scholarly journals Targeting of Strigolacatones Associated Pathways for Conferring Orobanche Resistant Traits in Tomato and Medicago

2011 ◽  
Author(s):  
Yoram Kapulnik ◽  
Maria J. Harrison ◽  
Hinanit Koltai ◽  
Joseph Hershenhorn
Keyword(s):  
Life Cycle ◽  
Seed Germination ◽  
Root Exudates ◽  
Plant Root ◽  
Specific Effect ◽  
Carotenoid Biosynthesis ◽  
Plant Interactions ◽  
Tomato Plants ◽  
Transgenic Lines

This proposal is focused on examination of two plant interactions: parasitic with Orobanche, and symbiosis with arbuscular mycorrhiza fungi (AMF), and the involvement of a newly define plant hormones, strigolactones (SLs), in these plant interactions. In addition to strigolactones role in regulation of above-ground plant architecture, they are also known to be secreted from roots, and to be a signal for seed germination of the parasitic plants Orobanche. Moreover, secreted strigolactones were recognized as inducers of AMFhyphae branching. The present work was aimed at Generation of RNAi mutants of both tomato and Medicago, targeting multiple genes that may be involved in strigolactone production, carotenoid biosynthesis pathway, Pi signaling or other metabolic pathways, and hence affect AMF colonization and/or Orobanche resistance. Following the newly formed and existing RNAi mutants were examined for AMF colonization and Orobanche resistance. At the first phase of this project Orobanche seed germination assays and AMF colonization were examined in intact plants. These assays were shown to be effective and resulted with enhancement of Orobanche seed germination and AMF colonization in WT tomato plants, whereas roots of strigolactones impaired lines did not result with Orobanche seed germination and mycorrhiza colonization. Unexpectedly, root organ cultures (ROC) that were produced from the same wild type (WT) and mutant lines did not induce the Orobanche seed germination and AMFhyphal branching. This implies that under in vitro conditions ROC cultures are missing an important component for induction of Orobanche seed germination and AMFhyphal branching. In another line of experiments we have tested transgenic lines of Medicagotruncatula for AMFhuyphal branching and Orobanche seed germination assays. These lines included lines silenced for a GRAS transcription factor (RNAi 1845), an NBS-LRR type resistance gene (RNAi 1847), a kinase (RNAi 2403) and a protein of unknown function (RNAi 2417). In all cases, five independent transgenic root lines showed altered AMFphenotypes with reduced or aberrant colonization patterns. Following, we transformed tomato plants with the M. truncatulaTC 127050 PhosphoinositidekinaseRNAi construct. Transgenic lines that contained GUS constructs were used as control. All transgenic lines showed reduced level of Orobanche seed germination, masking any strigoalctones-specific effect. The research demonstrated that SLs production may not be examined in ROC –based bioassays. It was shown by the 3 independent assays employed in this project that none of the recognized characters of SLs may be reflected in these bioassays. However, when the whole plant root exudates were examined, SLs activity in root exudates was demonstrated. Hence, it can be concluded that the presence of an intact shoot, and possibly, shoot factors, may be necessary for production of SLs in roots. Another point of interest that rises from these results is that the presence of SLs is not necessary for AMF completion of life cycle. Hence, it may be concluded that SLs are important for AMFhyphal branching, before symbiosis, but not essential for AMF colonization and life cycle completion under ROC system conditions.

In vitro studies on the behaviour of second-stage juveniles of Heterodera schachtii (Nematoda: Heteroderidae) in response to host plant root exudates

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 149-155 ◽  
Author(s):  
F. Grundler ◽  
L. Schnibbe ◽  
U. Wyss
Keyword(s):  
Root Exudates ◽  
Root Exudate ◽  
Plant Root ◽  
Time Lapse ◽  
Heterodera Schachtii ◽  
Second Stage ◽  
Video Recordings ◽  
Aseptic Conditions ◽  
Agarose Layer

The behaviour of Heterodera schachtii second-stage juveniles in response to mustard (Sinapis alba) rooxudates was observed and analysed under aseptic conditions in a standardized bioassay. Aggregation of juveniles on an agarose layer occurred within less than 30 min in the area where root exudates had been applied and persisted for several hours. Analysis of time-lapse video recordings showed that the aggregation did not result from a directed orientation of the juvenile towards the root exudate. This was supported by an orientation assay using single juveniles. Aggregated juveniles showed pre-infection exploratory behaviour, including stylet thrusting and head-end bending, while staying at rest for several minutes.

