scholarly journals Rhythmic Control of The Plant-Microbiome Holobiont

2020 ◽  
Author(s):  
Tao Lu ◽  
Zhenyan Zhang ◽  
Yan Li ◽  
Qi Zhang ◽  
Liwei Sun ◽  
...  
Keyword(s):  
Microbial Community ◽  
Circadian Clock ◽  
Root Exudates ◽  
Root Exudation ◽  
Biological Clock ◽  
Diurnal Rhythms ◽  
Growth Stages ◽  
Plant Host ◽  
Different Growth Stages

Abstract Background: Many physiological and metabolic processes in plants are modulated by a circadian clock. Rhizospheric microorganisms fed by root exudates provide beneficial functions to their plant host. The intricate connection between the circadian clock and the rhizospheric microbial community remains poorly understood. Results: We investigated the role of the Arabidopsis circadian clock in shaping the rhizospheric microbial community using wild-type plants and clock mutants (cca1-1 and toc1-101). We performed transcriptomic and metabolomic analyses and sequenced amplicons of the 16S ribosomal RNA gene to characterize gene transcription, root exudation and the bacterial communities, respectively, throughout the day (24 h). Deficiencies of the central circadian clock led to abnormal diurnal rhythms for thousands of expressed genes and dozens of root exudates. Bacterial community failed to follow obvious patterns in the 24-h period, and lack of coordination with plant growth in the clock mutants. Conclusions: Our findings suggested that the biological clock was an important force that drove plants to adjust their rhizospheric microbiomes for adapting to different growth stages.

Response to water stress of soil enzymes and root exudates from drought and non-drought tolerant corn hybrids at different growth stages

2012 ◽  
Vol 92 (3) ◽  
pp. 501-507 ◽  
Author(s):  
Fengbin Song ◽  
Xiying Han ◽  
Xiancan Zhu ◽  
Stephen J. Herbert
Keyword(s):  
Alkaline Phosphatase ◽  
Water Stress ◽  
Osmotic Stress ◽  
Root Exudates ◽  
Soil Enzymes ◽  
Growth Stages ◽  
Corn Hybrids ◽  
Drought Tolerant ◽  
Response To Water ◽  
Different Growth Stages

Song, F., Han, X., Zhu, X. and Herbert, S. J. 2012. Response to water stress of soil enzymes and root exudates from drought and non-drought tolerant corn hybrids at different growth stages. Can. J. Soil Sci 92: 501–507. Drought tolerant corn hybrids (Zea mays L.) are an excellent model to evaluate the effect of water stress on rhizosphere functions. The purpose of this study was to investigate the influences of water stress on soil pH, enzyme activities, and root exudates from corn. Two corn hybrids, Baidan 9 (drought tolerant) and Baidan 31 (non-drought tolerant) were grown in soil-filled pots for pH and enzyme assays and in hydroponics culture for root exudate analysis. Water stress was imposed at four growth stages: seedling, elongation, tasseling and grain-filling stages. Soil pH was lower in the rhizosphere than bulk soil, but was not affected by water deficiency. Water stress increased protease activity at the seedling stage, but reduced its activities at other stages compared to the control. A significant positive correlation was observed between pH and alkaline phosphatase activity under water stress. Compared to Baidan 31, the rhizosphere of drought-tolerant Baidan 9 had greater protease and catalase activities at all growth stages, greater alkaline phosphatase, lower acid phosphatase and greater invertase activities at elongation, tasseling and filling stages. Osmotic stress increased the organic acid concentration (malic, lactic, acetic, succinic, citric and maleic acids) in root exudates of Baidan 9 and Baidan 31; as well there was a greater fumaric acid concentration in Baidan 31 under osmotic stress than without stress. The increased soil enzyme activities and organic acids exuded from the rhizosphere of plants under water stress might contribute to drought tolerance in corn hybrids.

scholarly journals Alfalfa (Medicago sativaL.) shoot saponins: identification and bio-activity by the assessment of aphid feeding

2010 ◽  
Vol 105 (1) ◽  
pp. 62-70 ◽  
Author(s):  
H. Mazahery-Laghab ◽  
B. Yazdi-Samadi ◽  
M. Bagheri ◽  
A. R. Bagheri
Keyword(s):  
Plant Development ◽  
Insect Pests ◽  
Biological Effects ◽  
Biological Role ◽  
Growth Stages ◽  
Oral Toxicity ◽  
Medicagenic Acid ◽  
Significant Difference ◽  
Different Growth Stages

Biochemical components in alfalfa (Medicago sativaL.), such as saponins, can act as protecting factors against bio-stresses. Saponins are also antifeedants and show oral toxicity towards higher and lower animals. Changes in saponins, such as variation in the carbon skeleton, or hydrolysis of saponin glycosides and other conjugates, may change their biological effects. The aims of this research were to study saponin variation in different growth stages of alfalfa and to investigate the biological role of saponins in the spotted alfalfa aphid,Therioaphis maculata. Saponins from alfalfa shoots in different growth stages were extracted, chemically purified and analysed by TLC. Specific saponins such as soyasaponin1 from root and shoot and two bisdesmosides of medicagenic acid, one from shoot and another from root tissues, were identified using reference compounds allowing changes in saponin composition during plant development in different shoot tissues of alfalfa to be assessed. The response of the alfalfa aphid to feeding on alfalfa in different growth stages was studied. No significant difference in the survival of aphids, from neonate to adult, was observed, but due to the antibiotic effects of saponins, two differences were found in the onset of nymph production and cumulative nymph production. The results show that the saponin composition in alfalfa changes with plant development and this, in turn, can often negatively affect the development of specific insect pests such as the spotted alfalfa aphid, suggesting a possible biological role of alfalfa saponins.

