RESUMEN
In this study, two wheat-derived cadmium (Cd)-immobilizing endophytic Pseudomonas paralactis M14 and Priestia megaterium R27 were evaluated for their effects on wheat tissue Cd uptake under hydroponic conditions. Then, the impacts of the biochar (BC), M14+R27 (MR), and BC+MR treatments on wheat Cd uptake and the mechanisms involved were investigated at the jointing, heading, and mature stages of wheat plants under field-plot conditions. A hydroponic experiment showed that the MR treatment significantly decreased the above-ground tissue Cd content compared with the M14 or R27 treatment. The BC+MR treatment reduced the grain Cd content by 51.5%-67.7% and Cd translocation factor at the mature stage of wheat plants and increased the organic matter-bound Cd content by 31%-75% in the rhizosphere soils compared with the BC or MR treatment. Compared with the BC or MR treatment, the relative abundances of the biomarkers associated with Gemmatimonas, Altererythrobacter, Gammaproteobacteria, Xanthomonadaceae, Phenylobacterium, and Nocardioides in the BC+MR-treated rhizosphere microbiome decreased and negatively correlated with the organic matter-bound Cd contents. In the BC+MR-treated root interior microbiome, the relative abundance of the biomarker belonging to Exiguobacterium increased and negatively correlated with the Cd translocation factor, while the relative abundance of the biomarker belonging to Pseudonocardiaceae decreased and positively correlated with the Cd translocation factor. Our findings suggested that the BC+MR treatment reduced Cd availability and Cd transfer through affecting the abundances of these specific biomarkers in the rhizosphere soil and root interior microbiomes, leading to decreased wheat grain Cd uptake in the contaminated soil.
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Cadmio , Carbón Orgánico , Microbiología del Suelo , Contaminantes del Suelo , Triticum , Triticum/metabolismo , Triticum/microbiología , Cadmio/metabolismo , Contaminantes del Suelo/metabolismo , Endófitos/fisiología , Rizosfera , Suelo/química , Biodegradación Ambiental , Microbiota/efectos de los fármacosRESUMEN
Pollution accident of nonferrous metallurgy industry often lead to serious heavy metal pollution of the surrounding soil. Phytoremediation of contaminated soil is an environmental and sustainable technology, and soil native microorganisms in the process of phytoremediation also participate in the remediation of heavy metals. However, the effects of high concentrations of multiple heavy metals (HCMHMs) on plants and native soil microorganisms remain uncertain. Thus, further clarification of the mechanism of phytoremediation of HCMHMs soil by plants and native soil microorganisms is required. Using the plant Sedum alfredii (S. alfredii) to restore HCMHM-contaminated soil, we further explored the mechanism of S. alfredii and native soil microorganisms in the remediation of HCMHM soils. The results showed that (i) S. alfredii can promote heavy metals from non-rhizosphere soil to rhizosphere soil, which is conducive to the effect of plants on heavy metals. In addition, it can also enrich the absorbed heavy metals in its roots and leaves; (ii) native soil bacteria can increase the abundance of signal molecule-synthesizing enzymes, such as trpE, trpG, bjaI, rpfF, ACSL, and yidC, and promote the expression of the pathway that converts serine to cysteine, then synthesize substances to chelate heavy metals. In addition, we speculated that genes such as K19703, K07891, K09711, K19703, K07891, and K09711 in native bacteria may be involved in the stabilization or absorption of heavy metals. The results provide scientific basis for S. alfredii to remediate heavy metals contaminated soils, and confirm the potential of phytoremediation of HCMHM contaminated soil.
Asunto(s)
Biodegradación Ambiental , Metales Pesados , Sedum , Microbiología del Suelo , Contaminantes del Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/metabolismo , Sedum/metabolismo , Metales Pesados/análisis , Rizosfera , Suelo/químicaRESUMEN
Biological nitrogen fixation is the main source of nitrogen in ecosystems. The diversity of soil rhizobia and their effects on soybeans need further research. In this study, we collected soybean rhizosphere samples from eight sites in the black soil soybean planting area in Northeast China. A total of 94 strains of bacteria were isolated and identified using the 16S rRNA and symbiotic genes (nodC, nifH) analysis, of which 70 strains were identified as rhizobia belonging to the genus Bradyrhizobium. To further validate the application effects of rhizobia, we selec-ted seven representative indigenous rhizobia based on the results of phylogenetic analysis, and conducted laboratory experiments to determine their nodulation and the impacts on soybeans. The results showed that, compared to the control without rhizobial inoculation, all the seven indigenous rhizobia exhibited good promoting and nodulation abilities. Among them, strains H7-L22 and H34-L6 performed the best, with the former significantly increasing plant height by 25.7% and the latter increasing root nodule dry weight by 20.9% to 67.1% compared to other indi-genous rhizobia treatments. We tested these two efficient rhizobia strains as soybean rhizobial inoculants in field experiments. The promoting effect of mixed rhizobial inoculants was significantly better than single ones. Compared to the control without inoculation, soybean yield increased by 8.4% with the strain H7-L22 treatment and by 17.9% with the mixed inoculant treatment. Additionally, there was a significant increase in the number of four-seed pods in soybeans. In conclusion, the application of rhizobial inoculants can significantly increase soybean yield, thereby reducing dependence on nitrogen fertilizer during soybean production, improving soil health, and promoting green development in agriculture in the black soil region of Northeast China.
