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Laosuntisuk K, Vennapusa A, Somayanda IM, Leman AR, Jagadish SK, Doherty CJ. A normalization method that controls for total RNA abundance affects the identification of differentially expressed genes, revealing bias toward morning-expressed responses. Plant J 2024. [PMID: 38289828 DOI: 10.1111/tpj.16654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 02/01/2024]
Abstract
RNA-Sequencing is widely used to investigate changes in gene expression at the transcription level in plants. Most plant RNA-Seq analysis pipelines base the normalization approaches on the assumption that total transcript levels do not vary between samples. However, this assumption has not been demonstrated. In fact, many common experimental treatments and genetic alterations affect transcription efficiency or RNA stability, resulting in unequal transcript abundance. The addition of synthetic RNA controls is a simple correction that controls for variation in total mRNA levels. However, adding spike-ins appropriately is challenging with complex plant tissue, and carefully considering how they are added is essential to their successful use. We demonstrate that adding external RNA spike-ins as a normalization control produces differences in RNA-Seq analysis compared to traditional normalization methods, even between two times of day in untreated plants. We illustrate the use of RNA spike-ins with 3' RNA-Seq and present a normalization pipeline that accounts for differences in total transcriptional levels. We evaluate the effect of normalization methods on identifying differentially expressed genes in the context of identifying the effect of the time of day on gene expression and response to chilling stress in sorghum.
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Affiliation(s)
- Kanjana Laosuntisuk
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Amaranatha Vennapusa
- Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, USA
| | - Impa M Somayanda
- Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas, 79410, USA
| | - Adam R Leman
- Department of Science and Technology, The Good Food Institute, Washington, District of Columbia, 20090, USA
| | - Sv Krishna Jagadish
- Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas, 79410, USA
- Department of Agronomy, Kansas State University, Manhattan, Kansas, 66506, USA
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
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Land ES, Sheppard J, Doherty CJ, Perera IY. Conserved plant transcriptional responses to microgravity from two consecutive spaceflight experiments. Front Plant Sci 2024; 14:1308713. [PMID: 38259952 PMCID: PMC10800490 DOI: 10.3389/fpls.2023.1308713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024]
Abstract
Introduction Understanding how plants adapt to the space environment is essential, as plants will be a valuable component of long duration space missions. Several spaceflight experiments have focused on transcriptional profiling as a means of understanding plant adaptation to microgravity. However, there is limited overlap between results from different experiments. Differences in experimental conditions and hardware make it difficult to find a consistent response across experiments and to distinguish the primary effects of microgravity from other spaceflight effects. Methods Plant Signaling (PS) and Plant RNA Regulation (PRR) were two separate spaceflight experiments conducted on the International Space Station utilizing the European Modular Cultivation System (EMCS). The EMCS provided a lighted environment for plant growth with centrifugal capabilities providing an onboard 1 g control. Results and discussion An RNA-Seq analysis of shoot samples from PS and PRR revealed a significant overlap of genes differentially expressed in microgravity between the two experiments. Relative to onboard 1 g controls, genes involved in transcriptional regulation, shoot development, and response to auxin and light were upregulated in microgravity in both experiments. Conversely, genes involved in defense response, abiotic stress, Ca++ signaling, and cell wall modification were commonly downregulated in both datasets. The downregulation of stress responses in microgravity in these two experiments is interesting as these pathways have been previously observed as upregulated in spaceflight compared to ground controls. Similarly, we have observed many stress response genes to be upregulated in the 1 g onboard control compared to ground reference controls; however these genes were specifically downregulated in microgravity. In addition, we analyzed the sRNA landscape of the 1 g and microgravity (μ g) shoot samples from PRR. We identified three miRNAs (miR319c, miR398b, and miR8683) which were upregulated in microgravity, while several of their corresponding target genes were found to be downregulated in microgravity. Interestingly, the downregulated target genes are enriched in those encoding chloroplast-localized enzymes and proteins. These results uncover microgravity unique transcriptional changes and highlight the validity and importance of an onboard 1 g control.
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Affiliation(s)
- Eric S. Land
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
| | - James Sheppard
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | - Colleen J. Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | - Imara Y. Perera
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
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Yow AG, Laosuntisuk K, Young RA, Doherty CJ, Gillitt N, Perkins-Veazie P, Jenny Xiang QY, Iorizzo M. Comparative transcriptome analysis reveals candidate genes for cold stress response and early flowering in pineapple. Sci Rep 2023; 13:18890. [PMID: 37919298 PMCID: PMC10622448 DOI: 10.1038/s41598-023-45722-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023] Open
Abstract
Pineapple originates from tropical regions in South America and is therefore significantly impacted by cold stress. Periodic cold events in the equatorial regions where pineapple is grown may induce early flowering, also known as precocious flowering, resulting in monetary losses due to small fruit size and the need to make multiple passes for harvesting a single field. Currently, pineapple is one of the most important tropical fruits in the world in terms of consumption, and production losses caused by weather can have major impacts on worldwide exportation potential and economics. To further our understanding of and identify mechanisms for low-temperature tolerance in pineapple, and to identify the relationship between low-temperature stress and flowering time, we report here a transcriptomic analysis of two pineapple genotypes in response to low-temperature stress. Using meristem tissue collected from precocious flowering-susceptible MD2 and precocious flowering-tolerant Dole-17, we performed pairwise comparisons and weighted gene co-expression network analysis (WGCNA) to identify cold stress, genotype, and floral organ development-specific modules. Dole-17 had a greater increase in expression of genes that confer cold tolerance. The results suggested that low temperature stress in Dole-17 plants induces transcriptional changes to adapt and maintain homeostasis. Comparative transcriptomic analysis revealed differences in cuticular wax biosynthesis, carbohydrate accumulation, and vernalization-related gene expression between genotypes. Cold stress induced changes in ethylene and abscisic acid-mediated pathways differentially between genotypes, suggesting that MD2 may be more susceptible to hormone-mediated early flowering. The differentially expressed genes and module hub genes identified in this study are potential candidates for engineering cold tolerance in pineapple to develop new varieties capable of maintaining normal reproduction cycles under cold stress. In addition, a total of 461 core genes involved in the development of reproductive tissues in pineapple were also identified in this study. This research provides an important genomic resource for understanding molecular networks underlying cold stress response and how cold stress affects flowering time in pineapple.
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Affiliation(s)
- Ashley G Yow
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27695, USA
- Plants for Human Health Institute, North Carolina State University, Kannapolis, 28081, USA
| | - Kanjana Laosuntisuk
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Roberto A Young
- Research Department of Dole, Standard Fruit de Honduras, Zona Mazapan, 31101, La Ceiba, Honduras
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Penelope Perkins-Veazie
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27695, USA
- Plants for Human Health Institute, North Carolina State University, Kannapolis, 28081, USA
| | - Qiu-Yun Jenny Xiang
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Massimo Iorizzo
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27695, USA.
- Plants for Human Health Institute, North Carolina State University, Kannapolis, 28081, USA.
