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Inoculation of Azospirillum in maize has become a standard practice in Latin America. However, information on the behavior and population survival of the Azospirillum post-inoculation is scarce, making standardization difficult and generating variations in inoculation efficiency across assays. In this study, we tracked the colonization of three agriculturally relevant Azospirillum strains (Ab-V5, Az39, and the ammonium excreting HM053) after different inoculation methods in maize crops by qPCR. Besides, we assessed their ability to promote maize growth by measuring biometric parameters after conducting a greenhouse essay over 42 days. Inoculated plants exhibited Azospirillum population ranging from 103 to 107 cells plant-1 throughout the experiment. While all strains efficiently colonized roots, only A. argentinense Az39 demonstrated bidirectional translocation between roots and shoots, which characterizes a systemic behavior. Optimal inoculation methods for plant growth promotion varied among strains: soil inoculation promoted the best maize growth for the Ab-V5 and Az39 strains, while seed inoculation proved most effective for HM053. The findings of this study demonstrate that the inoculation method affects the behavior of Azospirillum strains and their effectiveness in promoting maize growth, thereby guiding practices to enhance crop yield.

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Ribopeaks is a rapid, sensitive, and economic web tool for bacterial identification based on m/z data from MALDI-TOF MS. To provide greater accuracy and robustness in the Ribopeaks analyzes we present an updated bacterial identification tool version, called Ribopeaks II (RPK-II). RPK-II contains a larger database, with r-protein data from fully sequenced bacterial genomes and optimized algorithms. Furthermore, this new version provides additional information about the identified bacterium, regarding antibiotic resistance.

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Abstract wastewater treatment (WT) is of major importance on modern cities, removing wastewater pollutants resultant from anthropogenic activities. The unique abilities of microbes to degrade organic matter, remove nutrients and transform toxic compounds into harmless products make them essential players in waste treatment. The microbial diversity determines the metabolic pathways that may occur in WT and quality of treated wastewater. Therefore, understanding WT microbial community structure, distribution, and metabolic functioning is essential for development and optimization of efficient microbial engineering systems. Since cultivation methods can only detect a small fraction of the microbial diversity, the use of culture-independent molecular methods has circumvented this issue, allowing unprecedented access to genes and genomes used for microbial composition and function evaluation. Traditional approaches like RAPD, DGGE, ARDRA, RISA, SSCP, T-RFLP, and FISH and modern approaches like microarray, qPCR, and metagenomics are essential techniques for identifying and depicting the total microbial community structure and their interaction with environmental and biotic factors. Thus, this review describes traditional and state of the art molecular techniques which provide insights into phylogenetic and functional activities of microbial assemblages in a WT system.

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BACKGROUND: The non-climacteric 'Yellow' melon (Cucumis melo, inodorus group) is an economically important crop and its quality is mainly determined by the sugar content. Thus, knowledge of sugar metabolism and its related pathways can contribute to the development of new field management and post-harvest practices, making it possible to deliver better quality fruits to consumers. RESULTS: The RNA-seq associated with RT-qPCR analyses of four maturation stages were performed to identify important enzymes and pathways that are involved in the ripening profile of non-climacteric 'Yellow' melon fruit focusing on sugar metabolism. We identified 895 genes 10 days after pollination (DAP)-biased and 909 genes 40 DAP-biased. The KEGG pathway enrichment analysis of these differentially expressed (DE) genes revealed that 'hormone signal transduction', 'carbon metabolism', 'sucrose metabolism', 'protein processing in endoplasmic reticulum' and 'spliceosome' were the most differentially regulated processes occurring during melon development. In the sucrose metabolism, five DE genes are up-regulated and 12 are down-regulated during fruit ripening. CONCLUSIONS: The results demonstrated important enzymes in the sugar pathway that are responsible for the sucrose content and maturation profile in non-climacteric 'Yellow' melon. New DE genes were first detected for melon in this study such as invertase inhibitor LIKE 3 (CmINH3), trehalose phosphate phosphatase (CmTPP1) and trehalose phosphate synthases (CmTPS5, CmTPS7, CmTPS9). Furthermore, the results of the protein-protein network interaction demonstrated general characteristics of the transcriptome of young and full-ripe melon and provide new perspectives for the understanding of ripening.