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Bradyrhizobium , Glycine max , Microbiología del Suelo , Glycine max/microbiología , Glycine max/crecimiento & desarrollo , China , Bradyrhizobium/aislamiento & purificación , Bradyrhizobium/fisiología , Bradyrhizobium/genética , Bradyrhizobium/clasificación , Rhizobium/aislamiento & purificación , Rhizobium/fisiología , Rhizobium/genética , Rhizobium/clasificación , Simbiosis , Filogenia , Fijación del Nitrógeno , Biodiversidad , Rizosfera , ARN Ribosómico 16S/genéticaRESUMEN
Improving the availability of soil phosphorus (P) and promoting tree growth through tree species selection and assembly are the critical issue. We conducted an afforestation experiment following randomized block experimental design with 1, 2, 4, and 6 tree species richness in south subtropics, including Pinus massoniana, Mytilaria laosensis, Erythrophleum fordii, Castanopsis hystrix, Michelia macclurei, Manglietia glauca, Aquilaria sinensis, and Dalbergia odorifera. We measured the bioavailable P components (CaCl2-P, citrate-P, enzyme-P and HCl-P) and examined the effects of different tree species assembly on bioavailable P components and tree growth. The results showed that, compared with non-nitrogen-fixing tree species, the mixing of nitrogen-fixing tree species (E. fordii and D. odorifera) effectively increased the contents of soil water, total nitrogen, total phosphorus, and microbial biomass P (MBP). The assembly of specific tree species improved the accumulation of bioavailable P. Mixing of nitrogen-fixing tree species significantly increased CaCl2-P content by 46.2% to 160.3%, the enzyme-P content produced by microbial mineralization by 69.3% to 688.2%, and HCl-P by 31.5% to 81.3%, increased MBP by 81.8% to 149.4%, and microbial biomass N (MBN) by 88.1% to 160.6%, respectively. Redundancy and correlation analysis results showed that MBP, available P, total phosphorus, L-leucine aminopeptidase, cellobiose, acid phosphatase, MBN and soil organic carbon were key factors driving the variation of rhizosphere soil bioavailable P. Mixing of nitrogen-fixing tree species increased enzyme-P and citrate-P, and the availability of which were positively correlated to tree basal area. In this study, mixing of nitrogen-fixing tree species increased the rhizosphere soil bioavailable P content, which facilitates tree growth.
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Fósforo , Rizosfera , Suelo , Árboles , Fósforo/metabolismo , Fósforo/análisis , Árboles/crecimiento & desarrollo , Árboles/metabolismo , Suelo/química , China , Clima Tropical , Nitrógeno/metabolismo , Nitrógeno/análisis , Pinus/crecimiento & desarrollo , Pinus/metabolismoRESUMEN
Effective microorganisms (EM) might alleviate deterioration of soil environmental quality and yield decline of pepper (Capsicum annuum) caused by continuous replanting and imbalanced fertilizer application in Xinjiang. We investigated the effects of applying EM microbial agent on the growth of pepper plants, yield, soil nutrient content, soil enzyme activity, and rhizosphere eukaryotic community. The results showed that the application of EM microbial agent increased plant height, stem diameter, leaf length, leaf width and root length by 22.6%, 35.3%, 33.3%, 29.7% and 15.1%, respectively. It also increased fruit width, individual fruit weight, and yield by 5.3%, 42.9%, and 74.7%, respectively. After the application of EM microbial agent, the levels of soil available nitrogen increased by 10.2% and 5.8% during the flowering and maturity stages, respectively. Similarly, available phosphorus increased by 10.4% and 13.4%, respectively. The soil sucrase activity was increased by 40.7%, 14.6%, and 9.3% during the seedling, flowering, and maturity stages, respectively. Urease activity was also increased by 7.9%, 10.2%, and 11.5%, respectively. Furthermore, the application of EM microbial agent increased soil peroxidase activity by 16.8% and 44.6% at flowering and maturity stages, respectively. The application of microbial agent significantly altered the ß-diversity of the rhizosphere eukaryotic community in pepper plants. Specifically, microbial agent increased the relative abundances of populations belonging to Enchytraeus and Sminthurides genera, which could contribute to soil improvement and nutrient cycling. Compared to the CK, the relative abundance of pathogenic microorganisms including Olpidium and Aplanochytrium genera decreased by 98.0% and 89.3%, and the relative abundance of the Verticillium decreased to 0. These results demonstrated that EM microbial agent could increase soil nutrient content, enhance soil enzyme activity, and reduce soil pathogenic fungi in the pepper cultivation areas of Xinjiang, thus achieving beneficial effects on pepper growth and fruit yield.
