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Koichi Yoneyama - One of the best experts on this subject based on the ideXlab platform.
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difference in striga susceptibility is reflected in Strigolactone secretion profile but not in compatibility and host preference in arbuscular mycorrhizal symbiosis in two maize cultivars
New Phytologist, 2015Co-Authors: Kaori Yoneyama, Ryota Arakawa, Keiko Ishimoto, Takaya Kisugi, Takahito Nomura, Fred Kanampiu, Takao Yokota, Tatsuhiro Ezawa, Koichi YoneyamaAbstract:Summary Strigolactones released from plant roots trigger both seed germination of parasitic weeds such as Striga spp. and hyphal branching of the symbionts arbuscular mycorrhizal (AM) fungi. Generally, Strigolactone composition in exudates is quantitatively and qualitatively different among plants, which may be involved in susceptibility and host specificity in the parasite–plant interactions. We hypothesized that difference in Strigolactone composition would have a significant impact on compatibility and host specificity/preference in AM symbiosis. Strigolactones in root exudates of Striga-susceptible (Pioneer 3253) and -resistant (KST 94) maize (Zea mays) cultivars were characterized by LC-MS/MS combined with germination assay using Striga hermonthica seeds. Levels of colonization and community compositions of AM fungi in the two cultivars were investigated in field and glasshouse experiments. 5-Deoxystrigol was exuded exclusively by the susceptible cultivar, while the resistant cultivar mainly exuded sorgomol. Despite the distinctive difference in Strigolactone composition, the levels of AM colonization and the community compositions were not different between the cultivars. The present study demonstrated that the difference in Strigolactone composition has no appreciable impact on AM symbiosis, at least in the two maize cultivars, and further suggests that the traits involved in Striga-resistance are not necessarily accompanied by reduction in compatibility to AM fungi.
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Origin of Strigolactones in the green lineage
New Phytologist, 2012Co-Authors: Pierre-marc Delaux, Ruth E. Timme, Virginie Puech-pages, Christophe Dunand, Emilie Lecompte, Koichi Yoneyama, Guillaume Bécard, Charles F. Delwiche, Nathalie Séjalon-delmasAbstract:Summary •The aims of this study were to investigate the appearance of Strigolactones in the green lineage and to determine the primitive function of these molecules. •We measured the Strigolactone content of several isolated liverworts, mosses, charophyte and chlorophyte green algae using a sensitive biological assay and LC-MS/MS analyses. In parallel, sequence comparison of Strigolactone-related genes and phylogenetic analyses were performed using available genomic data and newly sequenced expressed sequence tags. The primitive function of Strigolactones was determined by exogenous application of the synthetic Strigolactone analog, GR24, and by mutant phenotyping. •Liverworts, the most basal Embryophytes and Charales, one of the closest green algal relatives to Embryophytes, produce Strigolactones, whereas several other species of green algae do not. We showed that GR24 stimulates rhizoid elongation of Charales, liverworts and mosses, and rescues the phenotype of the Strigolactone-deficient Ppccd8 mutant of Physcomitrella patens. •These findings demonstrate that the first function of Strigolactones was not to promote arbuscular mycorrhizal symbiosis. Rather, they suggest that the Strigolactones appeared earlier in the streptophyte lineage to control rhizoid elongation. They may have been conserved in basal Embryophytes for this role and then recruited for the stimulation of colonization by glomeromycotan fungi.
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Strigolactones regulate protonema branching and act as a quorum sensing like signal in the moss physcomitrella patens
Development, 2011Co-Authors: Helene Proust, Kaori Yoneyama, Koichi Yoneyama, Beate Hoffmann, Didier G Schaefer, Fabien Nogue, Catherine RameauAbstract:Strigolactones are a novel class of plant hormones controlling shoot branching in seed plants. They also signal host root proximity during symbiotic and parasitic interactions. To gain a better understanding of the origin of Strigolactone functions, we characterised a moss mutant strongly affected in Strigolactone biosynthesis following deletion of the CAROTENOID CLEAVAGE DIOXYGENASE 8 (CCD8) gene. Here, we show that wild-type Physcomitrella patens produces and releases Strigolactones into the medium where they control branching of protonemal filaments and colony extension. We further show that Ppccd8 mutant colonies fail to sense the proximity of neighbouring colonies, which in wild-type plants causes the arrest of colony extension. The mutant phenotype is rescued when grown in the proximity of wild-type colonies, by exogenous supply of synthetic Strigolactones or by ectopic expression of seed plant CCD8. Thus, our data demonstrate for the first time that Bryophytes (P. patens) produce Strigolactones that act as signalling factors controlling developmental and potentially ecophysiological processes. We propose that in P. patens, Strigolactones are reminiscent of quorum-sensing molecules used by bacteria to communicate with one another.
