There is an increasing demand for bioinoculants based on plant growth-promoting rhizobacteria (PGPR) for use in agricultural ecosystems. However, there are still concerns and limited data on their reproducibility in different soil types and their effects on endemic rhizosphere communities. Therefore, this study explored the effects of inoculating the PGPR, Pseudomonas fluorescens strain UM270, on maize growth (Zea mays L.) and its associated rhizosphere bacteriome by sequencing the 16S ribosomal genes under greenhouse conditions. The results showed that inoculation with PGPR P. fluorescens UM270 improved shoot and root dry weights, chlorophyll concentration, and total biomass in the three soil types evaluated (clay, sandy-loam, and loam) compared to those of the controls. Bacterial community analysis of the three soil types revealed that maize plants inoculated with the UM270 strain showed a significant increase in Proteobacteria and Acidobacteria populations, whereas Actinobacteria and Bacteroidetes decreased. Shannon, Pielou, and Faith alpha-biodiversity indices did not reveal significant differences between treatments. Beta diversity revealed a bacterial community differential structure in each soil type, with some variation among treatments. Finally, some bacterial groups were found to co-occur and co-exclude with respect to UM270 inoculation. Considered together, these results show that PGPR P. fluorescens UM270 increases maize plant growth and has an important effect on the resident rhizobacterial communities of each soil type, making it a potential agricultural biofertilizer.
- MeSH
- Bacteria klasifikace genetika izolace a purifikace růst a vývoj MeSH
- biodiverzita MeSH
- biomasa MeSH
- fylogeneze MeSH
- kořeny rostlin * mikrobiologie růst a vývoj MeSH
- kukuřice setá * mikrobiologie růst a vývoj MeSH
- Pseudomonas fluorescens * genetika růst a vývoj fyziologie MeSH
- půda * chemie MeSH
- půdní mikrobiologie * MeSH
- rhizosféra * MeSH
- RNA ribozomální 16S genetika MeSH
- Publikační typ
- časopisecké články MeSH
KEY MESSAGE: The new 4.2-kb transposable insertion in the intron of ZmCCT reversely responded relative to the known 5.1-kb transposable insertion to photoperiods between low- and high-latitude regions. Flowering time is a key trait for cereal adaptation that is controlled by a complex genetic background in maize. The effect of multiple alleles from a quantitative trait locus (QTL) on flowering time remains largely unknown. Here, we fine-mapped a major QTL for flowering time on maize chromosome 10 corresponding to ZmCCT, where a new allele with a 4.2-kilobase (kb) transposable insertion was present in the intron. The known allele with a 5.1-kb transposon insertion in the promoter of ZmCCT enhances flowering in high-latitude regions, but has no effect on flowering time in low-latitude regions in comparison with the null allele lacking this insertion. However, our new allele with a 4.2-kb insertion reduced flowering in the low-latitude region, but produced unchanged flowering time in the high-latitude region relative to the 5.1-kb transposable insertion. Transcription analysis revealed that the new allele with 4.2-kb insertion versus the 5.1-kb insertion repressed and unchanged the transcription of ZmCCT in the low- and high-latitude regions, respectively. Thus, the allele with the 4.2-kb transposable insertion showed a completely opposite response to photoperiods between these two regions. Phylogenetic analysis revealed that the 4.2-kb transposable insertion in the two Northern flint corns originated from tropical maize. RNA-seq analysis and dual-luciferase transient expression assays further identified a conserved gene regulation network of ZmCCT between maize and rice, in which ZmCCT directly repressed the transcription of the florigen gene ZCN8 via ZmEhd1. Our results suggest that transposable elements play an important role in maize adaptation.
