scholarly journals Transcriptome sequencing analysis of maize roots reveals the effects of substrate and root hair formation in a spatial context

2021 ◽  
Author(s):  
Minh Ganther ◽  
Doris Vetterlein ◽  
Anna Heintz-Buschart ◽  
Mika Tapio Tarkka

Abstract Background Plant roots sense and respond to changes in their soil environment, but conversely contribute to rhizosphere organization through chemical, mechanical and biotic interactions. Transcriptomic profiling of plant roots can be used to assess how the plant adjusts its gene expression in relation to environment, genotype and rhizosphere processes; thus enabling us to achieve a better understanding of root-soil interactions. Methods We used a standardized soil column experimental platform to investigate the impact of soil texture (loam, sand) and root hair formation (wildtype, root hair defective rth3 mutant) in a spatial context (three sampling depths) and assessed maize root transcriptomic profiles using next-generation RNA sequencing. Results Substrate induced the largest changes in root gene expression patterns, affecting gene functions related to immunity, stress, growth and water uptake. Genes with column depth-related expression levels were associated with growth and plant defense. The influence of root hairs mainly manifested in differential expression of epidermal cell differentiation and cell wall organization, and defense response-related genes. Substrate type strongly modified the transcriptomic patterns related to column depth and root hair elongation, highlighting the strong impact of soil texture. Conclusions Our results demonstrate that substrate, sampling depth and plant genotype interactively affect maize gene expression, and suggest feedback processes between the plant, the soil and the microbiome. The obtained results form a foundational basis for the integration and interpretation of future experiments utilizing the same experimental platform.

2021 ◽  
Vol 12 ◽  
Author(s):  
Yang Liu ◽  
Lu-Lu Yu ◽  
Ye Peng ◽  
Xin-Xin Geng ◽  
Fei Xu

Alternative oxidase (AOX) is the terminal oxidase of the mitochondrial respiratory electron transport chain in plant cells and is critical for the balance of mitochondrial hemostasis. In this study, the effect of inhibition of AOX with different concentrations of salicylhydroxamic acid (SHAM) on the tobacco root development was investigated. We show here that AOX inhibition significantly impaired the development of the main root and root hair formation of tobacco. The length of the main root of SHAM-treated tobacco was significantly shorter than that of the control, and no root hairs were formed after treatment with a concentration of 1 mM SHAM or more. The transcriptome analysis showed that AOX inhibition by 1 mM SHAM involved in the regulation of gene expression related to root architecture. A total of 5,855 differentially expressed genes (DEGs) were obtained by comparing SHAM-treated roots with control. Of these, the gene expression related to auxin biosynthesis and perception were significantly downregulated by 1 mM SHAM. Similarly, genes related to cell wall loosening, cell cycle, and root meristem growth factor 1 (RGF1) also showed downregulation on SHAM treatment. Moreover, combined with the results of physiological measurements, the transcriptome analysis demonstrated that AOX inhibition resulted in excessive accumulation of reactive oxygen species in roots, which further induced oxidative damage and cell apoptosis. It is worth noting that when indoleacetic acid (20 nM) and dimethylthiourea (10 mM) were added to the medium containing SHAM, the defects of tobacco root development were alleviated, but to a limited extent. Together, these findings indicated that AOX-mediated respiratory pathway plays a crucial role in the tobacco root development, including root hair formation.


2021 ◽  
Author(s):  
Minh Ganther ◽  
Lioba Rüger ◽  
Michael Bonkowski ◽  
Anna Heintz-Buschart ◽  
Mika Tarkka

<p>This study was conducted within the framework of the DFG project SPP2089 “Rhizosphere Spatiotemporal Organization – a Key to Rhizosphere Functions” (project number 403641192).</p><p>As plant roots grow into the soil, the formation of biological gradients occurs at different spatial scales. It has been shown that plants recruit specific subsets of the soil bacterial community at their roots through excretion of mucilage at root tips and exudates at the sites of root hair formation. The promotion of or defense against certain bacterial taxa is also reflected in the composition of the protist communities that feed on bacteria.</p><p>Using high-throughput sequencing methods, we investigated emerging patterns in root gene expression in relation to bacterial and protozoan community structures. We found highly distinct root region specific patterns relating to differential root gene expression relating to growth, defense and transporter activity, as well as bacterial and protist (cercozoan) diversity. Root cap removal led to differently composed microbial communities, as well as a regulation of root genes relating to stress and defense. The lack of root hairs was only reflected in the amount of microbial carbon in soil and a small number of differentially expressed genes involved in cell wall processes.</p><p>We could show that the rhizosphere microbiome, is as dynamic as its environment. Root regions differentially affect microbial communities, which is also reflected in the expression of plant genes of categories relating to defense, immunity and stress. Our findings will further enhance our understanding of microbial root interactions at single root scale.</p>