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a tomato Strigolactone impaired mutant displays aberrant shoot morphology and plant interactions
Journal of Experimental Botany, 2010Co-Authors: Hinanit Koltai, Kaori Yoneyama, Koichi Yoneyama, Chaitali Bhattacharya, Nathalie Resnick, Sivarama P Lekkala, Einav Mayzlishgati, Smadar Wininger, Evgenya Dor, Joseph HershenhornAbstract:Strigolactones are considered a new group of plant hormones. Their role as modulators of plant growth and signalling molecules for plant interactions first became evident in Arabidopsis, pea, and rice mutants that were flawed in Strigolactone production, release, or perception. The first evidence in tomato (Solanum lycopersicon) of Strigolactone deficiency is presented here. Sl-ORT1, previously identified as resistant to the parasitic plant Orobanche, had lower levels of arbuscular mycorrhizal fungus (Glomus intraradices) colonization, possibly as a result of its reduced ability to induce mycorrhizal hyphal branching. Biochemical analysis of mutant root extracts suggested that it produces only minute amounts of two of the tomato Strigolactones: solanacol and didehydro-orobanchol. Accordingly, the transcription level of a key enzyme (CCD7) putatively involved in Strigolactone synthesis in tomato was reduced in Sl-ORT1 compared with the wild type (WT). Sl-ORT1 shoots exhibited increased lateral shoot branching, whereas exogenous application of the synthetic Strigolactone GR24 to the mutant restored the WT phenotype by reducing the number of lateral branches. Reduced lateral shoot branching was also evident in grafted plants which included a WT interstock, which was grafted between the mutant rootstock and the scion. In roots of these grafted plants, the CCD7 transcription level was not significantly induced, nor was mycorrhizal sensitivity restored. Hence, WT-interstock grafting, which restores mutant shoot morphology to WT, does not restore mutant root properties to WT. Characterization of the first tomato Strigolactone-deficient mutant supports the putative general role of Strigolactones as messengers of suppression of lateral shoot branching in a diversity of plant species.
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Strigolactones: structures and biological activities.
Pest Management Science, 2009Co-Authors: Koichi Yoneyama, Kaori Yoneyama, Xiaonan Xie, Yasutomo TakeuchiAbstract:Strigolactones released from plant roots induce seed germination of root parasitic weeds, witchweeds (Striga spp.) and broomrapes (Orobanche spp.), and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. In addition to these functions in the rhizosphere, Strigolactones have recently been shown to be a novel class of plant hormones regulating shoot outgrowth. The natural Strigolactones identified so far have the common C-D ring moiety, which is thought to be the essential structure for exhibiting biological activity. The introduction of substitutions on the A-B ring moiety of 5-deoxystrigol, the basic Strigolactone, affords various Strigolactones, e.g. hydroxylation on C-4, C-5 and C-9 leads to orobanchol, strigol and sorgomol respectively. Then, acetylation and probably other derivatisations of these hydroxy-Strigolactones would occur. Although the C-2'-(R) stereochemistry was thought to be an important structural feature for potent germination stimulation activity, 2'-epi-Strigolactones were found in root exudates of tobacco, rice, pea and other plant species, indicating that at least some plants produce both epimers.
Hinanit Koltai - One of the best experts on this subject based on the ideXlab platform.
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Cellular events of Strigolactone signalling and their crosstalk with auxin in roots
Journal of Experimental Botany, 2015Co-Authors: Hinanit KoltaiAbstract:Strigolactones are a new group of plant hormones that suppress shoot branching. In roots, they regulate primary-root growth and lateral-root formation and increase root-hair elongation. Reception of Strigolactones occurs via a specific cellular system which includes a D14-like/MAX2-like/SCF complex that, upon perception of Strigolactone signalling, leads to certain degradation of receptors and to the release of downstream targets. This signalling pathway may eventually result in changes in actin-filament bundling, cellular trafficking, and PIN localization in the plasma membrane. As a result, auxin flux may be regulated in the shoot or root. Strigolactones are also involved with the response to phosphate conditions in roots, acting by both dampening auxin transport via depletion of PIN2 from the plasma membrane and inducing TIR1 transcription to increase auxin perception. In these instances and, possibly, others, Strigolactones manipulate the auxin pathway, affecting its transport, perception or both. However, other mechanisms for Strigolactone-regulated plant development and the involvement of other plant hormones are evident.
