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Several fungi act as parasites for crops causing huge annual crop losses at both pre- and post-harvest stages. For years, chemical fungicides were the solution; however, their wide use has caused environmental contamination and human health problems. For this reason, the use of biofungicides has been in practice as a green solution against fungal phytopathogens. In the context of a more sustainable agriculture, microbial biofungicides have the largest share among the commercial biocontrol products that are available in the market. Precisely, the genus Bacillus has been largely studied for the management of plant pathogenic fungi because they offer a chemically diverse arsenal of antifungal secondary metabolites, which have spawned a heightened industrial engrossment of it as a biopesticide. In this sense, it is indispensable to know the wide arsenal that Bacillus genus has to apply these products for sustainable agriculture. Having this idea in our minds, in this review, secondary metabolites from Bacillus having antifungal activity are chemically and structurally described giving details of their action against several phytopathogens. Knowing the current status of Bacillus secreted antifungals is the base for the goal to apply these in agriculture and it is addressed in depth in the second part of this review.
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Antifúngicos , Bacillus , Microbiologia Industrial , Controle Biológico de Vetores , Doenças das Plantas , Humanos , Agricultura/métodos , Agricultura/tendências , Antifúngicos/metabolismo , Bacillus/genética , Bacillus/metabolismo , Fungicidas Industriais/metabolismo , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia , Produtos Agrícolas/microbiologia , Controle Biológico de Vetores/métodos , Controle Biológico de Vetores/tendências , Família Multigênica/genéticaRESUMO
The whole organisms can be packaged as biopesticides, but secondary metabolites secreted by microorganisms can also have a wide range of biological activities that either protect the plant against pests and pathogens or act as plant growth promotors which can be beneficial for the agricultural crops. In this review, we have compiled information about the most important secondary metabolites of three important bacterial genera currently used in agriculture pest and disease management.
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Bactérias/metabolismo , Agentes de Controle Biológico , Metabolismo Secundário , Agricultura/métodos , Bacillus/metabolismo , Produtos Agrícolas , Controle Biológico de Vetores , Pseudomonas/metabolismo , Serratia/metabolismoRESUMO
Synthetic chemical pesticides have been used for many years to increase the yield of agricultural crops. However, in the future, this approach is likely to be limited due to negative impacts on human health and the environment. Therefore, studies of the secondary metabolites produced by agriculturally important microorganisms have an important role in improving the quality of the crops entering the human food chain. In this review, we have compiled information about the most important secondary metabolites of fungal species currently used in agriculture pest and disease management.
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Anti-Infecciosos/metabolismo , Agentes de Controle Biológico/metabolismo , Produtos Agrícolas/microbiologia , Fungos/metabolismo , Metabolismo Secundário , Agricultura , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Agentes de Controle Biológico/química , Agentes de Controle Biológico/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Fungos/classificação , Controle Biológico de Vetores , Praguicidas/química , Praguicidas/metabolismo , Praguicidas/farmacologiaRESUMO
Lignifications in secondary cell walls play a significant role in defense mechanisms of plants against the invading pathogens. In the present study, we investigated Trichoderma strain specific lignifications in chickpea plants pre-treated with 10 potential Trichoderma strains and subsequently challenged with the wilt pathogen Fusarium oxysporum f. sp. ciceris (Foc). Trichoderma-induced lignifications in chickpea were observed through histochemical staining and expression of some genes of the lignin biosynthetic pathway. Lignifications were observed in transverse sections of shoots near the soil line through histochemical staining and expression pattern of the target genes was observed in root tissues through semi quantitative RT-PCR at different time intervals after inoculation of F. oxysporum f. sp. ciceris. Lignin deposition and expression pattern of the target genes were variable in each treatment. Lignifications were enhanced in all 10 Trichoderma strain treated and F. oxysporum f. sp. ciceris challenged chickpea plants. However, four Trichoderma strains viz., T-42, MV-41, DFL, and RO, triggered significantly high lignifications compared to the other six strains. Time course studies showed that effective Trichoderma isolates induced lignifications very early compared to the other strains and the process of lignifications nearly completes within 6 days of pathogen challenge. Thus, from the results it can be concluded that effective Trichoderma strains trigger lignifications very early in chickpea under Foc challenge and provide better protection to chickpea plants.
