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Edward C Lulai - One of the best experts on this subject based on the ideXlab platform.
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Wounding induces changes in tuber polyamine content polyamine metabolic gene expression and enzyme activity during closing layer formation and initiation of Wound Periderm formation
Journal of Plant Physiology, 2015Co-Authors: Edward C Lulai, Jonathan D Neubauer, Linda L Olson, Jeffrey C SuttleAbstract:Abstract Tuber Wound-healing processes are complex, and the associated regulation and modulation of these processes are poorly understood. Polyamines (PA) are involved in modulating a variety of responses to biotic and abiotic plant stresses and have been suggested to be involved in tuber Wound responses. However, the time course of Wound-induced changes in tuber PA content, activity of key biosynthetic enzymes and associated gene expression has not been determined and coordinated with major Wound-healing processes. The objective of this study was to determine these Wound-induced changes and their coordination with Wound-healing processes. Wounding induced increases in putrescine (Put) and spermidine (Spd), but had only minor effects on spermine (Spm) content during the 168 h time course which encompassed the initiation and completion of the closing layer formation, and the initiation of cell division and Wound Periderm formation. As determinants of the first committed step in PA biosynthesis, arginine and ornithine decarboxylase (ADC and ODC, respectively) activities were below levels of detectability in resting tubers and expression of genes encoding these two enzymes was low. Within 6 h of Wounding, increases in the in vitro activities of ADC and ODC and expression of their cognate genes were observed. Expression of a gene encoding S-adenosylmethionine decarboxylase, required for Spd and Spm biosynthesis, was also increased 6 h after Wounding and remained elevated throughout the time course. Expression of a polyamine catabolic gene, encoding polyamine oxidase, was down-regulated after Wounding. Results indicated a rapid Wound-induced increase in PA biosynthesis during closing layer formation and the time of nuclei entry and exit from S-phase. PA content remained elevated as Wound-induced cells became meristematic and initiated formation of the Wound Periderm suggesting sustained involvement in Wound-healing.
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Wound induced suberization genes are differentially expressed spatially and temporally during closing layer and Wound Periderm formation
Postharvest Biology and Technology, 2014Co-Authors: Edward C Lulai, Jonathan D NeubauerAbstract:Abstract Potato tuber ( Solanum tuberosum L.) Wounds incurred at harvest and upon seed cutting require rapid suberization as a major part of the healing process to prevent infection and desiccation. However, little is known about the induction and expression of genes that are essential for these processes and in particular to the two major stages of Wound-induced suberization, i.e. closing layer formation and Wound Periderm formation. The objectives of this research were to address these needs by determining the effects of Wounding on the induction and expression profiles of specific genes involved in Wound-induced suberization in potato tuber ( S. tuberosum L.) during the initiation and completion of closing layer formation and Wound Periderm formation. Although both stages critically involve suberization, there are significant differences between the two processes. Closing layer development requires rapid suberization of existing parenchyma cells bordering the Wound surface to provide the initial protective barrier for the Wound. Wound Periderm development occurs later, i.e. after completion of closing layer formation, and requires development of a Wound phellogen layer which mediates the formation of highly organized files of suberized Wound-phellem cells that provide a more durable protective barrier for the tuber. The processes delineating these two separate stages of Wound-induced suberization are poorly understood. This research shows that, unlike some Wound responding genes such as phenylalanine ammonia lyase ( StPAL-1 ) and anionic peroxidase ( StPrx ), certain genes that are specifically involved in both of these processes do not remain uniformly up-regulated during the two stages of healing (i.e. StTHT encoding Hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase, StFHT encoding a fatty ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase, StKCS6 encoding a 3-ketoacyl-CoA synthase, StFAOH encoding a fatty acid ω-hydroxylase and StGPAT5 encoding a protein with acyl-CoA:glycerol-3-phosphate acyltransferase). Instead, they are up-regulated during closing layer formation; i.e. starting by ca. 1 d after Wounding, but then slightly down-regulated or pause near completion of the closing layer (ca. 5–6 d) and then again up-regulated as Wound Periderm development is fully initiated (ca. 7 d) and down-regulated near completion (ca. 28 d after Wounding). This differential in the expression profile, i.e. decrease between stages, was not anticipated and may be the first demonstration of measurable changes of any sort of biological flux as Wound induced suberization transitions from closing layer to Wound Periderm development. Results were repeated using minitubers from two different crop years and demonstrate that these processes are separate, but coupled in some yet to be determined fashion. The biology of this differential expression is important because of the roles closing layer and Wound Periderm development play in protecting the tuber from disease and other challenges.