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Strigolactones: Biosynthesis, Synthesis and Functions in Plant Growth and Stress Responses
Phytohormones: A Window to Metabolism Signaling and Biotechnological Applications, 2014Co-Authors: Hinanit Koltai, Cristina PrandiAbstract:Strigolactones, terpenoid lactones derived from carotenoids, are plant hormones with various biological roles. They act in both shoots and roots to regulate several aspects of plant growth and architecture. They also affect plant communication in the rhizosphere. In this chapter, we will present the role of Strigolactones as plant hormones and highlight the known modes of Strigolactone signalling and transport and their crosstalk with other plant hormones. Also, we will review growing bodies of evidence that Strigolactones contribute to plant response to nutrient and light conditions. Furthermore, the recent development in Strigolactone synthetic chemistry and their future applications for the benefit of agriculture will be discussed.
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Implications of non-specific Strigolactone signaling in the rhizosphere
Plant Science, 2014Co-Authors: Hinanit KoltaiAbstract:Strigolactones produced by various plant species are involved in the development of different plant parts. They are also exuded by plant roots to the rhizosphere, where they are involved in the induction of seed germination of the parasitic plants Striga and Orobanche, hyphal branching of the symbiotic arbuscular mycorrhizal fungi (AMF), and the symbiotic interaction with Rhizobium. In the present discussion paper, the essentialness of Strigolactones as communication signals in these plant interactions is discussed in view of the existence of other plant-derived substances that are able to promote these plant interactions. In addition, the importance of Strigolactones for determination of interaction specificity is discussed based on current knowledge on Strigolactone composition, perception and delivery. The different activities of Strigolactones in plant development and in the rhizosphere suggest their possible use in agriculture. However, despite efforts made in this direction, there is no current, practical implementation. Possible reasons for the encountered difficulties and suggested solutions to promote Strigolactone use in agriculture are discussed.
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Receptors, repressors, PINs: a playground for Strigolactone signaling.
Trends in Plant Science, 2014Co-Authors: Hinanit KoltaiAbstract:Strigolactones, previously identified as active stimuli of seed germination in parasitic plants, are now recognized as a new group of plant hormones that are active in both shoots and roots. Here, we review recent insights into the concepts of Strigolactones-signal transduction and their mode of action. Although Strigolactones are sensed via a cell-specific reception system, at least some aspects of their activity are conducted in a non-cell-autonomous fashion. Strigolactones also affect trafficking and plasma-membrane localization of the auxin transporter PIN, thereby regulating auxin flux. We present a model for Strigolactone-signal transduction that might also explain the integration of Strigolactones into other hormone-signaling pathways via the regulation of PIN auxin transporters.
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Diverse roles of Strigolactones in plant development.
Molecular Plant, 2013Co-Authors: Philip B. Brewer, Hinanit Koltai, Christine A BeveridgeAbstract:With the discovery of Strigolactones as root exudate signals that trigger parasitic weed seed germination, and then as a branching inhibitor and plant hormone, the next phase of Strigolactone research has quickly revealed this hormone class as a major player in optimizing plant growth and development. From the early stages of plant evolution, it seems that Strigolactones were involved in enabling plants to modify growth in order to gain advantage in competition with neighboring organisms for limited resources. For example, a moss plant can alter its growth in response to Strigolactones emanating from a neighbor. Within a higher plant, Strigolactones appear to be involved in controlling the balance of resource distribution via strategic modification of growth and development. Most notably, higher plants that encounter phosphate deficiency increase Strigolactone production, which changes root growth and promotes fungal symbiosis to enhance phosphate intake. The shoot also changes by channeling resources away from unessential leaves and branches and into the main stem and root system. This hormonal response is a key adaption that radically alters whole-plant architecture in order to optimize growth and development under diverse environmental conditions.
Kaori Yoneyama - One of the best experts on this subject based on the ideXlab platform.
