Effectiveness of complex inoculation of spring wheat with N[2] -fi xing bacteria Azospirillum brasilense and mold-antagonist Chaetomium cochliodes

2014 ◽  
Vol 1 (3) ◽  
pp. 57-61
Author(s):  
E. Kopylov
Keyword(s):  
Spring Wheat ◽  
Root Zone ◽  
Wheat Root ◽  
Root Surface ◽  
Atmospheric Nitrogen ◽  
Rhizospheric Soil ◽  
Chain Reaction ◽  
Wheat Roots ◽  
Chlorophyll A And B ◽  
Polymerase Chain

Aim. To study the specifi cities of complex inoculation of spring wheat roots with the bacteria of Azospirillum genus and Chaetomium cochliodes Palliser 3250, and the isolation of bacteria of Azospirillum genus, capable of fi xing atmospheric nitrogen, from the rhizospheric soil, washed-off roots and histoshere. Materials and meth- ods. The phenotypic features of the selected bacteria were identifi ed according to Bergi key. The molecular the polymerase chain reaction and genetic analysis was used for the identifi cation the bacteria. Results. It has been demonstrated that during the introduction into the root system of spring wheat the strain of A. brasilensе 102 actively colonizes rhizospheric soil, root surface and is capable of penetrating into the inner plant tissues. Conclusions. The soil ascomucete of C. cochliodes 3250 promotes better settling down of Azospirillum cells in spring wheat root zone, especially in plant histosphere which induces the increase in the content of chlorophyll a and b in the leaves and yield of the crop.

scholarly journals SETTLING DOWN OF AZOSPIRILLUM BACTERIA IN ROOT ZONE OF SPRING WHEAT UNDER THE INFLUENCE OF SOIL FUNGUS CHAETOMIUM COCHLIODES 3250

2009 ◽  
Vol 9 ◽  
pp. 33-42
Author(s):  
E.P. Kopilov
Keyword(s):  
Spring Wheat ◽  
Rhizosphere Soil ◽  
Root Zone ◽  
Molecular Genetic ◽  
Soil Fungus ◽  
Root Surface ◽  
Molecular Genetic Analysis ◽  
Plant Tissues ◽  
Atmospheric Nitrogen ◽  
Chlorophyll A And B

Pure bacteria cultures of Azospirillum genus able to fix atmospheric nitrogen were isolated from rhizosphere soil, washed-off roots and histosphere of spring wheat plants. By their phenotype signs and the results of molecular-genetic analysis they were related to the Azospirillum brasilense species. It was shown that strain A. brasilensе 104 actively colonizes rhizospheric soil, root surface and is able to penetrate in inner plant tissues during its introduction in root system of spring wheat. The soil ascomycete Chaetomium cochliodes 3250 promotes settling down of Azospirillum bacteria in root zone of spring wheat especially in plants hystosphere which results in increasing of chlorophyll a and b content in leaves.

Rhythmic patterns of nutrient acquisition by wheat roots

2002 ◽  
Vol 29 (5) ◽  
pp. 595 ◽  
Author(s):  
Sergey Shabala ◽  
Andrew Knowles
Keyword(s):  
Root Zone ◽  
Root Hairs ◽  
Rhythmic Activity ◽  
Root Apex ◽  
Root Surface ◽  
Ion Flux ◽  
Nutrient Acquisition ◽  
Wheat Roots ◽  
Non Invasive ◽  
Functional Zone

Oscillatory patterns in H+, K+, Ca2+ and Cl- uptake were observed at different regions of the root surface, including root hairs, using a non-invasive ion flux measuring technique (the MIFE™ technique). To our knowledge, this is the first report of ultradian oscillations in nutrient acquisition in the mature root zone. Oscillations of the largest magnitude were usually measured in the elongation region, 2–4 mm from the root apex. There were usually at least two oscillatory components present for each ion measured: fast, with periods of several minutes; and slow, with periods of 50–80 min. Even within the same functional zone, the periods of ion flux oscillations were significantly different, suggesting that they are driven by some internal mechanisms located in each cell rather than originating from one ‘central clock pacemaker’. There were also significant changes in the oscillatory characteristics (both periods and amplitudes) of fluxes from a single small cluster of cells over time. Analysis of phase shifts between oscillations in different ions suggested that rhythmic activity of a plasma membrane H+-pump may be central to observed rhythmic nutrient acquisition by plant roots. We discuss the possible adaptive significance of such an oscillatory strategy for root nutrient acquisition.