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Cicer/metabolismo , Cicer/microbiologia , Fusarium/patogenicidade , Lignina/biossíntese , Doenças das Plantas/microbiologia , Trichoderma/fisiologia , Antibiose , Cicer/genética , Cicer/imunologia , DNA de Plantas , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Interações Hospedeiro-Patógeno , Lignina/genética , Doenças das Plantas/genética , Doenças das Plantas/prevenção & controle , Imunidade Vegetal/genética , Imunidade Vegetal/fisiologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Trichoderma/isolamento & purificaçãoRESUMO
Hawaijar, ethnic vegan fermented soybean food of Manipur, India is culturally and gastronomically important indigenously produced food. It is alkaline, sticky, mucilaginous and slightly pungent and bears similar properties with many fermented soybean foods of Southeast Asia like natto of Japan, douchi of China, thua nao of Thailand, choongkook jang of Korea. The functional microorganism is Bacillus and has numerous health benefits like fibrinolytic enzyme, antioxidant, antidiabetic, and ACE inhibitory activities. It is also very rich in nutrients but unscrupulous production method and sale lead to food safety issues. Huge potential pathogen population upto the level of 107-10 cfu/g Bacillus cereus and Proteus mirabilis were detected. Recent studies revealed presence of enterotoxic and urease gene in microorganisms originated from hawaijar. Improved and regulated food chain will result in hygienic and safe hawaijar. It has scope for functional food and nutraceutical global market and hold potential to provide employment to enhance the overall socioeconomic status of the region. Scientific production of fermented soybean over the traditional methods is summarized in this paper along with food safety and health benefits. Microbiological aspects on fermented soybean along with nutritive values are critically explained inside the paper.
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Alimentos Fermentados , Veganos , Humanos , Glycine max , Índia , Alimento FuncionalRESUMO
The CRISPR/Cas9 system is a genome-editing tool that allows for precise and efficient modifications to the DNA of a cell. This technology can be used in endophytic fungi, which live within plants and can have beneficial effects on their host, making them important for agriculture. Using CRISPR/Cas9, researchers can introduce specific genetic changes into endophytic fungal genomes, allowing them to study the function of genes, improve their plant-growth-promoting properties, and create new, more beneficial endophytes. This system works by using the Cas9 protein, which acts as a pair of molecular scissors, to cut DNA at specific locations determined by a guide RNA. Once the DNA is cut, the cell's natural repair mechanisms can be used to insert or delete specific genes, allowing for precise editing of the fungal genome. This article discusses the mechanism and applications of CRISPR/Cas9 to fungal endophytes.
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The recent advancement in the human glycome and progress in the development of an inclusive network of glycosylation pathways allow the incorporation of suitable machinery for protein modification in non-natural hosts and explore novel opportunities for constructing next-generation tailored glycans and glycoconjugates. Fortunately, the emerging field of bacterial metabolic engineering has enabled the production of tailored biopolymers by harnessing living microbial factories (prokaryotes) as whole-cell biocatalysts. Microbial catalysts offer sophisticated means to develop a variety of valuable polysaccharides in bulk quantities for practical clinical applications. Glycans production through this technique is highly efficient and cost-effective, as it does not involve expensive initial materials. Metabolic glycoengineering primarily focuses on utilizing small metabolite molecules to alter biosynthetic pathways, optimization of cellular processes for glycan and glycoconjugate production, characteristic to a specific organism to produce interest tailored glycans in microbes, using preferably cheap and simple substrate. However, metabolic engineering faces one of the unique challenges, such as the need for an enzyme to catalyze desired substrate conversion when natural native substrates are already present. So, in metabolic engineering, such challenges are evaluated, and different strategies have been developed to overcome them. The generation of glycans and glycoconjugates via metabolic intermediate pathways can still be supported by glycol modeling achieved through metabolic engineering. It is evident that modern glycans engineering requires adoption of improved strain engineering strategies for creating competent glycoprotein expression platforms in bacterial hosts, in the future. These strategies include logically designing and introducing orthogonal glycosylation pathways, identifying metabolic engineering targets at the genome level, and strategically improving pathway performance (for example, through genetic modification of pathway enzymes). Here, we highlight current strategies, applications, and recent progress in metabolic engineering for producing high-value tailored glycans and their applications in biotherapeutics and diagnostics.
