Progress 03/01/14 to 12/31/18
Outputs
Target Audience:Efforts were made to reach out to a diverse as possible audience of participants in terms of scientific background (from phyllosphere microbiobiology, to phytobiome research, plant biology, food microbiology, and microbial ecology in general), career stage (undergraduate students, graduate students, postdocs, PIs) and affiliation (academia, industry, regulatory, farmers). The outlets we used to reach these audiences were manifold, but mostly involved publications and presentations. All these are detailed in sections down below. One of the outcomes of the project, related directly to the presentation of our project at the 2015 Phyllosphere meeting in Switzerland, is that we will be organizing the 2020 Phyllosphere meeting at UC Davis, allowing us to continue reaching out and expand our target audience for our research program and for this project in particular. Another expansion of our audience past the lifetime of the project involves our contribution to the COSMOS program starting 2019. This summer program (https://cosmos-ucop.ucdavis.edu/app/main) allows us to work with talented high school students for a period of 4 weeks and to introduce them to the principles of plant microbiology (http://cosmos.ucdavis.edu/cluster7.htm). For our teaching materials, we will draw directly from this USDA-NIFA-funded project, including the use of artificial leaf surfaces to study plant-microbe interactions. Changes/Problems:Several manuscripts were still in preparation at the official end of the project (31 December 2018). In 2018, my student working on the project, Hung Doan, applied for and was awarded a UC Davis Dissertation Year Fellowship. The funds and time that come with the award will be used toward finalizing and submitting these manuscripts for peer review by the end of June 2019. USDA-NIFA funding will be acknowledged in every case. What opportunities for training and professional development has the project provided?Training activities are defined as 'those in which individuals with advanced professional skills and experience assist others in attaining greater proficiency'. Hung Doan was a key team member on this project and was mentored by PI Leveau during the lifetime of the project. Another mentee of Dr. Leveau's, Lorena Rangel, contributed to the latter stages of the project as well, using Hung's artificial leaves in experiments to compare and contrast the survival of bacteria on real and artificial leaf surfaces. Dr. Viviane Ngassam played an important role at the start of the project, optimizing the fabrication of the artificial leaf surfaces. She was mentored by coPI Parikh. Training was also provided to researchers who came to visit from other universities and who were interested in using artificial leaves in their own projects. Two of these were graduate students Marisa Antequera (Department of Microbiology, University of Malaga, Spain) and Chadd Fautt (Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University). How have the results been disseminated to communities of interest?We disseminated results from the project to different communities of interest using various outlets. In one of the above sections, we already listed the body of publications that resulted from this project as well as all the publications that will be forthcoming later this year. Below, we list all presentations that were given by Dr. Leveau (all oral presentations, unless noted otherwise) at various national and international meetings, conferences, and workshops. 'Form and function of phyllospheric microbiota on leafy greens', invited speaker at the Lettuce Workshop, Technical University of Graz, Austria, October 26-28, 2014. 'Microbial associations with plant foliage', National Chung Hsing University (NCHU), Taichung, Taiwan; seminar as part of NCHU-UC Davis Bilateral Workshop, November 29 - December 3, 2014. 'In vivo, in vitro, and in silico approaches to bacterial distribution and dispersal on leaf surfaces', 10th International Symposium on Phyllosphere Microbiology, Congressi Stefano Franscini, Monte Verità, Ascona, Switzerland, July 19-23, 2015. 'Individual-based ecology of a plant microbial biome', @ASM Conference on The Individual Microbe: Single-cell Analysis and Agent-based Modeling, American Society for Microbiology (ASM) Headquarters, Washington DC, March 18-20, 2016. 'Plant surface microbiota', Phytobiome Convening Meeting, Marriott Waterside Hotel, Tampa FL. July 29, 2016. 'Use of artificial leaf surfaces for improved mechanistic understanding of pathogen survival on fresh produce', USDA National Institute of Food and Agriculture (NIFA) Project Directors' Meeting, St Louis, MO, Convention Center (poster presentation). July 30, 2016. 