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Abstract We evaluated the effect of combined Rhizobium tropici, Trichoderma asperellum and plant growth-promoting rhizobacteria (PGPR) in beans crop. The hypothesis that strains of T. asperullum, R. tropici and PGPR combined could improve growth, biomass accumulation and beans yield was tested under greenhouse and field conditions. The treatments consisted of control, mineral nitrogen application and inoculation, isolated and associated with the following microorganisms: Rhizobium tropici, Bacillus subtilis, Trichoderma asperellum and Burkholderia sp. 10N6. Results were evaluated by shoot dry weight (SDW) and root dry weight (RDW), number of nodules and yield components. In greenhouse environment all the microorganisms behaved similarly, and the treatments inoculated with Burkholderia sp. 10N6 (IBu) and R. tropici (IR) stood out regarding the production components. In field conditions the treatments IR and IRTBa presented the highest values of SDW and RDW. Our results suggest that inoculation with R. tropici, T. asperellum and PGPR may promote beans growth and bring benefits to shoot and root accumulation, increase the number of nodules as well as improve yield components, contributing to a sustainable agriculture.

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Abstract Soil management influences organic matter decomposition rates as well soil microbial community functional behavior. No-till (NT) is the most used management system by farmers due to its conservation practices and high productivity. The main objective of this study was to evaluate the impact of surface-applied lime, nitrogen (N) application, and black oat residues on soil microbial community of a Typic Hapludox under continuous NT. Therefore, soil chemical attributes, microbial biomass carbon, basal respiration, metabolic quotient, most probable number of diazotrophs, as well as bacterial functional analysis were performed. The effect of liming and N fertilization amendments inputs were saw in soil respiration and metabolic quotient measurements, showing them to be good indicators of soil quality. Further studies should be carried out in order to molecularly identify microbial communities present in soils with different liming and N fertilization management to evaluate the behavior of specific bacterial taxa under such conditions.

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Summary: MALDI-TOF MS is a rapid, sensitive and economic tool for bacterial identification. Highly abundant bacterial proteins are detected by this technique, including ribosomal proteins (r-protein), and the generated mass spectra are compared with a MALDI-TOF MS spectra database. Currently, it allows mainly the classification of clinical bacteria due to the limited number of environmental bacteria included in the spectra database. We present a wide-ranging bacterium classifier tool, called Ribopeaks, which was created based on r-protein data from the Genbank. The Ribopeaks database has more than 28 500 bacterial taxonomic records. It compares the incoming m/z data from MALDI-TOF MS analysis with models stored in the Ribopeaks database created by machine learning and then taxonomically classifies the bacteria. Availability and implementation: The software is available at http://www.ribopeaks.com. Supplementary information: Supplementary data are available at Bioinformatics online.

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Melon, a member of the family Cucurbitaceae, is the fourth most important fruit in the world market and, on a volume basis, is Brazils main fresh fruit export. Many molecular techniques used to understand the maturation of these fruits require high concentrations of highly purified RNA. However, melons are rich in polyphenolic compounds and polysaccharides, which interfere with RNA extraction. This study aimed to determine the most appropriate method for total RNA extraction from melon fruits. Six extraction buffers were tested: T1) guanidine thiocyanate/phenol/chloroform; T2) sodium azide/?-mercaptoethanol; T3) phenol/guanidine thiocyanate; T4) CTAB/PVP/?-mercaptoethanol; T5) SDS/sodium perchlorate/PVP/?-mercaptoethanol, and T6) sarkosyl/PVP/guanidine thiocyanate, using the AxyPrepTM Multisource Total RNA Miniprep Kit. The best method for extracting RNA from both mature and green fruit was based on the SDS/PVP/?-mercaptoethanol buffer, because it rapidly generated a high quality and quantity of material. In general, higher amounts of RNA were obtained from green than mature fruits, probably due to the lower concentration of polysaccharides and water. The purified material can be used as a template in molecular techniques, such as microarrays, RT-PCR, and in the construction of cDNA and RNA-seq data.(AU)