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Lateral branching oxidoreductase acts in the final stages of Strigolactone biosynthesis in Arabidopsis
Proceedings of the National Academy of Sciences, 2016Co-Authors: Philip B. Brewer, Kaori Yoneyama, Elizabeth A. Dun, Adrian Scaffidi, Fiona Filardo, Emma Meyers, Tancred Frickey, Kohki Akiyama, Yoshiya Seto, Julia E. CremerAbstract:Strigolactones are a group of plant compounds of diverse but related chemical structures. They have similar bioactivity across a broad range of plant species, act to optimize plant growth and development, and promote soil microbe interactions. Carlactone, a common precursor to Strigolactones, is produced by conserved enzymes found in a number of diverse species. Versions of the MORE AXILLARY GROWTH1 (MAX1) cytochrome P450 from rice and Arabidopsis thaliana make specific subsets of Strigolactones from carlactone. However, the diversity of natural Strigolactones suggests that additional enzymes are involved and remain to be discovered. Here, we use an innovative method that has revealed a missing enzyme involved in Strigolactone metabolism. By using a transcriptomics approach involving a range of treatments that modify Strigolactone biosynthesis gene expression coupled with reverse genetics, we identified LATERAL BRANCHING OXIDOREDUCTASE (LBO), a gene encoding an oxidoreductase-like enzyme of the 2-oxoglutarate and Fe(II)-dependent dioxygenase superfamily. Arabidopsis lbo mutants exhibited increased shoot branching, but the lbo mutation did not enhance the max mutant phenotype. Grafting indicated that LBO is required for a graft-transmissible signal that, in turn, requires a product of MAX1. Mutant lbo backgrounds showed reduced responses to carlactone, the substrate of MAX1, and methyl carlactonoate (MeCLA), a product downstream of MAX1. Furthermore, lbo mutants contained increased amounts of these compounds, and the LBO protein specifically converts MeCLA to an unidentified Strigolactone-like compound. Thus, LBO function may be important in the later steps of Strigolactone biosynthesis to inhibit shoot branching in Arabidopsis and other seed plants.
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difference in striga susceptibility is reflected in Strigolactone secretion profile but not in compatibility and host preference in arbuscular mycorrhizal symbiosis in two maize cultivars
New Phytologist, 2015Co-Authors: Kaori Yoneyama, Ryota Arakawa, Keiko Ishimoto, Takaya Kisugi, Takahito Nomura, Fred Kanampiu, Takao Yokota, Tatsuhiro Ezawa, Koichi YoneyamaAbstract:Summary Strigolactones released from plant roots trigger both seed germination of parasitic weeds such as Striga spp. and hyphal branching of the symbionts arbuscular mycorrhizal (AM) fungi. Generally, Strigolactone composition in exudates is quantitatively and qualitatively different among plants, which may be involved in susceptibility and host specificity in the parasite–plant interactions. We hypothesized that difference in Strigolactone composition would have a significant impact on compatibility and host specificity/preference in AM symbiosis. Strigolactones in root exudates of Striga-susceptible (Pioneer 3253) and -resistant (KST 94) maize (Zea mays) cultivars were characterized by LC-MS/MS combined with germination assay using Striga hermonthica seeds. Levels of colonization and community compositions of AM fungi in the two cultivars were investigated in field and glasshouse experiments. 5-Deoxystrigol was exuded exclusively by the susceptible cultivar, while the resistant cultivar mainly exuded sorgomol. Despite the distinctive difference in Strigolactone composition, the levels of AM colonization and the community compositions were not different between the cultivars. The present study demonstrated that the difference in Strigolactone composition has no appreciable impact on AM symbiosis, at least in the two maize cultivars, and further suggests that the traits involved in Striga-resistance are not necessarily accompanied by reduction in compatibility to AM fungi.
