Project description:Citrus greening or huanglongbing (HLB) is a devastating disease of citrus. HLB is associated with the phloem-limited fastidious prokaryotic alpha-proteobacterium Candidatus Liberibacter spp. In this report, we used sweet orange (Citrus sinensis) leaf tissue infected with 'Ca. Liberibacter asiaticus' and compared this with healthy controls. Investigation of the host response was examined with citrus microarray hybridization based on 30,171 sets expressed sequence tag sequences from several citrus species and hybrids. The microarray analysis indicated that HLB infection significantly affected expression of 624 genes whose encoded proteins were categorized according to function. The categories included genes associated with sugar metabolism, plant defense, phytohormone, and cell wall metabolism, as well as 14 other gene categories. Young, healthy Valencia sweet orange (C. sinensis) plants were graft inoculated with budwood from Ca. L. asiaticus-infected citrus plants. Prior to the innocualtion, the plants were confirmed to be Ca. L. asiaticus-free in ordinary and quantitative PCR tests. The presence of the bacteria in the inoculated plants was confirmed in both conventional and quantitative PCR with specific primers to Ca. L. asiaticus. The stem and root samples used for RNA extraction and hybridization on Affymetrix microarrays were obtained from three symptomatic and three healthy control trees of similar size, approximately 1 year after inoculation.
Project description:HLB is suggested to be caused by the phloem-limited fastidious prokaryotic α-proteobacterium “Candidatus Liberibacter spp.” Previous studies focused on the proteome and transcriptome analyses of citrus 5 to 35-week-after “Ca. L. spp.” inoculation. In this study, gene expression profiles was analyzed using mandarin of Citrus reticulate Blanco cv. jiaogan leaves after 2-year infection with “Ca. L. asiaticus”. The Affymetrix GeneChip® citrus genome were applied to study the molecular pathways mediated by “Ca. L. asiaticus” inoculated 3-year-old jiaogan seedlings. Each of them was graft-inoculated with one sweet orange scions with or without “Ca. L. asiaticus” in Dectember, 2009. RNA samples from three mandarin trees infected with 'Candidatus Liberibacter asiaticus' and three uninfected trees were used for affymatrix genochip
Project description:Citrus greening or huanglongbing (HLB) is a devastating disease of citrus. HLB is associated with the phloem-limited fastidious prokaryotic alpha-proteobacterium Candidatus Liberibacter spp. In this report, we used sweet orange (Citrus sinensis) leaf tissue infected with 'Ca. Liberibacter asiaticus' and compared this with healthy controls. Investigation of the host response was examined with citrus microarray hybridization based on 30,171 sets expressed sequence tag sequences from several citrus species and hybrids. The microarray analysis indicated that HLB infection significantly affected expression of 624 genes whose encoded proteins were categorized according to function. The categories included genes associated with sugar metabolism, plant defense, phytohormone, and cell wall metabolism, as well as 14 other gene categories.
Project description:Candidatus Liberibacter asiaticus infection of citrus is characterized by symptom variability within and among organs. In order to identify molecular processes involved in the regulation of organ response to Ca. Liberibacter infection, the gene expression patterns in C. sinensis leaf, stem, and root was examined in Affymetrix microarray. Our analyses showed that Ca. L. asiaticus reprograms several cellular and metabolic processes in C. sinensis, with most categories regulated in leaves, followed by stems and least in roots. Among them, we identified genes whose expression is regulated in organ-specific manner, reflecting organ specialization in the molecular response to Ca. L. asiaticus. Differences in gene expression were expected between these organs because of functional divergence among them. Two-year old Valencia sweet orange (C. sinensis) plants were graft inoculated with budwood from Ca. L. asiaticus-infected citrus plants. Successful infection of the inoculated plants was confirmed in both conventional and quantitative PCR with specific primers to Ca. L. asiaticus. The stem and root samples used for RNA extraction and hybridization on Affymetrix microarrays were obtained from three symptomatic and three healthy control trees of similar size, 16 months after the inoculation.
Project description:Candidatus Liberibacter asiaticus infection of citrus is characterized by symptom variability within and among organs. In order to identify molecular processes involved in the regulation of organ response to Ca. Liberibacter infection, the gene expression patterns in C. sinensis leaf, stem, and root was examined in Affymetrix microarray. Our analyses showed that Ca. L. asiaticus reprograms several cellular and metabolic processes in C. sinensis, with most categories regulated in leaves, followed by stems and least in roots. Among them, we identified genes whose expression is regulated in organ-specific manner, reflecting organ specialization in the molecular response to Ca. L. asiaticus. Differences in gene expression were expected between these organs because of functional divergence among them.