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Horvath DP, Doherty CJ, Desai J, Clark N, Anderson JV, Chao WS. Weed-induced changes in the maize root transcriptome reveal transcription factors and physiological processes impacted early in crop-weed interactions. AoB Plants 2023; 15:plad013. [PMID: 37228420 PMCID: PMC10202722 DOI: 10.1093/aobpla/plad013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
A new paradigm suggests weeds primarily reduce crop yield by altering crop developmental and physiological processes long before the weeds reduce resources through competition. Multiple studies have implicated stress response pathways are activated when crops such as maize are grown in close proximity with weeds during the first 4-8 weeks of growth-the point at which weeds have their greatest impact on subsequent crop yields. To date, these studies have mostly focused on the response of above-ground plant parts and have not examined the early signal transduction processes associated with maize root response to weeds. To investigate the impact of signals from a below-ground competitor on the maize root transcriptome when most vulnerable to weed pressure, a system was designed to expose maize to only below-ground signals. Gene set enrichment analyses identified over-represented ontologies associated with oxidative stress signalling throughout the time of weed exposure, with additional ontologies associated with nitrogen use and transport and abscisic acid (ABA) signalling, and defence responses being enriched at later time points. Enrichment of promoter motifs indicated over-representation of sequences known to bind FAR-RED IMPAIRED RESPONSE 1 (FAR1), several AP2/ERF transcription factors and others. Likewise, co-expression networks were identified using Weighted-Gene Correlation Network Analysis (WGCNA) and Spatiotemporal Clustering and Inference of Omics Networks (SC-ION) algorithms. WGCNA highlighted the potential roles of several transcription factors including a MYB 3r-4, TB1, WRKY65, CONSTANS-like5, ABF3, HOMEOBOX 12, among others. These studies also highlighted the role of several specific proteins involved in ABA signalling as being important for the initiation of the early response of maize to weeds. SC-ION highlighted potential roles for NAC28, LOB37, NAC58 and GATA2 transcription factors, among many others.
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Affiliation(s)
| | - Colleen J Doherty
- Metabolism and Disease Molecular and Systems Biology, North Carolina State University, 120 Broughton Dr., Raleigh, NC 27607, USA
| | - Jigar Desai
- Wave Life Sciences, 733 Concord Ave, Cambridge, MA 02138, USA
| | - Natalie Clark
- Massachusetts Institute of Technology, Merkin Building, 415 Main St., Cambridge, MA 02142, USA
| | - James V Anderson
- Sunflower and Plant Biology Research Unit, USDA-ARS-ETSARC, 1616 Albrecht Blvd., Fargo, ND 58102, USA
| | - Wun S Chao
- Sunflower and Plant Biology Research Unit, USDA-ARS-ETSARC, 1616 Albrecht Blvd., Fargo, ND 58102, USA
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Laosuntisuk K, Elorriaga E, Doherty CJ. The Game of Timing: Circadian Rhythms Intersect with Changing Environments. Annu Rev Plant Biol 2023; 74:511-538. [PMID: 36854482 DOI: 10.1146/annurev-arplant-070522-065329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recurring patterns are an integral part of life on Earth. Through evolution or breeding, plants have acquired systems that coordinate with the cyclic patterns driven by Earth's movement through space. The biosystem responses to these physical rhythms result in biological cycles of daily and seasonal activity that feed back into the physical cycles. Signaling networks to coordinate growth and molecular activities with these persistent cycles have been integrated into plant biochemistry. The plant circadian clock is the coordinator of this complex, multiscale, temporal schedule. However, we have detailed knowledge of the circadian clock components and functions in only a few species under controlled conditions. We are just beginning to understand how the clock functions in real-world conditions. This review examines what we know about the circadian clock in diverse plant species, the challenges with extrapolating data from controlled environments, and the need to anticipate how plants will respond to climate change.
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Affiliation(s)
- Kanjana Laosuntisuk
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA; , ,
| | - Estefania Elorriaga
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA; , ,
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA; , ,
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Tiwari M, Kumar R, Subramanian S, Doherty CJ, Jagadish SVK. Auxin-cytokinin interplay shapes root functionality under low-temperature stress. Trends Plant Sci 2023; 28:447-459. [PMID: 36599768 DOI: 10.1016/j.tplants.2022.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 11/16/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Low-temperature stress alters root system architecture. In particular, changes in the levels and response to auxin and cytokinin determine the fate of root architecture and function under stress because of their vital roles in regulating root cell division, differentiation, and elongation. An intricate nexus of genes encoding components of auxin and cytokinin biosynthesis, signaling, and transport components operate to counteract stress and facilitate optimum development. We review the role of auxin transport and signaling and its regulation by cytokinin during root development and stem cell maintenance under low-temperature stress. We highlight intricate mechanisms operating in root stem cells to minimize DNA damage by altering phytohormone levels, and discuss a working model for cytokinin in low-temperatures stress response.
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Affiliation(s)
- Manish Tiwari
- Department of Agronomy, Kansas State University, Manhattan, KA 66506, USA.
| | - Ritesh Kumar
- Department of Agronomy, Kansas State University, Manhattan, KA 66506, USA
| | - Senthil Subramanian
- Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD 57006, USA
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - S V Krishna Jagadish
- Department of Agronomy, Kansas State University, Manhattan, KA 66506, USA; Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79410, USA.
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7
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Kudenov MW, Krafft D, Scarboro CG, Doherty CJ, Balint-Kurti P. Hybrid spatial-temporal Mueller matrix imaging spectropolarimeter for high throughput plant phenotyping. Appl Opt 2023; 62:2078-2091. [PMID: 37133096 DOI: 10.1364/ao.483870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many correlations exist between spectral reflectance or transmission with various phenotypic responses from plants. Of interest to us are metabolic characteristics, namely, how the various polarimetric components of plants may correlate to underlying environmental, metabolic, and genotypic differences among different varieties within a given species, as conducted during large field experimental trials. In this paper, we overview a portable Mueller matrix imaging spectropolarimeter, optimized for field use, by combining a temporal and spatial modulation scheme. Key aspects of the design include minimizing the measurement time while maximizing the signal-to-noise ratio by mitigating systematic error. This was achieved while maintaining an imaging capability across multiple measurement wavelengths, spanning the blue to near-infrared spectral region (405-730 nm). To this end, we present our optimization procedure, simulations, and calibration methods. Validation results, which were taken in redundant and non-redundant measurement configurations, indicated that the polarimeter provides average absolute errors of (5.3±2.2)×10-3 and (7.1±3.1)×10-3, respectively. Finally, we provide preliminary field data (depolarization, retardance, and diattenuation) to establish baselines of barren and non-barren Zea maize hybrids (G90 variety), as captured from various leaf and canopy positions during our summer 2022 field experiments. Results indicate that subtle variations in retardance and diattenuation versus leaf canopy position may be present before they are clearly visible in the spectral transmission.
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8
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Scarboro CG, Doherty CJ, Balint-Kurti PJ, Kudenov MW. Multistatic fiber-based system for measuring the Mueller matrix bidirectional reflectance distribution function. Appl Opt 2022; 61:9832-9842. [PMID: 36606813 DOI: 10.1364/ao.470608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/21/2022] [Indexed: 06/17/2023]
Abstract
Bidirectionality effects can be a significant confounding factor when measuring hyperspectral reflectance data. The bidirectional reflectance distribution function (BRDF) can effectively characterize the reflectivity of surfaces to correct remote sensing measurements. However, measuring BRDFs can be time-consuming, especially when collecting Mueller matrix BRDF (mmBRDF) measurements of a surface via conventional goniometric techniques. In this paper, we present a system for collecting mmBRDF measurements using static optical fiber detectors that sample the hemisphere surrounding an object. The entrance to each fiber contains a polarization state analyzer configuration, allowing for the simultaneous acquisition of the Stokes vector intensity components at many altitudinal and azimuthal viewing positions. We describe the setup, calibration, and data processing used for this system and present its performance as applied to mmBRDF measurements of a ground glass diffuser.
