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Peter Mccourt - One of the best experts on this subject based on the ideXlab platform.
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The perception of strigolactones in vascular Plants.
Nature Chemical Biology, 2017Co-Authors: Shelley Lumba, Duncan Holbrook-smith, Peter MccourtAbstract:Small-molecule hormones play central roles in Plant development, ranging from cellular differentiation and organ formation to developmental response instruction in changing environments. A recently discovered collection of related small molecules collectively called strigolactones are of particular interest, as these hormones also function as ecological communicators between Plants and fungi and between Parasitic Plants and their hosts. Advances from model Plant systems have begun to unravel how, as a hormone, strigolactone is perceived and transduced. In this Review, we summarize this information and examine how understanding strigolactone hormone signaling is leading to insights into Parasitic Plant infections. We specifically focus on how the development of chemical probes can be used in combination with model Plant systems to dissect strigolactone's perception in the Parasitic Plant Striga hermonthica. This information is particularly relevant since Striga is considered one of the largest impediments to food security in sub-Saharan Africa.
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Small-molecule antagonists of germination of the Parasitic Plant Striga hermonthica.
Nature chemical biology, 2016Co-Authors: Duncan Holbrook-smith, Yuichiro Tsuchiya, Shigeo Toh, Peter MccourtAbstract:Striga spp. (witchweed) is an obligate Parasitic Plant that attaches to host roots to deplete them of nutrients. In Sub-Saharan Africa, the most destructive Striga species, Striga hermonthica, parasitizes major food crops affecting two-thirds of the arable land and over 100 million people. One potential weakness in the Striga infection process is the way it senses the presence of a host crop. Striga only germinates in the presence of the Plant hormone strigolactone, which exudes from a host root. Hence small molecules that perturb strigolactone signaling may be useful tools for disrupting the Striga lifecycle. Here we developed a chemical screen to suppress strigolactone signaling in the model Plant Arabidopsis. One compound, soporidine, specifically inhibited a S. hermonthica strigolactone receptor and inhibited the parasite's germination. This indicates that strigolactone-based screens using Arabidopsis are useful in identifying lead compounds to combat Striga infestations.
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Structure-function analysis identifies highly sensitive strigolactone receptors in Striga.
Science, 2015Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Peter J. Stogios, O. Onopriyenko, Shelley Lumba, Alexei Savchenko, Peter MccourtAbstract:Strigolactones are naturally occurring signaling molecules that affect Plant development, fungi-Plant interactions, and Parasitic Plant infestations. We characterized the function of 11 strigolactone receptors from the Parasitic Plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host Plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels.
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detection of Parasitic Plant suicide germination compounds using a high throughput arabidopsis htl kai2 strigolactone perception system
Chemistry & Biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrooksmith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
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Detection of Parasitic Plant Suicide Germination Compounds Using a High-Throughput Arabidopsis HTL/KAI2 Strigolactone Perception System
Chemistry & biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
Shigeo Toh - One of the best experts on this subject based on the ideXlab platform.
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smax1 dependent seed germination bypasses ga signalling in arabidopsis and striga
Nature plants, 2020Co-Authors: Michael Bunsick, Shigeo Toh, Cynthia Wong, Christopher S P Mcerlean, Gianni Pescetto, Kawther Elfituri Nemrish, Priscilla Sung, J D Scholes, Shelley LumbaAbstract:Parasitic Plant infestations dramatically reduce the yield of many major food crops of sub-Saharan Africa and pose a serious threat to food security on that continent1. The first committed step of a successful infestation is the germination of parasite seeds primarily in response to a group of related small-molecule hormones called strigolactones (SLs), which are emitted by host roots2. Despite the important role of SLs, it is not clear how host-derived SLs germinate Parasitic Plants. In contrast, gibberellins (GA) acts as the dominant hormone for stimulation of germination in non-Parasitic Plant species by inhibiting a set of DELLA repressors3. Here, we show that expression of SL receptors from the Parasitic Plant Striga hermonthica in the presence of SLs circumvents the GA requirement for germination of Arabidopsis thaliana seed. Striga receptors co-opt and enhance signalling through the HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE 2 (AtHTL/KAI2) pathway, which normally plays a rudimentary role in Arabidopsis seed germination4,5. AtHTL/KAI2 negatively controls the SUPPRESSOR OF MAX2 1 (SMAX1) protein5, and loss of SMAX1 function allows germination in the presence of DELLA repressors. Our data suggest that ligand-dependent inactivation of SMAX1 in Striga and Arabidopsis can bypass GA-dependent germination in these species. The Parasitic Plant Striga hermonthica germinates when it senses strigolactones (SLs). By expressing Striga SL receptors in Arabidopsis, the authors show that the SL pathway can regulate germination independently of gibberellin signalling.
