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Antonio Evidente - One of the best experts on this subject based on the ideXlab platform.
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induction of Haustorium development by sphaeropsidones in radicles of the parasitic weeds striga and orobanche a structure activity relationship study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandezaparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure–Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Mónica Fernández-aparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandez-aparicio Ruiz, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the Haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for Haustorium induction. The results suggested that the Haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.
Satoko Yoshida - One of the best experts on this subject based on the ideXlab platform.
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Haustorium Inducing Factors for Parasitic Orobanchaceae.
Frontiers in Plant Science, 2019Co-Authors: Vincent Goyet, Syogo Wada, Songkui Cui, Grégory Montiel, Takanori Wakatake, Ken Shirasu, Philippe Simier, Satoko YoshidaAbstract:Parasitic plants in the Orobanchaceae family include devastating weed species, such as Striga, Orobanche, and Phelipanche, which infest important crops and cause economic losses of over a billion US dollars worldwide, yet the molecular and cellular processes responsible for such parasitic relationships remain largely unknown. Parasitic species of the Orobanchaceae family form specialized invasion organs called haustoria on their roots to enable the invasion of host root tissues. The process of forming haustoria can be divided into two steps, preHaustorium formation and Haustorium maturation, the processes occurring before and after host attachment, respectively. PreHaustorium formation is provoked by host-derived signal molecules, collectively called Haustorium-inducing factors (HIFs). Cell wall-related quinones and phenolics have been known for a long time to induce haustoria in many Orobanchaceae species. Although such phenolics are widely produced in plants, structural specificities exist among these molecules that modulate their competency to induce haustoria in different parasitic plant species. In addition, the plant hormone cytokinins, structurally distinct from phenolic compounds, also trigger preHaustorium formation in Orobanchaceae. Recent findings demonstrate their involvement as rhizopsheric HIFs for Orobanche and Phelipanche species and thus address new activities for cytokinins in Haustorium formation in Orobanchaceae, as well as in rhizospheric signaling. This review highlights Haustorium-inducing signals in the Orobanchaceae family in the context of their host origin, action mechanisms, and species specificity.
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Reactive Oxygen Species (ROS) Generation Is Indispensable for Haustorium Formation of the Root Parasitic Plant Striga hermonthica.
Frontiers in Plant Science, 2019Co-Authors: Syogo Wada, Songkui Cui, Satoko YoshidaAbstract:The parasitic witchweed Striga hermonthica causes devastating damage to crops in sub-Saharan Africa, yet the mechanism of its parasitism is not well understood. Parasitic plants form a special organ called a Haustorium to obtain water and nutrients from host plants. The Haustorium is induced by host-derived small molecules, collectively named Haustorium-inducing factors (HIFs). The most active HIF known to date is 2,6-dimethoxy-p-benzoquinone (DMBQ), originally isolated from sorghum root extracts. It has been suggested that DMBQ is produced by oxidation of its precursor, syringic acid, and that reactive oxygen species (ROS) and peroxidases are involved in the process. However, the roles of ROS in Haustorium formation after HIF recognition remain to be elucidated. Here, we investigated the effects of various inhibitors of ROS and ROS-regulating enzymes on Haustorium formation in S. hermonthica. Inhibitors of NADPH oxidases and peroxidases inhibited Haustorium formation during treatment with DMBQ, syringic acid, and host root extracts, suggesting that ROS production and/or regulation via NADPH oxidases and peroxidases are essential for Haustorium formation. We observed hydrogen peroxide accumulation in the Haustorium upon treatment with various HIFs. Our results suggest that ROS and ROS-regulating enzymes are indispensable in downstream signaling of HIFs for Haustorium formation.
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Video_2_Reactive Oxygen Species (ROS) Generation Is Indispensable for Haustorium Formation of the Root Parasitic Plant Striga hermonthica.AVI
2019Co-Authors: Syogo Wada, Songkui Cui, Satoko YoshidaAbstract:The parasitic witchweed Striga hermonthica causes devastating damage to crops in sub-Saharan Africa, yet the mechanism of its parasitism is not well understood. Parasitic plants form a special organ called a Haustorium to obtain water and nutrients from host plants. The Haustorium is induced by host-derived small molecules, collectively named Haustorium-inducing factors (HIFs). The most active HIF known to date is 2,6-dimethoxy-p-benzoquinone (DMBQ), originally isolated from sorghum root extracts. It has been suggested that DMBQ is produced by oxidation of its precursor, syringic acid, and that reactive oxygen species (ROS) and peroxidases are involved in the process. However, the roles of ROS in Haustorium formation after HIF recognition remain to be elucidated. Here, we investigated the effects of various inhibitors of ROS and ROS-regulating enzymes on Haustorium formation in S. hermonthica. Inhibitors of NADPH oxidases and peroxidases inhibited Haustorium formation during treatment with DMBQ, syringic acid, and host root extracts, suggesting that ROS production and/or regulation via NADPH oxidases and peroxidases are essential for Haustorium formation. We observed hydrogen peroxide accumulation in the Haustorium upon treatment with various HIFs. Our results suggest that ROS and ROS-regulating enzymes are indispensable in downstream signaling of HIFs for Haustorium formation.