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9
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Scarboro CG, Ruzsa SM, Doherty CJ, Kudenov MW. Quantification of gray mold infection in lettuce using a bispectral imaging system under laboratory conditions. Plant Direct 2021; 5:e00317. [PMID: 33778364 PMCID: PMC7989972 DOI: 10.1002/pld3.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 02/15/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Gray mold disease caused by the fungus Botrytis cinerea damages many crop hosts worldwide and is responsible for heavy economic losses. Early diagnosis and detection of the disease would allow for more effective crop management practices to prevent outbreaks in field or greenhouse settings. Furthermore, having a simple, non-invasive way to quantify the extent of gray mold disease is important for plant pathologists interested in measuring infection rates. In this paper, we design and build a bispectral imaging system for discriminating between leaf regions infected with gray mold and those that remain unharmed on a lettuce (Lactuca spp.) host. First, we describe a method to select two optimal (high contrast) spectral bands from continuous hyperspectral imagery (450-800 nm). We then explain the process of building a system based on these two spectral bands, located at 540 and 670 nm. The resultant system uses two cameras, with a narrow band-pass spectral filter mounted on each, to measure the bispectral reflectance of a lettuce leaf. The two resulting images are combined using a normalized difference calculation that produces a single image with high contrast between the leaves' infected and healthy regions. A classifier was then created based on the thresholding of single pixel values. We demonstrate that this simple classification produces a true-positive rate of 95.25% with a false-positive rate of 9.316% in laboratory conditions.
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Affiliation(s)
- Clifton G. Scarboro
- Department of Electrical and Computer EngineeringOptical Sensing LaboratoryNorth Carolina State UniversityRaleighNCUSA
| | - Stephanie M. Ruzsa
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNCUSA
| | - Colleen J. Doherty
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNCUSA
| | - Michael W. Kudenov
- Department of Electrical and Computer EngineeringOptical Sensing LaboratoryNorth Carolina State UniversityRaleighNCUSA
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10
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Grinevich DO, Desai JS, Stroup KP, Duan J, Slabaugh E, Doherty CJ. Novel transcriptional responses to heat revealed by turning up the heat at night. Plant Mol Biol 2019; 101:1-19. [PMID: 31062216 PMCID: PMC6695350 DOI: 10.1007/s11103-019-00873-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 04/11/2019] [Indexed: 05/29/2023]
Abstract
KEY MESSAGE The circadian clock controls many molecular activities, impacting experimental interpretation. We quantify the genome-wide effects of time-of-day on the heat-shock response and the effects of "diurnal bias" in stress experiments. Heat stress has significant adverse effects on plant productivity worldwide. Most experiments examining heat stress are performed during daytime hours, generating a 'diurnal bias' in the pathways and regulatory mechanisms identified. Such bias may confound downstream interpretations and limit our understanding of the full response to heat stress. Here we show that the transcriptional and physiological responses to a sudden heat shock in Arabidopsis are profoundly sensitive to the time of day. We observe that plant tolerance and acclimation to heat shock vary throughout the day and are maximal at dusk. Consistently, over 75% of heat-responsive transcripts show a time of day-dependent response, including many previously characterized heat-response genes. This temporal sensitivity implies a complex interaction between time and temperature where daily variations in basal transcription influence thermotolerance. When we examined these transcriptional responses, we uncovered novel night-response genes and cis-regulatory elements, underpinning new aspects of heat stress responses not previously appreciated. Exploiting this temporal variation can be applied to most environmental responses to understand the underlying network wiring. Therefore, we propose that using time as a perturbagen is an approach that will enhance our understanding of plant regulatory networks and responses to environmental stresses.
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Affiliation(s)
- Dmitry O. Grinevich
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Jigar S. Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Kevin P. Stroup
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Jiaqi Duan
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Erin Slabaugh
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Colleen J. Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
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11
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Moghimi N, Desai JS, Bheemanahalli R, Impa SM, Vennapusa AR, Sebela D, Perumal R, Doherty CJ, Jagadish SVK. New candidate loci and marker genes on chromosome 7 for improved chilling tolerance in sorghum. J Exp Bot 2019; 70:3357-3371. [PMID: 30949711 DOI: 10.1093/jxb/erz143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
Sorghum is often exposed to suboptimal low temperature stress under field conditions, particularly at the seedling establishment stage. Enhancing chilling tolerance will facilitate earlier planting and so minimize the negative impacts of other stresses experienced at later growth stages. Genome-wide association mapping was performed on a sorghum association panel grown under control (30/20 °C; day/night) and chilling (20/10 °C) conditions. Genomic regions on chromosome 7, controlling the emergence index and seedling (root and shoot) vigor, were associated with increased chilling tolerance but they did not co-localize with undesirable tannin content quantitative trait loci (QTLs). Shoot and root samples from highly contrasting haplotype pairs expressing differential responses to chilling stress were used to identify candidate genes. Three candidate genes (an alpha/beta hydrolase domain protein, a DnaJ/Hsp40 motif-containing protein, and a YTH domain-containing RNA-binding protein) were expressed at significantly higher levels under chilling stress in the tolerant haplotype compared with the sensitive haplotype and BTx623. Moreover, two CBF/DREB1A transcription factors on chromosome 2 showed a divergent response to chilling in the contrasting haplotypes. These studies identify haplotype differences on chromosome 7 that modulate chilling tolerance by either regulating CBF or feeding back into this signaling pathway. We have identified new candidate genes that will be useful markers in ongoing efforts to develop tannin-free chilling-tolerant sorghum hybrids.
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Affiliation(s)
- Naghmeh Moghimi
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | - Jigar S Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, USA
| | | | - Somayanda M Impa
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | | | - David Sebela
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | - Ramasamy Perumal
- Agricultural Research Center, Kansas State University, Hays, KS, USA
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, USA
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12
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Slabaugh E, Desai JS, Sartor RC, Lawas LMF, Jagadish SVK, Doherty CJ. Analysis of differential gene expression and alternative splicing is significantly influenced by choice of reference genome. RNA 2019; 25:669-684. [PMID: 30872414 PMCID: PMC6521602 DOI: 10.1261/rna.070227.118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/06/2019] [Indexed: 05/19/2023]
Abstract
RNA-seq analysis has enabled the evaluation of transcriptional changes in many species including nonmodel organisms. However, in most species only a single reference genome is available and RNA-seq reads from highly divergent varieties are typically aligned to this reference. Here, we quantify the impacts of the choice of mapping genome in rice where three high-quality reference genomes are available. We aligned RNA-seq data from a popular productive rice variety to three different reference genomes and found that the identification of differentially expressed genes differed depending on which reference genome was used for mapping. Furthermore, the ability to detect differentially used transcript isoforms was profoundly affected by the choice of reference genome: Only 30% of the differentially used splicing features were detected when reads were mapped to the more commonly used, but more distantly related reference genome. This demonstrated that gene expression and splicing analysis varies considerably depending on the mapping reference genome, and that analysis of individuals that are distantly related to an available reference genome may be improved by acquisition of new genomic reference material. We observed that these differences in transcriptome analysis are, in part, due to the presence of single nucleotide polymorphisms between the sequenced individual and each respective reference genome, as well as annotation differences between the reference genomes that exist even between syntenic orthologs. We conclude that even between two closely related genomes of similar quality, using the reference genome that is most closely related to the species being sampled significantly improves transcriptome analysis.