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Strigolactones and the Regulation of Pea Symbioses in Response to Nitrate and Phosphate Deficiency
Molecular Plant, 2013Co-Authors: Eloise Foo, Kaori Yoneyama, Cj Hugill, Laura J. Quittenden, James B. ReidAbstract:New roles for the recently identified group of plant hormones, the Strigolactones, are currently under active investigation. One of their key roles is to regulate plant symbioses. These compounds act as a rhizosphere signal in arbuscular mycorrhizal symbioses and as a positive regulator of nodulation in legumes. The phosphorous and nitrogen status of the soil has emerged as a powerful regulator of Strigolactone production. However, until now, the potential role of Strigolactones in regulating mycorrhizal development and nodulation in response to nutrient deficiency has not been proven. In this paper, the role of Strigolactone synthesis and response in regulating these symbioses is examined in pea (Pisum sativum L.). Pea is well suited to this study, since there is a range of well-characterized Strigolactone biosynthesis and response mutants that is unique amongst legumes. Evidence is provided for a novel endogenous role for Strigolactone response within the root during mycorrhizal development, in addition to the action of Strigolactones on the fungal partner. The Strigolactone response pathway that regulates mycorrhizal development also appears to differ somewhat from the response pathway that regulates nodulation. Finally, studies with Strigolactone-deficient pea mutants indicate that, despite strong regulation of Strigolactone production by both nitrogen and phosphate, Strigolactones are not required to regulate these symbioses in response to nutrient deficiency.
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Strigolactones: Internal and external signals in plant symbioses?
Plant Signaling & Behavior, 2013Co-Authors: Eloise Foo, Kaori Yoneyama, Cj Hugill, Laura J. Quittenden, James B. ReidAbstract:As the newest plant hormone, Strigolactone research is undergoing an exciting expansion. In less than five years, roles for Strigolactones have been defined in shoot branching, secondary growth, root growth and nodulation, to add to the growing understanding of their role in arbuscular mycorrhizae and parasitic weed interactions.1 Strigolactones are particularly fascinating as signaling molecules as they can act both inside the plant as an endogenous hormone and in the soil as a rhizosphere signal.2-4 Our recent research has highlighted such a dual role for Strigolactones, potentially acting as both an endogenous and exogenous signal for arbuscular mycorrhizal development.5 There is also significant interest in examining Strigolactones as putative regulators of responses to environmental stimuli, especially the response to nutrient availability, given the strong regulation of Strigolactone production by nitrate and phosphate observed in many species.5,6 In particular, the potential for Strigolactones to m...
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Strigolactones regulate protonema branching and act as a quorum sensing like signal in the moss physcomitrella patens
Development, 2011Co-Authors: Helene Proust, Kaori Yoneyama, Koichi Yoneyama, Beate Hoffmann, Didier G Schaefer, Fabien Nogue, Catherine RameauAbstract:Strigolactones are a novel class of plant hormones controlling shoot branching in seed plants. They also signal host root proximity during symbiotic and parasitic interactions. To gain a better understanding of the origin of Strigolactone functions, we characterised a moss mutant strongly affected in Strigolactone biosynthesis following deletion of the CAROTENOID CLEAVAGE DIOXYGENASE 8 (CCD8) gene. Here, we show that wild-type Physcomitrella patens produces and releases Strigolactones into the medium where they control branching of protonemal filaments and colony extension. We further show that Ppccd8 mutant colonies fail to sense the proximity of neighbouring colonies, which in wild-type plants causes the arrest of colony extension. The mutant phenotype is rescued when grown in the proximity of wild-type colonies, by exogenous supply of synthetic Strigolactones or by ectopic expression of seed plant CCD8. Thus, our data demonstrate for the first time that Bryophytes (P. patens) produce Strigolactones that act as signalling factors controlling developmental and potentially ecophysiological processes. We propose that in P. patens, Strigolactones are reminiscent of quorum-sensing molecules used by bacteria to communicate with one another.
Harro J. Bouwmeester - One of the best experts on this subject based on the ideXlab platform.
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Zealactones. Novel natural Strigolactones from maize
Phytochemistry, 2017Co-Authors: Tatsiana Charnikhova, Carolien Ruyter-spira, Claudio Screpanti, Alexandre Lumbroso, Alain De Mesmaeker, Katharina Gaus, Mark Sanders, Jean-paul Vincken, Harro J. BouwmeesterAbstract:Abstract In the root exudate and root extracts of maize hybrid cv NK Falkone seven putative Strigolactones were detected using UPLC-TQ-MS-MS. All seven compounds displayed MS-MS-fragmentation common for Strigolactones and particularly the presence of a fragment of m/z 97 Da, which may indicate the presence of the so-called D-ring, suggests they are Strigolactones. The levels of all these putative Strigolactones increased upon phosphate starvation and decreased upon fluridone (carotenoid biosynthesis inhibitor) treatment, both of which are a common response for Strigolactones. All seven compounds were subsequently isolated with prep-HPLC-MS. They all exhibited Striga hermonthica seed germination inducing activity just as the synthetic Strigolactone analog GR24. The structure of two of the seven compounds was elucidated by NMR spectroscopy as: methyl (2E,3E)-4-(3,3-dimethyl-5-oxo-2-(prop-1-en-2-yl)tetrahydrofuran-2-yl)-2-(((4-methyl-5-oxo-2,5-dihydrofuran-2-yl)oxy)methylene)but-3-enoate (two diastereomers 1a and 1b). Strigolactones (1a/b) are closely related to the methyl ester of carlactonoic acid (MeCLA) and heliolactone. However, they contain a unique 4,4-dimethyltetrahydrofuran-2-one motif as the “A-ring” instead of the classical (di)methylcyclohexene. Because these compounds were isolated from maize (Zea mays) we called them “zealactone 1a and 1b”. The implications of this discovery for our view on Strigolactones and their biosynthesis are discussed.