Bacterial rhizosphere community profile at different growth stages of Umorok (Capsicum chinense) and its response to the root exudates

2019 ◽  
Vol 23 (2) ◽  
pp. 241-251 ◽  
Author(s):  
Phazna Devi T. A. ◽  
Dinabandhu Sahoo ◽  
Aravind Setti ◽  
Chandradev Sharma ◽  
M. C. Kalita ◽  
...  
Keyword(s):  
Root Exudates ◽  
Growth Stages ◽  
Capsicum Chinense ◽  
Community Profile ◽  
Rhizosphere Community ◽  
Different Growth Stages

Genetics of Gibberella fujikuroi. II. Natural occurrence and significance of heterokaryosis in sorghum isolates

1983 ◽  
Vol 61 (12) ◽  
pp. 3314-3319 ◽  
Author(s):  
Gurmel S. Sidhu
Keyword(s):  
Fusarium Moniliforme ◽  
Growth Stage ◽  
Gibberella Fujikuroi ◽  
Growth Stages ◽  
Natural Occurrence ◽  
Stalk Rot ◽  
Colony Color ◽  
Different Growth Stages ◽  
Natural Media

Of all the stalk rot fungi, Gibberella fujikuroi (Sawada) Wollenw. (anamorph stage Fusarium moniliforme Sheld.) was most frequently isolated from naturally infected, symptomless sorghum plants. Phenotypically distinct isolates of G. fujikuroi were recovered. This variability is ascribed to heterokaryosis. The homokaryotic components of the most frequently recovered heterokaryons found at a given growth stage were identified on the basis of colony color, texture, growth rate, and sporulation. Nuclear ratios were determined to confirm the presence and stability of heterokaryons. Natural and laboratory-induced heterokaryons were compared on synthetic and natural media, prepared from plant tissue, for stability and other attributes. The occurrence of different heterokaryons at different growth stages suggests genetic adaptation and a possible role of heterokaryosis in generating and maintaining natural variability in this fungus.

Characterization of Root Exudates at Different Growth Stages of Ten Rice (Oryza sativa L.) Cultivars

Plant Biology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 139-148 ◽  
Author(s):  
M. S. Aulakh ◽  
R. Wassmann ◽  
C. Bueno ◽  
J. Kreuzwieser ◽  
H. Rennenberg
Keyword(s):  
Oryza Sativa ◽  
Root Exudates ◽  
Oryza Sativa L ◽  
Growth Stages ◽  
Different Growth Stages

scholarly journals Host genotype explains rhizospheric microbial community composition: the case of wild cotton metapopulations (Gossypium hirsutum L.) in Mexico

2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Alejandra Hernández-Terán ◽  
Marcelo Navarro-Díaz ◽  
Mariana Benítez ◽  
Rafael Lira ◽  
Ana Wegier ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Microbial Community ◽  
Microbial Communities ◽  
Microbial Community Composition ◽  
Community Diversity ◽  
Rrna Gene ◽  
Host Genotype ◽  
Plant Host ◽  
Wild Cotton

ABSTRACT The rhizosphere provides several benefits to the plant host being a strong determinant for its health, growth and productivity. Nonetheless, the factors behind the assembly of the microbial communities associated with the rhizosphere such as the role of plant genotypes are not completely understood. In this study, we tested the role that intraspecific genetic variation has in rhizospheric microbial community assemblages, using genetically distinct wild cotton populations as a model of study. We followed a common garden experiment including five wild cotton populations, controlling for plant genotypes, environmental conditions and soil microbial community inoculum, to test for microbial differences associated with genetic variation of the plant hosts. Microbial communities of the treatments were characterized by culture-independent 16S rRNA gene amplicon sequencing with Illumina MiSeq platform. We analyzed microbial community diversity (alpha and beta), and diversity structure of such communities, determined by co-occurrence networks. Results show that different plant genotypes select for different and specific microbial communities from a common inoculum. Although we found common amplicon sequence variants (ASVs) to all plant populations (235), we also found unique ASVs for different populations that could be related to potential functional role of such ASVs in the rhizosphere.

Genetics of Gibberella fujikuroi. III. Significance of heterokaryosis in naturally occurring corn isolates

1983 ◽  
Vol 61 (12) ◽  
pp. 3320-3325 ◽  
Author(s):  
Gurmel S. Sidhu
Keyword(s):  
Gibberella Fujikuroi ◽  
Growth Stages ◽  
Corn Plant ◽  
Stalk Rot ◽  
Naturally Occurring ◽  
Fungal Organisms ◽  
Colony Color ◽  
The Subject ◽  
Different Growth Stages

Among the stalk rot fungal organisms, Gibberella fujikuroi (Saw.) Wn. (conidial anamorph Fusarium moniliforme Sheld.) was abundant in naturally infected com plants. Numerous phenotypically different isolates of F. moniliforme were recovered from the host. Some of these isolates formed heterokaryons more frequently in a given stage of plant growth. Frequently occurring heterokaryons were termed major and became the subject of this report. The component homokaryons exhibited differences in colony color, texture, growth rate, and sporulation. Based on these differences, ratios of two homokaryons recovered from a single representative of each of the four major heterokaryons were found to be balanced. Representative natural and laboratory-induced heterokaryons were compared for stability and balance of nuclear ratios on MM and SRM (stalk residue medium). Different heterokaryons predominated at different growth stages of the corn plant indicating preferential adaptation. Possible role of these heterokaryons in generating and maintaining natural variability was evaluated.

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