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Affiliation(s)
- Erin Slabaugh
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Jigar S Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Ryan C Sartor
- Crop and Soil Science Department, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Lovely Mae F Lawas
- International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines
- Max Planck Institute of Molecular Plant Physiology, D-14476, Potsdam, Germany
| | - S V Krishna Jagadish
- International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines
- Department of Agronomy, Kansas State University, Manhattan, Kansas 66506, USA
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
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Argueso CT, Assmann SM, Birnbaum KD, Chen S, Dinneny JR, Doherty CJ, Eveland AL, Friesner J, Greenlee VR, Law JA, Marshall‐Colón A, Mason GA, O'Lexy R, Peck SC, Schmitz RJ, Song L, Stern D, Varagona MJ, Walley JW, Williams CM. Directions for research and training in plant omics: Big Questions and Big Data. Plant Direct 2019; 3:e00133. [PMID: 31245771 PMCID: PMC6589541 DOI: 10.1002/pld3.133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 05/04/2023]
Abstract
A key remit of the NSF-funded "Arabidopsis Research and Training for the 21st Century" (ART-21) Research Coordination Network has been to convene a series of workshops with community members to explore issues concerning research and training in plant biology, including the role that research using Arabidopsis thaliana can play in addressing those issues. A first workshop focused on training needs for bioinformatic and computational approaches in plant biology was held in 2016, and recommendations from that workshop have been published (Friesner et al., Plant Physiology, 175, 2017, 1499). In this white paper, we provide a summary of the discussions and insights arising from the second ART-21 workshop. The second workshop focused on experimental aspects of omics data acquisition and analysis and involved a broad spectrum of participants from academics and industry, ranging from graduate students through post-doctorates, early career and established investigators. Our hope is that this article will inspire beginning and established scientists, corporations, and funding agencies to pursue directions in research and training identified by this workshop, capitalizing on the reference species Arabidopsis thaliana and other valuable plant systems.
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Affiliation(s)
- Cristiana T. Argueso
- Department of Bioagricultural Sciences and Pest ManagementColorado State UniversityFort CollinsColorado
| | - Sarah M. Assmann
- Biology DepartmentPenn State UniversityUniversity ParkPennsylvania
| | - Kenneth D. Birnbaum
- Department of BiologyCenter for Genomics and Systems BiologyNew York UniversityNew YorkNew York
| | - Sixue Chen
- Department of BiologyGenetics InstitutePlant Molecular and Cellular Biology ProgramUniversity of FloridaGainesvilleFlorida
- Proteomics and Mass SpectrometryInterdisciplinary Center for Biotechnology ResearchUniversity of FloridaGainesvilleFlorida
| | | | - Colleen J. Doherty
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNorth Carolina
| | | | | | - Vanessa R. Greenlee
- International ProgramsCollege of Agriculture and Life SciencesCornell UniversityIthacaNew York
| | - Julie A. Law
- Plant Molecular and Cellular Biology LaboratorySalk Institute for Biological StudiesLa JollaCalifornia
- Division of Biological SciencesUniversity of California, San DiegoLa JollaCalifornia
| | - Amy Marshall‐Colón
- Department of Plant BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinois
| | - Grace Alex Mason
- Department of Plant Biology and Genome CenterUC DavisDavisCalifornia
| | - Ruby O'Lexy
- Coriell Institute for Medical ResearchCamdenNew Jersey
| | - Scott C. Peck
- Division of BiochemistryChristopher S. Bond Life Sciences CenterInterdisciplinary Plant GroupUniversity of MissouriColumbiaMissouri
| | | | - Liang Song
- Department of BotanyThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | | | | | - Justin W. Walley
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIowa
| | - Cranos M. Williams
- Department of Electrical and Computer EngineeringNorth Carolina State UniversityRaleighNorth Carolina
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14
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Smith IDM, Milto KM, Doherty CJ, Amyes SGB, Simpson AHRW, Hall AC. A potential key role for alpha-haemolysin of Staphylococcus aureus in mediating chondrocyte death in septic arthritis. Bone Joint Res 2018; 7:457-467. [PMID: 30123495 PMCID: PMC6076354 DOI: 10.1302/2046-3758.77.bjr-2017-0165.r1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objectives Staphylococcus aureus (S. aureus) is the most commonly implicated organism in septic arthritis, a condition that may be highly destructive to articular cartilage. Previous studies investigating laboratory and clinical strains of S. aureus have demonstrated that potent toxins induced significant chondrocyte death, although the precise toxin or toxins that were involved was unknown. In this study, we used isogenic S. aureus mutants to assess the influence of alpha (Hla)-, beta (Hlb)-, and gamma (Hlg)-haemolysins, toxins considered important for the destruction of host tissue, on in situ bovine chondrocyte viability. Methods Bovine cartilage explants were cultured with isogenic S. aureus mutants and/or their culture supernatants. Chondrocyte viability was then assessed within defined regions of interest in the axial and coronal plane following live- and dead-cell imaging using the fluorescent probes 5-chloromethylfluorescein diacetate and propidium iodide, respectively, and confocal laser-scanning microscopy. Results Hla-producing mutants caused substantial chondrocyte death compared with the toxin-deficient control (Hla-Hlb-Hlg-), whilst mutants producing Hlb and Hlg in the absence of Hla induced minimal chondrocyte death. Coronal studies established that Hla-induced chondrocyte death started in the superficial zone of cartilage and spread to deeper layers, whereas Hlb and Hlg toxins were without significant effect. Conclusion This study identified Hla as a highly potent S. aureus toxin that caused rapid chondrocyte death in bovine cartilage, with other toxins or metabolic products produced by the bacteria playing a minor role. The identification of Hla in mediating chondrocyte death may assist in the development of therapeutic strategies aimed at reducing the extent of cartilage damage during and after an episode of septic arthritis. Cite this article: I. D. M. Smith, K. M. Milto, C. J. Doherty, S. G. B. Amyes, A. H. R. W. Simpson, A. C. Hall. A potential key role for alpha-haemolysin of Staphylococcus aureus in mediating chondrocyte death in septic arthritis. Bone Joint Res 2018;7:457–467. DOI: 10.1302/2046-3758.77.BJR-2017-0165.R1.
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Affiliation(s)
- I D M Smith
- Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - K M Milto
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - C J Doherty
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, UK
| | - S G B Amyes
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, UK
| | - A H R W Simpson
- Musculoskeletal Research Unit, Department of Orthopaedic Surgery, University of Edinburgh, Edinburgh, UK
| | - A C Hall
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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15
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Desai JS, Slabaugh E, Liebelt DJ, Fredenberg JD, Gray BN, Jagadish SVK, Wilkins O, Doherty CJ. Neural Net Classification Combined With Movement Analysis to Evaluate Setaria viridis as a Model System for Time of Day of Anther Appearance. Front Plant Sci 2018; 9:1585. [PMID: 30429868 PMCID: PMC6220418 DOI: 10.3389/fpls.2018.01585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 10/11/2018] [Indexed: 05/13/2023]
Abstract
In many plant species, the time of day at which flowers open to permit pollination is tightly regulated. Proper time of flower opening, or Time of Day of Anther Appearance (TAA), may coordinate flowering opening with pollinator activity or may shift temperature sensitive developmental processes to cooler times of the day. The genetic mechanisms that regulate the timing of this process in cereal crops are unknown. To address this knowledge gap, it is necessary to establish a monocot model system that exhibits variation in TAA. Here, we examine the suitability of Setaria viridis, the model for C4 photosynthesis, for such a role. We developed an imaging system to monitor the temporal regulation of growth, flower opening time, and other physiological characteristics in Setaria. This system enabled us to compare Setaria varieties Ames 32254, Ames 32276, and PI 669942 variation in growth and daily flower opening time. We observed that TAA occurs primarily at night in these three Setaria accessions. However, significant variation between the accessions was observed for both the ratio of flowers that open in the day vs. night and the specific time of day where the rate is maximal. Characterizing this physiological variation is a requisite step toward uncovering the molecular mechanisms regulating TAA. Leveraging the regulation of TAA could provide researchers with a genetic tool to improve crop productivity in new environments.
