Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 215 - Biological Control of Pests Affecting Plants | 110 - Soil | 1100 - Bacteriology | 100% |
The aim of this project is to make a continued contribution to the development of novel products and practices that protect or improve the health, yield, and quality of plants with economic value to the state of California. Specifically, the project is about the exploitation of naturally occurring microorganisms and their activities to prevent or reduce fungal diseases of important crops. The proposed study focuses on the phenomenon of bacterial fungistasis, which is the ability of bacteria to stop or slow down the growth of fungi. The project builds on ongoing research into the fungistatic activity of bacteria belonging to the genus Collimonas, and the project's goals are to gain a better understanding of the mechanisms that underlie this activity and to find ways in which to formulate Collimonas bacteria for improved storage and easier field application.
The supporting objectives of this proposal are as follows: a) to uncover the mode of action that underlies Collimonas biocontrol activity in planta and in synergy with commercial biofungicides; b) to quantify and improve the shelf-life and soil persistence of Collimonas strains with biocontrol potential. To meet these objectives, we have formulated the following approach and corresponding methods: a) In greenhouse experiments with Fusarium-challenged tomato plants, we will compare wildtype Collimonas with mutants in the chi genes (Fritsche et al., 2008) to quantify the contribution of chitinolysis to biocontrol activity. We will also test mutants lacking the ability to produce a compound with fungistatic activity (Mela et al. 2011, Mela et al., 2012). We will use auxotrophic derivatives of Collimonas to test whether these exhibit greater dependency on fungi for survival and whether this makes them better biocontrol agents. We will also set up experimental bacterial-fungal assays that are designed to in vivo evolve Collimonas with more efficient mycophagous behaviors. We will use a split-root system and fluorescent labeling of Collimonas to assess whether the observed synergism between Collimonas and other biofungicides requires direct interaction or not. b) We plan to assess the effect of growth medium on the ability of Collimonas to survive prolonged storage and to be recovered from soil microcosms and field samples. We will try the impact of different additives, such as chitin, on soil survival. We will seek collaborators with expertise in bacterial formulation to work on a cost-effective protocol that renders Collimonas bacteria stable during storage for prolonged periods of time and with minimal loss of activity after soil application.
Target Audience
Target audiences for this project included various stakeholders, including scientists, students, agrotech companies, commodity groups, farm advisors, and growers. More specifically, these audiences were (listed for the entirety of the project, 2014-2017): 1) attendants at these meetings or events: - January 23, 2014: presentation by Johan Leveau to representatives from Monsanto, UC Davis campus - February 25, 2014: presentation by Johan Leveau to attendants at the 2014 UCCE Advisor Workshop, hosted by the UC Davis Entomology & Nematology Department and Plant Pathology Department, UC Davis campus - March 12, 2014: presentation by Johan Leveau at the 60th Annual Conference on Soilborne Plant Pathogens, Dominican University of California, San Rafael, CA - June 25, 2014: presentation by Johan Leveau to representative from BASF, UC Davis campus - June 30, 2014: presentation by Johan Leveau to representatives from BioConsortia, UC Davis campus - July 22, 2014: presentation by Johan Leveau to representatives from Novozymes, UC Davis campus - September 3, 2014: poster presentation by student Nilesh Maharaj at the Complex Soil Systems Conference in Berkeley, CA - March 26, 2015: presentation by Johan Leveau at the Citrus Research Board meeting, Bakersfield, CA - August 1-5, 2015 presentation by student Hung Doan at the 2015 annual meeting of the American Phytopathological Society, Pasadena CA. - August 31, 2015: presentation by Johan Leveau at the Novozymes symposium, Davis campus. - September 9, 2015: presentation by Johan Leveau at the California Asian Citrus Psyllid and Huanglongbing Research and Extension Summit, Davis campus - September 17, 2015: presentation by Johan Leveau at the JH Biotech annual meeting, Las Vegas NV - October 17, 2015: presentation by Johan Leveau at the Farm to Table Academy, UC Davis campus - September 7, 2016: presentation by Johan Leveau at the Citrus Research Board External Scientific Review panel meeting, UC Davis campus - September 12, 2016: presentation by Johan Leveau at the Phytobiome seminar series at The Pennsylvania State University, University Park, PA - October 4, 2016: presentation by Johan Leveau at the California ACP and HLB Research and Extension Summit, Riverside CA - October 12, 2016: presentation by student Hung Doan at the 4th Recent Advances in Microbial Control meeting, San Diego, CA - October 13, 2016: presentation by Johan Leveau at Seed Central's DISCOVER Series, Conference Center, UC Davis - December 12, 2016: presentation by Johan Leveau at the International Symposium on Agricultural Biotechnology, National Chung Hsing University, Taichung, Taiwan - January 19, 2017: presentation by Johan Leveau at the meeting of the California Pistachio Research Board, Visalia Convention Center, Visalia, CA - May 23, 2017: presentation by Johan Leveau at the Pistachio Bushy Top Research Meeting, Kearney Ag Center, Parlier, CA - June 28, 2017: presentation by Johan Leveau in the session "Emerging diseases in California's agricultural and natural ecosystems" at the APS Pacific Division Meeting, Riverside, CA - October 11, 2017: presentation by Johan Leveau at the 2017 California Citrus Conference, Visalia, CA 2) undergraduate and graduate students in these classes at UC Davis (lectures or lecture sections on biocontrol, Collimonas, or plant microbiota in the context of disease): ENT 135: Introduction