Asunto(s)
Capsicum , Rizosfera , Microbiología del Suelo , Capsicum/crecimiento & desarrollo , Capsicum/microbiología , China , Suelo/química , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismoRESUMEN
Rhizosphere is a vital area for substance exchange and energy transfer between roots and soil microorganisms. Therefore, diazotrophs in the rhizosphere play a pivotal role in facilitating plant nitrogen acquisition. We investigated the variability in the abundance and community structure of soil diazotrophs and the influencing factors across rhizosphere soils of Cunninghamia lanceolata in three locations: Baisha State-owned Forest Farm in Longyan City (BS), Sanming Forest Ecosystem and Global Change Research Station (SM), and Wuyishan National Forest Park in Nanping City (WYS), located in the western region of Fujian Province, quantified the diazotrophic abundance by using real-time quantitative PCR, and assessed the community structure by high-throughput sequencing. The results showed that soil pH, C:N ratio, and C:(N:P) stoichiometry in SM were notably lower compared to those in BS and WYS. In SM, the abundance of the nifH gene was 6.38×108 copies·g-1, significantly lower than 1.35×109 copies·g-1 in BS and 1.10×109 copies·g-1 in WYS. Additionally, α diversity index of diazotrophs was lower in SM compared to BS and WYS, while the community structure of diazotrophs in rhizosphere soils of BS and WYS was similar, which differed significantly from that in SM. The diazotrophic sequences in the three forest farms could be divided into 5 phylum, 8 classes, 15 orders, 23 families and 33 genera, with Proteobacteria, α-proteobacteria, and Bradyrhizobium as the dominant phylotypes. Soil pH, available phosphorus, NO3--N and C:(N:P) ratio were identified as significant factors influencing both the abundance and community structure of nifH genes, with soil pH performing the greatest. Taken together, there were spatial variations in the distribution of diazotrophic abundance and community structure in C. lanceolata rhizosphere soils, with soil pH as the primary driving factor.
Asunto(s)
Cunninghamia , Rizosfera , Microbiología del Suelo , Cunninghamia/crecimiento & desarrollo , China , Suelo/química , Nitrógeno/análisis , Nitrógeno/metabolismo , Fijación del Nitrógeno , Bacterias Fijadoras de Nitrógeno/metabolismo , Bacterias Fijadoras de Nitrógeno/clasificación , Bacterias Fijadoras de Nitrógeno/aislamiento & purificación , Bacterias Fijadoras de Nitrógeno/genética , Clima TropicalRESUMEN
BACKGROUND: Plant growth-promoting rhizobacteria (PGPR), as a group of environmentally friendly bacteria growing in the rhizosphere of plants, play an important role in plant growth and development and resistance to environmental stresses. However, their limited understanding has led to the fact that their large-scale use in agriculture is still scarce, and the mechanisms by which beneficial bacteria are selected by plants and how they interact with them are still unclear. METHOD: In this study, we investigated the interaction between the auxin-producing strain Bacillus aryabhattai LAD and maize roots, and performed transcriptomic and metabolomic analyses of Bacillus aryabhattai LAD after treatment with maize root secretions(RS). RESULTS: Our results show that there is a feedback effect between the plant immune system and bacterial auxin. Bacteria activate the immune response of plant roots to produce reactive oxygen species(ROS), which in turn stimulates bacteria to synthesize IAA, and the synthesized IAA further promotes plant growth. Under the condition of co-culture with LAD, the main root length, seedling length, root surface area and root volume of maize increased by 197%, 107%, 89% and 75%, respectively. In addition, the results of transcriptome metabolome analysis showed that LAD was significantly enriched in amino acid metabolism, carbohydrate metabolism and lipid metabolism pathways after RS treatment, including 93 differentially expressed genes and 45 differentially accumulated metabolites. CONCLUSION: Our findings not only provide a relevant model for exploring the effects of plant-soil microbial interactions on plant defense functions and thereby promoting plant growth, but also lay a solid foundation for the future large-scale use of PGPR in agriculture for sustainable agricultural development.