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Low-Phosphate Induction of Plastidal Stromules Is Dependent on Strigolactones But Not on the Canonical Strigolactone Signaling Component MAX2
Plant Physiology, 2016Co-Authors: Gilles Vismans, Tom Van Der Meer, Olivier Langevoort, Marielle Schreuder, Harro J. Bouwmeester, Helga Peisker, Peter Dörman, Tijs Ketelaar, Alexander R. Van Der KrolAbstract:Stromules are highly dynamic protrusions of the plastids in plants. Several factors, such as drought and light conditions, influence the stromule frequency (SF) in a positive or negative way. A relatively recently discovered class of plant hormones are the Strigolactones; Strigolactones inhibit branching of the shoots and promote beneficial interactions between roots and arbuscular mycorrhizal fungi. Here, we investigate the link between the formation of stromules and Strigolactones. This research shows a strong link between Strigolactones and the formation of stromules: SF correlates with Strigolactone levels in the wild type and Strigolactone mutants (max2-1 max3-9), and SF is stimulated by Strigolactone GR24 and reduced by Strigolactone inhibitor D2.
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Parasitic Plants Striga and Phelipanche Dependent upon Exogenous Strigolactones for Germination Have Retained Genes for Strigolactone Biosynthesis
American Journal of Plant Sciences, 2015Co-Authors: Malay Das, Harro J. Bouwmeester, Mónica Fernández-aparicio, Zhenzhen Yang, Kan Huang, Norman J. Wickett, Shannon Alford, Eric K. Wafula, Claude W. Depamphilis, Michael P. TimkoAbstract:Strigolactones are plant hormones with multiple functions, including regulating various aspects of plant architecture such as shoot branching, facilitating the colonization of plant roots by arbuscular mycorrhizal fungi, and acting as seed germination stimulants for certain parasitic plants of the family Orobanchaceae. The obligate parasitic species Phelipanche aegyptiaca and Striga hermonthica require Strigolactones for germination, while the facultative parasite Triphysaria versicolor does not. It has been hypothesized that P. aegyptiaca and S. hermonthica would have undergone evolutionary loss of Strigolactone biosynthesis as a part of their mechanism to enable specific detection of exogenous Strigolactones. We analyzed the transcriptomes of P. aegyptiaca, S. hermonthica and T. versicolor and identified genes known to act in Strigolactone synthesis (D27, CCD7, CCD8, and MAX1), perception (MAX2 and D14) and transport (PDR12). These genes were then analyzed to assess likelihood of function. Transcripts of all Strigolactone-related genes were found in P. aegyptiaca and S. hermonthica, and evidence points to their encoding functional proteins. Gene open reading frames were consistent with homologs from Arabidopsis and other Strigolactone-producing plants, and all genes were expressed in parasite tissues. In general, the genes related to Strigolactone synthesis and perception appeared to be evolving under codon-based selective constraints in Strigolactone-dependent species. Bioassays of S. hermonthica root extracts indicated the presence of Strigolactone class stimulants on germination of P. aegyptiaca seeds. Taken together, these results indicate that Phelipanche aegyptiaca and S. hermonthica have retained functional genes involved in Strigolactone biosynthesis, suggesting that the parasites use both endogenous and exogenous Strigolactones and have mechanisms to differentiate the two.
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Asymmetric localizations of the ABC transporter PaPDR1 trace paths of directional Strigolactone transport.
