scholarly journals Assembly Patterns of the Rhizosphere Microbiome Along the Longitudinal Root Axis of Maize (Zea mays L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Lioba Rüger ◽  
Kai Feng ◽  
Kenneth Dumack ◽  
Jule Freudenthal ◽  
Yan Chen ◽  
...  
Keyword(s):  
Zea Mays ◽  
Community Assembly ◽  
Root Hair ◽  
Beta Diversity ◽  
Bulk Soil ◽  
Root Tips ◽  
Network Analyses ◽  
Rhizosphere Microbiome ◽  
Maize Roots ◽  
Root Axis

It is by now well proven that different plant species within their specific root systems select for distinct subsets of microbiota from bulk soil – their individual rhizosphere microbiomes. In maize, root growth advances several centimeters each day, with the locations, quality and quantity of rhizodeposition changing. We investigated the assembly of communities of prokaryotes (archaea and bacteria) and their protistan predators (Cercozoa, Rhizaria) along the longitudinal root axis of maize (Zea mays L.). We grew maize plants in an agricultural loamy soil and sampled rhizosphere soil at distinct locations along maize roots. We applied high-throughput sequencing, followed by diversity and network analyses in order to track changes in relative abundances, diversity and co-occurrence of rhizosphere microbiota along the root axis. Apart from a reduction of operational taxonomic unit (OTU) richness and a strong shift in community composition between bulk soil and root tips, patterns of microbial community assembly along maize-roots were more complex than expected. High variation in beta diversity at root tips and the root hair zone indicated substantial randomness of community assembly. Root hair zone communities were characterized by massive co-occurrence of microbial taxa, likely fueled by abundant resource supply from rhizodeposition. Further up the root where lateral roots emerged processes of community assembly appeared to be more deterministic (e.g., through competition and predation). This shift toward significance of deterministic processes was revealed by low variability of beta diversity, changes in network topology, and the appearance of regular phylogenetic co-occurrence patterns in bipartite networks between prokaryotes and their potential protistan predators. Such patterns were strongest in regions with fully developed laterals, suggesting that a consistent rhizosphere microbiome finally assembled. For the targeted improvement of microbiome function, such knowledge on the processes of microbiome assembly on roots and its temporal and spatial variability is crucially important.

Assembly patterns of the rhizosphere microbiome along the longitudinal root axis of maize (Zea mays L.)

2021 ◽  
Author(s):  
Lioba Rüger ◽  
Feng Kai ◽  
Dumack Kenneth ◽  
Chen Yan ◽  
Sun Ruibo ◽  
...  
Keyword(s):  
Zea Mays ◽  
Plant Species ◽  
Community Assembly ◽  
Beta Diversity ◽  
Zea Mays L ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Rhizosphere Microbiome ◽  
Deterministic Processes ◽  
Root Axis

<p>This study was conducted within the framework of the DFG project SPP2089 “Rhizosphere Spatiotemporal Organization – a Key to Rhizosphere Functions”.</p><p>Different plant species select for individual subsets of bulk soil microbial communities within root systems. The fast variability of root environments implies that roots constitute highly dynamic habitats. Rapid root elongation, combined with widely varying quality and quantity of rhizodeposition between different root regions, lead to continuously changing conditions for colonizing microorganisms. As the microbiome concept implies a rather static outcome of the microbial assembly, it raises the question as to where and how the dynamic transition of a microbial bulk soil community into a plant species-specific rhizosphere microbiome is taking place.</p><p>To investigate the assembly of communities of prokaryotes and their microbial predators (Cercozoa, Rhizaria; protists) along the longitudinal root axis of maize (Zea mays L.), plants were grown in an agricultural loamy soil. Rhizosphere soil was sampled at distinct locations along roots. Diversity and co-occurrence of rhizosphere microbiota along the root axis were tracked by high-throughput sequencing, diversity measures and network analyses.</p><p>High variation in beta diversity at root tips and the root hair zone indicated substantial randomness of community assembly. Deterministic processes of community assembly were revealed by low variability of beta diversity, changes in network topology, and the appearance of regular phylogenetic co-occurrence patterns in bipartite networks between prokaryotes and their microbial predators. Deterministic processes were most robust in regions with fully developed lateral roots, suggesting that a consistent rhizosphere microbiome finally assembled. For the targeted improvement of microbiome function, such knowledge on the processes of microbiome assembly on roots and its temporal and spatial variability is of crucial importance.</p>

