scholarly journals The MAD1 Adhesin of Metarhizium anisopliae Links Adhesion with Blastospore Production and Virulence to Insects, and the MAD2 Adhesin Enables Attachment to Plants

2007 ◽  
Vol 6 (5) ◽  
pp. 808-816 ◽  
Author(s):  
Chengshu Wang ◽  
Raymond J. St Leger
Keyword(s):  
Metarhizium Anisopliae ◽  
Plant Root ◽  
Yeast Cells ◽  
Plant Roots ◽  
Insect Cuticle ◽  
Plant Surface ◽  
Adhesive Properties ◽  
Regional Localization ◽  
Expression Of Genes ◽  
Ecological Versatility

ABSTRACT Metarhizium anisopliae is a fungus of considerable metabolic and ecological versatility, being a potent insect pathogen that can also colonize plant roots. The mechanistic details of these interactions are unresolved. We provide evidence that M. anisopliae adheres to insects and plants using two different proteins, MAD1 and MAD2, that are differentially induced in insect hemolymph and plant root exudates, respectively, and produce regional localization of adhesive conidial surfaces. Expression of Mad1 in Saccharomyces cerevisiae allowed this yeast to adhere to insect cuticle. Expression of Mad2 caused yeast cells to adhere to a plant surface. Our study demonstrated that as well as allowing adhesion to insects, MAD1 at the surface of M. anisopliae conidia or blastospores is required to orientate the cytoskeleton and stimulate the expression of genes involved in the cell cycle. Consequently, the disruption of Mad1 in M. anisopliae delayed germination, suppressed blastospore formation, and greatly reduced virulence to caterpillars. The disruption of Mad2 blocked the adhesion of M. anisopliae to plant epidermis but had no effects on fungal differentiation and entomopathogenicity. Thus, regulation, localization, and specificity control the functional distinction between Mad1 and Mad2 and enable M. anisopliae cells to adapt their adhesive properties to different habitats.

scholarly journals Model Test of the Reinforcement of Surface Soil by Plant Roots under the Influence of Precipitation

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hengxing Wang ◽  
Yulong He ◽  
Zufeng Shang ◽  
Chunpeng Han ◽  
Yilu Wang
Keyword(s):  
Water Content ◽  
Model Test ◽  
Surface Soil ◽  
Plant Root ◽  
Root Systems ◽  
Reinforced Soil ◽  
Plant Roots ◽  
Interfacial Friction ◽  
Negative Power ◽  
Pull Out

We present the results of the reinforcement of plant root systems in surface soil in a model test to simulate actual precipitation conditions. In the test, Eleusine indica was selected as herbage to reinforce the soil. Based on the various moisture contents of plant roots in a pull-out test, a fitting formula describing the interfacial friction strength between the roots and soil and soil moisture content was obtained to explain the amount of slippage of the side slope during the process of rainfall. The experimental results showed that the root systems of plants successfully reinforced soil and stabilized the water content in the surface soil of a slope and that the occurrence time of landslides was delayed significantly in the grass-planting slope model. After the simulated rainfall started, the reinforcement effect of the plant roots changed. As the rainfall increased, the interfacial friction between the roots and the soil exhibited a negative power function relationship with the water content. These conclusions can be used as a reference for the design of plant slope protection and reinforcement.

scholarly journals OPTIMALISASI PRODUKSI ENZIM KITINASE PADA ISOLAT JAMUR KITINOLITIK DARI SAMPEL TANAH RIZOSFER

2018 ◽  
Vol 3 (01) ◽  
pp. 62-69
Author(s):  
Eka Corneliyawati ◽  
Massora Massora ◽  
Khikmah Khikmah ◽  
As’ad Syamsul Arifin
Keyword(s):  
Biological Control ◽  
Cell Wall ◽  
Rhizosphere Soil ◽  
Plant Root ◽  
Optimal Growth ◽  
Chitinase Activity ◽  
Fungal Species ◽  
Plant Roots ◽  
Chitinase Production