Current Biology, 2015Co-Authors: Joelle Sasse, Enrico Martinoia, Harro J. Bouwmeester, Sibu Simon, Christian Gübeli, Guo Wei Liu, Xi Cheng, Jiří Friml, Lorenzo BorghiAbstract:Strigolactones, first discovered as germination stimulants for parasitic weeds [1], are carotenoid-derived phytohormones that play major roles in inhibiting lateral bud outgrowth and promoting plant-mycorrhizal symbiosis [2-4]. Furthermore, Strigolactones are involved in the regulation of lateral and adventitious root development, root cell division [5, 6], secondary growth [7], and leaf senescence [8]. Recently, we discovered the Strigolactone transporter Petunia axillaris PLEIOTROPIC DRUG RESISTANCE 1 (PaPDR1), which is required for efficient mycorrhizal colonization and inhibition of lateral bud outgrowth [9]. However, how Strigolactones are transported through the plant remained unknown. Here we show that PaPDR1 exhibits a cell-type-specific asymmetric localization in different root tissues. In root tips, PaPDR1 is co-expressed with the Strigolactone biosynthetic gene DAD1 (CCD8), and it is localized at the apical membrane of root hypodermal cells, presumably mediating the shootward transport of Strigolactone. Above the root tip, in the hypodermal passage cells that form gates for the entry of mycorrhizal fungi, PaPDR1 is present in the outer-lateral membrane, compatible with its postulated function as Strigolactone exporter from root to soil. Transport studies are in line with our localization studies since (1) a papdr1 mutant displays impaired transport of Strigolactones out of the root tip to the shoot as well as into the rhizosphere and (2) DAD1 expression and PIN1/PIN2 levels change in plants deregulated for PDR1 expression, suggestive of variations in endogenous Strigolactone contents. In conclusion, our results indicate that the polar localizations of PaPDR1 mediate directional shootward Strigolactone transport as well as localized exudation into the soil.
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Molecular Microbial Ecology of the Rhizosphere: Volume 1 & 2 - Strigolactone Biosynthesis and Biology
Molecular Microbial Ecology of the Rhizosphere, 2013Co-Authors: Yanxia Zhang, Carolien Ruyter-spira, Imran Haider, Harro J. BouwmeesterAbstract:Strigolactones belong to a newly identified class of plant hormones that are involved in the inhibition of shoot branching. Prior to this finding, Strigolactones were proven to be root rhizosphere-signaling molecules that mediate plant–parasitic plant, and the symbiotic plant–AM fungi interactions. More recently, Strigolactones were shown to have other biological functions as endogenous plant hormones in shoot development, root architecture, and seed germination (also in nonparasitic plants) and to regulate plant developmental processes in interaction with other signaling pathways (i.e., light and senescence signaling) or hormones. Gene discovery in the Strigolactone biosynthesis and signal perception pathways is a key step in elucidating the mechanism and mode of action of the existing roles and discovering potential additional roles of Strigolactones. Furthermore, insights into Strigolactone and Strigolactone-associated pathways will provide more knowledge for the control of parasitic weeds and improvement of crop yield. In this chapter, we outline different aspects of the roles that Strigolactones play both in the rhizosphere and during plant development. Gene characterization in Strigolactone pathways and Strigolactone-related hormone cross-talk is also addressed.
Danny Geelen - One of the best experts on this subject based on the ideXlab platform.
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Ethylene Controls Adventitious Root Initiation Sites in Arabidopsis Hypocotyls Independently of Strigolactones
Journal of Plant Growth Regulation, 2017Co-Authors: Amanda Rasmussen, Thomas Depaepe, Filip Vandenbussche, Dominique Van Der Straeten, Yuming Hu, François-didier Boyer, Danny GeelenAbstract:Adventitious root formation is essential for cutting propagation of diverse species; however, until recently little was known about its regulation. Strigolactones and ethylene have both been shown to inhibit adventitious roots and it has been suggested that ethylene interacts with Strigolactones in root hair elongation. We have investigated the interaction between Strigolactones and ethylene in regulating adventitious root formation in intact seedlings of Arabidopsis thaliana. We used Strigolactone mutants together with 1-aminocyclopropane-1-carboxylic acid (ACC) (ethylene precursor) treatments and ethylene mutants together with GR24 (Strigolactone agonist) treatments. Importantly, we conducted a detailed mapping of adventitious root initiation along the hypocotyl and measured ethylene production in Strigolactone mutants. ACC treatments resulted in a slight increase in adventitious root formation at low doses and a decrease at higher doses, in both wild-type and Strigolactone mutants. Furthermore, the distribution of adventitious roots dramatically changed to the top third of the hypocotyl in a dose-dependent manner with ACC treatments in both wild-type and Strigolactone mutants. The ethylene mutants all responded to treatments with GR24. Wild type and max4 (Strigolactone-deficient mutant) produced the same amount of ethylene, while emanation from max2 (Strigolactone-insensitive mutant) was lower. We conclude that Strigolactones and ethylene act largely independently in regulating adventitious root formation with ethylene controlling the distribution of root initiation sites. This role for ethylene may have implications for flood response because both ethylene and adventitious root development are crucial for flood tolerance.