scholarly journals Influence of graphene on the multiple metabolic pathways of Zea mays roots based on transcriptome analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244856
Author(s):  
Zhiwen Chen ◽  
Jianguo Zhao ◽  
Jie Song ◽  
Shenghua Han ◽  
Yaqin Du ◽  
...  
Keyword(s):  
Zea Mays ◽  
Root Growth ◽  
Growth And Development ◽  
Plant Root ◽  
Control Group ◽  
Molecular Response ◽  
Root Tips ◽  
Positive Effects ◽  
Maize Seeds ◽  
Maize Roots

Graphene reportedly exerts positive effects on plant root growth and development, although the corresponding molecular response mechanism remains to be elucidated. Maize seeds were randomly divided into a control and experimental group, and the roots of Zea mays L. seedlings were watered with different concentrations (0–100 mg/L) of graphene to explore the effects and molecular mechanism of graphene on the growth and development of Z. mays L. Upon evaluating root growth indices, 50 mg/L graphene remarkably increased total root length, root volume, and the number of root tips and forks of maize seedlings compared to those of the control group. We observed that the contents of nitrogen and potassium in rhizosphere soil increased following the 50 mg/L graphene treatment. Thereafter, we compared the transcriptome changes in Z. mays roots in response to the 50 mg/L graphene treatment. Transcriptional factor regulation, plant hormone signal transduction, nitrogen and potassium metabolism, as well as secondary metabolism in maize roots subjected to graphene treatment, exhibited significantly upregulated expression, all of which could be related to mechanisms underlying the response to graphene. Based on qPCR validations, we proposed several candidate genes that might have been affected with the graphene treatment of maize roots. The transcriptional profiles presented here provide a foundation for deciphering the mechanism underlying graphene and maize root interaction.

scholarly journals Polyprenyl phosphate sugars synthesized during slime-polysaccharide production by membranes of the root-cap cells of maize (Zea mays)

1979 ◽  
Vol 178 (3) ◽  
pp. 661-671 ◽  
Author(s):  
J R Green ◽  
D H Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Zea Mays ◽  
Neutral Lipids ◽  
Root Tip ◽  
Synthetase Activity ◽  
Root Tips ◽  
Maize Roots ◽  
Glucose Derivatives

Two types of experiments were carried out; either maize roots were incubated in L-[1-3H]fucose or membranes were prepared from root tips and these were incubated with GDP-L-[U-14C]fucose or UDP-D-[U-4C]glucose. The radioactively labelled lipids that were synthesized in vivo and in vitro were extracted and separated into polar and neutral components. The polar lipids had the characteristics of polyprenyl phosphate and diphosphate fucose or glucose derivatives, and the neutral lipids of sterol glycosides (fucose or glucose). A partial separation of the glycolipid synthetase reactions was achieved. Membranes were fractionated into material that sedimented at 20,000g and 100,000g. Most of the polar glycolipid synthetase activity (for the incorporation of both fucose and glucose) was located in the 100,000 g pellet, and this activity was probably located in the endoplasmic reticulum. The neutral lipid, which contained fucose, was synthesized mainly by membranes of the 20,000g pellet, and the activity was probably associated with the dictyosomes, whereas the neutral glucolipids were synthesized by all the membrane fractions. It is suggested that the polar (polyprenyl) lipids labelled with fucose could act as possible intermediates during the synthesis of the glycoproteins and slime in the root tip.

scholarly journals Transcriptome analysis reveals that multiple metabolic pathways operate in Zea mays roots subjected to graphene

