field to spark new inspiration and improve the development of environmentally friendly and cost-effective delivery systems for the agricultural sector.

Development of High-Efficiency Fertilizer by Hydrogels Obtained from Cassava Starch and Citric Acid for Slow Release of Ammonium and Potassium.

Fertilizers with enhanced efficiency or high-efficiency fertilizers increase the nutrient availability, minimize losses, and reduce costs, thereby increasing crop yields and food production while mitigating environmental impacts. This research evaluates the synthesis of biodegradable hydrogels from cassava starch and citric acid for agrochemical applications. Hydrogels were synthesized using water as the solvent and applied for the controlled release of macronutrients (N and K). Four concentrations of nutrient-containing salts were tested (0.5 to 10.0% w/w). Materials were analyzed using ATR-FTIR spectroscopy and swelling studies. The presence of nutrients reduced both the crosslinking efficacy and the water absorption capacity, with the latter dropping from 183.4 ± 0.6% to 117.9 ± 3.7% and 157.4 ± 25.0% for hydrogels loaded with NH4Cl and KCl, respectively. The cumulative release of K and N from the hydrogel was monitored for 144 h and examined using kinetics models, revealing that the releases follow Fickian's diffusion and anomalous diffusion, respectively. Additionally, the material was formed using cassava with peel previously milled to reduce the production costs, and its potential for nutrient-controlled delivery was evaluated, with the finding that this hydrogel decreases the release rate of nitrogen. The results suggest that these biomaterials may have promising applications in the agrochemical industry in the making of high-efficiency fertilizers.

Five Underutilized Ecuadorian Fruits and Their Bioactive Potential as Functional Foods and in Metabolic Syndrome: A Review.

The Ecuadorian Amazon harbors numerous wild and cultivated species used as food, many of which are underutilized. This review explores the bioactive potential of five such fruits-Borojó (Alibertia patinoi); Chonta (Bactris gasipaes); Arazá (Eugenia stipitata); Amazon grape (Pourouma cecropiifolia), a wild edible plant; and Cocona (Solanum sessiliflorum)-and their applications against metabolic syndrome. This study highlights their health-promoting ingredients and validates traditional medicinal properties, emphasizing their significance in improving health and mitigating the effects of the Western diet. These fruits, integral to Ecuadorian cuisine, are consumed fresh and processed. Chonta is widely cultivated but less prominent than in pre-Hispanic times, Borojó is known for its aphrodisiac properties, Cocona is traditional in northern provinces, Arazá is economically significant in food products, and Amazon grape is the least utilized and researched. The fruits are rich in phenolics (A. patinoi, E. stipitata) and carotenoids (B. gasipaes, E. stipitata), which are beneficial in controlling metabolic syndrome. This study advocates for more research and product development, especially for lesser-known species with high phenolic and anthocyanin content. This research underscores the economic, cultural, and nutritional value of these fruits, promoting their integration into modern diets and contributing to sustainable agriculture, cultural preservation, and public health through functional foods and nutraceuticals.

Facilitating Seed Iron Uptake through Amine-Epoxide Microgels: A Novel Approach to Enhance Cucumber (Cucumis sativus) Germination.

Enhancing the initial stages of plant growth by using polymeric gels for seed priming presents a significant challenge. This study aimed to investigate a microgel derived from polyetheramine-poly(propylene oxide) (PPO) and a bisepoxide (referred to as micro-PPO) as a promising alternative to optimize the seed germination process. The micro-PPO integrated with an iron micronutrient showed a positive impact on seed germination compared with control (Fe solutions) in which the root length yield improved up to 39%. Therefore, the element map by synchrotron-based X-ray fluorescence shows that the Fe intensities in the seed primers with the micro-PPO-Fe gel are about 3-fold higher than those in the control group, leading to a gradual distribution of Fe species through most internal embryo tissues. The use of micro-PPO for seed priming underscores their potential for industrial applications due to the nontoxicity results in zebrafish assays and environmentally friendly synthesis of the water-dispersible monomers employed.

