ABSTRACT
Soils comprise a huge fraction of the world's biodiversity, contributing to several crucial ecosystem functions. However, how the forest-to-pasture conversion impact soil bacterial diversity remains poorly understood, mainly in the Caatinga biome, the largest tropical dry forest of the world. Here, we hypothesized that forest-to-pasture conversion would shape the microbial community. Thus, the soil bacterial community was assessed using the 16S rRNA gene sequencing into the Illumina MiSeq platform. Then, we analyzed ecological patterns and correlated the bacterial community with environmental parameters in forest, and two distinct pastures areas, one less productive and another more productive. The variation in soil properties in pastures and forest influenced the structure and diversity of the bacterial community. Thus, the more productive pasture positively influenced the proportion of specialists and the co-occurrence network compared to the less productive pasture. Also, Proteobacteria, Acidobacteria, and Verrucomicrobia were abundant under forest, while Actinobacteria, Firmicutes, and Chloroflexi were abundant under pastures. Also, the more productive pasture presented a higher bacterial diversity, which is important since that a more stable and connected bacterial community could benefit the agricultural environment and enhance plant performance, as can be observed by the highest network complexity in this pasture. Together, our findings elucidate a significant shift in soil bacterial communities as a consequence of forest-to-pasture conversion and bring important information for the development of preservation strategies.
Subject(s)
Microbiota , Soil , Biodiversity , Forests , RNA, Ribosomal, 16S/genetics , Soil MicrobiologyABSTRACT
The data included in this article supplement the research article titled "Forest-to-pasture conversion modifies the soil bacterial community in Brazilian dry forest Caatinga (manuscript ID: STOTEN-D-21-19067R1)". This data article included the analysis of 18 chemical variables in 36 composite samples (included 4 replicates) of soils from the Microregion of Garanhuns (Northeast Brazil) and also partial 16S rRNA gene sequences from genomic DNA extracted from 27 of these samples (included 3 best quality replicates) for paired-end sequencing (up to 2 × 300 bp) in Illumina MiSeq platform (NCBI - BioProject accession: PRJNA753707). Soils were collected in August 2018 in a tropical subhumid region from the Brazilian Caatinga, along with 27 composite samples from the aboveground part of pastures to determine nutritional quality based on leaf N content. The analysis of variance (ANOVA) and post-hoc tests of environmental data and the main alpha-diversity indices based on linear mixed models (LMM) were represented in the tables. In this case, the collection region (C1 - Brejão, C2 - Garanhuns, and C3 - São João) was the random-effect variable and adjacent habitats formed by a forest (FO) and two pastures (PA and PB succeeded by this forest) composed the fixed-effect variable (land cover), both nested within C. In addition, a table with similarity percentages breakdown (SIMPER) was also shown, a procedure to assess the average percent contribution of individual phyla and bacterial classes. The figures showed the details of the study location, sampling procedure, vegetation status through the Normalized Difference Vegetation Index (NDVI), in addition to the general abundance and composition of the main bacterial phyla.
ABSTRACT
The current agricultural scenario faces diverse challenges, among which phytosanitary issues are crucial. Plant diseases are mostly treated with chemicals, which cause environmental pollution and pathogen resistance. In light of the UN Sustainable Development Goals (SDGs), the biochar alternative use to chemical inputs fits into at least six of the proposed goals (2, 3, 7, 13, 15, and 17), highlighting the 12th, which explains responsible consumption and production. Biochar is valuable for inducing systemic resistance in plants because it is a practical and frequently used resource for improving physical, chemical, and biological soil attributes. This review assessed the beneficial and potential effects of applying biochar to agricultural soils on bacterial pathogen management. Such application is a recent strategy; therefore, this research evaluated 20 studies that used biochar to manage plant diseases caused by pathogens inhabiting the soil in different systems. The effectiveness of biochar application in controlling plant diseases has been attributed to its alkaline pH, which contributes to the growth of beneficial microorganisms and increases nutrient availability, and its porous structure, which provides habitat and protection for soil microbiome development. Therefore, the combined effect of improvements on soil attributes through biochar application aids pathogen control. Biochar application helps manage plant diseases through different mechanisms, inducing plant resistance, increasing activities and abundance of beneficial microorganisms, and changing soil quality for nutrient availability and abiotic conditions.
ABSTRACT
A cana-de-açúcar é uma cultura de grande importância agrícola, nacional e mundial, requerendo grandes quantidades de fertilizantes nitrogenados e fosfatados. Além disso, apresenta associação com bactérias que podem promover o desenvolvimento vegetal. O objetivo deste trabalho foi selecionar bactérias diazotróficas, associadas a plantas de cana-de-açúcar, capazes de solubilizar fosfato inorgânico e avaliar a variabilidade genética bacteriana. Para tanto, foram avaliadas 68 linhagens bacterianas diazotróficas, endofíticas de folha e raiz e do rizoplano, de plantas de três variedades de cana-de-açúcar. A seleção de bactérias solubilizadoras de fosfato inorgânico foi realizada em meio sólido suplementado com fosfato insolúvel, sendo avaliado o índice de solubilização. A análise da variabilidade genética foi realizada pela técnica de BOX-PCR. Os resultados revelaram que 74% das linhagens diazotróficas foram capazes de solubilizar fosfato, apresentando índices de solubilização diferentes. Foi observado que o tecido vegetal e a variedade de cana influenciaram a interação entre bactérias diazotróficas solubilizadoras de fosfato e plantas de cana. O BOX-PCR revelou alta variabilidade genética entre as linhagens analisadas. Logo, conclui-se que as bactérias diazotróficas associadas a plantas de cana-deaçúcar avaliadas expressam a capacidade de solubilizar fosfato inorgânico e que algumas bactérias avaliadas pela técnica de BOX-PCR apresentam alta variabilidade genética.
The sugarcane is a culture of great importance for the Brazilian agriculture. Every year this culture consumes great amounts of nitrogen and phosphate fertilizers. However, the use of plant growth-promoting bacteria can reduce the use of the chemical fertilizers, contributing to the economy and the environment conservation. So, the goal of this study was to select sugarcane-associated diazotrophic bacteria able to solubilize inorganic phosphate and to evaluate the genetic diversity of these bacteria. A total of 68 diazotrophic bacteria, leaf and root endophytic and rizoplane, of three sugarcane varieties. The selection of inorganic phosphate solubilizing diazotrophic bacteria was assayed by the solubilization index (SI) in solid medium containing insoluble phosphate. The genetic variability was analyzed by the BOX-PCR technique. The results showed that 74% of the diazotrophic strains were able to solubilize inorganic phosphate, presenting classes of different SI. The results showed that the vegetal tissue and the genotype plant influenced in the interaction between phosphate solubilizing diazotrophic bacteria and sugarcane plants. BOX-PCR revealed high genetic variability among the strains analyzed. So, sugarcane-associated diazotrophic bacteria express the capacity to solubilize inorganic phosphate and they present high genetic diversity.