2020 ◽  
Author(s):  
Zhiwen Chen ◽  
Jianguo Zhao ◽  
Jie Song ◽  
Shenghua Han ◽  
Yaqin Du ◽  
...  
Keyword(s):  
Zea Mays ◽  
Metabolic Pathways ◽  
Plant Hormone ◽  
Control Group ◽  
Maize Seedlings ◽  
Root Tips ◽  
Growth Indices ◽  
Root Volume ◽  
Maize Roots ◽  
Potassium Metabolism

Abstract Background: To explore the effects and molecular mechanism of graphene on the growth and development of Zea mays L., the seeds were randomly divided into the control and experimental groups in this study, the roots of Zea mays L. seedlings were watered by different concentrations (0~100 mg/L) graphene. Results: By evaluating the root growth indices of maize, 50 mg/L graphene increased significantly the total root length, root volume, the number of root tips and root forks of maize seedlings compared with the control group. The contents of nitrogen and potassium in the soil around the roots were elevated after the treatment of 50 mg/L graphene. Then, we compared the transcriptome changes of Zea mays roots in response to 50 mg/L graphene treatment. Transcriptional factor regulation, plant hormone signal transduction, nitrogen and potassium metabolism as well as secondary metabolism in maize roots subjected to graphene showed significant up-regulated expressions, all of which might be related to mechanisms underlying graphene response. Based on qPCR validations, we proposed several candidate genes that might be responded to the graphene treatment in maize roots. Conclusion: The transcriptional profiles presented here provide a foundation for deciphering the mechanism between the graphene and maize roots interaction.

scholarly journals Predominance of soil vs root effect in rhizosphere microbiota reassembly

2019 ◽  
Vol 95 (10) ◽  
Author(s):  
Mengli Zhao ◽  
Jun Yuan ◽  
Zongzhuan Shen ◽  
Menghui Dong ◽  
Hongjun Liu ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Disease Incidence ◽  
Bulk Soil ◽  
Pathogen Population ◽  
Root Effect ◽  
Rhizosphere Microbiome ◽  
Distinct Disease ◽  
Pathogenic Microbes ◽  
Disease Suppressive Soil ◽  
Rhizosphere Community

ABSTRACT Rhizosphere community assembly is simultaneously affected by both plants and bulk soils and is vital for plant health. However, it is still unclear how and to what extent disease-suppressive rhizosphere microbiota can be constructed from bulk soil, and the underlying agents involved in the process that render the rhizosphere suppressive against pathogenic microbes remain elusive. In this study, the evolutionary processes of the rhizosphere microbiome were explored based on transplanting plants previously growing in distinct disease-incidence soils to one disease-suppressive soil. Our results showed that distinct rhizoplane bacterial communities were assembled on account of the original bulk soil communities with different disease incidences. Furthermore, the bacterial communities in the transplanted rhizosphere were noticeably influenced by the second disease-suppressive microbial pool, rather than that of original formed rhizoplane microbiota and homogenous nontransplanted rhizosphere microbiome, contributing to a significant decrease in the pathogen population. In addition, Spearman's correlations between relative abundances of bacterial taxa and the abundance of Ralstonia solanacearum indicated Anoxybacillus, Flavobacterium, Permianibacter and Pseudomonas were predicted to be associated with disease-suppressive function formation. Altogether, our results showed that bulk soil played an important role in the process of assembling and reassembling the rhizosphere microbiome of plants.

scholarly journals Plant Growth Promotion and Biocontrol Properties of Aneurinibacillus migulanus Isolated from Maize Roots (Zea mays)

2021 ◽  
pp. 46-59
Author(s):  
Lynda Kelvin Asogwa ◽  
Frank C. Ogbo
Keyword(s):  
Zea Mays ◽  
Plant Growth ◽  
Plant Height ◽  
Pot Experiment ◽  
Root Weight ◽  
Dual Culture ◽  
Maize Roots ◽  
Plant Growth Promoting ◽  
Growth Promoting