'Use of artificial leaf surfaces for improved mechanistic understanding of microbial colonization of the phyllosphere', oral presentation at the 16th International Symposium on Microbial Ecology (ISME 16), Montreal, Canada, August 21-26, 2016. '(Inter)activities in the phytobiome', Phytobiome seminar series at The Pennsylvania State University, University Park, PA. September 12, 2016. 'There's an iota in microbiota: stories of life and scale in the phyllosphere', Annual UMass Amherst Plant Biology Graduate Program symposium "Phytobiomes: The Social Networks of Plants and Microbes", Amherst, MA. October 1, 2016. 'Microscopic life on plants', invited lecture in Microbiology graduate course at Midwestern University, Glendale AZ. February 16, 2017. 'Individual-based ecology of the phyllosphere', invited lecture at the 2nd Plant Microbe Interaction Symposium at the Joint Genome Institute (JGI), Walnut Creek, CA. April 21, 2017. 'Individual-based ecology of the phyllomicrobiome', keynote lecture at the 12th Meeting of the European Foundation for Plant Pathology (EFPP) and the 10th Meeting of the French Society for Plant Pathology (SFP), Dunkerque - Malo-les-Bains, France, May 29 - June 2, 2017. 'Fabrication and application of topomimetic leaf surfaces for a mechanistic and quantitative understanding of the colonization of leafy greens by enteropathogenic Escherichia coli', poster presentation at the 2017 USDA NIFA Food Safety Project Directors' Meeting, Tampa, FL, July 8, 2017. 'Scales, types, and outcomes of microbial interactions in the phyllosphere', invited talk at the 2018 Annual Meeting of the Ecological Society of America (ESA), 5-10 August, 2018, New Orleans, LA. 'Individual-based microbial ecology of the phyllosphere', invited presentation at the Workshop on Microbial Ecology and Evolution in the Phyllosphere, Kavli Institute for Theoretical Physics, UC Santa Barbara. September 21, 2018. 'Topomimetic leaves as research tools in phyllosphere microbiology', invited speaker at the 2018 Host-Microbe Interaction Retreat, Granlibakken, Lake Tahoe, CA. October, 19, 2018. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The main goal of this project was to fabricate artifical leaf surfaces to help assess and quantify the role of leaf surface topography on the foliar survival and attachment of bacteria. We have met this goal and demonstrated that a higher degree of surface topography (e.g. bigger veins, deeper crevices) is positively correlated with greater retention of water and bacteria on the leaf, with higher probability for dispersal by splash, and with increased bacterial resilience to removal and sanitation. Our findings offer novel insights into phyllosphere microbiology, in particular the role of water landscapes in the ecology of foliar microorganisms, with practical implications for the field of food safety, in particular the contamination of leafy greens with enteropathogenic bacteria. We are detailing our findings in three separate manuscripts which we aim to submit for peer-review and publications by this Summer. We anticipate that these publications will generate much interest in the scientific community, based on positive feedback received while presenting our work at national and international meetings. Through those interactions, we already have had several colleagues visit our lab to learn how to make and use these leaves, leading to new collaborations. Dr. Leveau also is planning to collaborate, as part of his Fall 2019-Winter 2020 sabbatical leave, with researchers at the Lawrence Berkeley National Lab to explore and exploit the compatibility of the artificial leaf surfaces with the EcoFab setup that was developed at LBNL for the purpose of discovering, quantifying, and predicting how the environment regulates biology and how biology shapes the environment.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Esser, D.S., J.H.J. Leveau, K.M. Meyer, and K. Wiegand. 2015. Spatial scales of interactions among bacteria and between bacteria and the leaf surface. FEMS Microbiology Ecology, 91: fiu034.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Doan, H.K. and J.H.J. Leveau. 2015. Artificial surfaces in phyllosphere microbiology. Phytopathology, 105: 1036-1042.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Esser, D.S., J.H.J. Leveau, and K.M. Meyer. 2015. Modeling microbial growth and dynamics. Applied Microbiology and Biotechnology, 99: 8831-8846.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Kreft, J.-U., C.M. Plugge, C. Prats, J.H.J. Leveau, W. Zhang, and F.L. Hellweger. 2017. From genes to ecosystems in microbiology: Modeling approaches and the importance of individuality. Frontiers in Microbiology, 8: 2299.