scholarly journals The effect of psychrotrophic bacteria isolated from the root zone of winter wheat on selected biotic and abiotic factors

2014 ◽  
Vol 54 (4) ◽  
pp. 407-413 ◽  
Author(s):  
Sebastian Wojciech Przemieniecki ◽  
Tomasz Paweł Kurowski ◽  
Karol Korzekwa ◽  
Anna Karwowska
Keyword(s):  
Polymerase Chain Reaction ◽  
Winter Wheat ◽  
Root Zone ◽  
Abiotic Factors ◽  
Pathogenic Fungi ◽  
Growth And Yield ◽  
Chain Reaction ◽  
Psychrotrophic Bacteria ◽  
Rapd Pcr ◽  
Polymerase Chain

Abstract The roots of winter wheat plants, cv. Mikon, grown in 45-year monoculture, were analysed in the study. Twenty-two bacterial isolates obtained from the rhizosphere, rhizoplane, and endorhizosphere that were capable of growth at 8°C and at 28°C, were selected for further analysis. The isolated psychrotrophs accounted for 25% of all bacteria present in the wheat rhizosphere and capable of growth at 8°C. Psychrotrophic bacteria were analysed at a temperature of 10°C and 28°C to determine their ability to inhibit the growth of pathogenic fungi, solubilise mineral phosphates, and to determine their ability to degrade chitin and cellulose. Similarity between the isolates was determined by Enterobacterial Repetitive Intergenic Consensus – Polymerase Chain Reaction (ERIC-PCR) and Random Amplification of Polymorphic DNA – Polymerase Chain Reaction (RAPD-PCR). The majority of isolated psychrotrophs inhibited the growth of pathogenic fungi and solubilised mineral phosphates at both incubation temperatures. Psychrotrophic bacteria exerted a two-fold stronger inhibitory effect on mycelial growth at 10°C than at 28°C. The growth of Fusarium culmorum and F. oxysporum was inhibited to the highest extent at 10°C and at 28°C, respectively. Phosphate solubilisation rates were higher at 28°C, particularly in the rhizosphere. Regardless of temperature, the bacteria exhibited low chitin-degrading potential, and none of the isolates was capable of degrading cellulose. A high similarity between the selected psychrotrophs was revealed by ERIC-PCR and RAPD- -PCR analyses. Based on RAPD-PCR, the analysed population was divided into a group of isolates obtained from the rhizosphere, and two groups comprising representatives of both the rhizoplane and the endorhizosphere. Due to their ability to grow over a wide temperature range and increase phosphorus availability to plants, and their antagonism against pathogens, psychrotrophic bacteria can be used to improve the growth and yield of cereal crops.

Bacterial endophytes mediate positive feedback effects of early legume termination times on the yield of subsequent durum wheat crops

2012 ◽  
Vol 58 (12) ◽  
pp. 1368-1377 ◽  
Author(s):  
Chao Yang ◽  
Chantal Hamel ◽  
Yantai Gan ◽  
Vladimir Vujanovic
Keyword(s):  
Durum Wheat ◽  
Wheat Root ◽  
Bacterial Endophytes ◽  
Rotation Effect ◽  
Chain Reaction ◽  
Feedback Effects ◽  
Field Crops ◽  
Polymerase Chain ◽  
Termination Time