The arbuscular mycorrhizal host status of plants can not be linked with the Striga seed-germination-activity of plant root exudates

2009 ◽  
Vol 116 (2) ◽  
pp. 86-89 ◽  
Author(s):  
V. Lendzemo ◽  
T. W. Kuyper ◽  
A. Urban ◽  
G. Vegvari ◽  
M. Puschenreiter ◽  
...  
Keyword(s):  
Seed Germination ◽  
Root Exudates ◽  
Plant Root ◽  
Arbuscular Mycorrhizal ◽  
Host Status

scholarly journals Allelopathic effect of aqueous extracts from agro-industrial residues of pecan nut [Carya illinoinensis (Wangenh) C. Koch] and pinhão (Araucaria angustifolia)

2017 ◽  
Vol 3 (3) ◽  
pp. 495-507 ◽  
Author(s):  
Voltaire SANT'ANNA ◽  
Maico Ismael KLEIN ◽  
Elaine BIONDO ◽  
Eliane Maria KOLCHINSKI
Keyword(s):  
Seed Germination ◽  
Seed Coat ◽  
Plant Root ◽  
In Vitro Tests ◽  
Allelopathic Effect ◽  
Lettuce Seed ◽  
Aqueous Extracts ◽  
Industrial Residues ◽  
Pecan Nutshell

Pinhão seed coat and pecan nutshell are residues widely produced in households and industries, which present great potential to be used as source of natural preservatives in the food chain. The objective of the present study is to evaluate the effectiveness of pinhão seed coat and pecan nutshell aqueous extracts in inhibiting seed germination. Extracts were obtained in concentration of 10g/L, 5g/L and 2.5g/L and tested against lettuce seed germination in vitro tests. The results show that both aqueous extract presented the significant (p<0.05) ability to inhibit seeds germination as well as the germination seed index, in relation to control experiments, when used in concentrations of up to 5g/L. Extracts did not interfere significantly (p>0.05) the germinated plant root size. Thus, aqueous extracts of agro-industrial residues from pinhão seed coat and pecan nutshell presents alellopathic activity, showing up as interesting alternative to be used as natural herbicide, also representing a way of solid waste management by industries and small farmers.

scholarly journals Investigating the Role of Root Exudates in Recruiting Streptomyces Bacteria to the Arabidopsis thaliana Microbiome

2021 ◽  
Vol 8 ◽  
Author(s):  
Sarah F. Worsley ◽  
Michael C. Macey ◽  
Samuel M. M. Prudence ◽  
Barrie Wilkinson ◽  
J. Colin Murrell ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Exudates ◽  
Plant Root ◽  
Stable Isotope Probing ◽  
Plant Roots ◽  
Plant Metabolites ◽  
Published Report ◽  
Promote Plant Growth

Streptomyces species are saprophytic soil bacteria that produce a diverse array of specialized metabolites, including half of all known antibiotics. They are also rhizobacteria and plant endophytes that can promote plant growth and protect against disease. Several studies have shown that streptomycetes are enriched in the rhizosphere and endosphere of the model plant Arabidopsis thaliana. Here, we set out to test the hypothesis that they are attracted to plant roots by root exudates, and specifically by the plant phytohormone salicylate, which they might use as a nutrient source. We confirmed a previously published report that salicylate over-producing cpr5 plants are colonized more readily by streptomycetes but found that salicylate-deficient sid2-2 and pad4 plants had the same levels of root colonization by Streptomyces bacteria as the wild-type plants. We then tested eight genome sequenced Streptomyces endophyte strains in vitro and found that none were attracted to or could grow on salicylate as a sole carbon source. We next used 13CO2 DNA stable isotope probing to test whether Streptomyces species can feed off a wider range of plant metabolites but found that Streptomyces bacteria were outcompeted by faster growing proteobacteria and did not incorporate photosynthetically fixed carbon into their DNA. We conclude that, given their saprotrophic nature and under conditions of high competition, streptomycetes most likely feed on more complex organic material shed by growing plant roots. Understanding the factors that impact the competitiveness of strains in the plant root microbiome could have consequences for the effective application of biocontrol strains.