Asunto(s)
Bacillus , Ácidos Indolacéticos , Raíces de Plantas , Especies Reactivas de Oxígeno , Zea mays , Zea mays/microbiología , Zea mays/crecimiento & desarrollo , Zea mays/metabolismo , Bacillus/metabolismo , Bacillus/genética , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , Especies Reactivas de Oxígeno/metabolismo , Ácidos Indolacéticos/metabolismo , Rizosfera , Microbiología del Suelo , Transcriptoma , Desarrollo de la Planta , Reguladores del Crecimiento de las Plantas/metabolismoRESUMEN
Ralstonia solanacearum and R. pseudosolanacearum, the causative agents of bacterial wilt, ranks as the second most devastating phytopathogens, affecting over 310 plant species and causing substantial economic losses worldwide. R. solanacearum and R. pseudosolanacearum infect plants through the underground root system, where it interacts with both the host and the surrounding microbiota and multiply in the xylem where bacteria cell and its polysaccharide product block the water transportation from root to aboveground. Currently, effective control methods are limited, as resistance genes are unavailable and antibiotics prove ineffective. In current Commentary, we review recent advancements in combating bacterial wilt, categorizing the approaches (weapons) into three distinct strategies. The physical and chemical weapons focus on leveraging sound waves to trigger crop immunity and reducing bacterial virulence signaling, respectively. The biological weapon employs predatory protists to directly consume Ralstonia cells in the root zone, while also reshaping the protective rhizosphere microbiome to fortify the plant. We believe that these novel methods hold the potential to revolutionize crop protection from bacterial wilt and inspire new era in sustainable agriculture.
Asunto(s)
Enfermedades de las Plantas , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Ralstonia solanacearum/patogenicidad , Ralstonia solanacearum/fisiología , Raíces de Plantas/microbiología , Rizosfera , Ralstonia/patogenicidadRESUMEN
The Loess Plateau is one of the key areas for soil and water erosion control in China. Planting vegetation, such as Robinia pseudoacacia, is one of the mainstream methods to prevent soil and water erosion. However, the combination of abundant calcium ions and phosphate in the soil of the Loess Plateau limits the phosphorus nutrition of plants. In the present study, soil samples were collected under the R. pseudoacacia forest, from which two PSB strains with efficient phosphate solubilization capacities, named PSB2 and PSB7, were isolated and screened. The dissolved phosphate concentrations of their culture media were 9.68-fold and 11.61-fold higher, respectively, than that of the control group. After identification, PSB2 was classified as Pseudomonas and PSB7 as Inquilinus. This is the first time that Inquilinus has been isolated as a PSB from calcareous soil in the Loess Plateau. We then investigated the effects of different growth conditions on their phosphate solubilization capacities. Both strains effectively utilized glucose and ammonium nitrogen while maintaining high phosphate solubilization efficiency. In addition, PSB2 preferred to survive under neutral conditions and PSB7 under acidic conditions. Pot experiments indicated that the inoculation with PSB7 significantly increased the phosphorus content in the roots of R. pseudoacacia. These results imply the potential of this PSB as a phosphorus biofertilizer for R. pseudoacacia, which may be beneficial for soil and water management on the Loess Plateau.
Asunto(s)
Fosfatos , Raíces de Plantas , Rizosfera , Robinia , Microbiología del Suelo , Robinia/microbiología , Robinia/química , Fosfatos/metabolismo , China , Raíces de Plantas/microbiología , Suelo/química , Solubilidad , Fósforo/metabolismo , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/aislamiento & purificación , Bacterias/genética , Pseudomonas/metabolismo , Pseudomonas/aislamiento & purificación , Pseudomonas/clasificación , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
To investigate the effects of different typical exogenous salt concentrations on total soil salinity and the growth of Lycium barbarum under brackish water irrigation, and to determine the salinity threshold of irrigated brackish water that is conducive to the normal growth of Lycium barbarum while mitigating soil salinity accumulation. Four typical exogenous salts (NaCl, CaCl2, NaHCO3, Na2SO4) were selected and set at four concentrations (0.1, 0.5, 2.0, 4.0 g L-1) to conduct a field crossover experiments in the downstream region of the Hetao Irrigation District. The results showed that in the same fertility period, the growth rates of new branches, ground diameter, and crown width first increased and then decreased with rising concentrations of NaCl, CaCl2, and Na2SO4, but showed an inverse relationship with NaHCO3 concentrations. Furthermore, increasing salt concentrations linearly reduced the yield of dry fruits from Lycium barbarum and led to a notable accumulation of total soil salts. Utilizing an experimental research approach, a comprehensive analysis of involving multiple growth indices, stable yield, and soil salinity control of Lycium barbarum revealed that optimal growth occurs at salt concentrations of 0.1-0.5 g L-1 for different water quality areas within the irrigation area; using the method of path analysis identified the total soil salt and crown width as the primary direct and indirect factors influencing the yield of Lycium barbarum. The results of this study provide scientific basis and significant theoretical support for the safe and rational utilization of brackish water and cultivation of Lycium barbarum in typical regions with varying saline water qualities of Hetao irrigation area.