The rhizosphere is the zone of soil surrounding a plant root where plant roots, soil and the soil biota interact with each other. Chitinolytic fungi has been effectively used in biological control agens. The chitinase activity causes lysis of the fungi cell wall pathogen. The aim of the research was to find optimization of activity chitinase enzyme from rhizosphere soil was conducted in vitro. Optimal growth chitinase production for TKR3 fungi isolate were concentration of chitin 0,2% (b/v), pH 5,5, temperature 30ºC, agitation 150 rpm and incubation time at four days. The optimum yield of chitinase production is influenced by fungal species and environmental conditions.

Advances in understanding plant root responses to root-feeding insects

2021 ◽  
pp. 231-266
Author(s):  
Scott N. Johnson ◽  
◽  
Ximena Cibils-Stewart ◽  
◽  
Keyword(s):  
Plant Root ◽  
Plant Roots ◽  
Insect Herbivores ◽  
Soil Environment ◽  
Knowledge Gaps ◽  
Root Herbivores ◽  
Mutualistic Fungi ◽  
Root Responses ◽  
Insect Attack ◽  
Root Feeding

This chapter presents an overview of the interactions between plant roots and root-feeding insect herbivores, focussing on changes in growth and physiology and crucially how roots are defended against insect attack. Several reviews have covered the ecology and management of insect root herbivores, together with their interactions with the abiotic and biotic soil environment. Therefore, the chapter focuses particularly on advances in our understanding of how plant mutualistic fungi may affect root-herbivores. This is an emerging area of research, with many attendant knowledge gaps, but we argue that this is an important component of how plants resist attack by belowground insect herbivores.

scholarly journals Bacterial Community Members Increase Bacillus subtilis Maintenance on the Roots of Arabidopsis thaliana

2020 ◽  
Vol 4 (4) ◽  
pp. 303-313
Author(s):  
Noam Eckshtain-Levi ◽  
Susanna Leigh Harris ◽  
Reizo Quilat Roscios ◽  
Elizabeth Anne Shank
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Crop Production ◽  
Crop Yields ◽  
Plant Root ◽  
Plant Roots ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Strains ◽  
Root Microbiome ◽  
Over Time

Plant-growth-promoting bacteria (PGPB) are used to improve plant health and promote crop production. However, because some PGPB (including Bacillus subtilis) do not maintain substantial colonization on plant roots over time, it is unclear how effective PGPB are throughout the plant growing cycle. A better understanding of the dynamics of plant root community assembly is needed to develop and harness the potential of PGPB. Although B. subtilis is often a member of the root microbiome, it does not efficiently monoassociate with plant roots. We hypothesized that B. subtilis may require other primary colonizers to efficiently associate with plant roots. We utilized a previously designed hydroponic system to add bacteria to Arabidopsis thaliana roots and monitor their attachment over time. We inoculated seedlings with B. subtilis and individual bacterial isolates from the native A. thaliana root microbiome either alone or together. We then measured how the coinoculum affected the ability of B. subtilis to colonize and maintain on A. thaliana roots. We screened 96 fully genome-sequenced strains and identified five bacterial strains that were able to significantly improve the maintenance of B. subtilis. Three of these rhizobacteria also increased the maintenance of two strains of B. amyloliquefaciens commonly used in commercially available bioadditives. These results not only illustrate the utility of this model system to address questions about plant–microbe interactions and how other bacteria affect the ability of PGPB to maintain their relationships with plant roots but also may help inform future agricultural interventions to increase crop yields. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Differential roles for the low-affinity phosphate transporters Pho87 and Pho90 in Saccharomyces cerevisiae