- Type:
Journal Articles
Status:
Other
Year Published:
2019
Citation:
Biomimetic surfaces help detecting micro-scale effects of topography on bacterial leaf colonization. Esser D.S., Meyer K.M., Wiegand K., Tecon R., Gilmore S.F., Parikh A.N., Leveau J.H.J. In preparation.
- Type:
Journal Articles
Status:
Other
Year Published:
2019
Citation:
Fabrication and application of topomimetic leaves for studying the size, shape, and connectivity of the leaf surface waterscape in relation to phyllosphere microbiology. Doan, H.K, Leveau J.H.J. In preparation.
- Type:
Journal Articles
Status:
Other
Year Published:
2019
Citation:
Leaf surface topography as a major contributor to the survival, attachment, resistance to removal, and dispersal of E. coli on leafy greens. Doan, H.K, Leveau J.H.J. In preparation.
- Type:
Theses/Dissertations
Status:
Other
Year Published:
2020
Citation:
Use of artificial leaf surfaces for improved mechanistic understanding of pathogen survival on fresh produce.Hung K. Doan, Doctoral thesis, University of California, Davis.
- Type:
Theses/Dissertations
Status:
Submitted
Year Published:
2020
Citation:
Production of indole-3-acetic acid by members of the phyllosphere microbiota in reference to stress tolerance and foliar survival of enteropathogenic Escherichia coli.
- Type:
Book Chapters
Status:
Published
Year Published:
2015
Citation:
Life of microbes on aerial plant parts. 2015. J.H.J. Leveau. In: Principles of Plant-Microbe Interactions: Role of Microbes in Sustainable Agriculture, Lugtenberg, B.J.J., (ed), Springer.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Leveau, J.H.J., F. Hellweger, J.-U. Kreft, C. Prats, and W. Zhang. 2018. The Individual Microbe: Single-Cell Analysis and Agent-Based Modelling. Frontiers in Microbiology, 9: 2825.
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Progress 03/01/15 to 02/29/16
Outputs
Target Audience:For a description of target audiences and of the outlets that we used to target those audiences, see the section below on dissemination. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Hung Doan (graduate student in Plant Pathology) and Viviane Ngassam (senior researcher in ) were trained in lab protocol development, presentations skills, and manuscript preparation. How have the results been disseminated to communities of interest?We disseminated results from the project to different communities of interest using various outlets. Our review article on artificial surfaces in phyllosphere microbiology was officially published in Phytopathology in August 2015, and is now available as a Free Full Text article. PI Leveau also submitted a chapter for the new edition of the Compendium of Lettuce Diseases and Pests, entitled 'The lettuce-associated microbiota'. It is available pre-publication on the Lab Leveau website (http://leveau.ucdavis.edu/wp-content/uploads/sites/220/2015/05/LEVEAU-section-in-Lettuce-Disease-Compendium.pdf). We also presented our work at international conferences, such as the 10th International Symposium on Phyllosphere Microbiology, Congressi Stefano Franscini, Monte Verità, Ascona, Switzerland, July 19-23, 2015. The title of the presentation was 'In vivo, in vitro, and in silico approaches to bacterial distribution and dispersal on leaf surfaces'. This meeting brings together experts in phyllosphere microbiology from around the world every 5 years. PI Leveau will be hosting the 2020 meeting at UC Davis. We also incorporated our results into lectures for the general public, such as the one that PI Leveau gave ('Plant microbiota and health') for the open-to-the-public Farm to Table Academy, October 17, 2015 on the UC Davis campus. What do you plan to do during the next reporting period to accomplish the goals?Work so far has used Pantoea agglomerans as a model bacterium for studying the colonization of real and artificial leaf surfaces, because tools were available available for this bacterium. We have started to move these tools into E. coli, and shift our research focus to this bacterium and its ability to survive on real and artificial leaf surfaces.
Impacts
What was accomplished under these goals?