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Small-molecule antagonists of germination of the Parasitic Plant Striga hermonthica.
Nature chemical biology, 2016Co-Authors: Duncan Holbrook-smith, Yuichiro Tsuchiya, Shigeo Toh, Peter MccourtAbstract:Striga spp. (witchweed) is an obligate Parasitic Plant that attaches to host roots to deplete them of nutrients. In Sub-Saharan Africa, the most destructive Striga species, Striga hermonthica, parasitizes major food crops affecting two-thirds of the arable land and over 100 million people. One potential weakness in the Striga infection process is the way it senses the presence of a host crop. Striga only germinates in the presence of the Plant hormone strigolactone, which exudes from a host root. Hence small molecules that perturb strigolactone signaling may be useful tools for disrupting the Striga lifecycle. Here we developed a chemical screen to suppress strigolactone signaling in the model Plant Arabidopsis. One compound, soporidine, specifically inhibited a S. hermonthica strigolactone receptor and inhibited the parasite's germination. This indicates that strigolactone-based screens using Arabidopsis are useful in identifying lead compounds to combat Striga infestations.
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Structure-function analysis identifies highly sensitive strigolactone receptors in Striga.
Science, 2015Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Peter J. Stogios, O. Onopriyenko, Shelley Lumba, Alexei Savchenko, Peter MccourtAbstract:Strigolactones are naturally occurring signaling molecules that affect Plant development, fungi-Plant interactions, and Parasitic Plant infestations. We characterized the function of 11 strigolactone receptors from the Parasitic Plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host Plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels.
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detection of Parasitic Plant suicide germination compounds using a high throughput arabidopsis htl kai2 strigolactone perception system
Chemistry & Biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrooksmith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
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Detection of Parasitic Plant Suicide Germination Compounds Using a High-Throughput Arabidopsis HTL/KAI2 Strigolactone Perception System
Chemistry & biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
John I. Yoder - One of the best experts on this subject based on the ideXlab platform.
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Small-Molecule Screens Reveal Novel Haustorium Inhibitors in the Root Parasitic Plant Triphysaria versicolor.
Phytopathology®, 2019Co-Authors: Yaxin Wang, Daniel Steele, Maylin Murdock, Seigmund Wai Tsuen Lai, John I. YoderAbstract:Root Parasitic weeds in Orobanchaceae pose a tremendous threat to agriculture worldwide. We used an in vitro assay to screen libraries of small molecules for those capable of inhibiting or enhancing haustorium development in the Parasitic Plant Triphysaria versicolor. Several redox-modifying molecules and one structural analog of 2,6-dimethoxybenzoquine (DMBQ) inhibited haustorium development in the presence of the haustorium-inducing factor DMBQ, some of these without apparent growth inhibition to the root. Triphysaria seedlings were able to acclimate to some of these redox inhibitors. Transcript levels of four early-stage haustorium genes were differentially influenced by inhibitors. These novel haustorium inhibitors highlight the importance of redox cycling for haustorium development and suggest the potential of controlling Parasitic weeds by interrupting early-stage redox-signaling pathways.