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Affiliation(s)
- Jigar S. Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | - Erin Slabaugh
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | - Donna J. Liebelt
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | - Jacob D. Fredenberg
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
| | | | | | - Olivia Wilkins
- Department of Plant Science, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Colleen J. Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, United States
- *Correspondence: Colleen J. Doherty
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16
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Friesner J, Assmann SM, Bastow R, Bailey-Serres J, Beynon J, Brendel V, Buell CR, Bucksch A, Busch W, Demura T, Dinneny JR, Doherty CJ, Eveland AL, Falter-Braun P, Gehan MA, Gonzales M, Grotewold E, Gutierrez R, Kramer U, Krouk G, Ma S, Markelz RJC, Megraw M, Meyers BC, Murray JAH, Provart NJ, Rhee S, Smith R, Spalding EP, Taylor C, Teal TK, Torii KU, Town C, Vaughn M, Vierstra R, Ware D, Wilkins O, Williams C, Brady SM. The Next Generation of Training for Arabidopsis Researchers: Bioinformatics and Quantitative Biology. Plant Physiol 2017; 175:1499-1509. [PMID: 29208732 PMCID: PMC5717721 DOI: 10.1104/pp.17.01490] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/31/2017] [Indexed: 05/20/2023]
Abstract
Training for experimental plant biologists needs to combine bioinformatics, quantitative approaches, computational biology, and training in the art of collaboration, best achieved through fully integrated curriculum development.
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Affiliation(s)
- Joanna Friesner
- Agricultural Sustainability Institute and Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616
| | - Sarah M Assmann
- Biology Department, Penn State University, University Park, Pennsylvania 16802
| | - Ruth Bastow
- GARNet, School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Julia Bailey-Serres
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Jim Beynon
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Volker Brendel
- Department of Biology and Department of Computer Science, Indiana University, Bloomington, Indiana 47405
| | - C Robin Buell
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Alexander Bucksch
- Department of Plant Biology, Warnell School of Forestry and Natural Resources, and Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Wolfgang Busch
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter, 1030 Vienna, Austria; Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037
| | - Taku Demura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan; RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa 230-0045, Japan
| | - Jose R Dinneny
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695
| | | | - Pascal Falter-Braun
- Institute of Network Biology, Department of Environmental Science, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Malia A Gehan
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | | | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Rodrigo Gutierrez
- FONDAP Center for Genome Regulation, Millennium Nucleus Center for Plant Systems and Synthetic Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile 8331150
| | - Ute Kramer
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Gabriel Krouk
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, CNRS, INRA, Montpellier SupAgro, Université Montpellier, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier cedex, France
| | - Shisong Ma
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - R J Cody Markelz
- Department of Plant Biology, University of California, Davis, California 95616
| | - Molly Megraw
- Department of Botany and Plant Pathology, Department of Computer Science, and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132; Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211
| | - James A H Murray
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, United Kingdom
| | - Nicholas J Provart
- Department of Cell and Systems Biology/Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Sue Rhee
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Roger Smith
- Syngenta Crop Protection, Research Triangle Park, North Carolina 27709
| | - Edgar P Spalding
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706
| | - Crispin Taylor
- American Society of Plant Biologists, Rockville, Maryland 20855
| | | | - Keiko U Torii
- Howard Hughes Medical Institute and Department of Biology, University of Washington, Seattle, Washington 98195
| | - Chris Town
- J. Craig Venter Institute, Rockville, Maryland 20850
| | - Matthew Vaughn
- Life Sciences Computing, Texas Advanced Computing Center, Austin, Texas 78758
| | - Richard Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Doreen Ware
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724; U.S. Department of Agriculture Agricultural Research Service, Ithaca, New York 14853
| | - Olivia Wilkins
- Department of Plant Science, McGill University, Montreal, Quebec H9X 3V9, Canada
| | - Cranos Williams
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Siobhan M Brady
- Department of Plant Biology, Genome Center, University of California, Davis, California 95616
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17
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Park S, Lee CM, Doherty CJ, Gilmour SJ, Kim Y, Thomashow MF. Regulation of the Arabidopsis CBF regulon by a complex low-temperature regulatory network. Plant J 2015; 82:193-207. [PMID: 25736223 DOI: 10.1111/tpj.12796] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 01/26/2015] [Accepted: 02/09/2015] [Indexed: 05/18/2023]
Abstract
Exposure of Arabidopsis thaliana plants to low non-freezing temperatures results in an increase in freezing tolerance that involves action of the C-repeat binding factor (CBF) regulatory pathway. CBF1, CBF2 and CBF3, which are rapidly induced in response to low temperature, encode closely related AP2/ERF DNA-binding proteins that recognize the C-repeat (CRT)/dehydration-responsive element (DRE) DNA regulatory element present in the promoters of CBF-regulated genes. The CBF transcription factors alter the expression of more than 100 genes, known as the CBF regulon, which contribute to an increase in freezing tolerance. In this study, we investigated the extent to which cold induction of the CBF regulon is regulated by transcription factors other than CBF1, CBF2 and CBF3, and whether freezing tolerance is dependent on a functional CBF-CRT/DRE regulatory module. To address these issues we generated transgenic lines that constitutively overexpressed a truncated version of CBF2 that had dominant negative effects on the function of the CBF-CRT/DRE regulatory module, and 11 transcription factors encoded by genes that were rapidly cold-induced in parallel with the 'first-wave' CBF genes, and determined the effects that overexpressing these proteins had on global gene expression and freezing tolerance. Our results indicate that cold regulation of the CBF regulon involves extensive co-regulation by other first-wave transcription factors; that the low-temperature regulatory network beyond the CBF pathway is complex and highly interconnected; and that the increase in freezing tolerance that occurs with cold acclimation is only partially dependent on the CBF-CRT/DRE regulatory module.
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Affiliation(s)
- Sunchung Park
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
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18
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Pruneda-Paz JL, Breton G, Nagel DH, Kang SE, Bonaldi K, Doherty CJ, Ravelo S, Galli M, Ecker JR, Kay SA. A genome-scale resource for the functional characterization of Arabidopsis transcription factors. Cell Rep 2014; 8:622-32. [PMID: 25043187 DOI: 10.1016/j.celrep.2014.06.033] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/28/2014] [Accepted: 06/19/2014] [Indexed: 12/31/2022] Open
Abstract
Extensive transcriptional networks play major roles in cellular and organismal functions. Transcript levels are in part determined by the combinatorial and overlapping functions of multiple transcription factors (TFs) bound to gene promoters. Thus, TF-promoter interactions provide the basic molecular wiring of transcriptional regulatory networks. In plants, discovery of the functional roles of TFs is limited by an increased complexity of network circuitry due to a significant expansion of TF families. Here, we present the construction of a comprehensive collection of Arabidopsis TFs clones created to provide a versatile resource for uncovering TF biological functions. We leveraged this collection by implementing a high-throughput DNA binding assay and identified direct regulators of a key clock gene (CCA1) that provide molecular links between different signaling modules and the circadian clock. The resources introduced in this work will significantly contribute to a better understanding of the transcriptional regulatory landscape of plant genomes.
