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Qiang Sun - One of the best experts on this subject based on the ideXlab platform.
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Xylella fastidiosa causes transcriptional shifts that precede tylose formation and starch depletion in xylem.
Molecular plant pathology, 2020Co-Authors: Brian Ingel, Qiang Sun, Clarissa Reyes, Mélanie Massonnet, Bailey Boudreau, Yuling Sun, Andrew J. Mcelrone, Dario Cantu, M. Caroline RoperAbstract:Pierce's disease (PD) in grapevine (Vitis vinifera) is caused by the bacterial pathogen Xylella fastidiosa. X. fastidiosa is limited to the xylem tissue and following infection induces extensive plant-derived xylem blockages, primarily in the form of Tyloses. Tylose-mediated vessel occlusions are a hallmark of PD, particularly in susceptible V. vinifera. We temporally monitored tylose development over the course of the disease to link symptom severity to the level of tylose occlusion and the presence/absence of the bacterial pathogen at fine-scale resolution. The majority of vessels containing Tyloses were devoid of bacterial cells, indicating that direct, localized perception of X. fastidiosa was not a primary cause of tylose formation. In addition, we used X-ray computed microtomography and machine-learning to determine that X. fastidiosa induces significant starch depletion in xylem ray parenchyma cells. This suggests that a signalling mechanism emanating from the vessels colonized by bacteria enables a systemic response to X. fastidiosa infection. To understand the transcriptional changes underlying these phenotypes, we integrated global transcriptomics into the phenotypes we tracked over the disease spectrum. Differential gene expression analysis revealed that considerable transcriptomic reprogramming occurred during early PD before symptom appearance. Specifically, we determined that many genes associated with tylose formation (ethylene signalling and cell wall biogenesis) and drought stress were up-regulated during both Phase I and Phase II of PD. On the contrary, several genes related to photosynthesis and carbon fixation were down-regulated during both phases. These responses correlate with significant starch depletion observed in ray cells and tylose synthesis in vessels.
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Vascular Occlusions in Grapevines with Pierce’s Disease Make Disease Symptom Development Worse
Plant physiology, 2013Co-Authors: Qiang Sun, M. Andrew Walker, Yuliang Sun, John M. LabavitchAbstract:Vascular occlusions are common structural modifications made by many plant species in response to pathogen infection. However, the functional role(s) of occlusions in host plant disease resistance/susceptibility remains controversial. This study focuses on vascular occlusions that form in stem secondary xylem of grapevines (Vitis vinifera) infected with Pierce’s disease (PD) and the impact of occlusions on the hosts’ water transport and the systemic spread of the causal bacterium Xylella fastidiosa in infected vines. Tyloses are the predominant type of occlusion that forms in grapevine genotypes with differing PD resistances. Tyloses form throughout PD-susceptible grapevines with over 60% of the vessels in transverse sections of all examined internodes becoming fully blocked. By contrast, tylose development was mainly limited to a few internodes close to the point of inoculation in PD-resistant grapevines, impacting only 20% or less of the vessels. The extensive vessel blockage in PD-susceptible grapevines was correlated to a greater than 90% decrease in stem hydraulic conductivity, compared with an approximately 30% reduction in the stems of PD-resistant vines. Despite the systemic spread of X. fastidiosa in PD-susceptible grapevines, the pathogen colonized only 15% or less of the vessels in any internode and occurred in relatively small numbers, amounts much too small to directly block the vessels. Therefore, we concluded that the extensive formation of vascular occlusions in PD-susceptible grapevines does not prevent the pathogen’s systemic spread in them, but may significantly suppress the vines’ water conduction, contributing to PD symptom development and the vines’ eventual death.
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Wound-induced vascular occlusions in Vitis vinifera (Vitaceae): Tyloses in summer and gels in winter1.