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the Parasitic Plant genome project new tools for understanding the biology of orobanche and striga
Weed Science, 2012Co-Authors: James H. Westwood, Monica Fernandezaparicio, Eric K Wafula, Claude W Depamphilis, Michael P Timko, Norman J. Wickett, Loren A Honaas, John I. YoderAbstract:The Parasitic Plant Genome Project has sequenced transcripts from three Parasitic species and a nonParasitic relative in the Orobanchaceae with the goal of understanding genetic changes associated with parasitism. The species studied span the trophic spectrum from free-living nonparasite to obligate holoparasite. Parasitic species used were Triphysaria versicolor ,a photosynthetically competent species that opportunistically parasitizes roots of neighboring Plants; Striga hermonthica ,a hemiparasite that has an obligate need for a host; and Orobanche aegyptiaca, a holoparasite with absolute nutritional dependence on a host. Lindenbergia philippensis represents the closest nonparasite sister group to the Parasitic Orobanchaceae and was included for comparative purposes. Tissues for transcriptome sequencing from each Plant were gathered to identify expressed genes for key life stages from seed conditioning through anthesis. Two of the species studied, S. hermonthica and O. aegyptiaca, are economically important weeds and the data generated by this project are expected to aid in research and control of these species and their relatives. The sequences generated through this project will provide an abundant resource of molecular markers for understanding population dynamics, as well as provide insight into the biology of parasitism and advance progress toward understanding parasite virulence and host resistance mechanisms. In addition, the sequences provide important information on target sites for herbicide action or other novel control strategies such as trans-specific gene silencing. Nomenclature: Egyptian broomrape, Orobanche aegyptiaca (Pers.) (Syn. Phelipanche aegyptiaca) ORAAE; Lindenbergia philippensis (Cham. & Schltdl.) Benth. LINPH; yellowbeak owl’s-clover, Triphysaria versicolor (Fisch. & C.A. Mey) TRVEV; purple witchweed, Striga hermonthica, (Del.) Benth. STRHE.
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The TvPirin Gene Is Necessary for Haustorium Development in the Parasitic Plant Triphysaria versicolor
Plant Physiology, 2011Co-Authors: Pradeepa C. G. Bandaranayake, Claude W Depamphilis, Alexey Tomilov, Natalya Tomilova, Quy A. Ngo, Norman J. Wickett, John I. YoderAbstract:The rhizosphere is teemed with organisms that coordinate their symbioses using chemical signals traversing between the host root and symbionts. Chemical signals also mediate interactions between roots of different Plants, perhaps the most obvious being those between Parasitic Orobanchaceae and their Plant hosts. Parasitic Plants use specific molecules provided by host roots to initiate the development of haustoria, invasive structures critical for Plant parasitism. We took a transcriptomics approach to identify Parasitic Plant genes associated with host factor recognition and haustorium signaling and previously identified a gene, TvPirin, which is transcriptionally up-regulated in roots of the Parasitic Plant Triphysaria versicolor after being exposed to the haustorium-inducing molecule 2,6-dimethoxybenzoquinone (DMBQ). Because TvPirin shares homology with proteins associated with environmental signaling in some Plants, we hypothesized that TvPirin may function in host factor recognition in Parasitic Plants. We tested the function of TvPirin in T. versicolor roots using hairpin-mediated RNA interference. Reducing TvPirin transcripts in T. versicolor roots resulted in significantly less haustoria development in response to DMBQ exposure. We determined the transcript levels of other root expressed transcripts and found that several had reduced basal levels of gene expression but were similarly regulated by quinone exposure. Phylogenic investigations showed that TvPirin homologs are present in most flowering Plants, and we found no evidence of parasite-specific gene duplication or expansion. We propose that TvPirin is a generalized transcription factor associated with the expression of a number of genes, some of which are involved in haustorium development.
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A single-electron reducing quinone oxidoreductase is necessary to induce haustorium development in the root Parasitic Plant Triphysaria
The Plant Cell, 2010Co-Authors: Pradeepa C. G. Bandaranayake, Alexey Tomilov, Tatiana Filappova, Natalya Tomilova, Denneal Jamison-mcclung, Quy A. Ngo, Kentaro Inoue, John I. YoderAbstract:Parasitic Plants in the Orobanchaceae develop haustoria in response to contact with host roots or chemical haustoria-inducing factors. Experiments in this manuscript test the hypothesis that quinolic-inducing factors activate haustorium development via a signal mechanism initiated by redox cycling between quinone and hydroquinone states. Two cDNAs were previously isolated from roots of the Parasitic Plant Triphysaria versicolor that encode distinct quinone oxidoreductases. QR1 encodes a single-electron reducing NADPH quinone oxidoreductase similar to ζ-crystallin. The QR2 enzyme catalyzes two electron reductions typical of xenobiotic detoxification. QR1 and QR2 transcripts are upregulated in a primary response to chemical-inducing factors, but only QR1 was upregulated in response to host roots. RNA interference technology was used to reduce QR1 and QR2 transcripts in Triphysaria roots that were evaluated for their ability to form haustoria. There was a significant decrease in haustorium development in roots silenced for QR1 but not in roots silenced for QR2. The infrequent QR1 transgenic roots that did develop haustoria had levels of QR1 similar to those of nontransgenic roots. These experiments implicate QR1 as one of the earliest genes on the haustorium signal transduction pathway, encoding a quinone oxidoreductase necessary for the redox bioactivation of haustorial inducing factors.
