Progress 05/15/19 to 05/14/22
Outputs
Target Audience:The primary audience for these efforts is comprised of basic researchers in the fields of plant-microbe interactions, pathogen evolution and emergence, plant disease epidemiologists, and microbiology. The secondary audience for these efforts is comprised of applied researchers in crop development, plant pathology, and crop disease diagnostics. Changes/Problems:To study how different factors affect the mutation rate of bacteria in media and during in-planta interactions (GOAL 1), a computational simulation model was developed. This change was required because the COVID-19 pandemic caused long-term shutdown of in-person research activities at The Ohio State University. This limited access to scientific facilities caused a significant delay in expenditure of funds and significant deviations from research schedule. To account for the unique situation, goals were adapted to include more computational approaches. To study the objectives of GOALS 2 and 3, pre-existing and new genomic data was acquired from existing sources and collaborators. These data were acquired to design genomics approaches to be conducted in year 2 to investigate bacterial mutation rates (GOAL 2) and in drivers of mutation (GOAL 3). The changes to the approaches of GOALS 2 and 3 were required because the COVID-19 pandemic caused long-term shutdown of in-person research activities at The Ohio State University. This limited Cohen's access to scientific facilities, which caused significant delays and deviations from the research schedule. To account for the unique situation, goals were adapted to include more computational approaches. Primarily, for GOAL 2, Cohen still focused on the development of new tools to study pathogen evolution, but those tools were computational in-nature rather than laboratory bench tools. Similarly, for GOAL 3, because he was unable to conduct research to define plant properties that drive bacterial mutation during infection, Cohen instead conducted genomics research to define nutritional, metabolic, and communication-related properties of the bacteria that changed during interactions with different crop plants over evolutionary time. What opportunities for training and professional development has the project provided?During 2019-2020, Cohen (PD) became an expert at confocal microscopy, studying the use of a microscope under the one-on-one mentorship of Prof. Jonathan Jacobs. Because confocal microscopy is a highly technically difficult laboratory practice, this training gave Cohen the ability to use a rare and highly sought-after skill in the field. Using these skills, Cohen organized and conducted a microscopy workshop for the American Phytopathological Society (APS), a professional society in the area of studying Plant Disease. In the workshop, 32 professional scientists participated to learn microscopy techniques and theories from Cohen and other content facilitators. Cohen also engaged in several professional development activities. In 2019, Cohen served as the Assistant Chair of the Molecular and Cellular Phytopathology (MCP) committee for APS. The MCP committee is a subject area committee for APS comprised of over 70 members of scientists from the community who volunteer to organize seminars and workshops for APS. As Assistant Chair, Cohen helped committee members prepare and submit proposal materials for an unprecedented four proposals that were accepted and sponsored by the APS administration. Also during this time, Cohen served as a laboratory mentor and professional mentor to four graduate students (three doctoral, one master's) at The Ohio State University. In these roles, Cohen taught laboratory techniques and experimental design principles, provided guidance on multiple writing projects and student presentations. During 2020-2021, Cohen became an expert in processing big data concerning bacterial genomics. He developed the abilities required to efficiently search the over 1,400 Xanthomonas genomes available on public repositories. This expertise included learning existing tools and developing new customized tools and pipelines for quickly searching large datasets Cohen also engaged in several professional development activities. In 2020, Cohen served as the Immediate Past Chair of the Molecular and Cellular Phytopathology (MCP) committee for the American Phytopathological Society (APS). In this role, he organized and conducted the annual MCP committee meeting during the APS Virtual Plant Health meeting, and mentored the next chair and vice chair of the committee, including personally assisting them in developing session ideas and proposals to submit for future APS meetings. Cohen moderated a Technical Session at the APS Virtual Plant Health meeting, networked with others in the field, gave a talk, and submitted a proposal for a workshop for Plant Health 2021. Cohen also served as a laboratory and professional mentor to four graduate students (three doctoral, one master's) at The Ohio State University during this time. Contrary to the previous year, where Cohen served as a mentor teaching technical and laboratory skills, Cohen's mentorship during this period was focused more on planning and guiding student projects. Importantly, he contributed to a master's student's thesis project development, overseeing