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Wounding coordinately induces cell wall protein cell cycle and pectin methyl esterase genes involved in tuber closing layer and Wound Periderm development
Journal of Plant Physiology, 2012Co-Authors: Jonathan D Neubauer, Edward C Lulai, Jeffrey C Suttle, Asunta L Thompson, Melvin D BoltonAbstract:Abstract Little is known about the coordinate induction of genes that may be involved in agriculturally important Wound-healing events. In this study, Wound-healing events were determined together with Wound-induced expression profiles of selected cell cycle, cell wall protein, and pectin methyl esterase genes using two diverse potato genotypes and two harvests (NDTX4271-5R and Russet Burbank tubers; 2008 and 2009 harvests). By 5 d after Wounding, the closing layer and a nascent phellogen had formed. Phellogen cell divisions generated phellem layers until cessation of cell division at 28 d after Wounding for both genotypes and harvests. Cell cycle genes encoding epidermal growth factor binding protein (StEBP), cyclin-dependent kinase B (StCDKB) and cyclin-dependent kinase regulatory subunit (StCKS1At) were induced by 1 d after Wounding; these expressions coordinated with related phellogen formation and the induction and cessation of phellem cell formation. Genes encoding the structural cell wall proteins extensin (StExt1) and extensin-like (StExtlk) were dramatically up-regulated by 1–5 d after Wounding, suggesting involvement with closing layer and later phellem cell layer formation. Wounding up-regulated pectin methyl esterase genes (StPME and StPrePME); StPME expression increased during closing layer and phellem cell formation, whereas maximum expression of StPrePME occurred at 5–14 d after Wounding, implicating involvement in later modifications for closing layer and phellem cell formation. The coordinate induction and expression profile of StTLRP, a gene encoding a cell wall strengthening “tyrosine-and lysine-rich protein,” suggested a role in the formation of the closing layer followed by phellem cell generation and maturation. Collectively, the genes monitored were Wound-inducible and their expression profiles markedly coordinated with closing layer formation and the index for phellogen layer meristematic activity during Wound Periderm development; results were more influenced by harvest than genotype. Importantly, StTLRP was the only gene examined that may be involved in phellogen cell wall thickening after cessation of phellogen cell division.
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immunocytological comparison of native and Wound Periderm maturation in potato tuber
American Journal of Potato Research, 2004Co-Authors: Robert P Sabba, Edward C LulaiAbstract:The maturation of potato (Solanum tuberosum L.) tuber native Periderm and Wound Periderm, which develops to replace the native Periderm when it is damaged, are agriculturally important processes that are poorly understood. While both types of Periderm form from a phellogen layer that serves as a lateral meristem, there has been little research done on comparing the biochemical processes and steps involved in the maturation of the two types of Periderm. Here, we use immunological techniques to compare some of the cell wall changes during Wound and native Periderm maturation. Consistent with our recent work on native Periderm, we demonstrate that toluidine blue O is also useful for distinguishing between suberized and non-suberized cells in Wound Periderm. More importantly, we use the immunological probes JIM5 and JIM7 to show that there is no increase in either un-esterified or esterified homogalacturonan pectin epitopes in phellogen walls accompanying Wound Periderm maturation. In contrast, as we previously described, native Periderm maturation and resistance to excoriation (skinning) is accompanied by an increase in relatively un-esterified and esterified homogalacturonan pectin epitopes in the walls of phellogen cells. These results demonstrate that the biochemical processes responsible for maturation and resistance to excoriation differ between native and Wound Periderm. This dissimilarity between Wound and native Periderm maturation demonstrates the potential limitations in applying the Wound Periderm model to research on native Periderm.