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Riego Agrícola , Lycium , Rizosfera , Aguas Salinas , Salinidad , Suelo , Lycium/crecimiento & desarrollo , Lycium/metabolismo , Riego Agrícola/métodos , Suelo/química , Cloruro de Sodio/farmacologíaRESUMEN
Antagonistic bacterial strains from Bacillus spp. have been widely studied and utilized in the biocontrol of phytopathogens and the promotion of plant growth, but their impacts on the rhizosphere microecology when applied to crop plants are unclear. Herein, the effects of applying the antagonistic bacterium Bacillus subtilis S1 as a biofertilizer on the rhizosphere microecology of cucumbers were investigated. In a pot experiment on cucumber seedlings inoculated with S1, 3124 bacterial operational taxonomic units (OTUs) were obtained from the rhizosphere soils using high-throughput sequencing of 16S rRNA gene amplicons, and the most abundant phylum was Proteobacteria that accounted for 49.48% in the bacterial community. S1 treatment significantly reduced the abundances of soil bacterial taxa during a period of approximately 30 days but did not affect bacterial diversity in the rhizosphere soils of cucumbers. The enzymatic activities of soil nitrite reductase (S-Nir) and dehydrogenase (S-DHA) were significantly increased after S1 fertilization. However, the activities of soil urease (S-UE), cellulase (S-CL), and sucrase (S-SC) were significantly reduced compared to the control group. Additionally, the ammonium- and nitrate-nitrogen contents of S1-treated soil samples were significantly lower than those of the control group. S1 fertilization reshaped the rhizosphere soil bacterial community of cucumber plants. The S-CL activity and nitrate-nitrogen content in rhizosphere soil affected by S1 inoculation play important roles in altering the abundance of rhizosphere soil microbiota.
Asunto(s)
Bacillus subtilis , Bacterias , Cucumis sativus , Nitrógeno , Rizosfera , Microbiología del Suelo , Cucumis sativus/microbiología , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Nitrógeno/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/metabolismo , Bacterias/aislamiento & purificación , ARN Ribosómico 16S/genética , Fertilizantes/análisis , Suelo/química , Microbiota , FilogeniaRESUMEN
Expanding and intensifying agriculture has led to a loss of soil carbon. As agroecosystems cover over 40% of Earth's land surface, they must be part of the solution put in action to mitigate climate change. Development of efficient management practices to maximize soil carbon retention is currently limited, in part, by a poor understanding of how plants, which input carbon to soil, and microbes, which determine its fate there, interact. Here we implement a diversity gradient by intercropping undersown species with barley in a large field trial, ranging from one to eight undersown species. We find that increasing plant diversity strengthens positive associations within the rhizosphere soil microbial community in relation to negative associations. These associations, in turn, enhance community carbon use efficiency. Jointly, our results highlight how increasing plant diversity in agriculture can be used as a management strategy to enhance carbon retention potential in agricultural soils.
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Agricultura , Biodiversidad , Carbono , Rizosfera , Microbiología del Suelo , Suelo , Carbono/metabolismo , Agricultura/métodos , Suelo/química , Hordeum/microbiología , Hordeum/metabolismo , Plantas/metabolismo , Plantas/microbiología , Microbiota , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismoRESUMEN
Resource islands are vegetative formations in arid and semi-arid ecosystems that harbor microorganisms facing extreme conditions. However, there is a limitation in the knowledge of the agricultural biotechnological potential of microorganisms present in these islands. This study aimed to determine the capacity of Bacillus velezensis C3-3 and Cytobacillus sp. T106 isolates from resource islands to promote plant growth and control the phytopathogen Rhizoctonia solani. The bacteria were sequenced, and both grew at 50 °C, resisted 5% NaCl, withstood UV exposure, and grew in extreme pH conditions. Sixty-six genes in C3-3 and 71 in T106 were identified associated with plant growth promotion, and C3-3 was shown to promote leaf growth in lettuce plants. This promotional effect was associated with the production of indole-3-acetic acid (IAA), phosphorus solubilization, and the presence of genes related to the assimilation of rhizosphere exudates. Both strains inhibited R. solani through the production of volatile compounds and antagonism. Forty-five and 40 of these genes in C3-3 and T106, respectively, were associated with the production of proteases, lipases, siderophores, antimicrobial compounds, degradation enzymes, and secretion systems. Notably, Cytobacillus sp. has not been previously reported as a biocontrol agent. This work contributes to the evidence of the biotechnological potential of semi-arid region bacteria, offering prospects for improving agricultural production in areas with limiting conditions.