Competitive fitness and stability of ammonium-excreting Azotobacter vinelandii strains in the soil.

Non-symbiotic N2-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has successfully enhanced NH4+ release. In this study, we compared the competitive fitness of A. vinelandii mutant strains, which allowed us to analyze the burden of NH4+ release under a broad dynamic range. Long-term competition assays under regular culture conditions confirmed a large burden for NH4+ release, exclusion by the wt strain, phenotypic instability, and loss of the ability to release NH4+. In contrast, co-inoculation in mild autoclaved soil showed a much longer co-existence with the wt strain and a stable NH4+ release phenotype. All genetically modified strains increased the N content and changed its chemical speciation in the soil. This study contributes one step forward towards bridging a knowledge gap between molecular biology laboratory research and the incorporation of N from the air into the soil in a molecular species suitable for plant nutrition, a crucial requirement for developing improved bacterial inoculants for economic and environmentally sustainable agriculture. KEY POINTS: • Genetic engineering for NH4+ excretion imposes a fitness burden on the culture medium • Large phenotypic instability for NH4+-excreting bacteria in culture medium • Lower fitness burden and phenotypic instability for NH4+-excreting bacteria in soil.

What is the most effective analytical method for quantification and identification of microplastics in contaminated soils?

The increasing concern over microplastics (MPs) contamination in agricultural soils due to excessive plastic use is a worldwide concern. The objective of this study was to determine which analytical technique is most effective for the analysis of MPs in agricultural soils. Near-infrared spectroscopy (NIR), scanning electron microscopy (SEM), multispectral analysis, and X-ray diffraction were used to analyze sections of clay soil containing varying percentages of virgin white MPs from 0 to 100%. X-ray analysis only detected MPs at high concentrations (20%). However, NIR at 2.300 nm and multispectral analysis at 395 nm demonstrated greater accuracy and sensitivity in distinguishing between all MPs levels. SEM revealed that MPs have an amorphous structure that is distinct from crystalline soil, potentially influencing their interactions with other soil constituents. These findings highlight the value of NIR and multispectral analysis in accurately identifying and measuring MPs in soil. Efficient management plans rely on increased awareness of MPs' environmental impact.

Assessment of the Entomopathogenic Potential of Fungal and Bacterial Isolates from Fall Armyworm Cadavers Against Spodoptera frugiperda Caterpillars and the Adult Boll Weevil, Anthonomus grandis.

Increased attention is being focused on the biological control of agricultural pests using microorganisms, owing to their potential as a viable substitute for chemical control methods. Insect cadavers constitute a potential source of entomopathogenic microorganisms. We tested whether bacteria and fungi isolated from Spodoptera frugiperda (JE Smith) cadavers could affect its survival, development, egg-laying pattern, and hatchability, as well as induce mortality in Anthonomus grandis Boheman adults. We isolated the bacteria Enterobacter hormaechei and Serratia marcescens and the fungi Scopulariopsis sp. and Aspergillus nomiae from fall armyworm cadavers and the pest insects were subjected to an artificial diet enriched with bacteria cells or fungal spores to be tested, in the case of S. frugiperda, and only fungal spores in the case of A. grandis. Enterobacter hormaechei and A. nomiae were pathogenic to S. frugiperda, affecting the survival of adults and pupae. The fungus Scopulariopsis sp. does not affect the survival of S. frugiperda caterpillars and pupae; however, due to late action, moths and eggs may be affected. Aspergillus nomiae also increased mortality of A. grandis adults, as well as the development of S. frugiperda in the early stages of exposure to the diet, as indicated by the vertical spore transfer to offspring and low hatchability. Enterobacter hormaechei and A. nomiae are potential biocontrol agents for these pests, and warrant further investigation from a toxicological point of view and subsequently in field tests involving formulations that could improve agricultural sustainability practices.