Field crops influence the biotic properties of the soil, impacting the health and productivity of subsequent crops. Polymerase chain reaction and 454 GS FLX pyrosequencing of amplicons were used to clarify the legacy of chickpea and pea crops on the quality of the bacterial community colonizing the root endosphere of subsequent crops of wheat, in a replicated field study. Similar communities of root endosphere bacteria were formed in durum wheat grown after pea and chickpea crops when chickpea crops were terminated as early as pea (July). Termination of the chickpea crops in September led to the domination of Firmicutes in wheat root endosphere; Actinobacteria dominated the wheat root endosphere following early pulse crop termination. The architecture of wheat plants was correlated with the composition of its root endosphere community. High grain yield was associated with the production of fewer but larger wheat heads, the abundance of endospheric Actinobacteria and Acidobacteria, and the scarcity of endospheric Firmicutes. Pulse termination time affected wheat root endosphere colonization strongly in 2009 but weakly in 2010, an abnormally wet year. This study improved our understanding of the so-called “crop rotation effect” in pulse–wheat systems and showed how this system can be manipulated through agronomic decisions.

Genetic diversity of N2-fixing bacteria associated with rice roots by molecular evolutionary analysis of a nifD library

1995 ◽  
Vol 41 (3) ◽  
pp. 235-240 ◽  
Author(s):  
T. Ueda ◽  
Y. Suga ◽  
N. Yahiro ◽  
T. Matsuguchi
Keyword(s):  
Heterotrophic Bacteria ◽  
Root Zone ◽  
Rice Root ◽  
Evolutionary Analysis ◽  
Chain Reaction ◽  
Rice Roots ◽  
Rice Rhizosphere ◽  
Polymerase Chain ◽  
Molecular Evolutionary Analysis ◽  
Diazotrophic Community

The rhizosphere of wetland rice has significant N2-fixing activity. It has been suggested that N2 fixation in the rice root zone is associated with the activity of various N2-fixing heterotrophic bacteria that inhabit the rice rhizosphere. Because of the generic diversity, many different isolation media and conditions are required to count and isolate these bacteria. In an attempt to overcome any bias from culture-dependent methods we amplified nifD segments from crude rice root DNA by the polymerase chain reaction. The nifD fragments were then cloned into a pT7 BlueT-vector to construct a nifD library. Sixteen cloned nifD genes chosen at random from the library were sequenced. A comparison with published sequences indicated the presence of seven novel groups of NifD proteins, which implies the existence of at least seven components in the diazotrophic community of rice roots, dominated mainly by proteobacteria. We also observed genetic variability within the clusters, which suggests the coexistence of many closely related bacterial lineages. However, we did not find Azospirillum-like nifD clones, although many reports indicated the widespread presence of Azospirillum spp. Therefore, it remains to be clarified whether Azospirillum species are the widespread N2-fixing bacteria in rice roots.Key words: N2 fixation, molecular evolution, nifD, rice rhizosphere.

scholarly journals NITROGEN FIXING BACTERIA OF SPRING WHEAT ROOT ZONE

2013 ◽  
Vol 17 ◽  
pp. 7-20
Author(s):  
O. V. Nadkernychna ◽  
E. P. Kopylov
Keyword(s):  
Nitrogen Fixation ◽  
Spring Wheat ◽  
Root Zone ◽  
Molecular Nitrogen ◽  
Wheat Root ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Active Nitrogen ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

The paper presents the study of active nitrogen fixation bacteria of genera Azotobacter, Azospirillum, Bacillus, Flavobacterium, Enterobacter and Pseudomonas isolated from root zone of spring wheat plants. The ability of selected diazotrophs to form associative systems with spring wheat was investigated. The most significant increase of molecular nitrogen fixation activity in root zone of plants was observed under the Azospirillum species background.

scholarly journals Monitoring Fusarium Crown Rot Populations in Spring Wheat Residues Using Quantitative Real-Time Polymerase Chain Reaction