Asunto(s)
Bacillus , Microbiología del Suelo , Bacillus/genética , Bacillus/metabolismo , Bacillus/aislamiento & purificación , Rhizoctonia/genética , Rhizoctonia/crecimiento & desarrollo , Rizosfera , Enfermedades de las Plantas/microbiología , Agricultura , Lactuca/microbiología , Biotecnología/métodos , Islas , Ácidos IndolacéticosRESUMEN
It is increasingly recognized that different genetic variants of hosts can uniquely shape their microbiomes. Invasive species often evolve in their introduced ranges, but little is known about the potential for their microbial associations to change during invasion as a result. We asked whether host genotype (G), microbial environment (E), or their interaction (G × E) affected the composition and diversity of host-associated microbiomes in Centaurea solstitialis (yellow starthistle), a Eurasian plant that is known to have evolved novel genotypes and phenotypes and to have altered microbial interactions, in its severe invasion of CA, USA. We conducted an experiment in which native and invading plant genotypes were inoculated with native and invaded range soil microbial communities. We used amplicon sequencing to characterize rhizosphere bacteria in both the experiment and the field soils from which they were derived. We found that native and invading plant genotypes accumulated different microbial associations at the family level in each soil community, often counter to differences in family abundance between soil communities. Root associations with potentially beneficial Streptomycetaceae were particularly interesting, as these were more abundant in the invaded range field soil and accumulated on invading genotypes. We also found that bacterial diversity is higher in invaded soils, but that invading genotypes accumulated a lower diversity of bacteria and unique microbial composition in experimental inoculations, relative to native genotypes. Thus variation in microbial associations of invaders was driven by the interaction of plant G and microbial E, and rhizosphere microbial communities appear to change in composition in response to host evolution during invasion.
Asunto(s)
Bacterias , Genotipo , Especies Introducidas , Microbiota , Rizosfera , Microbiología del Suelo , Bacterias/genética , Bacterias/clasificación , Bacterias/aislamiento & purificación , Centaurea/microbiología , Centaurea/genética , Raíces de Plantas/microbiología , California , Suelo/químicaRESUMEN
Root-knot nematodes (Meloidogyne spp.) are highly destructive pests that cause significant yield losses annually. Biological control of nematodes has emerged as a potential alternative in sustainable agriculture. In this study, we originally isolated Bacillus cereus G5 from the rhizosphere soil of rice (Oryza sativa). Treatment with the fermentation supernatant of G5 in vitro demonstrated high toxicity to second-stage juveniles (J2) of Meloidogyne graminicola and remarkably inhibited egg hatching. Moreover, G5 steadily colonized rhizosphere soil and rice seedlings, and exhibited excellent biocontrol efficacy against M. graminicola under greenhouse conditions. Notably, the volatile organic compounds (VOCs) produced by G5 displayed high fumigant activity against M. graminicola. The G5 VOCs efficiently reduced the gall index and nematode population in rice roots, while also promoting rice growth in double-layered pot tests. Additionally, the expression of defense genes involved in the salicylic acid (OsNPR1, OsWRKY45, OsPAL1), jasmonic acid (OsJaMYB, OsAOS2) and ethylene (OsACS1) signalling pathways was significantly upregulated in rice seedlings treated with G5 VOCs. This suggests that G5 VOCs contribute to eliciting plant defense responses. Furthermore, we identified 14 major VOCs produced by G5 using solid-phase micro-extraction gas chromatography and mass spectrometry (SPEM-GC-MS). Notably, allomatrine, morantel, 1-octen-3-ol and 3-methyl-2-butanol displayed strong contact nematicidal activity. Among these, only 1-octen-3-ol demonstrated fumigant activity against J2s of M. graminicola, with an LC50 value of 758.95 mg/L at 24 h. Overall, these results indicated that the B. cereus G5 and its synthetic VOCs possess high potential as biocontrol agents for managing root-knot nematodes.
