Cynthia Damasceno - Academia.edu (original) (raw)
Papers by Cynthia Damasceno
O objetivo do presente trabalho foi desenvolver um metodo baseado em calibracao multivariada util... more O objetivo do presente trabalho foi desenvolver um metodo baseado em calibracao multivariada utilizando a espectroscopia no infravermelho proximo como fonte de informacao analitica, visando a determinacao do teor de sacarose em caldo de sorgo sacarino.
In trials of cultivars competition, the lack of uniformity in plant population may create a non-g... more In trials of cultivars competition, the lack of uniformity in plant population may create a non-genetic superiority among the tested materials. The objective of the present work was to verify the influence of the stand correction methods in the recommendation of sorghum biomass using the method of adaptability and stability of Annicchiarico. Twenty-five cultivars were evaluated in a randomized block design with three replications in five environments. The methods used to correct the stand were the rule of three, Zuber, covariance for average stand, covariance for ideal stand, Cruz, Vencovsky & Cruz and stratified correction. The uncorrected data were used as reference. Although changes occurred in the ranking of adaptability and stability, the indicated genotypes were the same for most methods of stand correction. The correction by covariance for ideal stand was considered the most efficient method, because it promoted a reduction in the coefficient of variation and in the relations...
O sorgo é uma importante cultura que tem ganhado destaque como potencial matéria-prima para produ... more O sorgo é uma importante cultura que tem ganhado destaque como potencial matéria-prima para produção de bioenergia, em especial o sorgo sacarino que, como a cana-de-açúcar, produz caldo açucarado no colmo, e também pode ter seu bagaço utilizado na cogeração de energia em usinas sucro-alcooleiras. Além disso, o sorgo é um excelente modelo para estudos genéticos em gramíneas, por ser uma espécie diploide com genoma compacto e sequenciado. O objetivo do presente estudo foi mapear QTLs relacionadas a produção de bioenergia. Para isso, foi utilizada uma população RIL de sorgo sacarino, constituída por 223 linhagens derivadas do cruzamento entre os genitores BR501-Brandes e BR505-Wray, contrastantes para qualidade e quantidade de açúcares presentes no caldo do colmo. Os experimentos foram conduzidos em três anos, em Sete Lagoas-MG, seguindo o delineamento látice 15x15 com três repetições. Foram avaliados florescimento, altura de plantas, e produção de massa verde (PMV), além de caracterís...
G3 Genes|Genomes|Genetics, 2021
During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for b... more During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for bioenergy production, especially biofuels. In this study, 223 recombinant inbred lines (RILs) derived from a cross between two sweet sorghum lines (Brandes × Wray) were evaluated in three trials. Single-nucleotide polymorphisms (SNPs) derived from genotyping by sequencing of 272 RILs were used to build a high-density genetic map comprising 3,767 SNPs spanning 1,368.83 cM. Multitrait multiple interval mapping (MT-MIM) was carried out to map quantitative trait loci (QTL) for eight bioenergy traits. A total of 33 QTLs were identified for flowering time, plant height, total soluble solids and sucrose (five QTLs each), fibers (four QTLs), and fresh biomass yield, juice extraction yield, and reducing sugars (three QTLs each). QTL hotspots were found on chromosomes 1, 3, 6, 9, and 10, in addition to other QTLs detected on chromosomes 4 and 8. We observed that 14 out of the 33 mapped QTLs were fo...
Molecular breeding : new strategies in plant improvement, 2018
The increasing cost of energy and finite oil and gas reserves have created a need to develop alte... more The increasing cost of energy and finite oil and gas reserves have created a need to develop alternative fuels from renewable sources. Due to its abiotic stress tolerance and annual cultivation, high-biomass sorghum ( L. Moench) shows potential as a bioenergy crop. Genomic selection is a useful tool for accelerating genetic gains and could restructure plant breeding programs by enabling early selection and reducing breeding cycle duration. This work aimed at predicting breeding values via genomic selection models for 200 sorghum genotypes comprising landrace accessions and breeding lines from biomass and saccharine groups. These genotypes were divided into two sub-panels, according to breeding purpose. We evaluated the following phenotypic biomass traits: days to flowering, plant height, fresh and dry matter yield, and fiber, cellulose, hemicellulose, and lignin proportions. Genotyping by sequencing yielded more than 258,000 single-nucleotide polymorphism markers, which revealed pop...