2010 ◽  
Vol 100 (1) ◽  
pp. 49-57 ◽  
Author(s):  
A. C. Hogg ◽  
R. H. Johnston ◽  
J. A. Johnston ◽  
L. Klouser ◽  
K. D. Kephart ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Population Dynamics ◽  
Real Time ◽  
Spring Wheat ◽  
Fusarium Species ◽  
Crown Rot ◽  
Taqman Assay ◽  
Chain Reaction ◽  
Fusarium Crown Rot ◽  
Polymerase Chain

Caused by a complex of Fusarium species including F. culmorum, F. graminearum, and F. pseudograminearum, Fusarium crown rot (FCR) is an important cereal disease worldwide. For this study, Fusarium population dynamics were examined in spring wheat residues sampled from dryland field locations near Bozeman and Huntley, MT, using a quantitative real-time polymerase chain reaction (qPCR) Taqman assay that detects F. culmorum, F. graminearum, and F. pseudograminearum. Between August 2005 and June 2007, Fusarium populations and residue decomposition were measured eight times for standing stubble (0 to 20 cm above the soil surface), lower stem (20 to 38 cm), middle stem (38 to 66 cm), and chaff residues. Large Fusarium populations were found in stubble collected in August 2005 from F. pseudograminearum-inoculated plots. These populations declined rapidly over the next 8 months. Remnant Fusarium populations in inoculated stubble were stable relative to residue biomass from April 2006 until June 2007. These two phases of population dynamics were observed at both locations. Relative to inoculated stubble populations, Fusarium populations in other residue fractions and from noninoculated plots were small. In no case were FCR species observed aggressively colonizing noninfested residues based on qPCR data. These results suggest that Fusarium populations are unstable in the first few months after harvest and do not expand into noninfested wheat residues. Fusarium populations remaining after 8 months were stable for at least another 14 months in standing stubble providing significant inoculums for newly sown crops.

Genetic diversity analysis of diazotrophs in the rice rhizosphere

2007 ◽  
Vol 4 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Chen Bin ◽  
Zheng Si-Ping ◽  
Zhou Li-Juan ◽  
Lin Zhi-Min ◽  
Song Ya-Na ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Fragment Length Polymorphism ◽  
Rhizospheric Soil ◽  
Chain Reaction ◽  
Rice Roots ◽  
Rice Rhizosphere ◽  
Pcr Rflp ◽  
Pcr Products ◽  
Polymerase Chain ◽  
Diazotrophic Community

SUMMARYThe genetic diversity of dinitrogen-fixing bacteria associated with rice (Oryza sativa) was assessed by a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) approach on thenifHgene amplified directly from DNA extracted from washed rice roots and rhizospheric soil. Restriction digestion with the enzymesMnlI andHaeIII was performed to characterize 54 clonednifHPCR products. RFLP profiles were clustered and analysed with the UPGMA program. Eight pairs of similar RFLP patterns (similarity>50%) and two pairs of homologous RFLP patterns (100% identity) were found from the washed roots and the rhizospheric soil, respectively. Three specific diazotrophic patterns were found from rhizospheric soil and rice roots. The analyses have revealed the presence of differentnifHtypes, which appear to be significant components of the diazotrophic community in paddy fields, indicating that some of the diazotrophs may colonize the inside and the surface of the rice roots.

scholarly journals Wheat Root and Rhizosphere Microbiome Structures and Functions Along Plant Growth

2021 ◽  
Author(s):  
Alla Usyskin-Tonne ◽  
Dror Minz ◽  
Yitzhak Hadar
Keyword(s):  
Developmental Stage ◽  
Root Zone ◽  
Antibiotic Production ◽  
Root Exudation ◽  
Wheat Root ◽  
Root Surface ◽  
Beta Lactam ◽  
Associated Bacteria ◽  
Microbe Interactions ◽  
Structure And Functions