key professional development of the student. During 2021-2022, Cohen developed a new remote microscopy workshop, based on the in-person workshop developed in 2019-2020. This workshop was conducted for scientists in APS via the APS Virtual Workshop series. Cohen's role in the workshop was to work with three content facilitators (a Research Scientist from Connecticut Agricultural Experiment Station, and two Ph.D. students from The Ohio State University) to develop the agenda, a curriculum, and content for the workshop. The workshop was attended by 32 professional scientists. During this period, Cohen also served as a laboratory mentor and professional mentor to five graduate students (five Ph.D. students). Cohen provided laboratory, computational, writing, and career guidance to these students as needed. Cohen served as the primary mentor for one of the Ph.D. students, contributing to the student's dissertation project development, providing intensive one-one-one laboratory training, and actively working with the student to prepare a manuscript for submission to a peer-reviewed journal. Cohen also developed an interview packet and seminar during this period that allowed him to interview for a job as Research Geneticist (SY) with the USDA Agricultural Research Service, which he was offered and accepted. How have the results been disseminated to communities of interest?Results of this project have been disseminated to the target audience via six peer-reviewed journal articles and three presentations to scientific societies. The publications were published in: (2019-2020) Plant Disease; Current Opinion in Plant Biology; (2020-2021) Microorganisms; Phytopathology; Plant Physiology and Biochemistry; (2021-2022) Bioinformatics. The presentations to scientific societies were (2020-2021) two presentations to American Phytopathological Society's Plant Health 2020 Online, (2020-2021) 4th Annual Conference of the EuroXanth COST Action. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
GOAL 1: TO DEFINE WHETHER PATHOGEN MUTATION RATES ARE INCREASED IN RESISTANT PLANT HOSTS. 1A: MAJOR ACTIVITIES COMPLETED: Cohen developed laboratory-based methods to use the bacterial pathogen Xanthomonas translucens to measure bacterial mutation rate. This bacteria can infect economically important crops such as wheat and barley, making it an ideal pathogen to study. A laboratory technique called a fluctuation assay was performed to measure the mutation rates of bacteria grown in media. From the results of these assays, a computational simulation/model was developed to predict how bacteria evolve over time based on factors such as starting bacterial concentration, host plant immunity, and length of infection. 1B: DATA COLLECTED: The mutation rates of Xanthomonas translucens growing in culture media was measured. A computational simulation/model was built to determine the effect of different factors on mutation rate. 1C: DISCUSSION OF RESULTS: The genomic mutation rate of Xanthomonas translucens growing in culture media, that is, the rate that a single base pair of DNA will change, was determined to be approximately 1 in 1 billion, or approximately a 1 in 200 chance for each bacterial cell to develop a mutation. With computational simulations, hypothetical mutation rate of a pathogen in a resistant plant host was determined to be 3 in 1 billion, or approximately a 3 in 200 chance for each bacterial cell to develop a mutation during an infection. 1D: KEY OUTCOMES REALIZED: The major outcomes realized for this goal were that bacterial pathogens likely mutate at a higher rate while causing an infection in resistant plants. The implications of this are that the common practice of using resistant plants to control bacterial disease in the field may ultimately lead to higher rates of new emerging diseases. GOAL 2: TO DEVELOP NEW TECHNOLOGY AND RESOURCES FOR STUDYING EMERGENCE OF BACTERIAL PATHOGENS 2A: MAJOR ACTIVITIES COMPLETED: Existing methods to study bacterial mutation rates are decades old, and are laborious and time-consuming. The goal of this activity was to adapt modern cutting-edge DNA-sequencing techniques to study mutation rates. To this end, Cohen developed a strategy, protocol, and DNA primers to utilize a technique called maximum-depth sequencing. Cohen purchased DNA primers and also contacted commercial DNA sequencing providers to negotiate the best price for DNA sequencing services. Cohen also developed a mutation rate reporter system whereupon bacterial mutation could be directly seen using a confocal microscope. Cohen also (1) helped develop and release a new method for detecting the bacterial spot disease-causing Xanthomonas gardneri in the field, (2) released a high-quality genome of the tea canker-causing bacteria Xanthomonas theicola, and (3) completed a new analysis of how bacterial communication systems have mutated / evolved. 2B: DATA COLLECTED: Data collected for the major activities above include (1) data on sensitivity and specificity of the field test, (2) DNA sequence information, including genome assembly and annotation, and curated information about disease causing (virulence) genes unique to the bacteria, and (3) data on bacterial communication systems from more than 1,500 diverse Xanthomonas bacteria. 