Revista Brasileira de Milho e Sorgo, 2014
In trials of cultivars competition, the lack of uniformity in plant population may create a non-g... more In trials of cultivars competition, the lack of uniformity in plant population may create a non-genetic superiority among the tested materials. The objective of the present work was to verify the influence of the stand correction methods in the recommendation of sorghum biomass using the method of adaptability and stability of Annicchiarico. Twenty-five cultivars were evaluated in a randomized block design with three replications in five environments. The methods used to correct the stand were the rule of three, Zuber, covariance for average stand, covariance for ideal stand, Cruz, Vencovsky & Cruz, stratified correction. The uncorrected data were used as reference. Although changes occurred in the ranking of adaptability and stability, the indicated genotypes were the same for most methods of stand correction. The correction by covariance for ideal stand was considered the most efficient method, because it promoted a reduction in the coefficient of variation and in the relationship between the largest and smallest mean square of residues of the evaluated environments.. Altogether ten hybrids developed by the breeding program at Embrapa Maize and Sorghum were considered suitable and stable by the method of Annicchiarico and surpassed the commercial cultivars evaluated.
Sweet sorghum, a C4 tropical grass, is becoming an important bioenergy crop. Characterizing quant... more Sweet sorghum, a C4 tropical grass, is becoming an important bioenergy crop. Characterizing quantitative trait loci (QTL) controlling sugar content in its stem can lead to the identification of target regions for molecular breeding programs. These QTLs may be conserved in related species such as sugarcane, expanding their potential usefulness for bioenergy production. In this study, 223 recombinant inbred lines (RILs) derived from the sweet sorghum parents, Brandes and Wray, were genotyped-by-sequencing (GBS). A lattice experiment with three replicates was established for evaluating three sugar related traits: soluble solids content (BRIX, in °Brix), sucrose content (POL, in %), and reducing sugars (RSU, in %). Phenotypic analysis and QTL scanning were conducted using mixed and general linear models approaches, using the softwares GenStat and TASSEL, respectively. GBS provided wide genome coverage, with ~1200 single-nucleotide polymorphisms (SNPs) per chromosome. Major QTLs were det...
Plants and BioEnergy, 2013
Sorghum is a drought-tolerant rainfed crop that requires about 30 % less nitrogen fertilizer than... more Sorghum is a drought-tolerant rainfed crop that requires about 30 % less nitrogen fertilizer than corn to produce equal amount of ethanol per acre under non- irrigated conditions. Excellent genetic and genomic resources exist for improvement of sorghum as a bioenergy source. We expect a huge impact on biomass yield, qual- ity, and conversion efficiency with appropriate plant breeding and biotechnology tools in order to develop energy sorghum germplasm that allows highly efficient pro- duction of biofuel. The outlined improvement should produce benefits that include: (1) genetic improvement of a biomass crop with significantly reduced overall cost of biomass-to-ethanol conversion; (2) selection of a reliable bioenergy feedstock that is drought tolerant, inexpensive to grow, environmentally friendly and cultivated in nearly all temperate and tropical climate regions; (3) expansion of the production area for bioenergy crops by developing cold tolerance germplasm and hybrids and by offering both annual and perennial sweet sorghum types; and (4) reduction in cell wall lignin for improved efficiency in production of biofuels.
Encyclopedia of Life Sciences, 2007
... Cynthia Maria Borges Damasceno,; Jocelyn Kenneth Campbell Rose. ... Even if the yeast contain... more ... Cynthia Maria Borges Damasceno,; Jocelyn Kenneth Campbell Rose. ... Even if the yeast contains appropriate PTM processing machinery, it may be bypassed since the Y2H screen involves directing the bait and prey proteins directly to the nucleus. ...