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histological analysis of the maturation of native and Wound Periderm in potato solanum tuberosum l tuber
Annals of Botany, 2002Co-Authors: Robert P Sabba, Edward C LulaiAbstract:Maturation of potato (Solanum tuberosum L.) tuber native and Wound Periderm and development of resistance to Periderm abrasion were investigated utilizing cytological and histochemical techniques. Both native and Wound Periderm consist of three different tissues: phellem, phellogen and phelloderm. It was previously determined that the phellogen walls of immature native Periderm are thin and prone to fracture during harvest, leading to Periderm abrasion (excoriation). Phellogen walls thicken and become less susceptible to fracture upon maturation of the Periderm, leading to resistance to excoriation. We now demonstrate that phellogen cells of immature Wound Periderm also have thin radial walls and that Wound Periderm abrasion is due to fracture of these walls. Maturation of the Wound Periderm is also associated with an increase in the thickness of the phellogen radial walls. Histological analysis with ruthenium red and hydroxylamine‐FeCl2, which stain unesterified and highly methyl-esterified pectins, respectively, indicates that the phellogen cell walls of native and Wound Periderm differ significantly regardless of the stage of maturity. Results obtained by staining with ruthenium red and hydroxylamine‐FeCl2 imply that phellogen cell walls of immature native Periderm contain methyl-esterified pectin, but are lacking in unesterified (acidic) pectins. Maturation of native Periderm is accompanied by an apparent increase in unesterified pectins in the walls of phellogen cells, which may allow for the strengthening of phellogen cell walls via calcium pectate formation. Histological staining of the phellogen walls of Wound Periderm, on the other hand, implies that these walls are deficient in pectins. Moreover, maturation of Wound Periderm is not accompanied by an increase in unesterified pectins in these walls. Since peroxidase is known to catalyse the cross-linking of cell wall polymers, we stained native and Wound Periderm for the presence of peroxidase utilizing guaiacol as a substrate. Peroxidase staining was strong in the phellogen walls of both immature and mature native Periderm and we could not detect any differences in staining between them. Peroxidase staining was weak in the phellogen walls of immature Wound Periderm and was not detectably different in mature Wound Periderm. Peroxidase data imply that there are distinct differences between native and Wound Periderm, though our data do not indicate that changes in peroxidase activity are involved in the development of resistance to Periderm abrasion that occurs upon maturation of the Periderm. However, we cannot rule out the involvement in this process of peroxidase isozymes that have low affinity for the substrates utilized here. a 2002 Annals of Botany Company
Ruth E Stark - One of the best experts on this subject based on the ideXlab platform.
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potato native and Wound Periderms are differently affected by down regulation of fht a suberin feruloyl transferase
Phytochemistry, 2018Co-Authors: Liqing Jin, Ruth E Stark, Keyvan Dastmalchi, Qing Cai, Wenlin Huang, Olga Serra, Joan Rigau, Marisa Molinas, Merce FiguerasAbstract:Abstract Potato native and Wound healing Periderms contain an external multilayered phellem tissue (potato skin) consisting of dead cells whose cell walls are impregnated with suberin polymers. The phellem provides physical and chemical barriers to tuber dehydration, heat transfer, and pathogenic infection. Previous RNAi-mediated gene silencing studies in native Periderm have demonstrated a role for a feruloyl transferase (FHT) in suberin biosynthesis and revealed how its down-regulation affects both chemical composition and physiology. To complement these prior analyses and to investigate the impact of FHT deficiency in Wound Periderms, a bottom-up methodology has been used to analyze soluble tissue extracts and solid polymers concurrently. Multivariate statistical analysis of LC-MS and GC-MS data, augmented by solid-state NMR and thioacidolysis, yields two types of new insights: the chemical compounds responsible for contrasting metabolic profiles of native and Wound Periderms, and the impact of FHT deficiency in each of these plant tissues. In the current report, we confirm a role for FHT in developing Wound Periderm and highlight its distinctive features as compared to the corresponding native potato Periderm.