2C: DISCUSSION OF RESULTS: (1) A new method was developed for bacterial spot disease monitoring in tomato and pepper fields. This test has the potential to be deployed as a point-of-care test, allowing rapid and accurate detection of the disease-causing bacteria. Monitoring for existing diseases is beneficial for the detection of new, emerging diseases in the field. The development of this test, therefore, empowers growers to take rapid management practices in the case of existing diseases, and researchers to identify potential new threats. (2) Sequencing the genome for the tea canker-causing pathogen was particularly informative to understanding how pathogens evolve because it revealed unique tools that the bacteria use to infect plants. In particular, this pathogen evolved to contain multiple plant-attacking genes that were not present in other, closely-related bacteria. Understanding how these genes evolved will empower researchers to make new models for predicting outbreak of new plant diseases. (3) The large-scale survey of publicly-available plant pathogen genomes allowed identification of unique differences in a critical bacterial pathogen communication system (called the quorum sensing system). These systems are used by pathogenic bacteria to self-monitor their population growth and coordinate attacks against plants. Differences in quorum sensing that exist among two or more closely-related bacteria will help researchers understand how new bacterial diseases emerge in the field when different, closely-related bacterial pathogens are competing. 2D: KEY OUTCOMES REALIZED: Cohen developed new project management skills during these activities. Primarily, he learned best record keeping practices during new experimental design and price negotiation with commercial DNA sequencing providers. Additionally, the following outcomes were realized: (1) a new, reliable, and field-deployable method for diagnosing the pathogen that causes bacterial spot of tomato and pepper was released to the community via publication (2) the complete genome and analysis of its unique virulence properties was released to the plant pathology community via publication and release on the public NCBI GenBank repository (3) key differences exist among the communication (quorum-sensing) systems of bacteria in the genus Xanthomonas GOAL 3: TO DEFINE PLANT FACTORS THAT INCREASE BACTERIAL MUTATION RATES DURING INFECTIONS 3A: MAJOR ACTIVITIES COMPLETED: During the stress of infections, plants may produce chemicals that increase bacterial mutation rate, leading to evolution of new and more dangerous pathogens. It is therefore critical to understand how plants respond to during infections. For this goal, Cohen (1) conducted laboratory work to help improve a novel microscopy technique for studying barley response to pathogen infection and (2) contributed to a meta-analysis of barley response to environmental stresses. 3B: DATA COLLECTED: Data collected for the major activities above include (1) exhaustive microscopy imaging of IGRI and IGRI-GFP barley during infection with Xanthomonas translucens wild type and X. translucens expressing a GFP-inducing protein, counts of plant cells expressing GFP induced by X. translucens GFP-inducing protein, and (2) a gene profile of barley that included universally stress-responsive genes. 3C: DISCUSSION OF RESULTS: (1) Confocal microscopy could be used to directly monitor how plants respond to bacterial pathogens during live infection. How plants changed their transcriptome, i.e. which genes were being expressed, could also be monitored with the novel microscopic technique, with a key finding that plant cells that in direct contact with GFP-inducing bacteria expressed GFP. A manuscript summarizing the results of these activities is currently being prepared for submission to peer-reviewed journals. (2) Meta-analysis revealed the gene network in barley during stress response. From this, a key gene was identified as more important during barley responses to multiple environmental stresses. The barley gene Rubisco activase A (RcaA) was identified to be a master regulator of barley response to environmental stress and was involved in enhancing plant photosynthesis. 3D: KEY OUTCOMES REALIZED: The following key outcomes were realized: (1) a new understanding of how bacterial pathogens interact with plants at a cellular level during interactions with plants. (2) a new understanding of key stress-responsive genes used by plants as well as insight into how plants perceive and respond to stress.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., Luna, E. K., Lang, J. M., Ziegle, J., Chang, C., Leach, J. E., ... & Jacobs, J. M. (2020). High-quality genome resource of Xanthomonas hyacinthi generated via long-read sequencing. Plant Disease, 104(4), 1011-1012.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., & Leach, J. E. (2020). High temperature-induced plant disease susceptibility: more than the sum of its parts. Current Opinion in Plant Biology, 56, 235-241.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Lewandowski, M. M., Long, J., Butchacas, J., Klass, T. L., Heiden, N., Olmos, C., ... & Jacobs, J. M. (2020). Investigating the role of quorum sensing in Xanthomonas translucens pv. undulosa infection in barley and wheat: A class research experience. Plant Health 2020 Online.