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Affiliation(s)
- Jose L Pruneda-Paz
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Ghislain Breton
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dawn H Nagel
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - S Earl Kang
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Katia Bonaldi
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Colleen J Doherty
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stephanie Ravelo
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mary Galli
- Genomic Analysis Laboratory, Howard Hughes Medical Institute and The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joseph R Ecker
- Genomic Analysis Laboratory, Howard Hughes Medical Institute and The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Steve A Kay
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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19
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Smith IDM, Winstanley JP, Milto KM, Doherty CJ, Czarniak E, Amyes SGB, Simpson AHRW, Hall AC. Rapid in situ chondrocyte death induced by Staphylococcus aureus toxins in a bovine cartilage explant model of septic arthritis. Osteoarthritis Cartilage 2013; 21:1755-65. [PMID: 23896315 DOI: 10.1016/j.joca.2013.07.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/29/2013] [Accepted: 07/17/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To assess in situ chondrocyte viability following exposure to a laboratory strain and clinical isolates of Staphylococcus aureus. METHODS Bovine cartilage explants were cultured in the presence of S. aureus 8325-4 (laboratory strain), clinical S. aureus isolates or non-infected culture medium of pH values 7.4, 6.4 and 5.4. All clinical isolates were isolated from the joint aspirates of patients presenting with S. aureus-induced septic arthritis (SA). At designated time points, in situ chondrocyte viability was assessed within defined regions-of-interest in the axial and coronal plane following live- and dead-cell image acquisition using the fluorescent probes 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI), respectively, and confocal laser-scanning microscopy (CLSM). Cartilage water content, following S. aureus 8325-4 exposure, was obtained by measuring cartilage wet and dry weights. RESULTS S. aureus 8325-4 and clinical S. aureus isolates rapidly reduced in situ chondrocyte viability (>45% chondrocyte death at 40 h). The increased acidity, observed during bacterial culture, had a minimal effect on chondrocyte viability. Chondrocyte death commenced within the superficial zone (SZ) and rapidly progressed to the deep zone (DZ). Simultaneous exposure of SZ and DZ chondrocytes to S. aureus 8325-4 toxins found SZ chondrocytes to be more susceptible to the toxins than DZ chondrocytes. Cartilage water content was not significantly altered compared to non-infected controls. CONCLUSIONS Toxins released by S. aureus have a rapid and fatal action on in situ chondrocytes in this experimental model of SA. These data advocate the prompt and thorough removal of bacteria and their toxins during the treatment of SA.
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Affiliation(s)
- I D M Smith
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, UK; Musculoskeletal Research Unit, Department of Orthopaedic and Trauma Surgery, The University of Edinburgh, Edinburgh, UK.
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20
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Affiliation(s)
- Colleen J. Doherty
- Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093–0116, USA
| | - Steve A. Kay
- Dana and David Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
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21
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Carvallo MA, Pino MT, Jeknić Z, Zou C, Doherty CJ, Shiu SH, Chen THH, Thomashow MF. A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana. J Exp Bot 2011; 62:3807-19. [PMID: 21511909 PMCID: PMC3134341 DOI: 10.1093/jxb/err066] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/03/2011] [Accepted: 02/11/2011] [Indexed: 05/18/2023]
Abstract
Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of S. commersonii and S. tuberosum were therefore compared to determine whether there might be differences that contribute to their differences in ability to cold acclimate. The results indicated that both plants alter gene expression in response to low temperature to similar degrees with similar kinetics and that both plants have CBF regulons composed of hundreds of genes. However, there were considerable differences in the sets of genes that comprised the low temperature transcriptomes and CBF regulons of the two species. Thus differences in cold regulatory programmes may contribute to the differences in freezing tolerance of these two species. However, 53 groups of putative orthologous genes that are cold-regulated in S. commersonii, S. tuberosum, and A. thaliana were identified. Given that the evolutionary distance between the two Solanum species and A. thaliana is 112-156 million years, it seems likely that these conserved cold-regulated genes-many of which encode transcription factors and proteins of unknown function-have fundamental roles in plant growth and development at low temperature.
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Affiliation(s)
- Marcela A. Carvallo
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - María-Teresa Pino
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Zoran Jeknić
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Cheng Zou
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Colleen J. Doherty
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Shin-Han Shiu
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Tony H. H. Chen
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Michael F. Thomashow
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Crop and Soil Sciences, Michigan State University, East Lansing, MI 48824, USA
- To whom correspondence should be addressed. E-mail:
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23
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Abstract
An internal time-keeping mechanism has been observed in almost every organism studied from archaea to humans. This circadian clock provides a competitive advantage in fitness and survival ( 18, 30, 95, 129, 137 ). Researchers have uncovered the molecular composition of this internal clock by combining enzymology, molecular biology, genetics, and modeling approaches. However, understanding the mechanistic link between the clock and output responses has been elusive. In three model organisms, Arabidopsis thaliana, Drosophila melanogaster, and Mus musculus, whole-genome expression arrays have enabled researchers to investigate how maintaining a time-keeping mechanism connects to an adaptive advantage. Here, we review the impacts transcriptomics have had on our understanding of the clock and how this molecular clock connects with system-level circadian responses. We explore the discoveries made possible by high-throughput RNA assays, the network approaches used to investigate these large transcript datasets, and potential future directions.
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Affiliation(s)
- Colleen J Doherty
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, USA.
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24
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Doherty CJ, Van Buskirk HA, Myers SJ, Thomashow MF. Roles for Arabidopsis CAMTA transcription factors in cold-regulated gene expression and freezing tolerance. Plant Cell 2009; 21:972-84. [PMID: 19270186 PMCID: PMC2671710 DOI: 10.1105/tpc.108.063958] [Citation(s) in RCA: 406] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The Arabidopsis thaliana CBF cold response pathway plays a central role in cold acclimation. It is characterized by rapid cold induction of genes encoding the CBF1-3 transcription factors, followed by expression of the CBF gene regulon, which imparts freezing tolerance. Our goal was to further the understanding of the cis-acting elements and trans-acting factors involved in expression of CBF2. We identified seven conserved DNA motifs (CM), CM1 to 7, that are present in the promoters of CBF2 and another rapidly cold-induced gene encoding a transcription factor, ZAT12. The results presented indicate that in the CBF2 promoter, CM4 and CM6 have negative regulatory activity and that CM2 has both negative and positive activity. A Myc binding site in the CBF2 promoter was also found to have positive regulatory effects. Moreover, our results indicate that members of the calmodulin binding transcription activator (CAMTA) family of transcription factors bind to the CM2 motif, that CAMTA3 is a positive regulator of CBF2 expression, and that double camta1 camta3 mutant plants are impaired in freezing tolerance. These results establish a role for CAMTA proteins in cold acclimation and provide a possible point of integrating low-temperature calcium and calmodulin signaling with cold-regulated gene expression.