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Solving the Jigsaw Puzzle of Wound-Healing Potato Cultivars: Metabolite Profiling and Antioxidant Activity of Polar Extracts
2016Co-Authors: Keyvan Dastmalchi, Qing Cai, Kevin Zhou, Wenlin Huang, Olga Serra, Ruth E StarkAbstract:ABSTRACT: Potato (Solanum tuberosum L.) is a worldwide food staple, but substantial waste accompanies the cultivation of this crop due to Wounding of the outer skin and subsequent unfavorable healing conditions. Motivated by both economic and nutritional considerations, this metabolite profiling study aims to improve understanding of closing layer and Wound Periderm formation and guide the development of new methods to ensure faster and more complete healing after skin breakage. The polar metabolites of Wound-healing tissues from four potato cultivars with differing patterns of tuber skin russeting (Norkotah Russet, Atlantic, Chipeta, and Yukon Gold) were analyzed at three and seven days after Wounding, during suberized closing layer formation and nascent Wound Periderm development, respectively. The polar extracts were assessed using LC-MS and NMR spectroscopic methods, including multivariate analysis and tentative identification of 22 of the 24 biomarkers that discriminate among the cultivars at a given Wound-healing time point or between developmental stages. Differences among the metabolites that could be identified from NMR- and MS-derived biomarkers highlight the strengths and limitations of each method, also demonstrating the complementarity of these approaches in terms of assembling a complete molecular picture of the tissue extracts. Both methods revealed that differences among the cultivar metabolite profiles diminish as healing proceeds during the period following Wounding. The biomarkers included polyphenolic amines, flavonoid glycosides, phenolic acids and glycoalkaloids. Because Wound healing is associated with oxidative stress, the free radical scavenging activities of the extracts from different cultivars were measured at each Wounding time point, revealing significantly higher scavenging activity of th
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Solving the Jigsaw Puzzle of Wound-Healing Potato Cultivars: Metabolite Profiling and Antioxidant Activity of Polar Extracts
2015Co-Authors: Keyvan Dastmalchi, Qing Cai, Kevin Zhou, Wenlin Huang, Olga Serra, Ruth E StarkAbstract:Potato (Solanum tuberosum L.) is a worldwide food staple, but substantial waste accompanies the cultivation of this crop due to Wounding of the outer skin and subsequent unfavorable healing conditions. Motivated by both economic and nutritional considerations, this metabolite profiling study aims to improve understanding of closing layer and Wound Periderm formation and guide the development of new methods to ensure faster and more complete healing after skin breakage. The polar metabolites of Wound-healing tissues from four potato cultivars with differing patterns of tuber skin russeting (Norkotah Russet, Atlantic, Chipeta, and Yukon Gold) were analyzed at three and seven days after Wounding, during suberized closing layer formation and nascent Wound Periderm development, respectively. The polar extracts were assessed using LC-MS and NMR spectroscopic methods, including multivariate analysis and tentative identification of 22 of the 24 biomarkers that discriminate among the cultivars at a given Wound-healing time point or between developmental stages. Differences among the metabolites that could be identified from NMR- and MS-derived biomarkers highlight the strengths and limitations of each method, also demonstrating the complementarity of these approaches in terms of assembling a complete molecular picture of the tissue extracts. Both methods revealed that differences among the cultivar metabolite profiles diminish as healing proceeds during the period following Wounding. The biomarkers included polyphenolic amines, flavonoid glycosides, phenolic acids and glycoalkaloids. Because Wound healing is associated with oxidative stress, the free radical scavenging activities of the extracts from different cultivars were measured at each Wounding time point, revealing significantly higher scavenging activity of the Yukon Gold Periderm especially after 7 days of Wounding
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following suberization in potato Wound Periderm by histochemical and solid state 13c nuclear magnetic resonance methods
Plant Physiology, 1994Co-Authors: Ruth E Stark, Won Sohn, Ralph A Pacchiano, Mohamed Albashir, Joel R GarbowAbstract:The time course of suberization in Wound Periderm from potato (Solanum tuberosum L.) has been monitored by histochemical and high-resolution solid-state nuclear magnetic resonance (NMR) methods. Light microscopy conducted after selective staining of the lipid and double-bonded constituents shows that suberin is deposited at the outermost intact cell-wall surface during the first 7 d of Wound healing; suberization forms a barrier to tissue infiltration at later times. Cross polarization-magic angle spinning 13C NMR spectra demonstrate the deposition of a polyester containing all major suberin functional groups after just 4 d of Wound healing. Initially the suberin includes a large proportion of aromatic groups and fairly short aliphatic chains, but the spectral data demonstrate the growing dominance of long-chain species during the period 7 to 14 d after Wounding. The results of preliminary 13C-labeling experiments with sodium [2–13C]acetate and DL-[1–13C]phenylalanine provide an excellent prospectus for future NMR-based studies of suberin biosynthesis.
Jonathan D Neubauer - One of the best experts on this subject based on the ideXlab platform.