During the period of review, we performed work towards two of the major goals of the project: 1. Generate and compare data from single-cell and population-level analyses of the establishment of E. coli on real and artificial leaf surfaces, and 2. Assess the role of attachment, dispersal, nutrient availability, and bacterial community structure as major contributing factors to E. coli survival on leaf surfaces. More specifically, we used our first set of artificial leaf surfaces to demonstrate bacterial growth and dispersal in relation to leaf topography and in particular in the context of the water landscape as it is defined by leaf topography. Also, in collaboration with colleagues at the Georg-August-Universität Göttingen (Germany), we conducted a leaf inoculation experiment that used spatial statistics to compare and contrast patterns of bacterial colonization of real and artificial leaf surfaces with the purpose to quantify differences in the attraction or repulsion of surface features (stomata, leaf hairs, cuticular grooves) to bacteria.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Doan HK and Leveau JHJ. Artificial surfaces in phyllosphere microbiology. Phytopathology (2015 Aug), 105(8): 1036-1042.
- Type:
Book Chapters
Status:
Awaiting Publication
Year Published:
2015
Citation:
Leveau JHJ. The lettuce-associated microbiota, in: Compendium of Lettuce Diseases and Pests, second edition, edited by K. V. Subbarao, R. M. Davis, R. L. Gilbertson, and R. N. Raid (American Phytopathological Society, St. Paul, MN).
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Progress 03/01/14 to 02/28/15
Outputs
Target Audience: With our review entitled "Artificial surfaces in phyllosphere microbiology" now published in the journal Phytopathology, we target an audience that is working on or interested in phyllosphere microbiology, i.e. the study of microorganisms that reside on plant leaf surfaces. The review summarizes the various uses of artificial surfaces in experimental phyllosphere microbiology and discusses how these have advanced our understanding of the biology of leaf-associated microorganisms (including plant and human pathogens) and the habitat they live in. The target audience includes researchers in the fields of plant microbiology, plant pathology, food safety, and food security, as well as relevant funding agencies, produce industries, health officials and consumers of leafy greens. Results from our project also were presented during several interactions with students, for example at the UC Merced Environmental Systems seminar series (9 April 2014), the Lettuce Workshop at the Technical University of Graz, Austria (October 26-28, 2014) and at the NCHU-UC Davis Bilateral Workshop at National Chung Hsing University (NCHU), Taichung, Taiwan (November 29 - December 3, 2014) Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? The rationale and preliminary results have been disseminated through publication of a review article on artificial leaf surfaces in phyllosphere microbiology and through presentations to diverse student audiences (see Target Audience). What do you plan to do during the next reporting period to accomplish the goals? We will be using our collection of artificial leaves to conduct experiments that are listed under Objective 2. These experiments are aimed to test the behavior of bacteria on artificial surfaces in relation to a number of experimentally controlled leaf surface conditions, such as water and nutrient availability. In parallel, our collaborator will start working on Objective 3 (the development of next-generation artificial leaves).
Impacts
What was accomplished under these goals?
In this project, we use artificial leaf surfaces to explore in a systematic and bottom-up manner the factors that impact pathogen attachment to and survival on leafy greens. We have generated a protocol (See: Other Products) for the generation of artificial (plastic) leaves that faithfully resemble real leaves in surface topography as seen under the microscope. We tested this protocol on leaves of several plants, including bean, lettuce, spinach, and strawberry, to confirm that our protocol has broad applicability. We have started using the protocol to generate a collection of artificial leaves that we are using in inoculation experiments to quantify the differences in bacterial growth and dispersal on real versus artificial leaves. These experiments address the first objective above. Preliminary results indicate that leaf topography, whether on real or artificial leaves, plays a significant role in where and how clumped bacteria occur on a plant leaf surface. This has important implications for interpreting bacterial distributions on the leaves of lettuce, spinach and other leafy greens: for example, it means that the observation of many bacteria clustered near a leaf structure such as a leaf hair does not necessarily require a biological or chemical explanation (as in, that is where bacteria migrated to or that is where nutrients are available); it could also be interpreted to mean that the observed clustering is due to physical interactions of the bacteria and the leaf topography.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2015
Citation:
H.K. Doan and J.H.J. Leveau (2015) Artificial surfaces in phyllosphere microbiology. Phytopathology (Epub ahead of print): http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-02-15-0050-RVW
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