American journal of botany, 2008Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Vascular occlusion in xylem conduits is a common response to environmental stresses, and plant species are recognized as primarily tylose-forming or gel-forming. These stresses occur throughout the year, but there is little information on the wound responses throughout the year and in growing and dormant tissues. Wound-induced vascular occlusions were evaluated by type (tylose or gel), temporal progress, and spatial distribution for grape stems pruned in four seasons through an entire year. Tyloses were formed predominantly in summer and gels in winter. Cytohistological analyses indicated that wound-induced gels were pectin-rich. Both gel formation and tylose development were complete within 7 d and 10 mm from the cut regardless of the season of the wounding. Most vessels were affected by wounding, but a higher fraction of vessels developed occlusions in summer and autumn (over 80%) than in winter and spring (about 60%). The study is the first to show a single species is capable of producing primarily either Tyloses or gels and that the type of wound-induced occlusion is dependent upon the season in which wounding occurs. Winter conditions limit the wound response to reversible gel formation that may contribute to refilling of embolized vessels in the spring.
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Ethylene and not embolism is required for wound-induced tylose development in stems of grapevines.
Plant physiology, 2007Co-Authors: Qiang Sun, Thomas L. Rost, Michael S. Reid, Mark A. MatthewsAbstract:The pruning of actively growing grapevines (Vitis vinifera) resulted in xylem vessel embolisms and a stimulation of tylose formation in the vessels below the pruning wound. Pruning was also followed by a 10-fold increase in the concentration of ethylene at the cut surface. When the pruning cut was made under water and maintained in water, embolisms were prevented, but there was no reduction in the formation of Tyloses or the accumulation of ethylene. Treatment of the stems with inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine) and/or action (silver thiosulfate) delayed and greatly reduced the formation of Tyloses in xylem tissue and the size and number of those that formed in individual vessels. Our data are consistent with the hypotheses that wound ethylene production is the cause of tylose formation and that embolisms in vessels are not directly required for wound-induced tylosis in pruned grapevines. The possible role of ethylene in the formation of Tyloses in response to other stresses and during development, maturation, and senescence is discussed.
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Pruning-induced tylose development in stems of current-year shoots of Vitis vinifera (Vitaceae)
American journal of botany, 2006Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Tyloses form in xylem vessels in response to various environmental stimuli, but little is known of the kinetics or regulation of their development. Preliminary investigations indicated that wounds seal quickly with Tyloses after pruning of grapevine shoots. In this study, tylose development was analyzed qualitatively and quantitatively at different depths and times from pruning cuts along current-year shoots of grapevines at basal, middle, and apical stem regions. Tyloses developed simultaneously within a single vessel but much separated in time among vessels. Pruning caused prodigious tylosis in vessels of grape stems, extending to approximately 1 cm deep and to 7 d after wounding, but about half of the vessels did not become completely occluded. The fraction of vessels forming Tyloses was greatest in basal (85%) and least in apical (50%) regions. The depth of maximum density of Tyloses was 4 mm from the cut in the basal region and 2 mm from the cut in the middle and apical regions. Tylose development was faster in the basal and middle than in the apical region. The pattern of tylose development is discussed in the context of wound repair and pathogen movement in grapevines.
Mark A. Matthews - One of the best experts on this subject based on the ideXlab platform.
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MECHANISMS OF PIERCE'S DISEASE TRANSMISSION IN GRAPEVINES: THE XYLEM PATHWAYS AND MOVEMENT OF XYLELLA FASTIDIOSA.
2015Co-Authors: Thomas L. Rost, Mark A. Matthews, Josh StevensonAbstract:During this period our focus was the comparative xylem anatomy of a resistant species, Muscadinia rotundifolia cv Cowart and a susceptible species, Vitis vinifera cv Chardonnay. When infected by Xylella fastidosa both species produced Tyloses (parenchyma ingrowths into tracheary elements) and gums; M. rotundifolia tended to have fewer Tyloses. The resistant species also had narrower vessels, but otherwise xylem anatomy was similar to V. vinifera. Fluorescently tagged beads were loaded into both species. Beads traveled through the stem xylem in both, but did not move into petioles in these experiments. Tyloses were first apparent 24 hours after pruning in both species and most vessels were blocked in both after eight days of pruning. This suggests that the mechanism to form Tyloses in both species is similar, although the resistant species tended to show fewer Tyloses in response to Xf. Two symptoms, green islands and matchsticks are reported in this study. Green islands formed as a result of incomplete initiation of the phellogen. In regions of the stem where a phellogen and subsequent periderm arose, immediately exterior tissue was cut off, causing it to brown. In regions of the stem where no periderm is formed, the exterior tissues remained green. Consequently, the stem is mottled with both green living epidermis and brown dying epidermis as determined by the presence or absence of an underlying periderm. Matchsticks formed when the leaf lamina separated from the petiole, and the petiole remained attached to the stem. Lamina broke off from the petioles consistently in a fracture zone where xylem from the petiole anastomoses into the five major veins of the leaf. N
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Wound-induced vascular occlusions in Vitis vinifera (Vitaceae): Tyloses in summer and gels in winter1.