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Strigolactones fine-tune the root system
Planta, 2013Co-Authors: Amanda Rasmussen, Sofie Goormachtig, Stephen Depuydt, Danny GeelenAbstract:Strigolactones were originally discovered to be involved in parasitic weed germination, in mycorrhizal association and in the control of shoot architecture. Despite their clear role in rhizosphere signaling, comparatively less attention has been given to the belowground function of Strigolactones on plant development. However, research has revealed that Strigolactones play a key role in the regulation of the root system including adventitious roots, primary root length, lateral roots, root hairs and nodulation. Here, we review the recent progress regarding Strigolactone regulation of the root system and the antagonism and interplay with other hormones.
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A Fluorescent Alternative to the Synthetic Strigolactone GR24
Molecular Plant, 2013Co-Authors: Amanda Rasmussen, François-didier Boyer, Sofie Goormachtig, Thomas S. A. Heugebaert, Cedrick Matthys, Rik Van Deun, Christian V. Stevens, Danny GeelenAbstract:Strigolactones have recently been implicated in both above- and below-ground developmental pathways in higher plants. To facilitate the molecular and chemical properties of Strigolactones in vitro and in vivo, we have developed a fluorescent Strigolactone molecule, CISA-1, synthesized via a novel method which was robust, high-yielding, and used simple starting materials. We demonstrate that CISA-1 has a broad range of known Strigolactone activities and further report on an adventitious rooting assay in Arabidopsis which is a highly sensitive and rapid method for testing biological activity of Strigolactone analogs. In this rooting assay and the widely used Orobanche germination assay, CISA-1 showed stronger biological activity than the commonly tested GR24. CISA-1 and GR24 were equally effective at inhibiting branching in Arabidopsis inflorescence stems. In both the branching and adventitious rooting assay, we also demonstrated that CISA-1 activity is dependent on the max Strigolactone signaling pathway. In water methanol solutions, CISA-1 was about threefold more stable than GR24, which may contribute to the increased activity observed in the various biological tests.
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Strigolactones Suppress Adventitious Rooting in Arabidopsis and Pea 1(C)(W)(OA)
2012Co-Authors: Amanda Rasmussen, Philip B. Brewer, Michael G Mason, Danny Geelen, Carolien De Cuyper, Silvia Herold, Javier Agusti, Thomas Greb, Sofie Goormachtig, Tom BeeckmanAbstract:Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone Strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a Strigolactone response mutant, suggesting that Strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are Strigolactone responsive and Strigolactone mutants are cytokinin responsive. In contrast, the interaction between the Strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of Strigolactones, cytokinins, and auxin in regulating adventitious root formation.
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Inhibition of Strigolactones promotes adventitious root formation
Plant Signaling & Behavior, 2012Co-Authors: Amanda Rasmussen, Christine A Beveridge, Danny GeelenAbstract:Roots that form from non-root tissues (adventitious roots) are crucial for cutting propagation in the forestry and horticulture industries. Strigolactone has been demonstrated to be an important regulator of these roots in both Arabidopsis and pea using Strigolactone deficient mutants and exogenous hormone applications. Strigolactones are produced from a carotenoid precursor which can be blocked using the widely available but broad terpenoid biosynthesis blocker, fluridone. We demonstrate here that fluridone can be used to promote adventitious rooting in the model species Pisum sativum (pea). In addition, in the garden species Plumbago auriculata and Jasminium polyanthum fluridone was equally as successful at promoting roots as a commercial rooting compound containing NAA and IBA. Our findings demonstrate that inhibition of Strigolactone signaling has the potential to be used to improve adventitious rooting in commercially relevant species.