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Stehlikova, D., Beran, P., Cohen, S.P., & Curn, V. (2020). Development of real-time and colorimetric loop mediated isothermal amplification assay for detection of Xanthomonas gardneri. Microorganisms 8(9):1301.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., Butchacas, J., Roman-Reyna, V., Long, J., Pesce, C., Vancheva, T., Bini F., Otto I., Szurek, B., Leach, J.E., Kumlehn, J., Bragard, C.G., Koebnik, R. & Jacobs, J.M. (2020). Tattle-TALEs: tools for testing type three targeting. Plant Health 2020 Online.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Koebnik, R., Burokiene, D., Bragard, C., Chang, C., Fisher-Le Saux, M., Kolliker, R., Lang, J., Leach, J.E., Luna, E.K., Portier, P., Sagia, A., Ziegle, J., Cohen, S.P., & Jacobs, J.M. (2021). The complete genome sequence of Xanthomonas theicola, the causal agent of canker on tea plants, reveals novel secretion systems in clade-1 xanthomonads. Phytopathology, 111(4), 611-616
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Aliakbari, M., Cohen, S. P., Lindlof, A., & Shamloo-Dashtpagerdi, R. (2021). Rubisco activase A (RcaA) is a central node
in overlapping gene network of drought and salinity in Barley (Hordeum vulgare L.) and may contribute to combined stress tolerance. Plant Physiology and Biochemistry, 161, 248-258.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Bragard, C., Burokiene, D., Chang, C., Cohen, S., Cunnac, S., Saux, F. L., ... & Koebnik, R. (2021). Complete genome sequences of clade-1 xanthomonads reveal novel genetic traits in the genus Xanthomonas. In Book of abstracts. 4th Annual Conference of the EuroXanth COST Action (p. 33). ARIA. ONE Conference & Consulting.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Beran, P., Stehlikova, D., Cohen, S. P., & Curn, V. (2021). KEC: unique sequence search by K-mer exclusion. Bioinformatics, 37(19), 3349-3350.
|
Progress 05/15/20 to 05/14/21
Outputs
Target Audience:The primary audience for these efforts is comprised of basic researchers in the fields of plant-microbe interactions, pathogen evolution and emergence, plant disease epidemiologists, and microbiology. The secondary audience for these efforts is comprised of applied researchers in crop development and plant pathology. Changes/Problems:Thechanges to the approaches of GOALS 2 and 3were required because the COVID-19 pandemic caused long-term shutdown of in-person research activities at The Ohio State University. This limited Cohen's access to scientific facilities, which caused significant delays and deviations from the research schedule. To account for the unique situation, goals were adapted to include more computational approaches. Primarily, for GOAL 2, Cohen still focused on the development of new tools to study pathogen evolution, but those tools were computational in-nature rather than laboratory bench tools. Similarly, for GOAL 3, because he was unable to conduct research to define plant properties that drive bacterial mutation during infection, Cohen instead conducted genomics research to define nutritional, metabolic, and communication-related properties of the bacteria that changed during interactions with different crop plants over evolutionary time. What opportunities for training and professional development has the project provided?During 2019-2020, Cohen (PD) became an expert in processing big data concerning bacterial genomics. He developed the abilities required to efficiently search the over 1,400 Xanthomonas genomes available on public repositories. This expertise included learning existing tools and developing new customized tools and pipelines for quickly searching large datasets. Cohen also engaged in several professional development activities. In 2020, Cohen served as the Immediate Past Chair of the Molecular and Cellular Phytopathology (MCP) committee for the American Phytopathological Society (APS). In this role, he organized and conducted the annual MCP committee meeting during the APS Virtual Plant Health meeting, and mentored the next chair and vice chairof the committee, including personally assisting them in developing session ideas and proposals to submit for future APS meetings. Cohen moderated a Technical Session at the APS Virtual Plant Health meeting, networked with others in the field, gave a talk, and submitted a proposal for a workshop for Plant Health 2021. Cohen also served as a laboratory and professional mentor to four graduate students (three doctoral, one master's) at The Ohio State University during this time. Contrary to the previous year, where Cohen served as a mentor teaching technical and laboratory skills, Cohen's mentorship during this period was focused more on planning and guiding student projects. Importantly, he contributed to a master's student's thesis project development, overseeing key professional development of the student. How have the results been disseminated to communities of interest?Cohen (PD) disseminated results to the community through publication of manuscripts and by giving aconference talk at the APS Virtual Plant Health 2020 meetings. The details of these disseminations are in the Products section (below). What do you plan to do during the next reporting period to accomplish the goals?During the next period, Cohen (PD) will focus on writing the manuscripts associated with the work conducted.