American journal of botany, 2008Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Vascular occlusion in xylem conduits is a common response to environmental stresses, and plant species are recognized as primarily tylose-forming or gel-forming. These stresses occur throughout the year, but there is little information on the wound responses throughout the year and in growing and dormant tissues. Wound-induced vascular occlusions were evaluated by type (tylose or gel), temporal progress, and spatial distribution for grape stems pruned in four seasons through an entire year. Tyloses were formed predominantly in summer and gels in winter. Cytohistological analyses indicated that wound-induced gels were pectin-rich. Both gel formation and tylose development were complete within 7 d and 10 mm from the cut regardless of the season of the wounding. Most vessels were affected by wounding, but a higher fraction of vessels developed occlusions in summer and autumn (over 80%) than in winter and spring (about 60%). The study is the first to show a single species is capable of producing primarily either Tyloses or gels and that the type of wound-induced occlusion is dependent upon the season in which wounding occurs. Winter conditions limit the wound response to reversible gel formation that may contribute to refilling of embolized vessels in the spring.
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Ethylene and not embolism is required for wound-induced tylose development in stems of grapevines.
Plant physiology, 2007Co-Authors: Qiang Sun, Thomas L. Rost, Michael S. Reid, Mark A. MatthewsAbstract:The pruning of actively growing grapevines (Vitis vinifera) resulted in xylem vessel embolisms and a stimulation of tylose formation in the vessels below the pruning wound. Pruning was also followed by a 10-fold increase in the concentration of ethylene at the cut surface. When the pruning cut was made under water and maintained in water, embolisms were prevented, but there was no reduction in the formation of Tyloses or the accumulation of ethylene. Treatment of the stems with inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine) and/or action (silver thiosulfate) delayed and greatly reduced the formation of Tyloses in xylem tissue and the size and number of those that formed in individual vessels. Our data are consistent with the hypotheses that wound ethylene production is the cause of tylose formation and that embolisms in vessels are not directly required for wound-induced tylosis in pruned grapevines. The possible role of ethylene in the formation of Tyloses in response to other stresses and during development, maturation, and senescence is discussed.
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Pruning-induced tylose development in stems of current-year shoots of Vitis vinifera (Vitaceae)
American journal of botany, 2006Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Tyloses form in xylem vessels in response to various environmental stimuli, but little is known of the kinetics or regulation of their development. Preliminary investigations indicated that wounds seal quickly with Tyloses after pruning of grapevine shoots. In this study, tylose development was analyzed qualitatively and quantitatively at different depths and times from pruning cuts along current-year shoots of grapevines at basal, middle, and apical stem regions. Tyloses developed simultaneously within a single vessel but much separated in time among vessels. Pruning caused prodigious tylosis in vessels of grape stems, extending to approximately 1 cm deep and to 7 d after wounding, but about half of the vessels did not become completely occluded. The fraction of vessels forming Tyloses was greatest in basal (85%) and least in apical (50%) regions. The depth of maximum density of Tyloses was 4 mm from the cut in the basal region and 2 mm from the cut in the middle and apical regions. Tylose development was faster in the basal and middle than in the apical region. The pattern of tylose development is discussed in the context of wound repair and pathogen movement in grapevines.