Climate change impacts on temperate fruit and nut production: a systematic review.

Temperate fruit and nut crops require distinctive cold and warm seasons to meet their physiological requirements and progress through their phenological stages. Consequently, they have been traditionally cultivated in warm temperate climate regions characterized by dry-summer and wet-winter seasons. However, fruit and nut production in these areas faces new challenging conditions due to increasingly severe and erratic weather patterns caused by climate change. This review represents an effort towards identifying the current state of knowledge, key challenges, and gaps that emerge from studies of climate change effects on fruit and nut crops produced in warm temperate climates. Following the PRISMA methodology for systematic reviews, we analyzed 403 articles published between 2000 and 2023 that met the defined eligibility criteria. A 44-fold increase in the number of publications during the last two decades reflects a growing interest in research related to both a better understanding of the effects of climate anomalies on temperate fruit and nut production and the need to find strategies that allow this industry to adapt to current and future weather conditions while reducing its environmental impacts. In an extended analysis beyond the scope of the systematic review methodology, we classified the literature into six main areas of research, including responses to environmental conditions, water management, sustainable agriculture, breeding and genetics, prediction models, and production systems. Given the rapid expansion of climate change-related literature, our analysis provides valuable information for researchers, as it can help them identify aspects that are well understood, topics that remain unexplored, and urgent questions that need to be addressed in the future.

Extracted Eucalyptus globulus Bark Fiber as a Potential Substrate for Pinus radiata and Quillaja saponaria Germination.

This study aimed to explore alternative substrates for growing forest species using eucalyptus bark. It evaluated the potential of extracted Eucalyptus globulus fiber bark as a substitute for commercial growing media such as coconut fiber, moss, peat, and compost pine. We determined the physicochemical parameters of the growing media, the germination rate, and the mean fresh and dry weights of seedlings. We used the Munoo-Liisa Vitality Index (MLVI) test to evaluate the phytotoxicity of the bark alone and when mixed with commercial substrates. Generally, the best mixture for seed growth was 75% extracted eucalyptus bark fiber and 25% commercial substrates. In particular, the 75E-25P (peat) mixture is a promising substitute for seedling growth of Pinus radiata, achieving up to 3-times higher MLVI than the control peat alone. For Quillaja saponaria, the best growth substrate was the 50E-50C (coconut fiber) mixture, which had the most significant MLVI values (127%). We added chitosan and alginate-encapsulated fulvic acid phytostimulants to improve the performance of the substrate mixtures. The fulvic acid, encapsulated or not, significantly improved MLVI values in Q. saponaria species and P. radiata in concentrations between 0.05 and 0.1% w/v. This study suggests that mixtures with higher levels of extracted fiber are suitable for growing forest species, thus promoting the application of circular economy principles in forestry.

Silvopastoral systems benefit invertebrate biodiversity on tropical livestock farms in Caquetá, Colombia.

In the Colombian Amazon, there has been long-term and sustained loss of primary forest threatening biodiversity and climate change mitigation. Silvopastoral practices that integrate trees into livestock production could help address both local economic and wider environmental challenges.We aimed to assess the effects of silvopastoral practices on invertebrate communities on smallholder farms in Caquetá, Colombia. Using sweep nets and malaise trapping, invertebrate communities were compared between traditional pasture, silvopasture and forest edge habitats.Invertebrate communities collected using sweep nets were contrasting among habitat types, communities were significantly different between traditional pasture and forest edge habitats and diversity and evenness were greatest in forest edges compared to traditional pastures. It appears that silvopasture areas, by supporting similar invertebrate assemblages to both traditional pasture and forest edges, may be acting as an intermediate habitat.When individual invertebrate orders were compared, Lepidoptera and Coleoptera were found in greater abundance in the forest edge habitats, while Hemiptera were more abundant in traditional pasture. Hemipterans are often pests of forage plants in pasture systems and these differences in abundance may have implications for ecosystem services and disservices.Silvopastoral approaches cannot replace the unique biodiversity supported by native forests but could deliver benefits for invertebrate conservation and ecosystem services if integrated into landscapes.