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Produtos Biológicos , Humanos , Produtos Biológicos/metabolismo , Polissacarídeos/química , Glicosilação , Glicoconjugados/genética , Glicoconjugados/metabolismo , Engenharia Metabólica/métodos , Bactérias/genéticaRESUMO
In recent years, cutting-edge nanotechnology research has revolutionized several facets of the food business, including food processing, packaging, transportation, preservation, and functioning. Nanotechnology has beginning to loom large in the food business as the industry's demand for biogenic nanomaterial grows. The intracellular and extracellular synthesis of metal, metal oxide, and other essential NPs has recently been explored in a variety of microorganisms, including bacteria, actinomycetes, fungi, yeasts, microalgae, and viruses. These microbes produce a variety extracellular material, exopolysaccharides, enzymes, and secondary metabolites which play key roles in synthesizing as well as stabilizing the nanoparticle (NPs). Furthermore, genetic engineering techniques can help them to improve their capacity to generate NPs more efficiently. As a result, using microorganisms to manufacture NPs is unique and has a promising future. Microbial-mediated synthesis of NPs has lately been popular as a more environmentally friendly alternative to physical and chemical methods of nanomaterial synthesis, which require higher prices, more energy consumption, and more complex reaction conditions, as well as a potentially dangerous environmental impact. It is critical to consider regulatory measures implemented at all stages of the process, from production through refining, packaging, preservation, and storage, when producing bionanomaterials derived from culturable microbes for efficient food preservation. The current review discusses the synthesis, mechanism of action, and possible food preservation uses of microbial mediated NPs, which can assist to minimize food deterioration from the inside out while also ensuring that food is safe and free of contaminants. Despite the numerous benefits, there are looming debates concerning their usage in food items, particularly regarding its aggregation in human bodies and other risks to the environment. Other applications and impacts of these microbe-fabricated NPs in the context of future food preservation prospects connected with regulatory problems and potential hazards are highlighted.
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Nanopartículas Metálicas , Nanopartículas , Materiais Biocompatíveis , Conservação de Alimentos/métodos , Fungos , Humanos , Nanopartículas Metálicas/química , Nanotecnologia/métodosRESUMO
PURPOSE: Adjuvant radiotherapy (RT) in buccal mucosa cancers is guided by histopathological factors. The decision to treat ipsilateral or bilateral draining lymph node is on physician discretion and guidelines do not have a defined indication regarding this. We aimed to analyze the failure patterns and survival in buccal mucosa cancers treated with adjuvant ipsilateral RT. MATERIALS AND METHODS: One hundred sixteen cases of post-operative buccal mucosa cancers-pT3 or more, node positive, close margins (1-5 mm), lymphovascular invasion positive, perineural invasion positive, depth of invasion >4 mm-treated with RT to primary and ipsilateral nodes from May 2013 to May 2019 were retrospectively analyzed. Patients were treated to a dose of 60-66 Gy (44 Gy in the first phase and a coned down boost of 16-22 Gy in the second phase) with three-dimensional conformal radiotherapy on a linear accelerator. Primary end point was to assess control rates and secondary end point was to evaluate the overall survival (OS) and disease-free survival (DFS) outcomes. RESULTS: Median age was 46 years with male; female ratio of 110:6. The edition of the American Joint Committee on Cancer stage distributions were I (3.4%), II (34.4%), III (24.1%), and IV (37.9%). At a median follow-up of 22 months, crude rates of local failure, regional failure, and contralateral neck failure were 9.4%, 10.3%, and 3.4%, respectively. The 2-year contralateral neck control rate was 94.9%. Pathological positive node portended poorer OS (86.6% vs. 68.6%; p = 0.015) and DFS (86.5% vs. 74.9%; p = 0.01). CONCLUSION: Incidence of contralateral recurrence with ipsilateral irradiation in buccal mucosa cancers is low with descent survival outcomes, particularly in node negative cases.