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Grapevine Susceptibility to Pierce's Disease II: Progression of Anatomical Symptoms
American Journal of Enology and Viticulture, 2004Co-Authors: Joshua F. Stevenson, Mark A. Matthews, L. Carl Greve, John M. Labavitch, Thomas L. RostAbstract:The progression of anatomical symptoms of Pierce's disease in susceptible Vitis vinifera cv. Chardonnay grapevines was studied over a time course following controlled inoculation of Y—shaped, two-shooted plants with Xylella fastidiosa . Leaf, petiole, and stem tissue samples collected from locations on inoculated and noninoculated shoots were taken at 10, 14, and 18 weeks following inoculation. After 10 weeks, leaf necrosis was visible in the inoculated shoots. Leaf and petiole xylem was predominantly occluded with gums and bacteria, whereas stem xylem was occluded almost exclusively with Tyloses. After 14 weeks, bacteria and gums were found in noninoculated shoots, but Tyloses were absent from these stem tissues. At 18 weeks, tylose development was observed in the xylem in stems of noninoculated shoots. Consequently, basipetal movement of bacteria occurred from the inoculated shoot into a noninoculated shoot. Results indicate that there is a predictable initial sequence of symptoms within infected shoots: gum and bacterial accumulation in leaves and petioles followed by tylose formation in stem tissue. This pattern is repeated with colonization of new shoots, eventually creating a systemic presence of the disease. Acknowledgments: Funding for this research was provided from the California Department of Food and Agriculture, agreement no. 01-0712. The authors would like to thank the cooperative efforts in maintaining bacterial cultures and inoculating grapevines from the Bruce Kirkpatrick lab, including M. Caroline Roper, and the preliminary anatomical contributions made by Philip Bates.
Michael Krings - One of the best experts on this subject based on the ideXlab platform.
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tylosis formation and fungal interactions in an early jurassic conifer from northern victoria land antarctica
Review of Palaeobotany and Palynology, 2012Co-Authors: Carla J Harper, Annelaure Decombeix, Benjamin Bomfleur, Edith L. Taylor, Michael Krings, Thomas N. TaylorAbstract:Well-preserved fungi occur in permineralized conifer axes from the Lower Jurassic of northern Victoria Land, Antarctica. The fungus is characterized by septate hyphae extending through the vascular ray system via penetration of cross-field pits. Tyloses are present in large numbers and might have been effective as a physical restraint to the spread of the fungus. However, knotted fungal hyphae within and around the Tyloses suggest that the fungus was able to surmount the barriers. Hyphae are also present in the secondary phloem. This plant-fungal interaction contributes to a better understanding of the antagonistic relationships that existed between pathogenic fungi and conifers in the Jurassic paleoecosystems of Antarctica, as well as providing evidence of interactions between fungi and Tyloses in Mesozoic wood.
Thomas L. Rost - One of the best experts on this subject based on the ideXlab platform.
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MECHANISMS OF PIERCE'S DISEASE TRANSMISSION IN GRAPEVINES: THE XYLEM PATHWAYS AND MOVEMENT OF XYLELLA FASTIDIOSA.
2015Co-Authors: Thomas L. Rost, Mark A. Matthews, Josh StevensonAbstract:During this period our focus was the comparative xylem anatomy of a resistant species, Muscadinia rotundifolia cv Cowart and a susceptible species, Vitis vinifera cv Chardonnay. When infected by Xylella fastidosa both species produced Tyloses (parenchyma ingrowths into tracheary elements) and gums; M. rotundifolia tended to have fewer Tyloses. The resistant species also had narrower vessels, but otherwise xylem anatomy was similar to V. vinifera. Fluorescently tagged beads were loaded into both species. Beads traveled through the stem xylem in both, but did not move into petioles in these experiments. Tyloses were first apparent 24 hours after pruning in both species and most vessels were blocked in both after eight days of pruning. This suggests that the mechanism to form Tyloses in both species is similar, although the resistant species tended to show fewer Tyloses in response to Xf. Two symptoms, green islands and matchsticks are reported in this study. Green islands formed as a result of incomplete initiation of the phellogen. In regions of the stem where a phellogen and subsequent periderm arose, immediately exterior tissue was cut off, causing it to brown. In regions of the stem where no periderm is formed, the exterior tissues remained green. Consequently, the stem is mottled with both green living epidermis and brown dying epidermis as determined by the presence or absence of an underlying periderm. Matchsticks formed when the leaf lamina separated from the petiole, and the petiole remained attached to the stem. Lamina broke off from the petioles consistently in a fracture zone where xylem from the petiole anastomoses into the five major veins of the leaf. N
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Wound-induced vascular occlusions in Vitis vinifera (Vitaceae): Tyloses in summer and gels in winter1.