The Plant Journal, 2010
Evasion or active suppression of host defenses are critical strategies employed by biotrophic phy... more Evasion or active suppression of host defenses are critical strategies employed by biotrophic phytopathogens and hemibiotrophs whose infection mechanism includes sequential biotrophic and necrotrophic stages. Although defense suppression by secreted effector proteins has been well studied in bacteria, equivalent systems in fungi and oomycetes are poorly understood. We report the characterization of SNE1 (suppressor of necrosis 1), a gene encoding a secreted protein from the hemibiotrophic oomycete Phytophthora infestans that is specifically expressed at the transcriptional level during biotrophic growth within the host plant tomato (Solanum lycopersicum). Using transient expression assays, we show that SNE1 suppresses the action of secreted cell death-inducing effectors from Phytophthora that are expressed during the necrotrophic growth phase, as well as programmed cell death mediated by a range of Avr-R protein interactions. We also report that SNE1 contains predicted NLS motifs and translocates to the plant nucleus in transient expression studies. A conceptual model is presented in which the sequential coordinated secretion of antagonistic effectors by P. infestans first suppresses, but then induces, host cell death, thereby providing a highly regulated means to control the transition from biotrophy to necrotrophy.
Plant Physiology and Biochemistry, 2004
The proteome of the plant cell wall/apoplast is less well characterized than those of other subce... more The proteome of the plant cell wall/apoplast is less well characterized than those of other subcellular compartments. This largely reflects the many technical challenges involved in extracting and identifying extracellular proteins, many of which resist isolation and identification, and in capturing a population that is both comprehensive and relatively uncontaminated with intracellular proteins. However, a range of disruptive techniques, involving tissue homogenization and subsequent sequential extraction and non-disruptive approaches has been developed. These approaches have been complemented more recently by other genome-scale screens, such as secretion traps that reveal the genes encoding proteins with N-terminal signal peptides that are targeted to the secretory pathway, many of which are subsequently localized in the wall. While the size and complexity of the wall proteome is still unresolved, the combination of experimental tools and computational prediction is rapidly expanding the catalog of known wall-localized proteins, suggesting the unexpected extracellular localization of other polypeptides and providing the basis for further exploration of plant wall structure and function.
Plant Physiology, 2008
A Citrus sinensis spontaneous mutant, navel negra (nan), produces fruit with an abnormal brown-co... more A Citrus sinensis spontaneous mutant, navel negra (nan), produces fruit with an abnormal brown-colored flavedo during ripening. Analysis of pigment composition in the wild-type and nan flavedo suggested that typical ripening-related chlorophyll (Chl) degradation, but not carotenoid biosynthesis, was impaired in the mutant, identifying nan as a type C stay-green mutant. nan exhibited normal expression of Chl biosynthetic and catabolic genes and chlorophyllase activity but no accumulation of dephytylated Chl compounds during ripening, suggesting that the mutation is not related to a lesion in any of the principal enzymatic steps in Chl catabolism. Transcript profiling using a citrus microarray indicated that a citrus ortholog of a number of SGR (for STAY-GREEN) genes was expressed at substantially lower levels in nan, both prior to and during ripening. However, the pattern of catabolite accumulation and SGR sequence analysis suggested that the nan mutation is distinct from those in pr...
Nature Protocols, 2006
Major improvements in proteomic techniques in recent years have led to an increase in their appli... more Major improvements in proteomic techniques in recent years have led to an increase in their application in all biological fields, including plant sciences. For all proteomic approaches, protein extraction and sample preparation are of utmost importance for optimal results; however, extraction of proteins from plant tissues represents a great challenge. Plant tissues usually contain relatively low amounts of proteins and high concentrations of proteases and compounds that potentially can limit tissue disintegration and interfere with subsequent protein separation and identification. An effective protein extraction protocol must also be adaptable to the great variation in the sets of secondary metabolites and potentially contaminating compounds that occurs between tissues (e.g., leaves, roots, fruit, seeds and stems) and between species. Here we present two basic protein extraction protocols that have successfully been used with diverse plant tissues, including recalcitrant tissues. The first method is based on phenol extraction coupled with ammonium acetate precipitation, and the second is based on trichloroacetic acid (TCA) precipitation. Both extraction protocols can be completed within 2 d.