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Wounding induces changes in tuber polyamine content polyamine metabolic gene expression and enzyme activity during closing layer formation and initiation of Wound Periderm formation
Journal of Plant Physiology, 2015Co-Authors: Edward C Lulai, Jonathan D Neubauer, Linda L Olson, Jeffrey C SuttleAbstract:Abstract Tuber Wound-healing processes are complex, and the associated regulation and modulation of these processes are poorly understood. Polyamines (PA) are involved in modulating a variety of responses to biotic and abiotic plant stresses and have been suggested to be involved in tuber Wound responses. However, the time course of Wound-induced changes in tuber PA content, activity of key biosynthetic enzymes and associated gene expression has not been determined and coordinated with major Wound-healing processes. The objective of this study was to determine these Wound-induced changes and their coordination with Wound-healing processes. Wounding induced increases in putrescine (Put) and spermidine (Spd), but had only minor effects on spermine (Spm) content during the 168 h time course which encompassed the initiation and completion of the closing layer formation, and the initiation of cell division and Wound Periderm formation. As determinants of the first committed step in PA biosynthesis, arginine and ornithine decarboxylase (ADC and ODC, respectively) activities were below levels of detectability in resting tubers and expression of genes encoding these two enzymes was low. Within 6 h of Wounding, increases in the in vitro activities of ADC and ODC and expression of their cognate genes were observed. Expression of a gene encoding S-adenosylmethionine decarboxylase, required for Spd and Spm biosynthesis, was also increased 6 h after Wounding and remained elevated throughout the time course. Expression of a polyamine catabolic gene, encoding polyamine oxidase, was down-regulated after Wounding. Results indicated a rapid Wound-induced increase in PA biosynthesis during closing layer formation and the time of nuclei entry and exit from S-phase. PA content remained elevated as Wound-induced cells became meristematic and initiated formation of the Wound Periderm suggesting sustained involvement in Wound-healing.
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Wound induced suberization genes are differentially expressed spatially and temporally during closing layer and Wound Periderm formation
Postharvest Biology and Technology, 2014Co-Authors: Edward C Lulai, Jonathan D NeubauerAbstract:Abstract Potato tuber ( Solanum tuberosum L.) Wounds incurred at harvest and upon seed cutting require rapid suberization as a major part of the healing process to prevent infection and desiccation. However, little is known about the induction and expression of genes that are essential for these processes and in particular to the two major stages of Wound-induced suberization, i.e. closing layer formation and Wound Periderm formation. The objectives of this research were to address these needs by determining the effects of Wounding on the induction and expression profiles of specific genes involved in Wound-induced suberization in potato tuber ( S. tuberosum L.) during the initiation and completion of closing layer formation and Wound Periderm formation. Although both stages critically involve suberization, there are significant differences between the two processes. Closing layer development requires rapid suberization of existing parenchyma cells bordering the Wound surface to provide the initial protective barrier for the Wound. Wound Periderm development occurs later, i.e. after completion of closing layer formation, and requires development of a Wound phellogen layer which mediates the formation of highly organized files of suberized Wound-phellem cells that provide a more durable protective barrier for the tuber. The processes delineating these two separate stages of Wound-induced suberization are poorly understood. This research shows that, unlike some Wound responding genes such as phenylalanine ammonia lyase ( StPAL-1 ) and anionic peroxidase ( StPrx ), certain genes that are specifically involved in both of these processes do not remain uniformly up-regulated during the two stages of healing (i.e. StTHT encoding Hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase, StFHT encoding a fatty ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase, StKCS6 encoding a 3-ketoacyl-CoA synthase, StFAOH encoding a fatty acid ω-hydroxylase and StGPAT5 encoding a protein with acyl-CoA:glycerol-3-phosphate acyltransferase). Instead, they are up-regulated during closing layer formation; i.e. starting by ca. 1 d after Wounding, but then slightly down-regulated or pause near completion of the closing layer (ca. 5–6 d) and then again up-regulated as Wound Periderm development is fully initiated (ca. 7 d) and down-regulated near completion (ca. 28 d after Wounding). This differential in the expression profile, i.e. decrease between stages, was not anticipated and may be the first demonstration of measurable changes of any sort of biological flux as Wound induced suberization transitions from closing layer to Wound Periderm development. Results were repeated using minitubers from two different crop years and demonstrate that these processes are separate, but coupled in some yet to be determined fashion. The biology of this differential expression is important because of the roles closing layer and Wound Periderm development play in protecting the tuber from disease and other challenges.