Impacts
What was accomplished under these goals?
Report 2: GOAL 1: TO DEFINE WHETHER PATHOGEN MUTATION RATES ARE INCREASED IN RESISTANT PLANT HOSTS. No work was conducted on goal 1 during this time period. GOAL 2: TO DEVELOP NEW TECHNOLOGY AND RESOURCES FOR STUDYING EMERGENCE OF BACTERIAL PATHOGENS 2A: MAJOR ACTIVITIES COMPLETED: The speed at which bacteria mutate their genomes is likely linked to emergence of new diseases in the field. However, the majority of tools available to measure mutation are decades-old, time-consuming, and tedious. Therefore, Cohen sought to develop new laboratory-based and computer-based methods and resources that would support the need to study bacterial mutation rate. During this time period, Cohen (1) helped develop and release a new method for detecting the bacterial spot disease-causing Xanthomonas gardneri in the field, (2) released a high-quality genome of the tea canker-causing bacteria Xanthomonas theicola, and (3) completed a new analysis of how bacterial communication systems have mutated/evolved. 2B: DATA COLLECTED: Data collected for the major activities above include (1) data on sensitivity and specificity of the field test, (2) DNA sequence information, including genome assembly and annotation, and curated information about disease-causing (virulence) genes unique to the bacteria, and (3) data on bacterial communication systems from more than 1,500 diverse Xanthomonas bacteria. 2C: DISCUSSION OF RESULTS: (1) A new method was developed for bacterial spot disease monitoring in tomato and pepper fields. This test has the potential to be deployed as a point-of-care test, allowing rapid and accurate detection of the disease-causing bacteria. Monitoring for existing diseases is beneficial for the detection of new, emerging diseases in the field. The development of this test, therefore, empowers growers to take rapid management practices in the case of existing diseases, and researchers to identify potential new threats. (2) Sequencing the genome for the tea canker-causing pathogen was particularly informative to understanding how pathogens evolve because it revealed unique tools that the bacteria use to infect plants. In particular, this pathogen evolved to contain multiple plant-attacking genes that were not present in other, closely-related bacteria. Understanding how these genes evolved will empower researchers to make new models for predicting outbreak of new plant diseases. (3) The large-scale survey of publicly-available plant pathogen genomes allowed identification of unique differences in a critical bacterial pathogen communication system (called the quorum sensing system). These systems are used by pathogenic bacteria to self-monitor their population growth and coordinate attacks against plants. Differences in quorum sensing that exist among two or more closely-related bacteria will help researchers understand how new bacterial diseases emerge in the field when different, closely-related bacterial pathogens are competing. 2D: KEY OUTCOMES REALIZED: (1) a new, reliable, and field-deployable method for diagnosing the pathogen that causes bacterial spot of tomato and pepper was released to the community via publication (2) the complete genome and analysis of its unique virulence properties was released to the plant pathology community via publication and release on the public NCBI GenBank repository (3) key differences exist among the communication (quorum-sensing) systems of bacteria in the genus Xanthomonas GOAL 3: TO DEFINE PLANT FACTORS THAT INFLUENCE BACTERIAL MUTATION RATES DURING INFECTIONS No work was conducted on goal 3 during this time period.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Stehl�kov�, D., Beran, P., Cohen, S.P., & Curn, V. (2020). Development of real-time and colorimetric loop mediated isothermal amplification assay for detection of Xanthomonas gardneri. Microorganisms 8(9):1301.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Koebnik, R., Burokiene, D., Bragard, C., Chang, C., Fisher-Le Saux, M., K�lliker, R., Lang, J., Leach, J.E., Luna, E.K., Portier, P., Sagia, A., Ziegle, J., Cohen, S.P., & Jacobs, J.M. (2021). The complete genome sequence of Xanthomonas theicola, the causal agent of canker on tea plants, reveals novel secretion systems in clade-1 xanthomonads. Phytopathology, 111(4), 611-616