- MeSH
- chromozomy rostlin genetika MeSH
- fenotyp MeSH
- fotoperioda * MeSH
- fyziologická adaptace MeSH
- kukuřice setá genetika růst a vývoj účinky záření MeSH
- květy genetika růst a vývoj účinky záření MeSH
- lokus kvantitativního znaku MeSH
- mapování chromozomů metody MeSH
- promotorové oblasti (genetika) MeSH
- regulace genové exprese u rostlin * MeSH
- rostlinné proteiny genetika metabolismus MeSH
- transpozibilní elementy DNA * MeSH
- Publikační typ
- časopisecké články MeSH
Zinc-solubilizing bacteria, namely Burkholderia cepacia and Acinetobacter baumannii (H1 and H3, respectively), able to grow in liquid basal medium supplemented with ZnO, Zn3 (PO4)2, and ZnSO4·7H2O (0.1%), showed plant growth promoting properties. The treatment of Acinetobacter baumannii (H3) solubilizes the ZnO (1.42 ppm), Zn3 (PO4)2 (1.15 ppm), and ZnSO4·7H2O (1.44 ppm).The maximum solubilization of ZnSO4·7H2O (1.42 ppm) was observed in Burkholderia cepacia (H1) after 15 days. Organic acids produced by the bacteria decreased the pH of the medium and helped in Zn solubilization. In pot experiment on maize, Burkholderia cepacia (H1) treatment significantly enhanced plant height and root length in the presence of ZnO (2%) added in 10 mL of inoculum in each pot. High-performance liquid chromatography (HPLC) analysis of maize root extract showed the presence of oxalic, maleic, tartaric, and fumaric acid after 60 days of the experiment. Bacterial treatments enhanced sugar and protein level in maize plants and were 55.2 and 42.55 µg/mL plant extract, respectively, under mixture of bacterial treatment. Hence, isolates H1 and H3 expressed highest potential throughout the experiments, as zinc solubilizers and plant growth-promoting strains. This study demonstrated that meticulous use of Zn-solubilizing bacterial strains could aid in enhanced plant growth and can be the potential bio-inoculants for biofortification of maize to overcome the problems of malnutrition.
The effects of the short-term application of Ascophyllum nodosum-fermented seaweed fertilizer on the bacterial community, soil nitrogen contents, and plant growth in maize rhizosphere soil were evaluated. The changes in the bacterial community composition and nitrogen contents including those of total nitrogen (TN), nitrate nitrogen (NO3--N) and ammonium nitrogen (NH4+-N) in rhizosphere soils in response to treatment with seaweed fertilizer were determined. Furthermore, soil enzymatic activity and crop biomass were analyzed. The relative abundance of the dominant phyla varied regularly with fertilization, and bacterial α-diversity was apparently influenced by seaweed fertilizer amendment. The TN contents of all soil samples decreased gradually, and the NO3--N and NH4+-N contents of the soils treated with seaweed fertilizer were much higher than those of the control soils. Similarly, the enzymatic activities of dehydrogenase, nitrite reductase, urease, and cellulase in the soil were significantly increased on day 3, day 8, and day 13 after the application of seaweed fertilizer to the maize rhizosphere soil. However, there was no difference in the activity of soil sucrase between the treatment group and the control group. In this study, the growth of maize seedlings was confirmed to be greatly promoted by the utilization of seaweed fertilizer. These results deepen our understanding of plant-microbe interactions in agroecosystems and should benefit the wide use of seaweed fertilizer in sustainable agricultural production.
- MeSH
- Ascophyllum chemie MeSH
- Bacteria klasifikace MeSH
- biomasa MeSH
- dusík analýza MeSH
- fylogeneze MeSH
- kukuřice setá růst a vývoj mikrobiologie MeSH
- mikrobiota * MeSH
- mořské řasy chemie MeSH
- průmyslová hnojiva analýza MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- rhizosféra * MeSH
- vývoj rostlin MeSH
- zemědělství metody MeSH
- Publikační typ
- časopisecké články MeSH
Knowledge on spatial distribution of crop yield in relation to fixed soil fertilisation with exogenous organic materials is essential for improving precise crop and soil management practices within a field. This study assessed the effect of various application rates and types of exogenous (recycled) organic materials (EOMs) containing different organic matter and nitrogen contents vs. mineral nitrogen on the yield of maize by means of linear regressions (trends), spatial kriging-interpolated maps, and Bland-Altman statistics. The experiments were conducted in 2013 and 2014 on two soils, i.e. loam silt in Braszowice (Poland) and clay silt loam in Pusté Jakartice (Czech Republic) under a cross-border cooperation project. The organic materials included compost from manure, slurry, and straw (Ag), industrial organic compost from sewage sludge (Ra), animal meal from animal by-products (Mb), and digestate from a biogas fries factory (Dg). The following 3 application rates of each EOM were adjusted according to the reference 100% = 200 kg N ha-1: 50 (50% N from EOM and 50% mineral N), 75 (75% N from EOM and 25% mineral N), and 100 (100% N from EOM). 100% mineral N was applied on control plots. All treatments were carried out in 4 replicates. The linear regressions between the EOM application rates and the maize yield were in general ascending in the Braszowice soil and descending in the more productive Pusté Jakartice soil. The spatial kriging-interpolated maps allowed separating zones of lower and higher yields with EOMs compared to the control. They were attributed in part to the different EOM application rates and soil water contents. The Bland-Altaman statistics showed that addition of 50% of N from EOMs in 2013 caused a decrease and an increase in the maize grain yield in Braszowice and Pusté Jakartice, respectively, whereas the inverse was true with the 75 and 100% EOM additions. In 2014, the yield of maize for silage increased with the increasing EOM application rate in Braszowice and decreased in Pusté Jakartice, but it was smaller on all EOM-amended plots than in the control. As shown by the limits of agreement lines, the maize yields were more even in Pusté Jakartice than Braszowice. These results provide helpful information for selection of the most yield-producing EOM rates depending on the site soil conditions and prevalent weather conditions.