Asunto(s)
Bacillus cereus , Oryza , Tylenchoidea , Compuestos Orgánicos Volátiles , Animales , Tylenchoidea/efectos de los fármacos , Tylenchoidea/fisiología , Bacillus cereus/efectos de los fármacos , Compuestos Orgánicos Volátiles/farmacología , Compuestos Orgánicos Volátiles/metabolismo , Oryza/parasitología , Oryza/microbiología , Control Biológico de Vectores/métodos , Enfermedades de las Plantas/prevención & control , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/parasitología , Rizosfera , Agentes de Control Biológico/farmacologíaRESUMEN
Fritillaria cirrhosa, an endangered medicinal plant in the Qinghai-Tibet Plateau, is facing resource scarcity. Artificial cultivation has been employed to address this issue, but problems related to continuous cultivation hinder successful transplantation. Imbalanced microbial communities are considered a potential cause, yet the overall changes in the microbial community under continuous cropping systems remain poorly understood. Here, we investigated the effects of varying durations of continuous cropping on the bacterial and fungal communities, as well as enzymatic activities, in the rhizospheric soil of F. cirrhosa. Our findings revealed that continuous cropping of F. cirrhosa resulted in soil acidification, nutrient imbalances, and increased enzyme activity. Specifically, after 10 years of continuous cropping, there was a notable shift in the abundance and diversity (e.g., Chao1 index) of soil bacteria and fungi. Moreover, microbial composition analyses revealed a significant accumulation of harmful microorganisms associated with soil-borne diseases (e.g., Luteimonas, Parastagonospora, Pseudogymnoascus) in successively cropped soils, in contrast to the significant reduction of beneficial microorganisms (e.g., Sphingomonas, Lysobacter, Cladosporium) that promote plant growth and development and protect against diseases such as Fusarium sp.These changes led to decreased connectivity and stability within the soil microbial community. Structural equation modeling and redundancy analysis revealed that alkaline hydrolytic nitrogen and available phosphorus directly influenced soil pH, which was identified as the primary driver of soil microbial community changes and subsequently contributed to soil health deterioration. Overall, our results highlight that soil acidification and imbalanced rhizosphere microbial communities are the primary challenges associated with continuous cropping of F. cirrhosa. These findings establish a theoretical foundation for standardized cultivation practices of F. cirrhosa and the bioremediation of continuously cultivated soils.
Asunto(s)
Bacterias , Fritillaria , Hongos , Microbiología del Suelo , Fritillaria/crecimiento & desarrollo , Fritillaria/microbiología , Tibet , Bacterias/clasificación , Bacterias/crecimiento & desarrollo , Suelo/química , Rizosfera , Microbiota , MicobiomaRESUMEN
The gut microbiome of worms from composting facilities potentially harbors organisms that are beneficial to plant growth and development. In this experiment, we sought to examine the potential impacts of rhizosphere microbiomes derived from Eisenia fetida worm castings (i.e. vermicompost) on tomato (Solanum lycopersicum, L.) plant growth and physiology. Our experiment consisted of a greenhouse trial lasting 17 weeks total in which tomato plants were grown with one of three inoculant treatments: a microbial inoculant created from vermicompost (V), a microbial inoculant created from sterilized vermicompost (SV), and a no-compost control inoculant (C). We hypothesized that living microbiomes from the vermicompost inoculant treatment would enhance host plant growth and gene expression profiles compared to plants grown in sterile and control treatments. Our data showed that bacterial community composition was significantly altered in tomato rhizospheres, but fungal community composition was highly variable in each treatment. Plant phenotypes that were significantly enhanced in the vermicompost and sterile vermicompost treatments, compared to the control, included aboveground biomass and foliar δ15N nitrogen. RNA sequencing revealed distinct gene expression changes in the vermicompost treatment, including upregulation of nutrient transporter genes such as Solyc06g074995 (high affinity nitrate transporter), which exhibited a 250.2-fold increase in expression in the vermicompost treatment compared to both the sterile vermicompost and control treatments. The plant transcriptome data suggest that rhizosphere microbiomes derived from vermicompost can influence tomato gene expression and growth-related regulatory pathways, which highlights the value of RNA sequencing in uncovering molecular responses in plant microbiome studies.
Asunto(s)
Microbiota , Rizosfera , Microbiología del Suelo , Solanum lycopersicum , Solanum lycopersicum/microbiología , Solanum lycopersicum/genética , Solanum lycopersicum/crecimiento & desarrollo , Microbiota/genética , Regulación de la Expresión Génica de las Plantas , Animales , Compostaje , Bacterias/genética , Bacterias/clasificación , Oligoquetos/microbiología , Oligoquetos/genética , Raíces de Plantas/microbiología , Raíces de Plantas/genéticaRESUMEN
The rhizosphere is the hotspot for microbial enzyme activities and contributes to carbon cycling. Precipitation is an important component of global climate change that can profoundly alter belowground microbial communities. However, the impact of precipitation on conifer rhizospheric microbial populations has not been investigated in detail. In the present study, using high-throughput amplicon sequencing, we investigated the impact of precipitation on the rhizospheric soil microbial communities in two Norway Spruce clonal seed orchards, Lipová Lhota (L-site) and Prenet (P-site). P-site has received nearly double the precipitation than L-site for the last three decades. P-site documented higher soil water content with a significantly higher abundance of Aluminium (Al), Iron (Fe), Phosphorous (P), and Sulphur (S) than L-site. Rhizospheric soil metabolite profiling revealed an increased abundance of acids, carbohydrates, fatty acids, and alcohols in P-site. There was variance in the relative abundance of distinct microbiomes between the sites. A higher abundance of Proteobacteria, Acidobacteriota, Ascomycota, and Mortiellomycota was observed in P-site receiving high precipitation, while Bacteroidota, Actinobacteria, Chloroflexi, Firmicutes, Gemmatimonadota, and Basidiomycota were prevalent in L-site. The higher clustering coefficient of the microbial network in P-site suggested that the microbial community structure is highly interconnected and tends to cluster closely. The current study unveils the impact of precipitation variations on the spruce rhizospheric microbial association and opens new avenues for understanding the impact of global change on conifer rizospheric microbial associations.