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Wounding coordinately induces cell wall protein cell cycle and pectin methyl esterase genes involved in tuber closing layer and Wound Periderm development
Journal of Plant Physiology, 2012Co-Authors: Jonathan D Neubauer, Edward C Lulai, Jeffrey C Suttle, Asunta L Thompson, Melvin D BoltonAbstract:Abstract Little is known about the coordinate induction of genes that may be involved in agriculturally important Wound-healing events. In this study, Wound-healing events were determined together with Wound-induced expression profiles of selected cell cycle, cell wall protein, and pectin methyl esterase genes using two diverse potato genotypes and two harvests (NDTX4271-5R and Russet Burbank tubers; 2008 and 2009 harvests). By 5 d after Wounding, the closing layer and a nascent phellogen had formed. Phellogen cell divisions generated phellem layers until cessation of cell division at 28 d after Wounding for both genotypes and harvests. Cell cycle genes encoding epidermal growth factor binding protein (StEBP), cyclin-dependent kinase B (StCDKB) and cyclin-dependent kinase regulatory subunit (StCKS1At) were induced by 1 d after Wounding; these expressions coordinated with related phellogen formation and the induction and cessation of phellem cell formation. Genes encoding the structural cell wall proteins extensin (StExt1) and extensin-like (StExtlk) were dramatically up-regulated by 1–5 d after Wounding, suggesting involvement with closing layer and later phellem cell layer formation. Wounding up-regulated pectin methyl esterase genes (StPME and StPrePME); StPME expression increased during closing layer and phellem cell formation, whereas maximum expression of StPrePME occurred at 5–14 d after Wounding, implicating involvement in later modifications for closing layer and phellem cell formation. The coordinate induction and expression profile of StTLRP, a gene encoding a cell wall strengthening “tyrosine-and lysine-rich protein,” suggested a role in the formation of the closing layer followed by phellem cell generation and maturation. Collectively, the genes monitored were Wound-inducible and their expression profiles markedly coordinated with closing layer formation and the index for phellogen layer meristematic activity during Wound Periderm development; results were more influenced by harvest than genotype. Importantly, StTLRP was the only gene examined that may be involved in phellogen cell wall thickening after cessation of phellogen cell division.
Jae Heung Jeon - One of the best experts on this subject based on the ideXlab platform.
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Short Communication Polyamine Biosynthesis Regulated by StARD Expression Plays an Important Role in Potato Wound Periderm Formation
2016Co-Authors: Jae Hyun Kim, Hyun Soon Kim, Yong Hwa Lee, Hyouk Joung, Suhn Kee Chae, Kyong Hoon Suh, Yoon Sik Kim, Jae Heung JeonAbstract:An acireductone dioxygenase (ARD) gene of potatoes was isolated from the expressed sequence tags (ESTs) of potato post-suberization cDNA libraries. The highest expres-sion levels of the StARD gene and the protein appeared 36 h after suberization. An approximate 9-fold increase in ARD activity was detected at 36 h after Wounding. Real-time reverse transcription–PCR (RT–PCR) analysis and immuno-localization studies revealed that StARD transcripts increase at the Wound surface of potato tubers. The polyamine (PA) contents increased significantly after Wounding at the Wound surface. The increased PA content and ARD activity may play an important role in Wound Periderm formation
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polyamine biosynthesis regulated by stard expression plays an important role in potato Wound Periderm formation
Plant and Cell Physiology, 2008Co-Authors: Jae Hyun Kim, Hyun Soon Kim, Yong Hwa Lee, Yoon Kim, Hyouk Joung, Suhn Kee Chae, Kyong Hoon Suh, Jae Heung JeonAbstract:An acireductone dioxygenase (ARD) gene of potatoes was isolated from the expressed sequence tags (ESTs) of potato post-suberization cDNA libraries. The highest expression levels of the StARD gene and the protein appeared 36 h after suberization. An approximate 9-fold increase in ARD activity was detected at 36 h after Wounding. Real-time reverse transcription-PCR (RT-PCR) analysis and immunolocalization studies revealed that StARD transcripts increase at the Wound surface of potato tubers. The polyamine (PA) contents increased significantly after Wounding at the Wound surface. The increased PA content and ARD activity may play an important role in Wound Periderm formation.