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
Aliakbari, M., Cohen, S. P., Lindl�f, A., & Shamloo-Dashtpagerdi, R. (2021). Rubisco activase A (RcaA) is a central node in overlapping gene network of drought and salinity in Barley (Hordeum vulgare L.) and may contribute to combined stress tolerance. Plant Physiology and Biochemistry, 161, 248-258.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., Butchacas, J., Roman-reyna, V., Long, J., Pesce, C., Vancheva, T., Bini F., Otto I., Szurek, B., Leach, J.E., Kumlehn, J., Bragard, C.G., Koebnik, R. & Jacobs, J.M. (2020). Tattle-TALEs: tools for testing type three targeting. Plant Health 2020 Online.
|
Progress 05/15/19 to 05/14/20
Outputs
Target Audience:The primary audiencefor theseefforts is comprised of basic researchers in the fields of plant-microbe interactions, pathogen evolution and emergence, plant disease epidemiologists, and microbiology. The secondary audience for these efforts is comprised of applied researchers in crop development and plant pathology. Changes/Problems:To study how different factors affect the mutation rate of bacteria in media and during in-planta interactions (GOAL 1), a computational simulation model was developed. This change was required because theCOVID-19 pandemic caused long-term shutdown of in-person research activities at The Ohio State University. This limited access to scientific facilitiescaused a significant delay in expenditure of funds and signficiant deviations from research schedule. To account for the unique situation, goals were adapted to include more computational approaches. To study the objectives of GOALS 2 and 3, pre-existing and new genomic data was acquired from existing sources and collaborators. These data wereacquired to design genomics approaches to be conducted in year 2 to investigate bacterial mutation rates (GOAL 2) and in drivers of mutation (GOAL 3). What opportunities for training and professional development has the project provided?During 2019-2020,Cohen (PD) became an expert at confocalmicroscopy, studying the use of amicroscope under the one-on-one mentorship of Prof. Jonathan Jacobs. Becauseconfocal microscopy is a highly technically difficult laboratory practice, this training gave Cohen the ability to usea rare and highly sought-after skill in the field. Using these skills, Cohen orgaized and conducteda microscopy workshop for the American Phytopathological Society (APS), a professional society in the area of studying Plant Disease. In the workshop, 32professional scientists participated to learn microscopy techniques and theories from Cohen and other content facilitators. Cohen also engaged in several professional development activities. In 2019, Cohen served as the Assistant Chair of the Molecular and Cellular Phytopathology (MCP) committee for APS. The MCPcommittee is a subject area committee for APSnet comprised of over 70 members of scientists from the community who volunteer to organize seminars and workshops for APS. As Assistant Chair, Cohen helped committee members prepare and submit proposal materials for an unprecedentedfour proposals that were accepted and sponsoredby theAPS administration. Also during this time, Cohen served as a laboratory mentor and professional mentor to four graduate students (three doctoral, one master's) at The Ohio State University. In these roles, Cohen taught laboratory techniques andexperimental design principles, provided guidance on multiplewriting projectsandstudent presentations. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?During the next period, work will be continued on all three previously mentioned goals. Due to the COVID-19 pandemic shutdown of in-person research activities, the greatest need of the project will be to re-assess realistic and deliverable goals to meet the objectives of the project under current limitations. This will be in the development of new computational approaches and approaches that focus on already-collected data.?