Asunto(s)
Microbiota , Picea , Rizosfera , Microbiología del Suelo , Picea/microbiología , Microbiota/genética , Bacterias/genética , Bacterias/clasificación , Bacterias/metabolismo , Suelo/química , Lluvia , Semillas/crecimiento & desarrollo , Semillas/microbiología , Cambio ClimáticoRESUMEN
Pinellia ternata (Thunb.) Breit is an important traditional Chinese medicine. In North China, conventional flat planting of P. ternate is prone to root rot during the rainy season, leading to severe yield loss. Variations in planting patterns (e.g., ridge planting) can effectively alleviate this situation. However, the relationship between planting patterns and the changes induced by rhizosphere microbiome still needs to be determined. In this study, we clarified the effect of ridge planting on the yield of P. ternata and rhizosphere microbial community using high-throughput amplicon sequencing of 16S rRNA. Field experiments showed that ridge planting could increase the yield of P. ternata by 72.69% compared with flat planting. The high-throughput sequencing results demonstrated that fungal and bacterial communities in rhizosphere siols of flat and ridge planting showed obvious difference in diversity, structure, relative abundance, and community composition. The fungal phyla Zygomycota, Basidiomycota, Glomeromycota, and the bacterial phyla Chlamydiae, Tenericutes, and Hydrogenedentes were present in a higher relative abundance in the rhizosphere of ridge planting. Adonis multivariate analysis of variance results showed that 29 bacterial genera were significantly up/down-regulated, and only 4 fungal genera were changed considerably in ridge planting soil, indicating that the bacterial community composition varied significantly between the two treatments. Correlation analysis revealed that the yield of P. ternata was positively correlated with fungal genera Emericellopsis while negatively correlated with bacterial genera Acetobacter, Iamia, and fungal genera Thielavia. Overall, this study showed that ridge cropping significantly impacts the diversity and composition of the rhizosphere microbiome. It creates an environment favorable for crop growth and can be an effective planting strategy for P. ternata in areas with irrigation and high monsoon rainfall in North China.
Asunto(s)
Microbiota , Pinellia , Rizosfera , Microbiología del Suelo , China , Pinellia/microbiología , ARN Ribosómico 16S/genética , Bacterias/genética , Bacterias/clasificación , Bacterias/aislamiento & purificación , Hongos/genética , Hongos/clasificación , Hongos/aislamiento & purificación , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
BACKGROUND: Plants have evolved various defense mechanisms against insect herbivores, including the formation of physical barriers, the synthesis of toxic metabolites, and the activation of phytohormone responses. Although plant-associated microbiota influence plant growth and health, whether they play a role in plant defense against insect pests in natural ecosystems is unknown. RESULTS: Here, we show that leaves of beetle-damaged weeping willow (Salix babylonica) trees are more resistant to the leaf beetle Plagiodera versicolora (Coleoptera) than those of undamaged leaves. Bacterial community transplantation experiments demonstrated that plant-associated microbiota from the beetle-damaged willow contribute to the resistance of the beetle-damaged willow to P. versicolora. Analysis of the composition and abundance of the microbiome revealed that Pseudomonas spp. is significantly enriched in the phyllosphere, roots, and rhizosphere soil of beetle-damaged willows relative to undamaged willows. From a total of 49 Pseudomonas strains isolated from willows and rhizosphere soil, we identified seven novel Pseudomonas strains that are toxic to P. versicolora. Moreover, re-inoculation of a synthetic microbial community (SynCom) with these Pseudomonas strains enhances willow resistance to P. versicolora. CONCLUSIONS: Collectively, our data reveal that willows can exploit specific entomopathogenic bacteria to enhance defense against P. versicolora, suggesting that there is a complex interplay among plants, insects, and plant-associated microbiota in natural ecosystems.