In vitro life cycle of Heterodera sacchari on Pluronic gel

Nematology ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 573-579 ◽  
Author(s):  
Somnath S. Pokhare ◽  
Samer S. Habash ◽  
John T. Jones ◽  
Abdelnaser Elashry ◽  
Florian M.W. Grundler
Keyword(s):  
Oryza Sativa ◽  
Life Cycle ◽  
Adult Female ◽  
Root Exudates ◽  
Rice Root ◽  
Post Inoculation ◽  
Rice Cultivars ◽  
Time Points

Summary This paper presents studies on the life cycle of Heterodera sacchari under in vitro conditions. Pluronic gel was used as a medium for growth of H. sacchari. The life cycle was completed in 7-9 weeks on rice (Oryza sativa, ‘Nipponbare’). After infection, juveniles developed and reached the reproducing adult female stage at 25 days post inoculation (dpi). At 35 dpi, all females produced eggs in various numbers. Some females were translucent and eggs inside could be counted. At 49 dpi females started to tan and developed into dark brown cysts. Hatching of H. sacchari juveniles from cysts could be stimulated by 3 mM ZnCl2 but not by rice root exudates. The in vitro culture of H. sacchari on Pluronic gel can be used efficiently to collect post-infective nematode/host samples at different time points for various studies and to screen different rice cultivars for resistance/susceptibility.

Effect of Sulfonylurea Herbicides on Early Development of Egyptian Broomrape (Orobanche aegyptiaca) in Tomato (Lycopersicon esculentum)

1998 ◽  
Vol 12 (1) ◽  
pp. 108-114 ◽  
Author(s):  
Joseph Hershenhorn ◽  
Dina Plakhine ◽  
Yaakov Goldwasser ◽  
James H. Westwood ◽  
Chester L. Foy ◽  
...  
Keyword(s):  
Seed Germination ◽  
Parasitic Plant ◽  
Parasite Development ◽  
Sulfonylurea Herbicides ◽  
Tomato Plants ◽  
Radicle Elongation ◽  
Tomato Roots ◽  
Polyethylene Bags ◽  
Orobanche Aegyptiaca

The effect of the sulfonylurea herbicides, bensulfuron, chlorsulfuron, nicosulfuron, primisulfuron, rimsulfuron, thifensulfuron, and triasulfuron, on seed germination and radicle elongation of the parasitic plant, Egyptian broomrape, was tested in vitro without a host plant. These herbicides applied to the seeds at the preconditioning and germination stages significantly reduced radicle elongation of the parasite. Chlorsulfuron, rimsulfuron, and triasulfuron were further tested in polyethylene bags, where the parasite was able to parasitize tomato roots. Chlorsulfuron and triasulfuron applied at 2.5 and 25 μM ai and rimsulfuron at 5.0 μM ai, at the preconditioning and germination stages, almost completely inhibited parasite development, but at lower concentrations the parasite partially recovered 26 days after application. Chlorsulfuron inhibited parasite development for 34 d. Chlorsulfuron, triasulfuron, and rimsulfuron damaged parasite organs and caused rapid death of Egyptian broomrape tubercles when applied after the parasite had completed attachment to host roots. However, chlorsulfuron and triasulfuron at 25 μM ai were toxic to the tomato plants.

scholarly journals Plant-derived benzoxazinoids act as antibiotics and shape bacterial communities

2021 ◽  
Author(s):  
Niklas Schandry ◽  
Katharina Jandrasits ◽  
Ruben Garrido-Oter ◽  
Claude Becker
Keyword(s):  
Root Exudates ◽  
Bacterial Communities ◽  
Rational Design ◽  
Plant Root ◽  
Associated Bacteria ◽  
Specialized Metabolites ◽  
The Impact ◽  
Derivatives Of ◽  
Community Systems

Plants synthesize and release specialized metabolites into their environment that can serve as chemical cues for other organisms. Metabolites that are released from the roots are important factors in determining which microorganisms will colonize the root and become part of the plant rhizosphere microbiota. Root exudates are often further converted by soil microorganisms, which can result in the formation of toxic compounds. How individual members of the plant rhizosphere respond to individual compounds and how the differential response of individual microorganisms contributes to the response of a microbial community remains unclear. Here, we investigated the impact of derivatives of one class of plant root exudates, benzoxazinoids, which are released by important crops such as wheat and maize, on a collection of 180 root-associated bacteria. We show that phenoxazine, derived from benzoxazinoids, inhibits the growth of root-associated bacteria in vitro in a strain-specific manner, with sensitive and resistant isolates in most of the studied clades. Synthetic bacterial communities that were assembled from only resistant isolates were more resilient to chemical perturbations than communities comprised of only sensitive members. Isolates that were shared between different communities revealed stable interactions, independent of the overall community composition. On the other hand, we could attribute differential community development to differences in interactions formed by closely related representatives of the same bacterial genus. Our findings highlight the fact that profiling isolate collections can aid the rational design of synthetic communities. Moreover, our data show that simplified in vitro community systems are able to recapitulate observations on the influence of metabolite exudation on the structure of root-associated communities, thus providing an avenue for reductionist explorations of the rhizosphere biology in defined, host-free settings.

scholarly journals Solanum betaceum in vitro seed germination and seedling development in response to pregerminative treatments