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Affiliation(s)
- Colleen J Doherty
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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Campana S, Taccetti G, Ravenni N, Favari F, Cariani L, Sciacca A, Savoia D, Collura A, Fiscarelli E, De Intinis G, Busetti M, Cipolloni A, d'Aprile A, Provenzano E, Collebrusco I, Frontini P, Stassi G, Trancassini M, Tovagliari D, Lavitola A, Doherty CJ, Coenye T, Govan JRW, Vandamme P. Transmission of Burkholderia cepacia complex: evidence for new epidemic clones infecting cystic fibrosis patients in Italy. J Clin Microbiol 2005; 43:5136-42. [PMID: 16207975 PMCID: PMC1248445 DOI: 10.1128/jcm.43.10.5136-5142.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To analyze national prevalence, genomovar distribution, and epidemiology of the Burkholderia cepacia complex in Italy, 225 putative B. cepacia complex isolates were obtained from 225 cystic fibrosis (CF) patients attending 18 CF centers. The genomovar status of these isolates was determined by a polyphasic approach, which included whole-cell protein electrophoresis and recA restriction fragment length polymorphism (RFLP) analysis. Two approaches were used to genotype B. cepacia complex isolates: BOX-PCR fingerprinting and pulsed-field gel electrophoresis (PFGE) of genomic macrorestriction fragments. A total of 208 (92%) of 225 isolates belonged to the B. cepacia complex, with Burkholderia cenocepacia as the most prevalent species (61.1%). Clones delineated by PFGE were predominantly linked to a single center; in contrast, BOX-PCR clones were composed of isolates collected either from the same center or from different CF centers and comprised multiple PFGE clusters. Three BOX-PCR clones appeared of special interest. One clone was composed of 17 B. cenocepacia isolates belonging to recA RFLP type H. These isolates were collected from six centers and represented three PFGE clusters. The presence of insertion sequence IS 1363 in all isolates and the comparison with PHDC reference isolates identified this clone as PHDC, an epidemic clone prominent in North American CF patients. The second clone included 22 isolates from eight centers and belonged to recA RFLP type AT. The genomovar status of strains with the latter RFLP type is not known. Most of these isolates belonged to four different PFGE clusters. Finally, a third clone comprised nine B. pyrrocinia isolates belonging to recA RFLP type Se 13. They represented three PFGE clusters and were collected in three CF centers.
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Affiliation(s)
- S Campana
- Department of Pediatrics, Cystic Fibrosis Center, University of Florence, 50132 Florence, Italy.
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Jones AM, Dodd ME, Govan JRW, Barcus V, Doherty CJ, Morris J, Webb AK. Burkholderia cenocepacia and Burkholderia multivorans: influence on survival in cystic fibrosis. Thorax 2004; 59:948-51. [PMID: 15516469 PMCID: PMC1746874 DOI: 10.1136/thx.2003.017210] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Burkholderia cepacia infection has been associated with a poor prognosis for patients with cystic fibrosis (CF). It is now recognised that organisms classified as B cepacia comprise a number of distinct genomic species each known as a genomovar of the B cepacia complex (BCC). The outcome of infection for CF patients with individual genomovars is unknown. The clinical outcome of infection with the two most commonly isolated genomovars (B cenocepacia and B multivorans) was studied at a specialist CF centre between 1982 and 2003. METHODS The numbers of patients who progressed from initial to chronic infection were assessed. Control groups were created by matching patients with chronic BCC infection by percentage forced expiratory volume in 1 second with patients with Pseudomonas aeruginosa infection. Outcome measures were survival time, deaths from "cepacia syndrome", rate of decline in spirometry and body mass index (BMI), and treatment requirements. RESULTS Forty nine patients had an initial infection with either B multivorans (n = 16) or B cenocepacia (n = 33); 8/16 and 31/33, respectively, developed chronic infection (p<0.001). Deaths from "cepacia syndrome" occurred in both BCC groups. Patients with B cenocepacia infection had a shorter survival than patients with P aeruginosa infection (p = 0.01). There was no difference in survival between CF patients infected with B multivorans and P aeruginosa. There were no observed differences in changes in spirometry and BMI or treatment requirements between the BCC groups and respective controls. CONCLUSION In CF, the genomovar status of BCC may influence both the likelihood of progression from initial to chronic infection and the overall survival of the patients.
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Affiliation(s)
- A M Jones
- Manchester Adult Cystic Fibrosis Centre, South Manchester University Hospitals NHS Trust, Wythenshawe Hospital, Manchester M23 9LT, UK.
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Edenborough FP, Stone HR, Kelly SJ, Zadik P, Doherty CJ, Govan JRW. Genotyping of Pseudomonas aeruginosa in cystic fibrosis suggests need for segregation. J Cyst Fibros 2004; 3:37-44. [PMID: 15463885 DOI: 10.1016/j.jcf.2003.12.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2003] [Indexed: 10/26/2022]
Abstract
BACKGROUND Emerging resistance of Pseudomonas aeruginosa within cystic fibrosis (CF) populations is attributed to antibiotic pressure and spread of transmissible strains. We describe increasing resistance of P. aeruginosa isolates, resulting in the identification of two multiresistant strains and their impact on morbidity. METHODS Susceptibility reports of all P. aeruginosa isolates since 1998 in our unit were reviewed. Isolates were submitted for genomic finger-printing by pulsed-field gel electrophoresis. Clinical measures and the consumption of treatment resources were compared between those harbouring resistant organisms and those with sensitive strains. RESULTS Analysis of 407 reports from 43 patients revealed isolation of multiresistant (MR) organisms increased during 1999. Those harbouring MR strains consumed more resources than non-MR. Strain typing showed a new 'Sheffield' strain in seven patients (100% MR), and the 'Liverpool' strain in 10 patients (40% MR). Individuals in these groups consumed significantly more resources than 23 patients with unique, susceptible strains (4% MR). DISCUSSION Increasing resistance in isolates of P. aeruginosa may herald the arrival of a transmissible strain in CF Units which though sometimes sensitive, may become multiply resistant and require more intensive treatment. We now segregate those with transmissible strains from each other and from those with unique strains.
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Affiliation(s)
- F P Edenborough
- Adult Cystic Fibrosis Unit, Northern General Hospital, Herries Road, Sheffield, S5 7AU, UK.
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Jones AM, Govan JRW, Doherty CJ, Dodd ME, Isalska BJ, Stanbridge TN, Webb AK. Identification of airborne dissemination of epidemic multiresistant strains of Pseudomonas aeruginosa at a CF centre during a cross infection outbreak. Thorax 2003; 58:525-7. [PMID: 12775867 PMCID: PMC1746694 DOI: 10.1136/thorax.58.6.525] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Chronic Pseudomonas aeruginosa infection is a major cause of morbidity and mortality for individuals with cystic fibrosis (CF). P aeruginosa cross infection outbreaks have recently been reported at CF holiday camps and specialist centres. The mechanism of cross infection is unknown. A study was performed to look for the presence of epidemic strains of P aeruginosa in the environment of a CF centre during a cross infection outbreak and to examine their potential modes of spread between patients. METHODS Microbiological sampling of the environment of the CF facility was performed, including room air sampling. Individual P aeruginosa strains were identified by bacterial fingerprinting. The typing patterns were compared with those of epidemic strains responsible for cross infection among the patients. RESULTS Epidemic P aeruginosa strains were isolated from room air when patients performed spirometric tests, nebulisation, and airway clearance, but were not present in other areas of the inanimate environment of the CF centre. CONCLUSIONS Aerosol dissemination may be the most important factor in patient-to-patient spread of epidemic strains of P aeruginosa during recent cross infection outbreaks at adult CF centres.
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Affiliation(s)
- A M Jones
- Adult Cystic Fibrosis Centre, Wythenshawe Hospital, Manchester M23 9LT, UK.