Molecular Plant-Microbe Interactions®, 2006
Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast... more Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast play crucial roles in surveillance, assault, defense, and counter-defense. High-throughput genome-scale strategies are being developed to better understand the nature of these “secretomes” and the identity of pathogen-derived effector proteins that subvert plant defenses and promote pathogenicity. Although combined bioinformatic and experimental approaches recently have provided comprehensive coverage of secreted proteins from bacterial phytopathogens, far less is known about the secretomes and batteries of effectors of eukaryotic phytopathogens; notably fungi and oomycetes. The yeast secretion trap (YST) represents a potentially valuable technique to simultaneously target pathogen and host secretomes in infected plant material. A YST screen, using a new vector system, was applied to study the interaction between tomato (Solanum lycopersicum) and the oomycete Phytophthora infestans, rev...
Molecular Plant-Microbe Interactions®, 2008
During invasion of their plant hosts, species of the oomycete genus Phytophthora secrete glucanas... more During invasion of their plant hosts, species of the oomycete genus Phytophthora secrete glucanase inhibitor proteins (GIPs) into the plant apoplast, which bind and inhibit the activity of plant extracellular endo-β-1,3-glucanases (EGases). GIPs show structural homology to the chymotrypsin class of serine proteases (SP) but lack proteolytic activity due to the absence of an intact catalytic triad and, thus, belong to a broader class of proteins called serine protease homologs (SPH). To study the evolutionary relationship between GIPs and functional SP, database searches were used to identify 48 GIP homologs in the P. sojae, P. ramorum, and P. infestans genomes, composing GIPs, SPH, and potentially functional SP. Analyses of P. infestans–inoculated tomato leaves showed that P. infestans GIPs and tomato EGases are present in the apoplast and form stable complexes in planta. Studies of the temporal expression of a four-membered GIP family from P. infestans (PiGIP1 to PiGIP4) further re...
Genetics, 2005
Plant endo-β-1,3-glucanases (EGases) degrade the cell wall polysaccharides of attacking pathogens... more Plant endo-β-1,3-glucanases (EGases) degrade the cell wall polysaccharides of attacking pathogens and release elicitors of additional plant defenses. Isozymes EGaseA and EGaseB of soybean differ in susceptibility to a glucanase inhibitor protein (GIP1) produced by Phytophthora sojae, a major soybean pathogen. EGaseA, the major elicitor-releasing isozyme, is a high-affinity ligand for GIP1, which completely inhibits it, whereas EGaseB is unaffected by GIP1. We tested for departures from neutral evolution on the basis of partial sequences of EGaseA and EGaseB from 20 widespread accessions of Glycine soja (the wild progenitor of soybean), from 4 other Glycine species, and across dicotyledonous plants. G. soja exhibited little intraspecific variation at either locus. Phylogeny-based codon evolution models detected strong evidence of positive selection on Glycine EGaseA and weaker evidence for selection on dicot EGases and Glycine EGaseB. Positively selected peptide sites were identified...
Current Opinion in Plant Biology, 2008
Much of what is currently known about the structure, properties and biochemical activities of gly... more Much of what is currently known about the structure, properties and biochemical activities of glycosyl hydrolases (GHs) has resulted from detailed studies of microbial enzymes. Conversely, such information is sparse in the plant GH literature, where the focus has traditionally been on studying expression and biological function. However, the current resurgence of interest in lignocellulosic biofuels is catalyzing new interest in this field, and recent reports suggest that some plant GH families have more in common with their microbial counterparts than was previously suspected. The repertoires of plant GHs, with their associated catalytic activities and polysaccharide binding affinities, may have valuable applications in modifying plant cell wall architecture and in the development and characterization of new bioenergy feedstocks.
Plant Physiology, 2011
Tomato (Solanum lycopersicum) is an established model to study fleshy fruit development and ripen... more Tomato (Solanum lycopersicum) is an established model to study fleshy fruit development and ripening. Tomato ripening is regulated independently and cooperatively by ethylene and transcription factors, including nonripening (NOR) and ripening-inhibitor (RIN). Mutations of NOR, RIN, and the ethylene receptor Never-ripe (Nr), which block ethylene perception and inhibit ripening, have proven to be great tools for advancing our understanding of the developmental programs regulating ripening. In this study, we present systems analysis of nor, rin, and Nr at the transcriptomic, proteomic, and metabolomic levels during development and ripening. Metabolic profiling marked shifts in the abundance of metabolites of primary metabolism, which lead to decreases in metabolic activity during ripening. When combined with transcriptomic and proteomic data, several aspects of the regulation of metabolism during ripening were revealed. First, correlations between the expression levels of a transcript ...