Peterson, Donnie L. - One of the best experts on this subject based on the ideXlab platform.
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Suitability of blue ash (fraxinus quadrangulata) and green ash (f. pennsylvanica) to emerald ash borer (agrilus planipennis) and its larval parasitoid tetrastichus planipennisi.
'Purdue University (bepress)', 2014Co-Authors: Peterson, Donnie L.Abstract:Emerald ash borer (EAB) (Agrilus planipennis ) is a primary pest that has killed tens of millions of North American ash (Fraxinus spp.) trees. The larval parasitoid Tetrastichus planipennisi was introduced from China as part of a classical biological control program for long-term EAB management. The high mortality rates of ash trees greatly reduce the number of EAB hosts and may make it difficult for parasitoids to persist. However, blue ash ( F. quadrangulata ) is relatively resistant and appears to be able to survive EAB infestation. If natural enemies can attack EAB in infested blue ash they may be better able to persist and protect regenerating ash trees. I compared the capacity of EAB larvae and its larval parasitoid to survive and develop in blue ash and the more susceptible green ash ( F. pennsylvanica ). Blue and green ash trees were infested with EAB eggs in the field and laboratory and their bark was peeled to determine larval survivorship and developmental stages. A subset of blue and green ash was exposed to T. planipennisi so that parasitism rates, brood sizes, sex ratios, and adult sizes could be determined. EAB larvae survivorship was high (\u3e96%) and mortality due to Wound Periderm formation was low (T. planipennisi brood sizes, sex ratios, and adult female sizes had no significant difference between ash species suggesting that hosts have no apparent affects. In the field, T. planipennisi was able to attack and develop on EAB larvae in caged blue and green ash trees. As such, if T. planipennisi can find blue ash trees, then they should readily attack and survive on living EAB. When joined with higher blue ash survival, it is possible that this ash species could serve as refuge for EAB and its parasitoids after susceptible ash are killed by this pest. Thus, blue ash presence may improve the capacity of parasitoids to parasitize, persist, and protect more susceptible ash species in forests
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Suitability of blue ash (fraxinus quadrangulata) and green ash (f. pennsylvanica) to emerald ash borer (agrilus planipennis) and its larval parasitoid tetrastichus planipennisi.
'Purdue University (bepress)', 2014Co-Authors: Peterson, Donnie L.Abstract:Emerald ash borer (EAB) (Agrilus planipennis) is a primary pest that has killed tens of millions of North American ash (Fraxinus spp.) trees. The larval parasitoid Tetrastichus planipennisi was introduced from China as part of a classical biological control program for long-term EAB management. The high mortality rates of ash trees greatly reduce the number of EAB hosts and may make it difficult for parasitoids to persist. However, blue ash (F. quadrangulata) is relatively resistant and appears to be able to survive EAB infestation. If natural enemies can attack EAB in infested blue ash they may be better able to persist and protect regenerating ash trees. I compared the capacity of EAB larvae and its larval parasitoid to survive and develop in blue ash and the more susceptible green ash (F. pennsylvanica). Blue and green ash trees were infested with EAB eggs in the field and laboratory and their bark was peeled to determine larval survivorship and developmental stages. A subset of blue and green ash was exposed to T. planipennisi so that parasitism rates, brood sizes, sex ratios, and adult sizes could be determined. EAB larvae survivorship was high (\u3e96%) and mortality due to Wound Periderm formation was low (\u3c4%) on green and blue ash in the field. However, EAB larvae developed slower in blue ash than in green ash in the field and laboratory. In contrast, T. planipennisi brood sizes, sex ratios, and adult female sizes had no significant difference between ash species suggesting that hosts have no apparent affects. In the field, T. planipennisi was able to attack and develop on EAB larvae in caged blue and green ash trees. As such, if T. planipennisi can find blue ash trees, then they should readily attack and survive on living EAB. When joined with higher blue ash survival, it is possible that this ash species could serve as refuge for EAB and its parasitoids after susceptible ash are killed by this pest. Thus, blue ash presence may improve the capacity of parasitoids to parasitize, persist, and protect more susceptible ash species in forests