O melão pertencente à família Cucurbitaceae é o quarto fruto mais importante no mercado mundial e a fruta mais exportada pelo Brasil. Muitas técnicas moleculares utilizadas para compreender a maturação destes frutos requerem o uso de RNA altamente purificado e em alta concentração. Entretanto, o elevado nível de compostos polifenólicos e polissacarídeos nos frutos tornam a extração de RNA um desafio. Este trabalho teve por objetivo determinar o método mais adequado para extração de RNA total em frutos de melão. Seis diferentes tampões de extração foram testados: T1) tiocianato de guanidina/fenol/clorofórmio; T2) azida de sódio/?-mercaptoetanol; T3) fenol/tiocianato de guanidina, T4) CTAB/PVP/?-mercaptoetanol, T5) SDS/perclorato de sódio/PVP/?-mercaptoetanol e T6) sarcosil/PVP/tiocianato de guanidina associado com AxyPrep TM Multisource Total RNA Miniprep Kit. O melhor método para extração do RNA tanto de fruto verde quanto maduro foi o baseado no tampão SDS/PVP/?-mercaptoetanol, por gerar material íntegro e de qualidade em grande quantidade, associado à rapidez de execução. Em geral, maiores quantidades de RNA foram obtidas a partir de frutos verdes, provavelmente devido à baixa concentração de polissacarídeos e água. O material purificado poderá ser utilizado como molde em técnicas de estudos moleculares como microarrays, RT-PCR e bibliotecas de cDNA e RNAseq, pelo qual foi testado.(AU)

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Soil bacteria colonization in plants is a complex process, which involves interaction between many bacterial characters and plant responses. In this work, we labeled Azospirillum brasilense FP2 (wild type) and HM053 (excretion-ammonium) strains by insertion of the reporter gene gusA-kanamycin into the dinitrogenase reductase coding gene, nifH, and evaluated bacteria colonization in barley (Hordeum vulgare). In addition, we determined inoculation effect based on growth promotion parameters. We report an uncommon endophytic behavior of A. brasilense Sp7 derivative inside the root hair cells of barley and highlight the promising use of A. brasilense HM053 as plant growth-promoting bacterium.

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Melon, a member of the family Cucurbitaceae, is the fourth most important fruit in the world market and, on a volume basis, is Brazils main fresh fruit export. Many molecular techniques used to understand the maturation of these fruits require high concentrations of highly purified RNA. However, melons are rich in polyphenolic compounds and polysaccharides, which interfere with RNA extraction. This study aimed to determine the most appropriate method for total RNA extraction from melon fruits. Six extraction buffers were tested: T1) guanidine thiocyanate/phenol/chloroform; T2) sodium azide/?-mercaptoethanol; T3) phenol/guanidine thiocyanate; T4) CTAB/PVP/?-mercaptoethanol; T5) SDS/sodium perchlorate/PVP/?-mercaptoethanol, and T6) sarkosyl/PVP/guanidine thiocyanate, using the AxyPrepTM Multisource Total RNA Miniprep Kit. The best method for extracting RNA from both mature and green fruit was based on the SDS/PVP/?-mercaptoethanol buffer, because it rapidly generated a high quality and quantity of material. In general, higher amounts of RNA were obtained from green than mature fruits, probably due to the lower concentration of polysaccharides and water. The purified material can be used as a template in molecular techniques, such as microarrays, RT-PCR, and in the construction of cDNA and RNA-seq data.

O melão pertencente à família Cucurbitaceae é o quarto fruto mais importante no mercado mundial e a fruta mais exportada pelo Brasil. Muitas técnicas moleculares utilizadas para compreender a maturação destes frutos requerem o uso de RNA altamente purificado e em alta concentração. Entretanto, o elevado nível de compostos polifenólicos e polissacarídeos nos frutos tornam a extração de RNA um desafio. Este trabalho teve por objetivo determinar o método mais adequado para extração de RNA total em frutos de melão. Seis diferentes tampões de extração foram testados: T1) tiocianato de guanidina/fenol/clorofórmio; T2) azida de sódio/?-mercaptoetanol; T3) fenol/tiocianato de guanidina, T4) CTAB/PVP/?-mercaptoetanol, T5) SDS/perclorato de sódio/PVP/?-mercaptoetanol e T6) sarcosil/PVP/tiocianato de guanidina associado com AxyPrep TM Multisource Total RNA Miniprep Kit. O melhor método para extração do RNA tanto de fruto verde quanto maduro foi o baseado no tampão SDS/PVP/?-mercaptoetanol, por gerar material íntegro e de qualidade em grande quantidade, associado à rapidez de execução. Em geral, maiores quantidades de RNA foram obtidas a partir de frutos verdes, provavelmente devido à baixa concentração de polissacarídeos e água. O material purificado poderá ser utilizado como molde em técnicas de estudos moleculares como microarrays, RT-PCR e bibliotecas de cDNA e RNAseq, pelo qual foi testado.

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