O objetivo do presente trabalho foi desenvolver um metodo baseado em calibracao multivariada util... more O objetivo do presente trabalho foi desenvolver um metodo baseado em calibracao multivariada utilizando a espectroscopia no infravermelho proximo como fonte de informacao analitica, visando a determinacao do teor de sacarose em caldo de sorgo sacarino.
In trials of cultivars competition, the lack of uniformity in plant population may create a non-g... more In trials of cultivars competition, the lack of uniformity in plant population may create a non-genetic superiority among the tested materials. The objective of the present work was to verify the influence of the stand correction methods in the recommendation of sorghum biomass using the method of adaptability and stability of Annicchiarico. Twenty-five cultivars were evaluated in a randomized block design with three replications in five environments. The methods used to correct the stand were the rule of three, Zuber, covariance for average stand, covariance for ideal stand, Cruz, Vencovsky & Cruz and stratified correction. The uncorrected data were used as reference. Although changes occurred in the ranking of adaptability and stability, the indicated genotypes were the same for most methods of stand correction. The correction by covariance for ideal stand was considered the most efficient method, because it promoted a reduction in the coefficient of variation and in the relations...
O sorgo é uma importante cultura que tem ganhado destaque como potencial matéria-prima para produ... more O sorgo é uma importante cultura que tem ganhado destaque como potencial matéria-prima para produção de bioenergia, em especial o sorgo sacarino que, como a cana-de-açúcar, produz caldo açucarado no colmo, e também pode ter seu bagaço utilizado na cogeração de energia em usinas sucro-alcooleiras. Além disso, o sorgo é um excelente modelo para estudos genéticos em gramíneas, por ser uma espécie diploide com genoma compacto e sequenciado. O objetivo do presente estudo foi mapear QTLs relacionadas a produção de bioenergia. Para isso, foi utilizada uma população RIL de sorgo sacarino, constituída por 223 linhagens derivadas do cruzamento entre os genitores BR501-Brandes e BR505-Wray, contrastantes para qualidade e quantidade de açúcares presentes no caldo do colmo. Os experimentos foram conduzidos em três anos, em Sete Lagoas-MG, seguindo o delineamento látice 15x15 com três repetições. Foram avaliados florescimento, altura de plantas, e produção de massa verde (PMV), além de caracterís...
G3 Genes|Genomes|Genetics, 2021
During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for b... more During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for bioenergy production, especially biofuels. In this study, 223 recombinant inbred lines (RILs) derived from a cross between two sweet sorghum lines (Brandes × Wray) were evaluated in three trials. Single-nucleotide polymorphisms (SNPs) derived from genotyping by sequencing of 272 RILs were used to build a high-density genetic map comprising 3,767 SNPs spanning 1,368.83 cM. Multitrait multiple interval mapping (MT-MIM) was carried out to map quantitative trait loci (QTL) for eight bioenergy traits. A total of 33 QTLs were identified for flowering time, plant height, total soluble solids and sucrose (five QTLs each), fibers (four QTLs), and fresh biomass yield, juice extraction yield, and reducing sugars (three QTLs each). QTL hotspots were found on chromosomes 1, 3, 6, 9, and 10, in addition to other QTLs detected on chromosomes 4 and 8. We observed that 14 out of the 33 mapped QTLs were fo...
Molecular breeding : new strategies in plant improvement, 2018
The increasing cost of energy and finite oil and gas reserves have created a need to develop alte... more The increasing cost of energy and finite oil and gas reserves have created a need to develop alternative fuels from renewable sources. Due to its abiotic stress tolerance and annual cultivation, high-biomass sorghum ( L. Moench) shows potential as a bioenergy crop. Genomic selection is a useful tool for accelerating genetic gains and could restructure plant breeding programs by enabling early selection and reducing breeding cycle duration. This work aimed at predicting breeding values via genomic selection models for 200 sorghum genotypes comprising landrace accessions and breeding lines from biomass and saccharine groups. These genotypes were divided into two sub-panels, according to breeding purpose. We evaluated the following phenotypic biomass traits: days to flowering, plant height, fresh and dry matter yield, and fiber, cellulose, hemicellulose, and lignin proportions. Genotyping by sequencing yielded more than 258,000 single-nucleotide polymorphism markers, which revealed pop...