2011 ◽  
Vol 434 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Ruben Ghillebert ◽  
Erwin Swinnen ◽  
Pepijn De Snijder ◽  
Bart Smets ◽  
Joris Winderickx
Keyword(s):  
Transport System ◽  
Nitrogen Starvation ◽  
Yeast Cells ◽  
Interacting Proteins ◽  
High Affinity ◽  
Pho Pathway ◽  
Pi Transport ◽  
Expression Of Genes ◽  
Pi Acquisition ◽  
Pi Starvation

When starved of Pi, yeast cells activate the PHO signalling pathway, wherein the Pho4 transcription factor mediates expression of genes involved in Pi acquisition, such as PHO84, encoding the high-affinity H+/Pi symporter. In contrast, transcription of PHO87 and PHO90, encoding the low-affinity H+/Pi transport system, is independent of phosphate status. In the present work, we reveal that, upon Pi starvation, these low-affinity Pi transporters are endocytosed and targeted to the vacuole. For Pho87, this process strictly depends on SPL2, another Pho4-dependent gene that encodes a protein known to interact with the N-terminal SPX domain of the transporter. In contrast, the vacuolar targeting of Pho90 upon Pi starvation is independent of both Pho4 and Spl2, although it still requires its SPX domain. Furthermore, both Pho87 and Pho90 are also targeted to the vacuole upon carbon-source starvation or upon treatment with rapamycin, which mimics nitrogen starvation, but although these responses are independent of PHO pathway signalling, they again require the N-terminal SPX domain of the transporters. These observations suggest that other SPX-interacting proteins must be involved. In addition, we show that Pho90 is the most important Pi transporter under high Pi conditions in the absence of a high-affinity Pi-transport system. Taken together, our results illustrate that Pho87 and Pho90 represent non-redundant Pi transporters, which are tuned by the integration of multiple nutrient signalling mechanisms in order to adjust Pi-transport capacity to the general nutritional status of the environment.

scholarly journals The Biocontrol Agent and Insect Pathogen Photorhabdus luminescens Interacts with Plant Roots

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Alice Regaiolo ◽  
Nazzareno Dominelli ◽  
Karsten Andresen ◽  
Ralf Heermann
Keyword(s):  
Biological Control ◽  
Pest Management ◽  
Root Exudates ◽  
Biological Control Agent ◽  
Plant Root ◽  
Specific Interaction ◽  
Plant Roots ◽  
Photorhabdus Luminescens ◽  
Content Type ◽  
Root Interactions

ABSTRACT The number of sustainable agriculture techniques to improve pest management and environmental safety is rising, as biological control agents are used to enhance disease resistance and abiotic stress tolerance in crops. Here, we investigated the capacity of the Photorhabdus luminescens secondary variant to react to plant root exudates and their behavior toward microorganisms in the rhizosphere. P. luminescens is known to live in symbiosis with entomopathogenic nematodes (EPNs) and to be highly pathogenic toward insects. The P. luminescens-EPN relationship has been widely studied, and this combination has been used as a biological control agent; however, not much attention has been paid to the putative lifestyle of P. luminescens in the rhizosphere. We performed transcriptome analysis to show how P. luminescens responds to plant root exudates. The analysis highlighted genes involved in chitin degradation, biofilm regulation, formation of flagella, and type VI secretion system. Furthermore, we provide evidence that P. luminescens can inhibit growth of phytopathogenic fungi. Finally, we demonstrated a specific interaction of P. luminescens with plant roots. Understanding the role and the function of this bacterium in the rhizosphere might accelerate the progress in biocontrol manipulation and elucidate the peculiar mechanisms adopted by plant growth-promoting rhizobacteria in plant root interactions. IMPORTANCE Insect-pathogenic Photorhabdus luminescens bacteria are widely used in biocontrol strategies against pests. Very little is known about the life of these bacteria in the rhizosphere. Here, we show that P. luminescens can specifically react to and interact with plant roots. Understanding the adaptation of P. luminescens in the rhizosphere is highly important for the biotechnological application of entomopathogenic bacteria and could improve future sustainable pest management in agriculture.