Resumen: En la Amazonía colombiana ha habido una pérdida sostenida y a largo plazo de bosque primario que amenaza la biodiversidad y la mitigación del cambio climático. Las prácticas silvopastoriles que integran los árboles en la producción ganadera podrían ayudar a abordar tanto los desafíos económicos locales como los ambientales.Nuestro objetivo fue evaluar los efectos de las prácticas silvopastoriles en comunidades de invertebrados en pequeñas fincas en Caquetá, Colombia. Las comunidades de invertebrados se compararon entre las pasturas nativas, el sistema silvopastoril y los hábitats del borde del bosque mediante el uso redes entomológicas de barrido y trampas Malaise.Las comunidades de invertebrados recolectadas usando redes entomológicas de barrido contrastaban entre los tipos de hábitat. Las comunidades eran significativamente diferentes entre las pasturas nativas y el borde de bosque. Pareciera que las áreas de silvopastoreo, al soportar conjuntos de invertebrados similares tanto a las pasturas nativas como a los bordes del bosque, pueden estar actuando como un hábitat intermedio.Cuando se compararon los órdenes individuales de invertebrados, los lepidópteros y los coleópteros se encontraron en mayor abundancia en los hábitats del borde del bosque, mientras que los hemípteros eran más abundantes en las pasturas nativas. Los hemípteros son a menudo plagas de plantas forrajeras en sistemas de pastoreo y estas diferencias en abundancia pueden tener implicaciones y perjuicios para los servicios ecosistémicos.Los sistemas silvopastoriles no pueden reemplazar la biodiversidad única apoyada por los bosques nativos, pero podrían ofrecer beneficios para la conservación de invertebrados y los servicios ecosistémicos si se integran en los paisajes.

Editorial: plant-microbial symbiosis toward sustainable food security.

The use of plant-associated microorganisms is increasingly being investigated as a key tool for mitigating the impact of biotic and abiotic threats to crops and facilitating migration to sustainable agricultural practices. The microbiome is responsible for several functions in agroecosystems, such as the transformation of organic matter, nutrient cycling, and plant/pathogen growth regulation. As climate change and global warming are altering the dynamics of plant-microbial interactions in the ecosystem, it has become essential to perform comprehensive studies to decipher current and future microbial interactions, as their useful symbiotic mechanisms could be better exploited to achieve sustainable agriculture. This will allow for the development of effective microbial inoculants that facilitate nutrient supply for the plant at its minimal energy expense, thus increasing its resilience to biotic and abiotic stresses. This article collection aims to compile state-of-the-art research focused on the elucidation and optimization of symbiotic relationships between crops and their associated microbes. The information presented here will contribute to the development of next-generation microbial inoculants for achieving a more sustainable agriculture.

Intercropping Systems to Modify Bioactive Compounds and Nutrient Profiles in Plants: Do We Have Enough Information to Take This as a Strategy to Improve Food Quality? A Review.

Various environmental, food security and population health problems have been correlated with the use of intensive agriculture production systems around the world. This type of system leads to the loss of biodiversity and natural habitats, high usage rates of agrochemicals and natural resources, and affects soil composition, human health, and nutritional plant quality in rural areas. Agroecological intercropping systems that respect agrobiodiversity, on the other hand, can significantly benefit ecosystems, human health, and food security by modifying the nutritional profile and content of some health-promoting bioactive compounds in the species cultivated in this system. However, research on intercropping strategies focuses more on the benefits they can offer to ecosystems, and less on plant nutrient composition, and the existing information is scattered. The topic merits further study, given the critical impact that it could have on human nutrition. The aim of this review is therefore to collect viable details on the status of research into the profile of nutrients and bioactive compounds in intercropping systems in different regions of the world with unique mixed crops using plant species, along with the criteria for combining them, as well as the nutrients and bioactive compounds analyzed, to exemplify the possible contributions of intercropping systems to food availability and quality.