- MeSH
- kompostování * MeSH
- kukuřice setá růst a vývoj MeSH
- pěstování plodin * MeSH
- průmyslová hnojiva * MeSH
- půda * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Polsko MeSH
Sweet maize and popcorn retain tillering growth habit during maize diversification. However, the underlying molecular genetic mechanism remains unknown. Here, we show that the retention of maize tillering is controlled by a major quantitative trait locus (QTL), tin1, which encodes a C2H2-zinc-finger transcription factor that acts independently of tb1. In sweet maize, a splice-site variant from G/GT to C/GT leads to intron retention, which enhances tin1 transcript levels and consequently increases tiller number. Comparative genomics analysis and DNA diversity analysis reveal that tin1 is under parallel selection across different cereal species. tin1 is involved in multiple pathways, directly represses two tiller-related genes, gt1 and Laba1/An-2, and interacts with three TOPLESS proteins to regulate the outgrowth of tiller buds. Our results support that maize tin1, derived from a standing variation in wild progenitor teosinte population, determines tillering retention during maize diversification.
- MeSH
- fenotyp MeSH
- genetické lokusy MeSH
- kukuřice setá genetika růst a vývoj metabolismus MeSH
- lokus kvantitativního znaku MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny genetika MeSH
- rostlinné proteiny genetika metabolismus MeSH
- vývoj rostlin genetika fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The establishment of phytoextraction crops on highly contaminated soils can be limited by metal toxicity. A recent proposal has suggested establishing support crops during the critical initial phase by metal immobilization through soil amendments followed by subsequent mobilization using elemental sulphur to enhance phytoextraction efficiency. This 'combined phytoremediation' approach is tested for the first time in a pot experiment with a highly contaminated soil. During a 14-week period, relatively metal-tolerant maize was grown in a greenhouse under immobilization (before sulphur (S) application) and mobilization (after S application) conditions with soil containing Cd, Pb and Zn contaminants. Apart from the control (C) sample, the soil was amended with activated carbon (AC), lignite (Lig) or vermicompost (VC) all in two different doses (dose 1~45 g additive kg-1 soil and dose 2~90 g additive kg-1 soil). Elemental S was added as a mobilization agent in these samples after 9 weeks. Biomass production, nutrient and metal bioavailability in the soil were determined, along with their uptake by plants and the resulting remediation factors. Before S application, Cd and Zn mobility was reduced in all the AC, Lig and VC treatments, while Pb mobility was increased only in the Lig1 and VC1 treatments. Upon sulphur application, Fe, Mn, Cd, Pb and Zn mobility was not significantly affected in the C, AC and VC treatments, nor total Cd, Pb and Zn contents in maize shoots. Increased sulphate, Mn, Cd, Pb and Zn mobilities in soil together with related higher total S, Mn, Pb and Zn contents in shoots were observed in investigated treatments in the last sampling period. The highest biomass production and the lowest metal toxicity were seen in the VC treatments. These results were associated with effective metal immobilization and showed the trend of steady release of some nutrients. The highest remediation factors and total elemental content in maize shoots were recorded in the VC treatments. This increased phytoremediation efficiency by 400% for Cd and by 100% for Zn compared to the control. Considering the extreme metal load of the soil, it might be interesting to use highly metal-tolerant plants in future research. Future investigations could also explore the effect of carbonaceous additives on S oxidation, focusing on the specific microorganisms and redox reactions in the soil. In addition, the homogeneous distribution of the S rate in the soil should be considered, as well as longer observation times.