Impacts
What was accomplished under these goals?
New diseases affecting crop plants emerge in the field every growing season. How previously harmless microbes evolve to start causing new diseases is largely unknown, but knowing how this happens would allow agricultural researchers to develop methods to prevent it.Therefore, the goal of this project was to study how bacterial pathogens evolve during plant disease. GOAL 1: TO DEFINE WHETHER PATHOGEN MUTATION RATES ARE INCREASED IN RESISTANT PLANT HOSTS. 1A:MAJOR ACTIVITIES COMPLETED: Cohen developed laboratory-based methods to use thebacterial pathogen Xanthomonas translucens to measure bacterial mutation rate. This bacteria can infecteconomically important crops such as wheat and barley, making it an ideal pathogen to study. A laboratory techniquecalled afluctuation assaywasperformed to measure the mutation rates of bacteria grown in media. From the results of these assays, a computational simulation/model was developed to predict how bacteria evolve over time based on factors such as starting bacterial concentration, hostplant immunity, and length of infection. 1B: DATA COLLECTED: The mutation rates of Xanthomonas translucens growing in culture media was measured. A computational simulation/model was built to determine the effect of different factors on mutation rate. 1C: DISCUSSION OF RESULTS: The genomic mutation rate of Xanthomonas translucens growing in culture media, that is, the rate that a single base pair of DNA will change, was determined to be approximately 1 in 1 billion,or approximately a 1 in 200 chance for each bacterial cell to develop a mutation. With computational simulations, hypothetical mutation rate of a pathogen in a resistant plant host was determined to be 3 in 1 billion, or approximately a 3 in 200 chance for each bacterial cell to develop a mutation during an infection. 1D: KEY OUTCOMES REALIZED: The major outcomes realized for this goal were that bacterial pathogens liekly mutate at a higher rate while causing an infection inresistant plants. The implications of this are that the common practice of using resistant plants to control bacterial disease in the field may ultimately lead to higher rates of new emerging diseases. GOAL 2: TO DEVELOP NEW TECHNOLOGICAL METHODS TO STUDY BACTERIAL MUTATION RATE. 2A: MAJOR ACTIVITIES COMPLETED: Existing methods to study bacterial mutation rates are decades old, and are laborious and time-consuming.The goal of this activity was to adapt modern cutting-edge DNA-sequencing techniques to study mutation rates. To this end, Cohen developed a strategy, protocol, and DNA primers to utilize a technique called maximum-depth sequencing. Cohen purchased DNA primers and also contacted commercial DNA sequencing providers to negotiate the best price for DNA sequencing services.Cohen also developed a mutation rate reporter system whereupon bacterial mutation could be directly seen using a confocal microscope. 2B: DATA COLLECTED: For this goal, all activities were in planning and purchasing. Thus, no data was collected for this goal during this period. 2C: DISCUSSION OF RESULTS: No results were generated for this goal during this period. 2D: KEY OUTCOMES REALIZED: Cohen developed new projectmanagement skills during these activities. Primarily, he learned best record keeping practices during newexperimental design andprice negotiationwith commercial DNA sequencing providers. GOAL 3: TO DEFINE PLANT PROPERTIESTHAT DRIVE BACTERIAL MUTATION DURING INFECTION. No work was conducted on goal 3 during this time period.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., Luna, E. K., Lang, J. M., Ziegle, J., Chang, C., Leach, J. E., ... & Jacobs, J. M. (2020). High-quality genome resource of Xanthomonas hyacinthi generated via long-read sequencing. Plant Disease, 104(4), 1011-1012.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Cohen, S. P., & Leach, J. E. (2020). High temperature-induced plant disease susceptibility: more than the sum of its parts. Current Opinion in Plant Biology, 56, 235-241.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Lewandowski, M. M., Long, J., Butchacas, J., Klass, T. L., Heiden, N., Olmos, C., ... & Jacobs, J. M. (2020). Investigating the role of quorum sensing in Xanthomonas translucens pv. undulosa infection in barley and wheat: A class research experience. Plant Health 2020 Online.
|