American journal of botany, 2008Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Vascular occlusion in xylem conduits is a common response to environmental stresses, and plant species are recognized as primarily tylose-forming or gel-forming. These stresses occur throughout the year, but there is little information on the wound responses throughout the year and in growing and dormant tissues. Wound-induced vascular occlusions were evaluated by type (tylose or gel), temporal progress, and spatial distribution for grape stems pruned in four seasons through an entire year. Tyloses were formed predominantly in summer and gels in winter. Cytohistological analyses indicated that wound-induced gels were pectin-rich. Both gel formation and tylose development were complete within 7 d and 10 mm from the cut regardless of the season of the wounding. Most vessels were affected by wounding, but a higher fraction of vessels developed occlusions in summer and autumn (over 80%) than in winter and spring (about 60%). The study is the first to show a single species is capable of producing primarily either Tyloses or gels and that the type of wound-induced occlusion is dependent upon the season in which wounding occurs. Winter conditions limit the wound response to reversible gel formation that may contribute to refilling of embolized vessels in the spring.
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Ethylene and not embolism is required for wound-induced tylose development in stems of grapevines.
Plant physiology, 2007Co-Authors: Qiang Sun, Thomas L. Rost, Michael S. Reid, Mark A. MatthewsAbstract:The pruning of actively growing grapevines (Vitis vinifera) resulted in xylem vessel embolisms and a stimulation of tylose formation in the vessels below the pruning wound. Pruning was also followed by a 10-fold increase in the concentration of ethylene at the cut surface. When the pruning cut was made under water and maintained in water, embolisms were prevented, but there was no reduction in the formation of Tyloses or the accumulation of ethylene. Treatment of the stems with inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine) and/or action (silver thiosulfate) delayed and greatly reduced the formation of Tyloses in xylem tissue and the size and number of those that formed in individual vessels. Our data are consistent with the hypotheses that wound ethylene production is the cause of tylose formation and that embolisms in vessels are not directly required for wound-induced tylosis in pruned grapevines. The possible role of ethylene in the formation of Tyloses in response to other stresses and during development, maturation, and senescence is discussed.
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Pruning-induced tylose development in stems of current-year shoots of Vitis vinifera (Vitaceae)
American journal of botany, 2006Co-Authors: Qiang Sun, Thomas L. Rost, Mark A. MatthewsAbstract:Tyloses form in xylem vessels in response to various environmental stimuli, but little is known of the kinetics or regulation of their development. Preliminary investigations indicated that wounds seal quickly with Tyloses after pruning of grapevine shoots. In this study, tylose development was analyzed qualitatively and quantitatively at different depths and times from pruning cuts along current-year shoots of grapevines at basal, middle, and apical stem regions. Tyloses developed simultaneously within a single vessel but much separated in time among vessels. Pruning caused prodigious tylosis in vessels of grape stems, extending to approximately 1 cm deep and to 7 d after wounding, but about half of the vessels did not become completely occluded. The fraction of vessels forming Tyloses was greatest in basal (85%) and least in apical (50%) regions. The depth of maximum density of Tyloses was 4 mm from the cut in the basal region and 2 mm from the cut in the middle and apical regions. Tylose development was faster in the basal and middle than in the apical region. The pattern of tylose development is discussed in the context of wound repair and pathogen movement in grapevines.