- MeSH
- biodegradace MeSH
- biologická dostupnost MeSH
- biomasa MeSH
- dřevěné a živočišné uhlí chemie MeSH
- fosfor farmakokinetika MeSH
- kompostování MeSH
- kukuřice setá účinky léků růst a vývoj metabolismus MeSH
- látky znečišťující půdu analýza farmakokinetika MeSH
- půda chemie MeSH
- regenerace a remediace životního prostředí metody MeSH
- síra * farmakokinetika MeSH
- těžké kovy analýza farmakokinetika MeSH
- výhonky rostlin účinky léků metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Biological treatments are considered an environmentally option to clean-up polluted soil with polycyclic aromatic hydrocarbons (PAHs). A pot experiment was conducted to comparatively evaluate four different strategies, including natural attenuation (NA), mycoaugmentation (M) by using Crucibulum leave, phytoremediation (P) using maize plants, and microbial-assisted phytoremediation (MAP) for the bioremediation of an aged PAH-polluted soil at 180 days. The P treatment had higher affinity degrading 2-3 and 4 ring compounds than NA and M treatments, respectively. However, M and P treatments were more efficient in regards to naphthalene, indeno[l,2,3-c,d]pyrene and benzo[g,h,i]perylene degradation respect to NA. However, 4, 5-6 rings undergo a strong decline during the microbe-assisted phytoremediation, being the treatment which determined the highest rates of PAHs degradation. Sixteen PAH compounds, except fluorene and dibenzo[a,h]anthracene, were found in maize roots, whereas the naphthalene, phenanthrene, anthracene, fluoranthene, and pyrene were accumulated in the shoots, in both P and MAP treatments. However, higher PAH content in maize biomass was achieved during the MAP treatment respect to P treatment. The bioconversion and translocation factors were less than 1, indicating that phystabilization/phytodegradation processes occurred rather than phytoextraction. The microbial biomass, activity and ergosterol content were significantly boosted in the MAP treatment respect to the other treatments at 180 days. Ours results demonstrated that maize-C. laeve association was the most profitable technique for the treatment of an aged PAH-polluted soil when compared to other bioremediation approaches.
- MeSH
- Agaricales růst a vývoj metabolismus MeSH
- biodegradace MeSH
- biomasa MeSH
- časové faktory MeSH
- kukuřice setá růst a vývoj metabolismus MeSH
- látky znečišťující půdu analýza metabolismus MeSH
- polycyklické aromatické uhlovodíky analýza metabolismus MeSH
- půda chemie MeSH
- teoretické modely MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
The contents of endogenous brassinosteroids (BRs) together with various aspects of plant morphology, water management, photosynthesis and protection against cell damage were assessed in two maize genotypes that differed in their drought sensitivity. The presence of 28-norbrassinolide in rather high quantities (1-2 pg mg-1 fresh mass) in the leaves of monocot plants is reported for the first time. The intraspecific variability in the presence/content of the individual BRs in drought-stressed plants is also described for the first time. The drought-resistant genotype was characterised by a significantly higher content of total endogenous BRs (particularly typhasterol and 28-norbrassinolide) compared with the drought-sensitive genotype. On the other hand, the drought-sensitive genotype showed higher levels of 28-norcastasterone. Both genotypes also differed in the drought-induced reduction/elevation of the levels of 28-norbrassinolide, 28-norcastasterone, 28-homocastasterone and 28-homodolichosterone. The differences observed between both genotypes in the endogenous BR content are probably correlated with their different degrees of drought sensitivity, which was demonstrated at various levels of plant morphology, physiology and biochemistry.
- MeSH
- brassinosteroidy farmakologie MeSH
- fotosyntéza * MeSH
- fyziologický stres * MeSH
- genotyp MeSH
- kukuřice setá účinky léků genetika růst a vývoj MeSH
- listy rostlin účinky léků genetika růst a vývoj MeSH
- období sucha * MeSH
- regulátory růstu rostlin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Spectropolarimetry of intact plant leaves allows to probe the molecular architecture of vegetation photosynthesis in a non-invasive and non-destructive way and, as such, can offer a wealth of physiological information. In addition to the molecular signals due to the photosynthetic machinery, the cell structure and its arrangement within a leaf can create and modify polarization signals. Using Mueller matrix polarimetry with rotating retarder modulation, we have visualized spatial variations in polarization in transmission around the chlorophyll a absorbance band from 650 nm to 710 nm. We show linear and circular polarization measurements of maple leaves and cultivated maize leaves and discuss the corresponding Mueller matrices and the Mueller matrix decompositions, which show distinct features in diattenuation, polarizance, retardance and depolarization. Importantly, while normal leaf tissue shows a typical split signal with both a negative and a positive peak in the induced fractional circular polarization and circular dichroism, the signals close to the veins only display a negative band. The results are similar to the negative band as reported earlier for single macrodomains. We discuss the possible role of the chloroplast orientation around the veins as a cause of this phenomenon. Systematic artefacts are ruled out as three independent measurements by different instruments gave similar results. These results provide better insight into circular polarization measurements on whole leaves and options for vegetation remote sensing using circular polarization.
- MeSH
- algoritmy * MeSH
- fotosyntéza * MeSH
- kukuřice setá růst a vývoj metabolismus MeSH
- listy rostlin růst a vývoj metabolismus MeSH
- počítačové zpracování obrazu metody MeSH
- polarizační mikroskopie metody MeSH
- refraktometrie metody MeSH
- světlo MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