Beauveria bassiana biogenic nanoparticles for the control of Noctuidae pests.

BACKGROUND: Biogenic metallic and oxide metal nanoparticles have potential as alternatives for several current problems in agriculture, such as the control of caterpillars which cause huge losses in the production of important crops. In the present study, capped and uncapped silver, iron oxide and titanium dioxide nanoparticles were synthesized from the filtrate of Beauveria bassiana and evaluated in regard to physico-chemical characteristics, capping composition, cytotoxicity, genotoxicity and biological activity on Helicoverpa armigera and Spodoptera frugiperda caterpillars. RESULTS: A difference in the physico-chemical parameters of the capped and uncapped nanoparticles was observed, with larger aggregation and lower stability of the uncapped. In regard to the study of the capping, the presence of functional groups of biomolecules as well as the activity of B. bassiana hydrolytic enzymes were observed. Cytotoxic effects on the tested cell lines were not observed and DNA damage levels increased with more intense effects of the uncapped nanoparticles. In regard to the biological activity against Noctuidae pests, the uncapped and capped iron oxide, and uncapped titanium dioxide nanoparticles occasioned higher mortality (76%, 60% and 51%, respectively) but no differences in LC50 were recorded. Moreover, sublethal effects were reported on Helicoverpa armigera whereas Spodoptera frugiperda showed low susceptibility to the nanoparticles. CONCLUSION: The results demonstrate that biogenic metallic and oxide metal nanoparticles might show promising effects for the control of caterpillars which cause damage on important agricultural crops. Further investigations are necessary to understand the mechanisms of action and optimize the biological activity of these new nanomaterials. © 2023 Society of Chemical Industry.

Small rodent communities and their associated damage to wheat-groundnut agriculture systems / Pequenas comunidades de roedores e seus danos associados aos sistemas de agricultura de trigo e amendoim

Rodents can cause significant damage to wheat-groundnut crops in developing countries, as well as to stored produce and infrastructure, affecting food security and income of small-holder farmers. Wheat (Triticum aestivum) and groundnuts (Arachis hypogea) are important cash crops for local farmers in Pakistan. Field experiments were performed to assess the extent of rodent damage to wheat-groundnut crops throughout their growth stages (i.e, germination, flowering/peg formation and maturity) in the agro-ecological zones of Pothwar Plateau, Pakistan. We used a quadrat method to record the number of damaged crop plants. On the basis of the trapping data four rodent species were captured from wheat-groundnut cropping systems which were responsible for causing damage, i.e., lesser bandicoot rat (Bandicota bengalensis) was the main species, followed by the short-tailed mole rat (Nesokia indica), the Indian gerbil (Tatera indica) and the bush rat (Golunda ellioti). In both crops, the maximum damage was recorded at crop maturity (10.7 and 14.4%, respectively). The lowest reported damage to wheat and groundnuts was at the germination stage (3.5% and 6.0%, respectively). The lower damage reported at germination could be due to availability of non-crop vegetation at field borders that may be a potential factor influencing damage. Our findings clearly show the considerable amount of damage caused by rodents to wheat-groundnut at maturity across all the agro-ecological zones of Pothwar and indicated that the small mammal composition was more related to maturity stage/season of crops, when the availability of food and climatic condition were favorable and having security under crop shelter. More detailed studies are needed to fully understand the population and breeding ecology of the relevant rodent pest species in relation to damage patterns to optimize management beyond individual structural measures.