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The WRKY gene family has never been identified in pigeonpea (Cajanus cajan). Therefore, objective of the present study was to identify the WRKY gene family in pigeonpea and characterize the Fusarium udum stress-responsive WRKY genes under normal, NaCl-stressed and Pseudomonas fluorescens OKC (a plant growth-promoting bacterial strain) treated conditions. The aim was to characterize the Fusarium udum stress-responsive WRKY genes under some commonly occurring field conditions. We identified 97 genes in the WRKY family of pigeonpea, using computational prediction method. The gene family was then classified into three groups through phylogenetic analysis of the homologous genes from the representative plant species. Among the 97 identified WRKY genes 35 were further classified as pathogen stress responsive genes. Functional validation of the 35 WRKY genes was done through generating transcriptional profiles of the genes from root tissues of pigeonpea plants under the influence of P. fluorescens OKC after 24 h of stress application (biotic: Fusarium udum, abiotic: NaCl). The entire experiment was conducted in two pigeonpea cultivars Asha (resistant to F. udum) and Bahar (susceptible to F. udum) and the results were concluded on the basis of transcriptional regulation of the WRKY genes in both the pigeonpea cultivars. The results revealed that among the 35 tentatively identified biotic stress responsive CcWRKY genes, 26 were highly F. udum responsive, 17 were better NaCl responsive compared to F. udum and 11 were dual responsive to both F. udum and NaCl. Application of OKC was able to enhance transcript accumulation of the individual CcWRKY genes to both the stresses when applied individually but not in combined challenge of the two stresses. The results thus indicated that CcWRKY genes play a vital role in the defense signaling against F. udum and some of the F. udum responsive CcWRKYs (at least 11 in pigeonpea) are also responsive to abiotic stresses such as NaCl. Further, plant beneficial microbes such as P. fluorescens OKC also help pegionpea to defend itself against the two stresses (F. udum and NaCl) through enhanced expression of the stress responsive CcWRKY genes when the stresses are applied individually.
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Cajanus/fisiologia , Regulação da Expressão Gênica de Plantas/imunologia , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Cajanus/microbiologia , Resistência à Doença/genética , Resistência à Doença/imunologia , Fusarium/patogenicidade , Perfilação da Expressão Gênica , Genes de Plantas , Interações entre Hospedeiro e Microrganismos/imunologia , Família Multigênica , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas fluorescens/imunologia , Estresse Salino/genética , Fatores de Transcrição/genéticaRESUMO
To promote agronomic sustainability, extensive research is being carried out globally, investigating biofertilizer development. Recently, it has been realized that some microorganisms used as biofertilizers behave as opportunistic pathogens and belong to the biosafety level 2 (BSL-2) classification. This poses serious risk to the environmental and human health. Evidence presented in various scientific forums is increasingly favoring the merits of using BSL-2 microorganisms as biofertilizers. In this review, we emphasize that partial characterization based on traditional microbiological approaches and small subunit rRNA gene sequences/conserved regions are insufficient for the characterization of biofertilizer strains. It is advised herein, that research and industrial laboratories developing biofertilizers for commercialization or environmental release must characterize microorganisms of interest using a multilateral polyphasic approach of microbial systematics. This will determine their risk group and biosafety characteristics before proceeding with formulation development and environmental application. It has also been suggested that microorganisms belonging to risk-group-1 and BSL-1 category should be used for formulation development and for field scale applications. While, BSL-2 microorganisms should be restricted for research using containment practices compliant with strict regulations.
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Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Microbiologia do Solo , Agricultura , Contenção de Riscos Biológicos , LaboratóriosRESUMO
Trichoderma spp., are saprophytic fungi that can improve plant growth through increased nutrient acquisition and change in the root architecture. In the present study, we demonstrate that Trichoderma asperellum T42 mediate enhancement in host biomass, total nitrogen content, nitric oxide (NO) production and cytosolic Ca2+ accumulation in tobacco. T42 inoculation enhanced lateral root, root hair length, root hair density and root/shoot dry mass in tobacco under deprived nutrients condition. Interestingly, these growth attributes were further elevated in presence of T42 and supplementation of NO3- and NH4+ nutrients to tobacco at 40 and 70 days, particularly in NO3- supplementation, whereas no significant increment was observed in nia30 mutant. In addition, NO production was more in tobacco roots in T42 inoculated plants fed with NO3- nutrient confirming NO generation was dependent on NR pathway. NO3- dependent NO production contributed to increase in lateral root initiation, Ca2+ accumulation and activities of nitrate transporters (NRTs) in tobacco. Higher activities of several NRT genes in response to T42 and N nutrients and suppression of ammonium transporter (AMT1) suggested that induction of high affinity NRTs help NO3- acquisition through roots of tobacco. Among the NRTs NRT2.1 and NRT2.2 were more up-regulated compared to the other NRTs. Addition of sodium nitroprusside (SNP), relative to those supplied with NO3-/NH4+ nutrition and T42 treated plants singly, and with application of NO inhibitor, cPTIO, confirmed the altered NO fluorescence intensity in tobacco roots. Our findings suggest that T42 promoted plant growth significantly ant N content in the tobacco plants grown under N nutrients, notably higher in NO3-, providing insight of the strategy for not only tobacco but probably for other crops as well to adapt to fluctuating nitrate availability in soil.