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Haustorium induction of Parasitic Plant: A new bioassay method to determine allelopathic potential
2008Co-Authors: Yiqing Guo, John I. Yoder, Kil-ung Kim, In-jung Lee, Dong-hyun ShinAbstract:Allelopathy has the potential to reduce the herbicide use as a component of integrated weed management technology. To develop a new bioassay method, we studied the effects of extracts from 3 rice cultivars (Kouketsumochi, Dongjinbyeo and K21) on the haustorium induction rate, phytotoxicity and ROS (reactive oxygen species) activity of Parasitic Plant Triphysaria versicolor as the target Plant. The three cultivars influenced the different rates of haustorium induction. Kouketsumochi caused the highest haustorium induction rate followed by K21 and Dongjinbyeo (lowest response at varying concentrations of rice tissue extracts). Application of UV irradiation to the rice cultivars increased the phytotoxic effects on root growth of T. versicolor. Activity of reactive oxygen species (ROS) was assayed by staining root tip of Parasitic Plant with probe CM-H2DCFDA [5-(and 6)-chloromethyl-2’, 7’dichlorodihydro-fluorescein diacetate, acetyl ester] and monitoring the change of fluorrescence. The fluorescence increased when the dye was oxidized by ROS. Fluorescence appeared in the shortest time in Kouketsumochi (allelopathic cultivar), followed by K21 and Dongjinbyeo (non-allelopathic cultivar). Results indicated that different haustorium rates of rice cultivars were related to different ROS activity. Thus T. versicolor can be used as a new target Plant to evaluate the allelopathic potential of Plant species.
Yuichiro Tsuchiya - One of the best experts on this subject based on the ideXlab platform.
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Small-molecule antagonists of germination of the Parasitic Plant Striga hermonthica.
Nature chemical biology, 2016Co-Authors: Duncan Holbrook-smith, Yuichiro Tsuchiya, Shigeo Toh, Peter MccourtAbstract:Striga spp. (witchweed) is an obligate Parasitic Plant that attaches to host roots to deplete them of nutrients. In Sub-Saharan Africa, the most destructive Striga species, Striga hermonthica, parasitizes major food crops affecting two-thirds of the arable land and over 100 million people. One potential weakness in the Striga infection process is the way it senses the presence of a host crop. Striga only germinates in the presence of the Plant hormone strigolactone, which exudes from a host root. Hence small molecules that perturb strigolactone signaling may be useful tools for disrupting the Striga lifecycle. Here we developed a chemical screen to suppress strigolactone signaling in the model Plant Arabidopsis. One compound, soporidine, specifically inhibited a S. hermonthica strigolactone receptor and inhibited the parasite's germination. This indicates that strigolactone-based screens using Arabidopsis are useful in identifying lead compounds to combat Striga infestations.
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Structure-function analysis identifies highly sensitive strigolactone receptors in Striga.
Science, 2015Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Peter J. Stogios, O. Onopriyenko, Shelley Lumba, Alexei Savchenko, Peter MccourtAbstract:Strigolactones are naturally occurring signaling molecules that affect Plant development, fungi-Plant interactions, and Parasitic Plant infestations. We characterized the function of 11 strigolactone receptors from the Parasitic Plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host Plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels.
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detection of Parasitic Plant suicide germination compounds using a high throughput arabidopsis htl kai2 strigolactone perception system
Chemistry & Biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrooksmith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
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Detection of Parasitic Plant Suicide Germination Compounds Using a High-Throughput Arabidopsis HTL/KAI2 Strigolactone Perception System
Chemistry & biology, 2014Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Michael E Stokes, Peter MccourtAbstract:Strigolactones are terpenoid-based Plant hormones that act as communication signals within a Plant, between Plants and fungi, and between Parasitic Plants and their hosts. Here we show that an active enantiomer form of the strigolactone GR24, the germination stimulant karrikin, and a number of structurally related small molecules called cotylimides all bind the HTL/KAI2 α/β hydrolase in Arabidopsis. Strigolactones and cotylimides also promoted an interaction between HTL/KAI2 and the F-box protein MAX2 in yeast. Identification of this chemically dependent protein-protein interaction prompted the development of a yeast-based, high-throughput chemical screen for potential strigolactone mimics. Of the 40 lead compounds identified, three were found to have in Planta strigolactone activity using Arabidopsis-based assays. More importantly, these three compounds were all found to stimulate suicide germination of the obligate Parasitic Plant Striga hermonthica. These results suggest that screening strategies involving yeast/Arabidopsis models may be useful in combating Parasitic Plant infestations.