Project description:Pathogens can trigger a broad array of changes in gene expression in plants. In this study we report the changes in gene expression patterns that occurred when greenhouse grown Washington Navel oranges (C. sinensis) was graft innoculated with citrus pathogens. Candidatus Liberibacter asiaticus, Spiroplasma citri, and two isolates of citrus tristeza virus were studied.
Project description:HLB is suggested to be caused by the phloem-limited fastidious prokaryotic α-proteobacterium “Candidatus Liberibacter spp.” Previous studies focused on the proteome and transcriptome analyses of citrus 5 to 35-week-after “Ca. L. spp.” inoculation. In this study, gene expression profiles was analyzed using mandarin of Citrus reticulate Blanco cv. jiaogan leaves after 2-year infection with “Ca. L. asiaticus”.
Project description:Huanglongbing (HLB) (=citrus greening) is a destructive disease of citrus which is caused by a fastidious, phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange leaves were studied during the course of 19 weeks after inoculation with Ca. L. asiaticus using the Affymetrix GeneChip® citrus genome array to provide new insights into the molecular basis of citrus response to this pathogen. Of the more than 33,000 probe sets on the microarray 21,067 were expressed in the leaves, of which 279 and 515 were differentially expressed (FDR ≤ 0.05) five to nine and 13-17 weeks after inoculation, respectively. Results from semi-quantitative RT-PCR analysis performed on 14 selected genes were highly correlated with those observed with the microarray. Gene expression changes involved a variety of different processes including cell defense, transport, cellular organization, photosynthesis, and carbohydrate metabolism. Notable was the pathogen-induced accumulation of transcripts for a phloem-specific lectin PP2-like protein. Transcriptional changes and their relation to disease symptom development are discussed. This is the first study of transcriptional profiling in citrus in response to liberibacter infection using microarray technology. Huanglongbing (HLB) is a destructive disease of citrus which is suspected to be caused by a phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange (C. sinensis) leaves were studied during the course of 19 weeks after inoculation with Ca. L. asiaticus (Las), the pathogen associated with HLB in Florida, using the Affymetrix GeneChip® citrus genome array to provide new insights into the molecular basis of citrus response to this pathogen. Three year-old 'Valencia' orange (C. sinensis) scions on Cleopatra mandarin (C. reticulata Blanco) rootstocks were graft-inoculated with non-infected (control) or Las-infected tissue from greenhouse- (control) or field-grown 'Lisbon' lemon (C. limon) trees. Fully expanded leaves were collected at 5, 9, 13, and 17 weeks after inoculation (wai). Total RNA was extracted from two control plants and from three Las-inoculated plants per time point. Equal amounts of RNA were combined from samples collected 5 wai and 9 wai and from samples collected 13 wai and 17 wai, resulting in two non-infected and three infected biological replicates for both early (5-9 wai) and late (13-17 wai) time points and used for hybridization on Affymetrix citrus microarrays.
Project description:Huanglongbing (HLB) (=citrus greening) is a destructive disease of citrus which is caused by a fastidious, phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange leaves were studied during the course of 19 weeks after inoculation with Ca. L. asiaticus using the Affymetrix GeneChip® citrus genome array to provide new insights into the molecular basis of citrus response to this pathogen. Of the more than 33,000 probe sets on the microarray 21,067 were expressed in the leaves, of which 279 and 515 were differentially expressed (FDR ≤ 0.05) five to nine and 13-17 weeks after inoculation, respectively. Results from semi-quantitative RT-PCR analysis performed on 14 selected genes were highly correlated with those observed with the microarray. Gene expression changes involved a variety of different processes including cell defense, transport, cellular organization, photosynthesis, and carbohydrate metabolism. Notable was the pathogen-induced accumulation of transcripts for a phloem-specific lectin PP2-like protein. Transcriptional changes and their relation to disease symptom development are discussed. This is the first study of transcriptional profiling in citrus in response to liberibacter infection using microarray technology. Huanglongbing (HLB) is a destructive disease of citrus which is suspected to be caused by a phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange (C. sinensis) leaves were studied during the course of 19 weeks after inoculation with Ca. L. asiaticus (Las), the pathogen associated with HLB in Florida, using the Affymetrix GeneChip® citrus genome array to provide new insights into the molecular basis of citrus response to this pathogen.
Project description:The dataset for this project was to identify significantly changing proteins in the vasculature of Washington Navel (Citrus sinensis (L) Osbeck) during Candidatus Liberibacter asiaticus (CLas) infection. The navel trees were graft-inoculated with the Hacienda Heights, CA CLas strain (HHCA) and then sampled ten months after graft inoculation.