Root-colonizing and soil-borne communities of arbuscular mycorrhizal fungi in a temperate forest understorey

Botany ◽  
2014 ◽  
Vol 92 (4) ◽  
pp. 277-285 ◽  
Author(s):  
Ülle Saks ◽  
John Davison ◽  
Maarja Öpik ◽  
Martti Vasar ◽  
Mari Moora ◽  
...  
Keyword(s):  
Plant Species ◽  
Mycorrhizal Fungi ◽  
Plant Root ◽  
Arbuscular Mycorrhizal ◽  
Small Subunit ◽  
Plant Roots ◽  
Individual Plant ◽  
Amf Communities ◽  
Arbuscular Mycorrhizal Fungal ◽  
Phylogenetic Dispersion

We analyzed arbuscular mycorrhizal fungal (AMF) communities in plant root samples from a natural forest ecosystem — a primeval forest in Järvselja, Estonia. AMF small-subunit (SSU) ribosomal RNA genes were subjected to 454-pyrosequencing and BLAST-based taxonomic identification. Seventy-six AMF sequence groups (virtual taxa, VT) were identified from plant roots. Taken together with seven additional VT recorded in an earlier investigation of soil AMF communities at the site, this represents the highest number of AMF reported from a single ecosystem to date. The six study plant species hosted similar AMF communities. However, AMF community composition in plant roots was significantly different from that in soil and considerably more VT were retrieved from roots than from soil. AMF VT identified from plant roots as a whole and from individual plant species were frequently phylogenetically clustered compared with local and global taxon pools, suggesting that nonrandom assembly processes, notably habitat filtering, may have shaped fungal assemblages. In contrast, the phylogenetic dispersion of AMF communities in soil did not differ from random subsets of the local or global taxon pools.

scholarly journals Effects of Low-Shear Modeled Microgravity on Cell Function, Gene Expression, and Phenotype in Saccharomyces cerevisiae

2006 ◽  
Vol 72 (7) ◽  
pp. 4569-4575 ◽  
Author(s):  
B. Purevdorj-Gage ◽  
K. B. Sheehan ◽  
L. E. Hyman
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Cell Function ◽  
Yeast Cells ◽  
Lag Phase ◽  
Limited Information ◽  
Cellular Functions ◽  
Modeled Microgravity ◽  
Expression Of Genes ◽  
Low Shear

ABSTRACT Only limited information is available concerning the effects of low-shear modeled microgravity (LSMMG) on cell function and morphology. We examined the behavior of Saccharomyces cerevisiae grown in a high-aspect-ratio vessel, which simulates the low-shear and microgravity conditions encountered in spaceflight. With the exception of a shortened lag phase (90 min less than controls; P < 0.05), yeast cells grown under LSMMG conditions did not differ in growth rate, size, shape, or viability from the controls but did differ in the establishment of polarity as exhibited by aberrant (random) budding compared to the usual bipolar pattern of controls. The aberrant budding was accompanied by an increased tendency of cells to clump, as indicated by aggregates containing five or more cells. We also found significant changes (greater than or equal to twofold) in the expression of genes associated with the establishment of polarity (BUD5), bipolar budding (RAX1, RAX2, and BUD25), and cell separation (DSE1, DSE2, and EGT2). Thus, low-shear environments may significantly alter yeast gene expression and phenotype as well as evolutionary conserved cellular functions such as polarization. The results provide a paradigm for understanding polarity-dependent cell responses to microgravity ranging from pathogenesis in fungi to the immune response in mammals.

scholarly journals Novel Characteristics of the Biological Properties of the YeastSaccharomyces cerevisiaeEukaryotic Initiation Factor 2A

2005 ◽  
Vol 280 (16) ◽  
pp. 15601-15611 ◽  
Author(s):  
Anton A. Komar ◽  
Stephane R. Gross ◽  
Diane Barth-Baus ◽  
Ryan Strachan ◽  
Jack O. Hensold ◽  
...  
Keyword(s):  
Translational Control ◽  
Internal Ribosome Entry Site ◽  
Biological Properties ◽  
Yeast Cells ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Entry Site ◽  
Regulation Of Expression ◽  
Internal Ribosome Entry ◽  
Expression Of Genes