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Jones AM, Dodd ME, Doherty CJ, Govan JRW, Webb AK. Increased treatment requirements of patients with cystic fibrosis who harbour a highly transmissible strain of Pseudomonas aeruginosa. Thorax 2002; 57:924-5. [PMID: 12403871 PMCID: PMC1746227 DOI: 10.1136/thorax.57.11.924] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND A group of patients who harbour the same highly transmissible strain of Pseudomonas aeruginosa were identified at a cystic fibrosis (CF) centre. Isolates of this strain display a number of unusual phenotypic features including resistance to most typical antipseudomonal antibiotics. A study was undertaken to see if there was a difference in treatment requirements between CF patients with chronic infection with their own unique P aeruginosa strains (group 1) and those who harbour a highly transmissible strain (group 2). METHODS Data on treatment requirements for the year 2000 were collected from the case records of CF patients with chronic P aeruginosa infection who had received inpatient treatment. Patients co-infected with Burkholderia cepacia or other highly transmissible strains of P aeruginosa were excluded. RESULTS There were 2/56 and 3/22 deaths in groups 1 and 2, respectively; these patients were excluded from the analysis. No difference was found between the two groups for mean age, % predicted forced expiratory volume in 1 second (FEV(1)), % predicted forced vital capacity (FVC), and body mass index. Patients in group 2 had a greater median (range) number of intravenous antibiotic days (60 (17-216) v 33 (4-237) days; p=0.01), inpatient days (39 (7-183) v 16 (1-172) days; p<0.01), and inpatient episodes (3 (1-9) v 2 (1-6); p<0.01), and more respiratory exacerbations (mean (SD) 8.2 (3.4) v 6.1 (3.2); p=0.01). CONCLUSIONS Patients who harbour the highly transmissible P aeruginosa strain have a greater treatment burden than patients with CF who harbour their own unique strains. These findings support the need for microbiological surveillance for highly transmissible P aeruginosa and the implementation of infection control measures to prevent cross infection.
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Affiliation(s)
- A M Jones
- Bradbury Cystic Fibrosis Unit, South Manchester NHS Trust, Wythenshawe Hospital, Manchester M23 9LT, UK.
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Jones AM, Govan JR, Doherty CJ, Dodd ME, Isalska BJ, Stanbridge TN, Webb AK. Spread of a multiresistant strain of Pseudomonas aeruginosa in an adult cystic fibrosis clinic. Lancet 2001; 358:557-8. [PMID: 11520529 DOI: 10.1016/s0140-6736(01)05714-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We initiated a prospective surveillance study to investigate possible Pseudomonas aeruginosa cross-infection in our cystic fibrosis centre. We characterised isolates by pyocin typing and pulsed-field gel electrophoresis. 22 (14%) of 154 patients with chronic P aeruginosa had isolates with similar and new pyocin and pulsed-field gel electrophoresis types. The shared isolates showed unusual phenotypic features: they were non-pigmented, non-motile, and resistant to a number of antipseudomonal antibiotics. Cross-infection by a multiresistant P aeruginosa strain has therefore occurred in patients attending our cystic fibrosis centre. We recommend microbiological surveillance in other cystic fibrosis centres.
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Duncan SH, Doherty CJ, Govan JR, Neogrady S, Galfi P, Stewart CS. Characteristics of sheep-rumen isolates of Pseudomonas aeruginosa inhibitory to the growth of Escherichia coli O157. FEMS Microbiol Lett 1999; 180:305-10. [PMID: 10556726 DOI: 10.1111/j.1574-6968.1999.tb08810.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Screening facultative sheep-rumen bacteria which inhibit growth of Escherichia coli produced 11 strains of Pseudomonas aeruginosa. The isolates showed three different pulsed-field gel electrophoresis patterns and strains from different sheep produced pyocins that varied in strain specificity. Representative strains were resistant to ampicillin, methicillin, erythromycin, fusidic acid and augmentin, but not to tetracycline or nalidixic acid. Tested strains attached in large numbers to cultured rumen epithelial cells, potentially providing a means of survival in this ecosystem.
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Affiliation(s)
- S H Duncan
- Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK.
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Butler SL, Doherty CJ, Hughes JE, Nelson JW, Govan JR. Burkholderia cepacia and cystic fibrosis: do natural environments present a potential hazard? J Clin Microbiol 1995; 33:1001-4. [PMID: 7540623 PMCID: PMC228085 DOI: 10.1128/jcm.33.4.1001-1004.1995] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An environmental survey of 55 sites yielded only 12 Burkholderia cepacia isolates, none of which displayed the phenotypic properties of a multiresistant epidemic strain associated with pulmonary colonization in patients with cystic fibrosis. Although the environment probably poses a low risk for patients with cystic fibrosis as a source of B. cepacia, the pathogenic potential of individual environmental strains remains unclear. We advise caution in the development of B. cepacia as a biocontrol agent.
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Affiliation(s)
- S L Butler
- Department of Medical Microbiology, University of Edinburgh Medical School, Scotland
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Abstract
Pulmonary colonisation with Pseudomonas cepacia in patients with cystic fibrosis can be associated with increased morbidity and mortality. The modes of transmission of P cepacia are, however, unclear. We used selective media and phenotypic and genomic typing systems to investigate the acquisition of P cepacia by adults with cystic fibrosis. An analysis of isolates from 210 patients attending regional clinics in Edinburgh and Manchester between 1986 and 1992 showed that the main cause of increased isolations of P cepacia from 1989 was the emergence of an epidemic strain that had spread between patients in both clinics. Epidemiological evidence indicated that social contact was important in spread of the epidemic strain within and between clinics. We suggest that guidelines to limit the acquisition of P cepacia should not be restricted to patients in hospital, and that intimate or frequent social contact is associated with a high risk of cross-infection.
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Affiliation(s)
- J R Govan
- Department of Medical Microbiology, University of Edinburgh Medical School, UK
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Abstract
The results of a three year evaluation of the incidence and type of trimethoprim resistance in pathogens responsible for significant bacteriuria in a general hospital in Edinburgh UK, are presented and compared to results of a previous study. In the present study, trimethoprim resistance was 50% more frequent in bacteria isolated from men and nearly twice as frequent in bacteria from elderly patients. However, the proportion of trimethoprim resistant strains fell annually when resistance was measured at trimethoprim concentrations of both 10 mg/l and 1000 mg/l. The proportion of strains able to transfer trimethoprim resistance also fell by half, and there was some movement of trimethoprim resistance transposons into the bacterial chromosome. These results suggest that migration of high-level trimethoprim resistance genes into the permanent location of the bacterial chromosome is occurring.
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Amyes SG, Doherty CJ, Wonnacott S. Trimethoprim and co-trimoxazole: a comparison of their use in respiratory tract infections. Scand J Infect Dis 1986; 18:561-6. [PMID: 3492759 DOI: 10.3109/00365548609021663] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A single blind prospective study was undertaken with 74 patients suffering from acute bronchitis, taken from general practice and one geriatric ward. Half were randomly allocated to treatment with 200 mg trimethoprim twice a day and the other half with 160 mg trimethoprim plus 800 mg sulphamethoxazole twice a day; both therapies were used for 7 days. We found little difference in the clinical or bacteriological responses to the different regimens although the higher concentration of trimethoprim in the single therapy gave a slightly more successful eradication of Haemophilus spp. Resistant bacteria appeared during and after therapy in a few cases but this was a greater problem with the sulphamethoxazole-containing preparation.
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