2010 ◽  
Vol 62 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Hidenori Takahashi ◽  
Testuhito Shinkawa ◽  
Shinjiro Nakai ◽  
Yasunori Inoue

2021 ◽  
Author(s):  
Christoph Tebbe ◽  
Damini Damini ◽  
Damien Finn ◽  
Nataliya Bilyera ◽  
Minh Ganther ◽  
...  

<p>The deposition of energy rich carbon sources released by plant roots during their growth fuels microbially driven ecosystem processes in soil, but there is a lack of understanding how microorganisms interact and collaborate. The objective of this research was therefore to characterize microbial networks as they assemble under the influence of plant roots. To identify the specific importance of root hairs, we compared the impact of a maize wild-type to a root-air defective mutant (rth3; (1).</p><p>The microbial community structure was analyzed by qPCR and 16S rRNA gene amplicon sequencing from soil DNA. In order to increase the probability of detecting truly interacting microbial partners as a basis for network analyses, we first evaluated a new protocol to obtain DNA from as little as 1 mg instead of the usual 250 mg soil samples, thereby approaching the aggregate level (2). While the diversity of bacterial 16S rRNA gene amplicons of 250-mg samples taken from the same soil was not distinct, DNA analyses from individual aggregates clearly differed from each other underlining that soil aggregates represent distinct microbial habitats.</p><p>Soil column experiments with maize grown in a loam soil (3) revealed distinct communities between rhizosphere and bulk soil. The community composition of individual aggregates showed more differences in bulk soil compared to rhizosphere. Less elaborated networks were seen in bulk soil and a profound effect of root hairs could be unravelled. Null model testing demonstrated that Actinobacteria were equally important for network connectivity independent of the root hair mutation, but for networks of the wildtype, Acidobacteria were essential for synergistic interactions and overall network structure. In contrast, Proteobacteria and Firmicutes connectivity became more important. The observed differences in community composition and interactions suggests carbon cycling, and perhaps other microbially-driven functions, are markedly affected by the presence of root hairs.</p><p>Utilizing maize root soil microcosms for studying soil zymography in the rhizosphere allowed to obtain soil samples from regions with distinct specific enzyme activities. In order to enhance the detection of actively metabolizing bacterial community members, we studied rRNA sequences and compared it to rRNA gene sequences from the same samples. Currently the data are under analysis.</p><p>References</p><p>(1) Wen, T-J, Schnable PS (1994) Analyses of mutants of three genes that influence root hair development in Zea mays (Gramineae) suggest that root hairs are dispensable. Am. J. Bot. 81, 833–842.</p><p>(2) Szoboszlay M, Tebbe CC (2020) Hidden heterogeneity and co-occurrence networks of soil prokaryotic communities revealed at the scale of individual soil aggregates. Microbiol. Open, e1144. DOI: 10.1002/mbo3.1144</p><p>(3) Vetterlein D et al. (2020) Experimental platforms for the investigation of spatiotemporal patterns in the rhizosphere – laboratory and field scale. J. Plant Nutr. Soil Sci., 000, 1–16 DOI: 10.1002/jpln.202000079</p>


2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Lulu Chen ◽  
Alejandro R. Walker ◽  
Robert A. Burne ◽  
Lin Zeng