Revista Brasileira de Milho e Sorgo, 2014
In trials of cultivars competition, the lack of uniformity in plant population may create a non-g... more In trials of cultivars competition, the lack of uniformity in plant population may create a non-genetic superiority among the tested materials. The objective of the present work was to verify the influence of the stand correction methods in the recommendation of sorghum biomass using the method of adaptability and stability of Annicchiarico. Twenty-five cultivars were evaluated in a randomized block design with three replications in five environments. The methods used to correct the stand were the rule of three, Zuber, covariance for average stand, covariance for ideal stand, Cruz, Vencovsky & Cruz, stratified correction. The uncorrected data were used as reference. Although changes occurred in the ranking of adaptability and stability, the indicated genotypes were the same for most methods of stand correction. The correction by covariance for ideal stand was considered the most efficient method, because it promoted a reduction in the coefficient of variation and in the relationship between the largest and smallest mean square of residues of the evaluated environments.. Altogether ten hybrids developed by the breeding program at Embrapa Maize and Sorghum were considered suitable and stable by the method of Annicchiarico and surpassed the commercial cultivars evaluated.
Sweet sorghum, a C4 tropical grass, is becoming an important bioenergy crop. Characterizing quant... more Sweet sorghum, a C4 tropical grass, is becoming an important bioenergy crop. Characterizing quantitative trait loci (QTL) controlling sugar content in its stem can lead to the identification of target regions for molecular breeding programs. These QTLs may be conserved in related species such as sugarcane, expanding their potential usefulness for bioenergy production. In this study, 223 recombinant inbred lines (RILs) derived from the sweet sorghum parents, Brandes and Wray, were genotyped-by-sequencing (GBS). A lattice experiment with three replicates was established for evaluating three sugar related traits: soluble solids content (BRIX, in °Brix), sucrose content (POL, in %), and reducing sugars (RSU, in %). Phenotypic analysis and QTL scanning were conducted using mixed and general linear models approaches, using the softwares GenStat and TASSEL, respectively. GBS provided wide genome coverage, with ~1200 single-nucleotide polymorphisms (SNPs) per chromosome. Major QTLs were det...
Plants and BioEnergy, 2013
Sorghum is a drought-tolerant rainfed crop that requires about 30 % less nitrogen fertilizer than... more Sorghum is a drought-tolerant rainfed crop that requires about 30 % less nitrogen fertilizer than corn to produce equal amount of ethanol per acre under non- irrigated conditions. Excellent genetic and genomic resources exist for improvement of sorghum as a bioenergy source. We expect a huge impact on biomass yield, qual- ity, and conversion efficiency with appropriate plant breeding and biotechnology tools in order to develop energy sorghum germplasm that allows highly efficient pro- duction of biofuel. The outlined improvement should produce benefits that include: (1) genetic improvement of a biomass crop with significantly reduced overall cost of biomass-to-ethanol conversion; (2) selection of a reliable bioenergy feedstock that is drought tolerant, inexpensive to grow, environmentally friendly and cultivated in nearly all temperate and tropical climate regions; (3) expansion of the production area for bioenergy crops by developing cold tolerance germplasm and hybrids and by offering both annual and perennial sweet sorghum types; and (4) reduction in cell wall lignin for improved efficiency in production of biofuels.
Encyclopedia of Life Sciences, 2007
... Cynthia Maria Borges Damasceno,; Jocelyn Kenneth Campbell Rose. ... Even if the yeast contain... more ... Cynthia Maria Borges Damasceno,; Jocelyn Kenneth Campbell Rose. ... Even if the yeast contains appropriate PTM processing machinery, it may be bypassed since the Y2H screen involves directing the bait and prey proteins directly to the nucleus. ...