Abstract Background Roots select their associated microbiome and affect its composition and activities through exudates that provide a nutrient-rich environment based on distance from the root. Root-exudation patterns depend on the plant's developmental stage. We followed field-grown wheat from emergence to spike maturation and compared the structure and functions of the microbiomes in two niches: adjacent, root-associated bacteria and the rhizosphere. The effects of growth stage on root-associated and rhizospheric communities structure and functions were investigated to enhance our understanding of plant–microbe interactions. Results A significant impact of wheat developmental stage during the transition from vegetative growth to spike formation was observed on structure and functions of both root-associated and rhizosphere microbiomes. On the root surface, abundance of the well-known wheat colonizers Proteobacteria and Actinobacteria decreased and increased, respectively, during spike formation, whereas abundance of Bacteroidetes was independent of spike formation. Three microbiome functional clusters were specifically associated with root proximity: (1) biofilm and sensorial movement; (2) antibiotic production and resistance; and (3) carbon biosynthesis, degradation and transporters, and amino acid biosynthesis and transporters. Interestingly, in the root-associated microbiome, genes related to all of these functions were influenced by spike formation. Abundance of genes related to nine other functions (lipopolysaccharide transporter and biosynthesis, beta-lactam resistance, metabolism of methane, alanine-aspartate-glutamate and arginine-proline, and biosynthesis of peptidoglycan, lysine and enediyne antibiotics) was significantly influenced by spike formation in both roots and rhizosphere. All of these genes were abundant in the rhizosphere, more so before spike formation when root exudation is high, supporting the notion that some of the root exudates are not fully utilized by the root-associated bacteria and subsequently diffuse into the surrounding soil, creating the rhizosphere. Conclusions We demonstrated functional division in the microbiome of the wheat root zone in both time and space: pre- and post-spike formation and root-associated vs. rhizospheric niches. The responses of the root microbiome were driven by both the plant and the microbial physiology and activities, both of which respond to environmental cues. These findings shed light on the dynamics of plant–microbe and microbe–microbe interactions in the root zone.

scholarly journals Spike Formation Is a Turning Point Determining Wheat Root Microbiome Abundance, Structures and Functions

2021 ◽  
Vol 22 (21) ◽  
pp. 11948
Author(s):  
Alla Usyskin-Tonne ◽  
Yitzhak Hadar ◽  
Dror Minz
Keyword(s):  
Developmental Stage ◽  
Vegetative Growth ◽  
Root Zone ◽  
Antibiotic Production ◽  
Wheat Root ◽  
Root Surface ◽  
Resistance Mechanisms ◽  
Wheat Growth ◽  
Microbiome Composition ◽  
Microbe Interactions

Root selection of their associated microbiome composition and activities is determined by the plant’s developmental stage and distance from the root. Total gene abundance, structure and functions of root-associated and rhizospheric microbiomes were studied throughout wheat growth season under field conditions. On the root surface, abundance of the well-known wheat colonizers Proteobacteria and Actinobacteria decreased and increased, respectively, during spike formation, whereas abundance of Bacteroidetes was independent of spike formation. Metagenomic analysis combined with functional co-occurrence networks revealed a significant impact of plant developmental stage on its microbiome during the transition from vegetative growth to spike formation. For example, gene functions related to biofilm and sensorial movement, antibiotic production and resistance and carbons and amino acids and their transporters. Genes associated with these functions were also in higher abundance in root vs. the rhizosphere microbiome. We propose that abundance of transporter-encoding genes related to carbon and amino acid, may mirror the availability and utilization of root exudates. Genes related to antibiotic resistance mechanisms were abundant during vegetative growth, while after spike formation, genes related to the biosynthesis of various antibiotics were enriched. This observation suggests that during root colonization and biofilm formation, bacteria cope with competitor’s antibiotics, whereas in the mature biofilm stage, they invest in inhibiting new colonizers. Additionally, there is higher abundance of genes related to denitrification in rhizosphere compared to root-associated microbiome during wheat growth, possibly due to competition with the plant over nitrogen in the root vicinity. We demonstrated functional and phylogenetic division in wheat root zone microbiome in both time and space: pre- and post-spike formation, and root-associated vs. rhizospheric niches. These findings shed light on the dynamics of plant–microbe and microbe–microbe interactions in the developing root zone.

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