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Chickpea is used as a high-energy and protein source in diets of humans and livestock. Moreover, chickpea straw can be used as alternative of forage in ruminant diets. The present study evaluates the effect of beneficial microbial inoculation on enhancing the nutritional values in edible parts of chickpea. Two rhizosphere-competent compatible microbes (Pseudomonas fluorescens OKC and Trichoderma asperellum T42) were selected and applied to seeds either individually or in consortium before sowing. Chickpea seeds treated with the microbes showed enhanced plant growth [88.93% shoot length at 60 days after sowing (DAS)] and biomass accumulation (21.37% at 120 DAS). Notably, the uptake of mineral nutrients, viz., N (90.27, 91.45, and 142.64%), P (14.13, 58.73, and 56.84%), K (20.5, 9.23, and 35.98%), Na (91.98, 101.66, and 36.46%), Ca (16.61, 29.46, and 16%), and organic carbon (28.54, 17.09, and 18.54%), was found in the seed, foliage, and pericarp of the chickpea plants, respectively. Additionally, nutritional quality, viz., total phenolic (59.7, 2.8, and 17.25%), protein (9.78, 18.53, and 7.68%), carbohydrate content (26.22, 30.21, and 26.63%), total flavonoid content (3.11, 9.15, and 7.81%), and reducing power (112.98, 75.42, and 111.75%), was also found in the seed, foliage, and pericarp of the chickpea plants. Most importantly, the microbial-consortium-treated plants showed the maximum increase of nutrient accumulation and enhancement in nutritional quality in all edible parts of chickpea. Nutritional partitioning in different edible parts of chickpea was also evident in the microbial treatments compared to their uninoculated ones. The results thus clearly demonstrated microbe-mediated enhancement in the dietary value of the edible parts of chickpea because seeds are consumed by humans, whereas pericarp and foliage (straw) are used as an alternative of forage and roughage in ruminant diets.
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Cicer/química , Cicer/microbiologia , Pseudomonas fluorescens/fisiologia , Trichoderma/fisiologia , Cicer/crescimento & desenvolvimento , Consórcios Microbianos , Valor Nutritivo , Rizosfera , Sementes/química , Sementes/crescimento & desenvolvimento , Sementes/microbiologiaRESUMO
Plant signaling mechanisms are not completely understood in plant-fungal biotrophic pathogen interactions. Further how such interactions are influenced by compatible rhizosphere microbes are also not well-studied. Therefore, we explored the pea-Erysiphe pisi (obligate biotroph) system to understand the interaction and applied compatible rhizospheric bio-agents Trichoderma asperellum (T42) and Pseudomonas fluorescens (OKC) singly or in combination to assess their influence on the host while under the pathogen challenge. Transcript accumulation pattern of some vital genes in the lignin biosynthetic pathway in pea under E. pisi challenge indicated enhanced activation of the pathway. Interestingly, transcript accumulations were even higher in the bio-agent treated plants compared to untreated plants after pathogen inoculation particularly in co-inoculated treatments. Further, down regulation of the lignifications-associated ABC transporter gene in the pathogen challenged plants possibly is an indication of passive diffusion of monolignols across the membrane from symplast. Additionally, up regulation of NADPH oxidase gene revealed ROS generation in the challenged plants which was confirmed through spectrophotometric estimation of H2O2. Up regulation of laccase and peroxidase along with higher H2O2 generation points out their involvement in lignifications which was further confirmed through cross section analysis of pea stems that showed increased lignifications in pathogen challenged plants co-inoculated with the bioagents. Interestingly, pathogen responsive MAPK homologs MAPK3/MAPK6 and the enzyme serine threonine kinase that activates MAPKs were down regulated and the results possibly indicate non-participation of the MAPK cascade in this interaction. Therefore, it can be concluded that the microbial treatments enhanced pea resistance to E. pisi by generation of ROS and lignifications.
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Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding of plant-microbe interactions that modulate cellular mechanisms in plants under extreme external conditions and help to optimize abiotic stresses. Vigilant amalgamation of these high-throughput approaches supports a higher level of knowledge generation about root-level mechanisms involved in the alleviation of abiotic stresses in organisms.