Eukaryotic initiation factor 2A (eIF2A) has been shown to direct binding of the initiator methionyl-tRNA (Met-tRNAi) to 40 S ribosomal subunits in a codon-dependent manner, in contrast to eIF2, which requires GTP but not the AUG codon to bind initiator tRNA to 40 S subunits. We show here that yeast eIF2A genetically interacts with initiation factor eIF4E, suggesting that both proteins function in the same pathway. The doubleeIF2A/eIF4E-tsmutant strain displays a severe slow growth phenotype, which correlated with the accumulation of 85% of the double mutant cells arrested at the G2/M border. These cells also exhibited a disorganized actin cytoskeleton and elevated actin levels, suggesting that eIF2A might be involved in controlling the expression of genes involved in morphogenic processes. Further insights into eIF2A function were gained from the studies of eIF2A distribution in ribosomal fractions obtained from either aneIF5BΔ (fun12Δ) strain or aeIF3b-ts(prt1-1) strain. It was found that the binding of eIF2A to 40 and 80 S ribosomes was not impaired in either strain. We also found that eIF2A functions as a suppressor of Ure2p internal ribosome entry site-mediated translation in yeast cells. The regulation of expression from theURE2internal ribosome entry site appears to be through the levels of eIF2A protein, which has been found to be inherently unstable with a half-life of ∼17 min. It was hypothesized that this instability allows for translational control through the level of eIF2A protein in yeast cells.

scholarly journals MISIRoot: A Robotic Minimum Invasion in Situ Imaging System for Plant Root Phenotyping

2020 ◽  
Author(s):  
Zhihang Song ◽  
Wei Qiu ◽  
Jian Jin
Keyword(s):  
Plant Protection ◽  
Plant Root ◽  
Low Cost ◽  
3D Structure ◽  
Color Images ◽  
Plant Roots ◽  
Natural Soil ◽  
Wide Range ◽  
Root Phenotyping

Abstract Background: Plant root phenotyping technologies play an important role in breeding, plant protection, and other plant science research projects. The root phenotyping customers urgently need technologies that are low-cost, in situ, non-destructive to the roots, and suitable for the natural soil environment. Many recently developed root phenotyping methods such as minirhizotron, X-CT, and MRI scanners have their unique advantages in observing plant roots, but they also have disadvantages and cannot meet all the critical requirements simultaneously. Results: The study in this paper focuses on the development of a new plant root phenotyping robot that is minimally invasive to plants and working in situ inside natural soil, called “MISIRoot”. The MISIRoot system mainly consists of an industrial-level robotic arm, a mini-size camera with lighting set, a plant pot holding platform, and the image processing software for root recognition and feature extraction. MISIRoot can take high-resolution color images of the roots in soil with minimal disturbance to the root and reconstruct the plant roots’ three-dimensional (3D) structure at an accuracy of 0.1 mm. In a test assay, well-watered and drought-stressed groups of corn plants were measured by MISIRoot at V3, V4, and V5 stages. The system successfully acquired the RGB color images of the roots and extracted the 3D points cloud data containing the locations of the detected roots. The plants measured by MISIRoot and plants not measured (control) were carefully compared with the results from the Hyperspectral Imaging Facility (reference). No significant differences were found between the two groups of plants at different growth stages. Conclusion: The MISIRoot system recently developed at Purdue University has been proved effective in root phenotyping with multiple advantages: With a comparatively low cost and minimal invasion to the plant, this system can automatically measure the root’s 3D structure and take color images of the roots in ordinary soil media, and in situ. This system provides a new option for root phenotyping researchers and has a potential to be applied in a wide range of research topics such as breeding, plant protection and so on.

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