The Plant Journal, 2010
Evasion or active suppression of host defenses are critical strategies employed by biotrophic phy... more Evasion or active suppression of host defenses are critical strategies employed by biotrophic phytopathogens and hemibiotrophs whose infection mechanism includes sequential biotrophic and necrotrophic stages. Although defense suppression by secreted effector proteins has been well studied in bacteria, equivalent systems in fungi and oomycetes are poorly understood. We report the characterization of SNE1 (suppressor of necrosis 1), a gene encoding a secreted protein from the hemibiotrophic oomycete Phytophthora infestans that is specifically expressed at the transcriptional level during biotrophic growth within the host plant tomato (Solanum lycopersicum). Using transient expression assays, we show that SNE1 suppresses the action of secreted cell death-inducing effectors from Phytophthora that are expressed during the necrotrophic growth phase, as well as programmed cell death mediated by a range of Avr-R protein interactions. We also report that SNE1 contains predicted NLS motifs and translocates to the plant nucleus in transient expression studies. A conceptual model is presented in which the sequential coordinated secretion of antagonistic effectors by P. infestans first suppresses, but then induces, host cell death, thereby providing a highly regulated means to control the transition from biotrophy to necrotrophy.
Plant Physiology and Biochemistry, 2004
The proteome of the plant cell wall/apoplast is less well characterized than those of other subce... more The proteome of the plant cell wall/apoplast is less well characterized than those of other subcellular compartments. This largely reflects the many technical challenges involved in extracting and identifying extracellular proteins, many of which resist isolation and identification, and in capturing a population that is both comprehensive and relatively uncontaminated with intracellular proteins. However, a range of disruptive techniques, involving tissue homogenization and subsequent sequential extraction and non-disruptive approaches has been developed. These approaches have been complemented more recently by other genome-scale screens, such as secretion traps that reveal the genes encoding proteins with N-terminal signal peptides that are targeted to the secretory pathway, many of which are subsequently localized in the wall. While the size and complexity of the wall proteome is still unresolved, the combination of experimental tools and computational prediction is rapidly expanding the catalog of known wall-localized proteins, suggesting the unexpected extracellular localization of other polypeptides and providing the basis for further exploration of plant wall structure and function.
Plant Physiology, 2008
A Citrus sinensis spontaneous mutant, navel negra (nan), produces fruit with an abnormal brown-co... more A Citrus sinensis spontaneous mutant, navel negra (nan), produces fruit with an abnormal brown-colored flavedo during ripening. Analysis of pigment composition in the wild-type and nan flavedo suggested that typical ripening-related chlorophyll (Chl) degradation, but not carotenoid biosynthesis, was impaired in the mutant, identifying nan as a type C stay-green mutant. nan exhibited normal expression of Chl biosynthetic and catabolic genes and chlorophyllase activity but no accumulation of dephytylated Chl compounds during ripening, suggesting that the mutation is not related to a lesion in any of the principal enzymatic steps in Chl catabolism. Transcript profiling using a citrus microarray indicated that a citrus ortholog of a number of SGR (for STAY-GREEN) genes was expressed at substantially lower levels in nan, both prior to and during ripening. However, the pattern of catabolite accumulation and SGR sequence analysis suggested that the nan mutation is distinct from those in pr...
Nature Protocols, 2006
Major improvements in proteomic techniques in recent years have led to an increase in their appli... more Major improvements in proteomic techniques in recent years have led to an increase in their application in all biological fields, including plant sciences. For all proteomic approaches, protein extraction and sample preparation are of utmost importance for optimal results; however, extraction of proteins from plant tissues represents a great challenge. Plant tissues usually contain relatively low amounts of proteins and high concentrations of proteases and compounds that potentially can limit tissue disintegration and interfere with subsequent protein separation and identification. An effective protein extraction protocol must also be adaptable to the great variation in the sets of secondary metabolites and potentially contaminating compounds that occurs between tissues (e.g., leaves, roots, fruit, seeds and stems) and between species. Here we present two basic protein extraction protocols that have successfully been used with diverse plant tissues, including recalcitrant tissues. The first method is based on phenol extraction coupled with ammonium acetate precipitation, and the second is based on trichloroacetic acid (TCA) precipitation. Both extraction protocols can be completed within 2 d.
Molecular Plant-Microbe Interactions®, 2006
Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast... more Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast play crucial roles in surveillance, assault, defense, and counter-defense. High-throughput genome-scale strategies are being developed to better understand the nature of these “secretomes” and the identity of pathogen-derived effector proteins that subvert plant defenses and promote pathogenicity. Although combined bioinformatic and experimental approaches recently have provided comprehensive coverage of secreted proteins from bacterial phytopathogens, far less is known about the secretomes and batteries of effectors of eukaryotic phytopathogens; notably fungi and oomycetes. The yeast secretion trap (YST) represents a potentially valuable technique to simultaneously target pathogen and host secretomes in infected plant material. A YST screen, using a new vector system, was applied to study the interaction between tomato (Solanum lycopersicum) and the oomycete Phytophthora infestans, rev...