Os roedores podem causar danos significativos às culturas de trigo e amendoim nos países em desenvolvimento, bem como aos produtos armazenados e infraestrutura, afetando a segurança alimentar e a renda dos pequenos agricultores. O trigo (Triticum aestivum) e o amendoim (Arachis hypogea) são culturas comerciais importantes para os agricultores locais no Paquistão. Experimentos de campo foram realizados para avaliar a extensão dos danos de roedores às culturas de trigo e amendoim ao longo de seus estágios de crescimento (ou seja, germinação, floração/formação e maturidade) nas zonas agroecológicas de Pothwar Plateau, Paquistão. Usamos um método de quadrat para registrar o número de plantas de cultura danificadas. Com base nos dados de armadilhagem foram capturadas quatro espécies de roedores de sistemas de cultivo de trigo-amendoim que foram responsáveis ​​por causar danos, ou seja, o rato-bandico-pequeno (Bandicota bengalensis) foi a espécie principal, seguido pelo rato-toupeira-de-cauda-curta (Nesokia indica), o gerbilo-da-índia (Tatera indica) e o rato-do-mato (Golunda ellioti). Em ambas as culturas, o dano máximo foi registrado na maturidade da cultura (10,7 e 14,4%, respectivamente). O menor dano relatado ao trigo e ao amendoim foi no estágio de germinação (3,5% e 6,0%, respectivamente). O menor dano relatado na germinação pode ser devido à disponibilidade de vegetação não cultivada nas bordas do campo, que pode ser um fator potencial que influencia o dano. Nossos resultados mostraram claramente a quantidade considerável de danos causados ​​por roedores ao trigo-amendoim na maturidade em todas as zonas agroecológicas de Pothwar e indicaram que a composição de pequenos mamíferos estava mais relacionada ao estágio de maturidade/estação das culturas quando a disponibilidade de alimentos e as condições climáticas eram favoráveis ​​e com segurança sob abrigo de cultivo. Estudos mais detalhados são necessários para entender completamente a ecologia populacional e reprodutiva das espécies de pragas de roedores relevantes em relação aos padrões de danos para otimizar o manejo, além das medidas estruturais individuais.

Rhizoglomus variabile and Nanoglomus plukenetiae, Native to Peru, Promote Coffee Growth in Western Amazonia.

Coffee (Coffea arabica) is among the world's most economically important crops. Coffee was shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) in traditionally managed coffee plantations in the tropics. The objective of this study was to assess AMF species richness in coffee plantations of four provinces in Perú, to isolate AMF isolates native to these provinces, and to test the effects of selected indigenous AMF strains on coffee growth. AMF species were identified by morphological tools on the genus level, and if possible further to the species level. Two native species, Rhizoglomus variabile and Nanoglomus plukenetiae, recently described from the Peruvian mountain ranges, were successfully cultured in the greenhouse on host plants. In two independent experiments, both species were assessed for their ability to colonize coffee seedlings and improve coffee growth over 135 days. A total of 35 AMF morphospecies were identified from 12 plantations. The two inoculated species effectively colonized coffee roots, which resulted in 3.0-8.6 times higher shoot, root and total biomass, when compared to the non-mycorrhizal controls. R. variabile was superior to N. plukenetiae in all measured parameters, increasing shoot, root, and total biomass dry weight by 4.7, 8.6 and 5.5 times, respectively. The dual inoculation of both species, however, did not further improve plant growth, when compared to single-species inoculations. The colonization of coffee by either R. variabile or N. plukenetiae strongly enhances coffee plant growth. R. variabile, in particular, offers enormous potential for improving coffee establishment and productivity. Assessment of further AMF species, including species from other AMF families should be considered for optimization of coffee growth promotion, both alone and in combination with R. variabile.

Effect of one or more microorganisms on the yield components of upland rice under greenhouse conditions.