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a small molecule screen identifies new functions for the Plant hormone strigolactone
Nature Chemical Biology, 2010Co-Authors: Yuichiro Tsuchiya, Shigeo Toh, Danielle Vidaurre, Atsushi Hanada, Eiji Nambara, Yuji Kamiya, Shinjiro Yamaguchi, Peter MccourtAbstract:Secretion of strigolactone from Plant roots mediates mutualistic fungal interactions but also facilitates Parasitic Plant invasion. A screen in Arabidopsis thaliana has identified compounds that perturb strigolactone levels and link this hormone to light signaling pathways in host Plants.
Shelley Lumba - One of the best experts on this subject based on the ideXlab platform.
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smax1 dependent seed germination bypasses ga signalling in arabidopsis and striga
Nature plants, 2020Co-Authors: Michael Bunsick, Shigeo Toh, Cynthia Wong, Christopher S P Mcerlean, Gianni Pescetto, Kawther Elfituri Nemrish, Priscilla Sung, J D Scholes, Shelley LumbaAbstract:Parasitic Plant infestations dramatically reduce the yield of many major food crops of sub-Saharan Africa and pose a serious threat to food security on that continent1. The first committed step of a successful infestation is the germination of parasite seeds primarily in response to a group of related small-molecule hormones called strigolactones (SLs), which are emitted by host roots2. Despite the important role of SLs, it is not clear how host-derived SLs germinate Parasitic Plants. In contrast, gibberellins (GA) acts as the dominant hormone for stimulation of germination in non-Parasitic Plant species by inhibiting a set of DELLA repressors3. Here, we show that expression of SL receptors from the Parasitic Plant Striga hermonthica in the presence of SLs circumvents the GA requirement for germination of Arabidopsis thaliana seed. Striga receptors co-opt and enhance signalling through the HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE 2 (AtHTL/KAI2) pathway, which normally plays a rudimentary role in Arabidopsis seed germination4,5. AtHTL/KAI2 negatively controls the SUPPRESSOR OF MAX2 1 (SMAX1) protein5, and loss of SMAX1 function allows germination in the presence of DELLA repressors. Our data suggest that ligand-dependent inactivation of SMAX1 in Striga and Arabidopsis can bypass GA-dependent germination in these species. The Parasitic Plant Striga hermonthica germinates when it senses strigolactones (SLs). By expressing Striga SL receptors in Arabidopsis, the authors show that the SL pathway can regulate germination independently of gibberellin signalling.
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The perception of strigolactones in vascular Plants.
Nature Chemical Biology, 2017Co-Authors: Shelley Lumba, Duncan Holbrook-smith, Peter MccourtAbstract:Small-molecule hormones play central roles in Plant development, ranging from cellular differentiation and organ formation to developmental response instruction in changing environments. A recently discovered collection of related small molecules collectively called strigolactones are of particular interest, as these hormones also function as ecological communicators between Plants and fungi and between Parasitic Plants and their hosts. Advances from model Plant systems have begun to unravel how, as a hormone, strigolactone is perceived and transduced. In this Review, we summarize this information and examine how understanding strigolactone hormone signaling is leading to insights into Parasitic Plant infections. We specifically focus on how the development of chemical probes can be used in combination with model Plant systems to dissect strigolactone's perception in the Parasitic Plant Striga hermonthica. This information is particularly relevant since Striga is considered one of the largest impediments to food security in sub-Saharan Africa.
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Structure-function analysis identifies highly sensitive strigolactone receptors in Striga.
Science, 2015Co-Authors: Shigeo Toh, Yuichiro Tsuchiya, Duncan Holbrook-smith, Peter J. Stogios, O. Onopriyenko, Shelley Lumba, Alexei Savchenko, Peter MccourtAbstract:Strigolactones are naturally occurring signaling molecules that affect Plant development, fungi-Plant interactions, and Parasitic Plant infestations. We characterized the function of 11 strigolactone receptors from the Parasitic Plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host Plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels.