Molecular Plant-Microbe Interactions®, 2008
During invasion of their plant hosts, species of the oomycete genus Phytophthora secrete glucanas... more During invasion of their plant hosts, species of the oomycete genus Phytophthora secrete glucanase inhibitor proteins (GIPs) into the plant apoplast, which bind and inhibit the activity of plant extracellular endo-β-1,3-glucanases (EGases). GIPs show structural homology to the chymotrypsin class of serine proteases (SP) but lack proteolytic activity due to the absence of an intact catalytic triad and, thus, belong to a broader class of proteins called serine protease homologs (SPH). To study the evolutionary relationship between GIPs and functional SP, database searches were used to identify 48 GIP homologs in the P. sojae, P. ramorum, and P. infestans genomes, composing GIPs, SPH, and potentially functional SP. Analyses of P. infestans–inoculated tomato leaves showed that P. infestans GIPs and tomato EGases are present in the apoplast and form stable complexes in planta. Studies of the temporal expression of a four-membered GIP family from P. infestans (PiGIP1 to PiGIP4) further re...
Genetics, 2005
Plant endo-β-1,3-glucanases (EGases) degrade the cell wall polysaccharides of attacking pathogens... more Plant endo-β-1,3-glucanases (EGases) degrade the cell wall polysaccharides of attacking pathogens and release elicitors of additional plant defenses. Isozymes EGaseA and EGaseB of soybean differ in susceptibility to a glucanase inhibitor protein (GIP1) produced by Phytophthora sojae, a major soybean pathogen. EGaseA, the major elicitor-releasing isozyme, is a high-affinity ligand for GIP1, which completely inhibits it, whereas EGaseB is unaffected by GIP1. We tested for departures from neutral evolution on the basis of partial sequences of EGaseA and EGaseB from 20 widespread accessions of Glycine soja (the wild progenitor of soybean), from 4 other Glycine species, and across dicotyledonous plants. G. soja exhibited little intraspecific variation at either locus. Phylogeny-based codon evolution models detected strong evidence of positive selection on Glycine EGaseA and weaker evidence for selection on dicot EGases and Glycine EGaseB. Positively selected peptide sites were identified...
Current Opinion in Plant Biology, 2008
Much of what is currently known about the structure, properties and biochemical activities of gly... more Much of what is currently known about the structure, properties and biochemical activities of glycosyl hydrolases (GHs) has resulted from detailed studies of microbial enzymes. Conversely, such information is sparse in the plant GH literature, where the focus has traditionally been on studying expression and biological function. However, the current resurgence of interest in lignocellulosic biofuels is catalyzing new interest in this field, and recent reports suggest that some plant GH families have more in common with their microbial counterparts than was previously suspected. The repertoires of plant GHs, with their associated catalytic activities and polysaccharide binding affinities, may have valuable applications in modifying plant cell wall architecture and in the development and characterization of new bioenergy feedstocks.
Plant Physiology, 2011
Tomato (Solanum lycopersicum) is an established model to study fleshy fruit development and ripen... more Tomato (Solanum lycopersicum) is an established model to study fleshy fruit development and ripening. Tomato ripening is regulated independently and cooperatively by ethylene and transcription factors, including nonripening (NOR) and ripening-inhibitor (RIN). Mutations of NOR, RIN, and the ethylene receptor Never-ripe (Nr), which block ethylene perception and inhibit ripening, have proven to be great tools for advancing our understanding of the developmental programs regulating ripening. In this study, we present systems analysis of nor, rin, and Nr at the transcriptomic, proteomic, and metabolomic levels during development and ripening. Metabolic profiling marked shifts in the abundance of metabolites of primary metabolism, which lead to decreases in metabolic activity during ripening. When combined with transcriptomic and proteomic data, several aspects of the regulation of metabolism during ripening were revealed. First, correlations between the expression levels of a transcript ...