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Data_Sheet_1_Reactive Oxygen Species (ROS) Generation Is Indispensable for Haustorium Formation of the Root Parasitic Plant Striga hermonthica.pdf
2019Co-Authors: Syogo Wada, Songkui Cui, Satoko YoshidaAbstract:The parasitic witchweed Striga hermonthica causes devastating damage to crops in sub-Saharan Africa, yet the mechanism of its parasitism is not well understood. Parasitic plants form a special organ called a Haustorium to obtain water and nutrients from host plants. The Haustorium is induced by host-derived small molecules, collectively named Haustorium-inducing factors (HIFs). The most active HIF known to date is 2,6-dimethoxy-p-benzoquinone (DMBQ), originally isolated from sorghum root extracts. It has been suggested that DMBQ is produced by oxidation of its precursor, syringic acid, and that reactive oxygen species (ROS) and peroxidases are involved in the process. However, the roles of ROS in Haustorium formation after HIF recognition remain to be elucidated. Here, we investigated the effects of various inhibitors of ROS and ROS-regulating enzymes on Haustorium formation in S. hermonthica. Inhibitors of NADPH oxidases and peroxidases inhibited Haustorium formation during treatment with DMBQ, syringic acid, and host root extracts, suggesting that ROS production and/or regulation via NADPH oxidases and peroxidases are essential for Haustorium formation. We observed hydrogen peroxide accumulation in the Haustorium upon treatment with various HIFs. Our results suggest that ROS and ROS-regulating enzymes are indispensable in downstream signaling of HIFs for Haustorium formation.
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induced cell fate transitions at multiple cell layers configure Haustorium development in parasitic plants
Development, 2018Co-Authors: Takanori Wakatake, Satoko Yoshida, Ken ShirasuAbstract:The Haustorium in parasitic plants is an organ specialized for invasion and nutrient uptake from host plant tissues. Despite its importance, the developmental processes of haustoria are mostly unknown. To understand the dynamics of cell fate change and cellular lineage during Haustorium development, we performed live imaging-based marker expression analysis and cell-lineage tracing during Haustorium formation in the model facultative root parasite Phtheirospermum japonicum Our live-imaging analysis revealed that Haustorium formation was associated with induction of simultaneous cell division in multiple cellular layers, such as epidermis, cortex and endodermis. In addition, we found that procambium-like cells, monitored by cell type-specific markers, emerged within the central region of the Haustorium before xylem connection to the host plant. Our clonal analysis of cell lineages showed that cells in multiple cellular layers differentiated into procambium-like cells, whereas epidermal cells eventually transitioned into specialized cells interfacing with the host plant. Thus, our data provide a cell fate transition map during de novo Haustorium organogenesis in parasitic plants.
Diego Rubiales - One of the best experts on this subject based on the ideXlab platform.
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induction of Haustorium development by sphaeropsidones in radicles of the parasitic weeds striga and orobanche a structure activity relationship study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandezaparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure–Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Mónica Fernández-aparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandez-aparicio Ruiz, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the Haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for Haustorium induction. The results suggested that the Haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.
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Uromyces viciae-fabae Haustorium formation in susceptible and resistant faba bean lines
European Journal of Plant Pathology, 2003Co-Authors: Diego Rubiales, Josefina C. SilleroAbstract:Haustorium formation by the faba bean rust (Uromyces viciae-fabae) was studied on susceptible and resistant faba bean lines. The resistant lines showed incomplete resistance, based on late acting hypersensitivity or on non-hypersensitive resistance acting before Haustorium formation. Histological observations on infected leaves showed that both the number of haustoria per infection unit and their developmental stage was reduced in both resistant lines. Isolation of haustoria confirmed that both the number and the size of haustoria were reduced in resistant lines, irrespective of whether the resistance was associated with hypersensitivity. Plant age had no detectable effect on both parameters.
Alessio Cimmino - One of the best experts on this subject based on the ideXlab platform.
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induction of Haustorium development by sphaeropsidones in radicles of the parasitic weeds striga and orobanche a structure activity relationship study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandezaparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure–Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Mónica Fernández-aparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandez-aparicio Ruiz, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the Haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for Haustorium induction. The results suggested that the Haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.
Marco Evidente - One of the best experts on this subject based on the ideXlab platform.
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induction of Haustorium development by sphaeropsidones in radicles of the parasitic weeds striga and orobanche a structure activity relationship study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandezaparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure–Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Mónica Fernández-aparicio, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by tes...
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Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Monica Fernandez-aparicio Ruiz, Lucia Maddau, Marco Evidente, Marco Masi, Alessio Cimmino, Diego Rubiales, Antonio EvidenteAbstract:Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of Haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of Haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce Haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of Haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the Haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for Haustorium induction. The results suggested that the Haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.