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Grapevine Susceptibility to Pierce's Disease II: Progression of Anatomical Symptoms
American Journal of Enology and Viticulture, 2004Co-Authors: Joshua F. Stevenson, Mark A. Matthews, L. Carl Greve, John M. Labavitch, Thomas L. RostAbstract:The progression of anatomical symptoms of Pierce's disease in susceptible Vitis vinifera cv. Chardonnay grapevines was studied over a time course following controlled inoculation of Y—shaped, two-shooted plants with Xylella fastidiosa . Leaf, petiole, and stem tissue samples collected from locations on inoculated and noninoculated shoots were taken at 10, 14, and 18 weeks following inoculation. After 10 weeks, leaf necrosis was visible in the inoculated shoots. Leaf and petiole xylem was predominantly occluded with gums and bacteria, whereas stem xylem was occluded almost exclusively with Tyloses. After 14 weeks, bacteria and gums were found in noninoculated shoots, but Tyloses were absent from these stem tissues. At 18 weeks, tylose development was observed in the xylem in stems of noninoculated shoots. Consequently, basipetal movement of bacteria occurred from the inoculated shoot into a noninoculated shoot. Results indicate that there is a predictable initial sequence of symptoms within infected shoots: gum and bacterial accumulation in leaves and petioles followed by tylose formation in stem tissue. This pattern is repeated with colonization of new shoots, eventually creating a systemic presence of the disease. Acknowledgments: Funding for this research was provided from the California Department of Food and Agriculture, agreement no. 01-0712. The authors would like to thank the cooperative efforts in maintaining bacterial cultures and inoculating grapevines from the Bruce Kirkpatrick lab, including M. Caroline Roper, and the preliminary anatomical contributions made by Philip Bates.
Ana Ortuño - One of the best experts on this subject based on the ideXlab platform.
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Dysfunctionality of the xylem in Olea europaea L. Plants associated with the infection process by Verticillium dahliae Kleb. Role of phenolic compounds in plant defense mechanism.
Journal of Agricultural and Food Chemistry, 2007Co-Authors: A.g. Báidez, Pedro Sanchez Gomez, Ana OrtuñoAbstract:Xylem ultrastructural modification and the possible participation of phenolic compounds in the natural defense or resistance mechanisms of olive plants infected with Verticillium dahliae Kleb. were studied. Microscopic study showed that the mycelium propagated and passed from one element to another through the pit. The formation of Tyloses and aggregates contributed to obstruction of the xylem lumen. In vivo changes in the levels of these phenolic compounds in infected olive plants and their antifungal activity against Verticillium dahliae Kleb., as revealed by in vitro study, strongly suggest that they are involved in natural defense or resistance mechanims in this plant material, the most active being quercetin and luteolin aglycons, followed by rutin, oleuropein, luteolin-7-glucoside, tyrosol, p-coumaric acid, and catechin. Keywords: Verticillium dahliae Kleb.; Olea europaea L.; plant defense mechanism; Tyloses; antifungal acitvity; phenolic compounds
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Tylose Formation and Changes in Phenolic Compounds of Grape Roots Infected with "Phaeomoniella chlamydospora" and "Phaeoacremonium" Species.
Phytopathologia Mediterranea, 2001Co-Authors: José Antonio Del Río, Ana Ortuño, Ana. Gonzalez, M. D. Fuster, Pedro Gómez, Victor Frias, J. M. BotíaAbstract:The role of phenolic compounds in strengthening resistance of grapevine to young grapevine decline was analysed. The formation of Tyloses has also been associated with this disease. A microscopic study showed that Tyloses originated in parenchyma cells associated with the xylem and from there invaded the xylem lumen. As Tyloses formed, there were changes in the cell wall, associated with the accumulation of crystalline structures. The cells surrounding the blocked xylem contained more polyphenolic compounds than the cells of intact xylem. Changes in the level and composition of polyphenolic compounds occurred in relation to the severity of infection. Tannin concentrations also increased with increasing numbers of xylem vessels containing Tyloses. Root extracts added to fungal culture media inhibited mycelial growth of Phaeomoniella chlamydospora, Phaeoacremonium aleophilum and Pm. inflatipes. Inhibition was greater with extracts from roots with Tyloses, and was also correlated with polyphenol content. Extracts of the leaves, stems and berries of vines treated with Brotomax, which increases the biosynthesis of phenolic compounds, inhibited mycelial growth of the fungi compared to untreated control plants.