ABSTRACT Amino sugars, particularly glucosamine (GlcN) and N-acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to the biofilms colonizing the human oral cavity. Evidence is emerging that these amino sugars provide ecological advantages to beneficial commensals over oral pathogens and pathobionts. Here, we performed transcriptome analysis on Streptococcus mutans and Streptococcus gordonii growing in single-species or dual-species cultures with glucose, GlcN, or GlcNAc as the primary carbohydrate source. Compared to glucose, GlcN caused drastic transcriptomic shifts in each species of bacteria when it was cultured alone. Likewise, cocultivation in the presence of GlcN yielded transcriptomic profiles that were dramatically different from the single-species results from GlcN-grown cells. In contrast, GlcNAc elicited only minor changes in the transcriptome of either organism in single- and dual-species cultures. Interestingly, genes involved in pyruvate metabolism were among the most significantly affected by GlcN in both species, and these changes were consistent with measurements of pyruvate in culture supernatants. Differing from what was found in a previous report, growth of S. mutans alone with GlcN inhibited the expression of multiple operons required for mutacin production. Cocultivation with S. gordonii consistently increased the expression of two manganese transporter operons (slo and mntH) and decreased expression of mutacin genes in S. mutans. Conversely, S. gordonii appeared to be less affected by the presence of S. mutans but did show increases in genes for biosynthetic processes in the cocultures. In conclusion, amino sugars profoundly alter the interactions between pathogenic and commensal streptococci by reprogramming central metabolism. IMPORTANCE Carbohydrate metabolism is central to the development of dental caries. A variety of sugars available to dental microorganisms influence the development of caries by affecting the physiology, ecology, and pathogenic potential of tooth biofilms. Using two well-characterized oral bacteria, one pathogen (Streptococcus mutans) and one commensal (Streptococcus gordonii), in an RNA deep-sequencing analysis, we studied the impact of two abundant amino sugars on bacterial gene expression and interspecies interactions. The results indicated large-scale remodeling of gene expression induced by GlcN in particular, affecting bacterial energy generation, acid production, protein synthesis, and release of antimicrobial molecules. Our study provides novel insights into how amino sugars modify bacterial behavior, information that will be valuable in the design of new technologies to detect and prevent oral infectious diseases.


2006 ◽  
Vol 141 (3) ◽  
pp. 1149-1158 ◽  
Author(s):  
Miroslaw Kwasniewski ◽  
Iwona Szarejko

1986 ◽  
Vol 68 (4) ◽  
pp. 653-656 ◽  
Author(s):  
Francoise Jaunin ◽  
Rose-Marie Hofer

2020 ◽  
Author(s):  
Minh Ganther ◽  
Marie-Lara Bouffaud ◽  
Lucie Gebauer ◽  
François Buscot ◽  
Doris Vetterlein ◽  
...  

<p>The complex interactions between plant roots and soil microbes enable a range of beneficial functions such as nutrient acquisition, defense against pathogens and production of plant growth hormones. The role of soil type and plant genotype in shaping rhizosphere communities has been explored in the past, but often without spatial context. The spatial resolution of rhizosphere processes enables us to observe pattern formation in the rhizosphere and investigate how spatial soil organization is shaped through soil–plant–microbiome interactions.</p><p>We applied spatial sampling in a standardized soil column experiment with two maize genotypes (wildtype vs. <em>roothairless3</em>) and two different soil textures (loam vs. sand) in order to investigate how in particular functions of the maize roots relating to nutrient/water uptake, immunity/defense, stress and exudation are affected. RNA sequencing and differential gene expression analysis were used to dissect impact of soil texture, root genotype and sampling depth. Our results indicate that variance in gene expression is predominantly explained by soil texture as well as sampling depth, whereas genotype appears to play a less pronounced role at the analyzed depths. Gene Ontology enrichment analysis of differentially expressed genes between soil textures revealed several functional categories and pathways relating to phytohormone-mediated signaling, cell growth, secondary metabolism, and water homeostasis. Community analysis of rhizosphere derived ACC deaminase active (acdS gene including) plant beneficial bacteria, which suppress the phytohormone ethylene production, suggests that soil texture and column depth are the major factors that affect acdS community composition.</p><p>From the comprehensive gene expression analyses we aim to identify maize marker genes from the relevant core functional groups. These marker genes will be potentially useful for future experiments; such as field plot experiments for investigation of later-emerging plant properties.</p><p>This research was conducted within the research program “Rhizosphere Spatiotemporal Organisation – a Key to Rhizosphere Functions” of the German Science Foundation (TA 290/5-1).</p>


2003 ◽  
Vol 116 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Masae Konno ◽  
Machiko Ooishi ◽  
Yasunori Inoue

Sign in / Sign up

Export Citation Format

Share Document