The use of beneficial microorganisms is an important strategy to improve rice production in a sustainable way. The study was carried out to determine the effect of single and combined beneficial microorganism on the development of upland rice. The experiment was performed in greenhouse and arranged in a completely randomized design with 29 treatments and 4 replications. Treatments consisted of rice seeds cultivar BRS A501 CL treated with single and combined multifunctional microorganisms (1 (Serratia marcescens), 2 (Bacillus toyonensis), 3 (Phanerochaete australis), 4 (Trichoderma koningiopsis), 5 (Azospirillum brasilense), 6 (Azospirillum sp.), 7 (Bacillus sp.), 8 to 28 (combination of all these microorganisms in pairs) and 29 (control)). Inoculation of upland rice with sole and combined microorganism on upland rice increased the roots and shoots development, yield components and grain yield of upland rice. The combinations of Bacillus sp. (BRM 63573) and A. brasilense (AbV5), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114) led to improved roots and shoots development; increased number of panicles and grains per pot, 1000 grains weight and grain yield of rice plants. Besides, the combinations allow helped in increased accumulation of nutrients in roots, shoots and grains of rice plants.

Microbiome engineering optimized by Antarctic microbiota to support a plant host under water deficit.

Climate change challenges modern agriculture to develop alternative and eco-friendly solutions to alleviate abiotic and/or biotic stresses. The use of soil microbiomes from extreme environments opens new avenues to discover novel microorganisms and microbial functions to protect plants. In this study we confirm the ability of a bioinoculant, generated by natural engineering, to promote host development under water stress. Microbiome engineering was mediated through three factors i) Antarctic soil donation, ii) water deficit and iii) multigenerational tomato host selection. We revealed that tomato plants growing in soils supplemented with Antarctic microbiota were tolerant to water deficit stress after 10 generations. A clear increase in tomato seedling tolerance against water deficit stress was observed in all soils over generations of Host Mediated Microbiome Engineering, being Fildes mixture the most representatives, which was evidenced by an increased survival time, plant stress index, biomass accumulation, and decreased leaf proline content. Microbial community analysis using 16s rRNA gene amplicon sequencing data suggested a microbiome restructuring that could be associated with increased tolerance of water deficit. Additionally, the results showed a significant increase in the relative abundance of Candidatus Nitrosocosmicus and Bacillus spp. which could be key taxa associated with the observed tolerance improvement. We proposed that in situ microbiota engineering through the evolution of three factors (long-standing extreme climate adaption and host and stress selection) could represent a promising strategy for novel generation of microbial inoculants.

Development and Evaluation of Zinc and Iron Nanoparticles Functionalized with Plant Growth-Promoting Rhizobacteria (PGPR) and Microalgae for Their Application as Bio-Nanofertilizers.

Micronutrient deficiencies are widespread and growing global concerns. Nanoscale nutrients present higher absorption rates and improved nutrient availability and nutrient use efficiency. Co-application of nanofertilizers (NFs) with biological agents or organic compounds increases NF biocompatibility, stability, and efficacy. This study aimed to develop and evaluate zinc and iron bio-nanofertilizers formulated with plant growth-promoting rhizobacteria (PGPR) and microalgae. Nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with Pseudomonas species and Spirulina platensis preparation. NPs were characterized and evaluated on seed germination, soil microbial growth, and early plant response under seedbed conditions. NPs corresponded to zinc oxide (ZnO; 77 nm) and maghemite (γ-Fe2O3; 68 nm). Functionalized nanoparticles showed larger sizes, around 145-233 nm. The seedling vigor index of tomato and maize was significantly increased (32.9-46.1%) by bacteria-functionalized ZnO- and γ-Fe2O3-NPs at 75 ppm. NFs at 250 and 75 ppm significantly increased bacterial growth. NFs also improved early plant growth by increasing plant height (14-44%), leaf diameter (22-47%), and fresh weight (46-119%) in broccoli and radish, which were mainly influenced by bacteria capped ZnO- and γ-Fe2O3-NPs at 250 ppm. Beneficial effects on plant growth can be attributed to the synergistic interaction of the biological components and the zinc and iron NPs in the bio-nanofertilizers.