Aims: To isolate Plant Growth Promoting Bacillus strain from maize roots, to evaluate its biocontrol potentials and to characterize the isolate using16S rRNA sequencing. Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Awka, between February 2019 and March 2020. Methodology: The isolation of Plant Growth Promoting Rhizobacteria (PGPR) from maize roots was done using Pikovskaya (PVK) agar. Quantitative determination of phosphate was carried out using PVK broth. Evaluations of other plant growth promoting properties were carried out such as IAA, etc. Fusarium and Enterobacter plant pathogens were isolated from diseased maize plants. The in vitro antagonism effects of the PGPR isolates against the pathogens were analyzed using the dual culture plate technique. The pot experiment was carried out in a completely randomized design. Plant characteristics such as plant height, shoot  and root weight, chlorophyll content, as well as disease assessment were recorded accordingly. The organisms were identified using phenotypic and molecular methods. Results: Seven PGPR bacteria were isolated from maize (Zea mays) roots using PVK agar. Aneurinibacillus migulanus gave the highest solubilization index of 4.21 while isolate IS48 gave the lowest solubilization index of 1.47. A. migulanus produced IAA, ammonia and cellulase enzyme but no hydrogen cyanide. The organism showed antagonism activity against the two tested phytopathogens. In the pot experiment, A. migulanus treated plants showed a statistically insignificant difference in maize plant height at P=0.05 but gave significant increases in shoot and root wet weights. The organism offered 83.33% and 71.43% protection against Enterobacter and Fusarium pathogens respectively in the pot experiment. Conclusion: A. migulanus solubilized phosphate in addition to other plant growth promoting  properties. It showed biocontrol potentials both in vitro and in vivo and thus can be used as substitute for synthetic agrochemicals.

Experimental control of the activity of the quiescent centre in excised root tips of Zea mays

Planta ◽  
1973 ◽  
Vol 112 (2) ◽  
pp. 91-100 ◽  
Author(s):  
Peter L. Webster ◽  
Haviva D. Langenauer
Keyword(s):  
Zea Mays ◽  
Quiescent Centre ◽  
Root Tips ◽  
Experimental Control

Uptake of Aluminium by the root tips of an Al-sensitive and Al-tolerant cultivar of Zea mays

1998 ◽  
Vol 36 (6) ◽  
pp. 463-467 ◽  
Author(s):  
José Pintro ◽  
Jean Barloy ◽  
Paul Fallavier
Keyword(s):  
Zea Mays ◽  
Root Tips

scholarly journals Genomic Analysis of the DNA Replication Timing Program during Mitotic S Phase in Maize (Zea mays) Root Tips

2017 ◽  
Vol 29 (9) ◽  
pp. 2126-2149 ◽  
Author(s):  
Emily E. Wear ◽  
Jawon Song ◽  
Gregory J. Zynda ◽  
Chantal LeBlanc ◽  
Tae-Jin Lee ◽  
...  
Keyword(s):  
Zea Mays ◽  
Dna Replication ◽  
Genomic Analysis ◽  
Replication Timing ◽  
S Phase ◽  
Root Tips ◽  
Dna Replication Timing

Diplodia maydis. [Descriptions of Fungi and Bacteria].

1966 ◽  
Author(s):  
B. C. Sutton
Keyword(s):  
United States ◽  
South Africa ◽  
Zea Mays ◽  
South America ◽  
Geographical Distribution ◽  
Ear Rot ◽  
Seedling Blight ◽  
Stalk Rot ◽  
Maize Roots ◽  
Stenocarpella Maydis

Abstract A description is provided for Diplodia maydis[Stenocarpella maydis]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Zea mays. Also on Arundinaria sp. DISEASES: Stalk rot, white ear rot, and seedling blight of maize. Roots may also become infected. GEOGRAPHICAL DISTRIBUTION: Africa (Congo, Kenya, Malawi, Rhodesia, South Africa, Tanzania); Asia (India); Australasia (Australia); Europe (U.S.S.R.), North America (Canada, Mexico, United States); South America (Argentina, Brazil, Colombia).

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