Bionatura ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 1520-1523
Author(s):  
K. S Salazar-Vega ◽  
I. Vaca,
Keyword(s):  
Life Cycle ◽  
Seed Germination ◽  
Woody Plants ◽  
Seedling Emergence ◽  
Germination Percentage ◽  
Seedling Development ◽  
Emergence Time ◽  
Germinated Seeds ◽  
Solanum Betaceum

Germination and seedling development are critical stages in the life cycle of plants. Insufficient seedling emergence and inadequate establishment of woody plants are significant constraints in producing crops such as tamarillo. The application of pregerminative protocols improves the germination percentage, reduces the seedling emergence time, and improves several species in vitro. The present study was conducted to contrast three pregerminative treatments on Solanum betaceum seeds. When evaluating the pregerminative treatments, treatment T3 (imbibition for 24 hours) obtained the best results, showing an average of 21.62 days to germination, 73% germinated seeds, and 2.31 leaves per explant.

Response of nitrogen assimilating enzymes during in vitro culture of Argyrolobium roseum

Biologia ◽  
2015 ◽  
Vol 70 (4) ◽  
Author(s):  
Darima Habib ◽  
Muhammad Zia ◽  
Yamin Bibi ◽  
Bilal Haider Abbasi ◽  
Muhammad Fayyaz Chaudhary
Keyword(s):  
Life Cycle ◽  
Seed Germination ◽  
In Vitro Culture ◽  
Growth And Development ◽  
Plant Cells ◽  
Root Explants ◽  
Reverse Pattern ◽  
Developmental Phases ◽  
Root Tissues

AbstractNitrogen assimilating enzymes play curtail role during un-differentiation and re-differentiation of plant cells. To investigate role and pattern of glutamine synthetase (GS), nitrate reductase (NR) and glutamate dehydrogenase (GDH) during in vitro life cycle of Argyrolobium roseum this study was conducted. The concentrations of these enzymes were determined during seed germination; callus induction from leaf, stem and root explants; shoot regeneration from callus; root development and acclimatization stages. GS and NR enzymes showed ascending pattern during in vitro plant development from seed while GDH concentration decreased during this process. Completely reverse pattern was showed by these enzymes during callogenesis and proliferation phase. Increase in GS and NR activities was noticed in regenerated leaves and stem during shoots and roots developmental phases; and vice verse for GDH. The acclimatization stress also up lifted NR and GS activities in leaf, stem and root tissues. This study highlights the importance of nitrogen assimilating enzymes (NR, GS, and GDH) during growth and development of A. roseum in vitro culture.

scholarly journals A New Phenol Glycoside from Root Exudates of Peperomia pellucida L. HBK. and its Role in Plant Invasion

2017 ◽  
pp. 13-24
Author(s):  
Suparna Biswas ◽  
Nabanita Chakraborty ◽  
Soma Patra ◽  
Prasanta Bhowmik
Keyword(s):  
Root Exudates ◽  
Plant Root ◽  
Mustard Seed ◽  
Weed Species ◽  
Methanol Fraction ◽  
Main Compound ◽  
Bioassay Experiment ◽  
North And South America ◽  
Phenol Glycoside

Peperomia pellucida is an annual, shallow-rooted, succulent, delicate, glabrous herb. It is a native weed species of tropical North and South America, and it is now pantropic in distribution and abundant in India as an invasive aggressive colonizer. Medicinal properties of the plant have been well documented but no work has been done to find out the reason behind its invasive aggressive nature. The objective of our present work was to study the allelopathic activity of allelochemicals released by root exudates of P. pellucida which may play an important role in invasive and aggressive properties of the plant. Root exudates of P. pellucida were collected in root exudates trapping system. Main compound was isolated from methanol fraction of root exudates of P. pellucida, purified by thin layer and column chromatography and finally subjected to mass spectra, infrared, and nuclear magnetic resonance (both 1H and 13C) for complete structural elucidation. In vitro allelopathic activities of the compound were studied by rice, wheat and mustard seed bioassays. A new phenol glycocide [(6-(4-hydroxyphenoxy)-tetrahydro-2H-pyran-2, 3, 4, 5-tetraol); C11H14O7; Mol. Wt. 258] has been isolated and purified from root exudates of P. pellucida. This pure compound exhibited significant allelopathic activities on rice, wheat and mustard seeds in vitro bioassay experiment. This compound showed maximum inhibitory activity on rice, than in wheat and mustard bioassays. Peperomia pellucida released a phenol glycoside through root exudates into rhizophere which may act as a major allelopathic agent and may be responsible for its invasive and aggressive nature.

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