to Biological Control (Fall 2014) GDB 103: The Microbiome of People, Animals and Plants (Fall 2015: 53 students; Fall 2016: 75 students) PLP 201A: Advanced Plant Pathology (Winter 2014: 12 students; Winter 2015: 11 students; Winter 2016: 14 students; Winter 2017: 9 students) PLP 298: Advanced Plant Pathology Lab (Fall 2014: 21 students; Fall 2016: 17 students) SAS 13: Disease and Society (Winter 2014: 198 students; Winter 2015: 294 students; Winter 2016: 357 students; Winter 2017: 354 students) 3) readers of articles that we published in peer-reviewed journals, including Soil Biology & Biochemistry, Environmental Microbiology, Microbial Ecology, Genome Announcements, Scientific Reports, Frontiers in Microbiology 4) readers of articles that we published in non-peer-reviewed journals, including Citrograph and Microbiologist 5) visitors to the Leveau lab website (http://leveau.ucdavis.edu) which was launched in 2015 (about 1,800 visitors annually) 6) outreach: YouTube video, radio broadcast (see "Other products")
Changes / Problems
Nothing Reported
Training & Professional Development
Over the course of the project, the Leveau lab has provided training for several graduate and undergraduate students as part of the Collimonas project or other AES-related projects on plant microbiota. These include Nilesh Maharaj, Hung Doan, Sandra Mosquera, and Peter Henry (all PhD student in Plant Pathology at UC Davis. Nilesh graduated in 2016 and currently is employed as the diagnostic lab director of a local seed testing company. The lab also hosted and trained several visiting scientists, including Je-Jia Wu (PhD student from National Ching Hsung University, Taichung, Taiwan), Tatiana Cuellar PhD student from the Universidad EAFIT, Medellin, Colombia), and Jonathan Bourquin (University of Lausanne, Switzerland), in addition to a number of undergraduate students rotating through the lab.
Dissemination Streams
Results were disseminated through peer-reviewed journal articles (detailed in previous Progress Reports), presentations at scientific meetings in classes or through presentations to students at UC Davis or on other campuses or to professionals at several biotech companies, the Leveau lab website (http://leveau.ucdavis.edu), and online video/audio broadcasts. See "Target Audience" and previous Progress Reports for specifics.
Next Reporting Steps
Nothing Reported
Target Audience
Target audiences for this project in the period under review (1 October 2015 - 30 September 2016) include various stakeholders, including scientists, students, and commodity groups. These audiences were reached through peer-review publications, popular-press articles, and presentations at conferences and workshops (see below).
Changes / Problems
Nothing Reported
Training & Professional Development
As part of the various projects listed in the section above, I trained several UC Davis graduate students including Nilesh Maharaj (who graduated in Fall 2016 and is now working as a postdoc in my lab on the citrus project), Hung Doan, Sandra Mosquera and Peter Henry, as well as postdoc Fidele Akum and Junior Specialist Kaitlyn Kelly. I also hosted Tatiana Cuellar (July 2015 - January 2016), visiting graduate student from the Universidad EAFIT, Medellin, Colombia (worked on Collimonas project) and Jonathan Bourquin (May - August 2016), visiting student from the University of Lausanne, Switzerland (worked on citrus project).
Dissemination Streams
Results were disseminated through publication of peer-reviewed articles, presentations at scientific meetings, through presentations on UC Davis campus and elsewhere, or to professionals in commodity groups or at biotech companies. Also see the sections 'Target audiences' and 'Products'.
Next Reporting Steps
We will continue our work on Collimonas under the collaboration with Novozymes. We will expand our non-Collimonas projects, and secure longer-term funding for the strawberry and pistachio projects. <br><br>
<br>What was accomplished under these goals? The overall goal of this Hatch project is to contribute to the development of novel products and practices that protect or improve the health, yield, and quality of plants of economic importance to the state of California. Specifically, the project seeks the exploitation of naturally occurring microorganisms and their activities to prevent or reduce fungal and bacterial diseases of important crops. The project continues to focus on bacteria from the genus Collimonas as they show potential for the management of agriculturally important fungal pathogens. These so-called collimonads have antifungal properties and we have shown that they can protect tomato plants from the fungal wilt pathogen Fusarium oxysporum f. sp. lycopersici. Our work has been of interest to companies that look for novel ways to keep crops healthy. One of those companies is Novozymes Inc., with whom we started during the period under review a collaboration to pursue answers to many of questions that were originally framed as part of this Hatch project, more specifically those related to Collimonas. We also have started or continued a number of non-Collimonas projects that contribute to the overall goal of this Hatch project. Major goals accomplished for this period of review: - we completed and analyzed greenhouse and field trials to show the synergistic effect between Collimonas arenae Cal35 and the Bacillus-based biofungicide Serenade Soil, a mixture we refer to as Collinade; - we documented our Collinade findings in Chapter 4 (Antifungal and antioomycetal properties of California-native Collimonas isolates and their use in synergy-based biocontrol of Fusarium wilt of tomato) of the PhD dissertation by Nilesh Maharaj who worked on this project together with another PhD student, Hung Doan; - we converted this Chapter 4 into a submission-ready manuscript for peer-review and publication; - we have presented our results on the Collinade project to various stakeholders and at various venues (see below); - we initiated a collaboration with Novozymes, Inc. to study the mechanisms that underlie the Collinade effect, more specifically, the synergy between Collimonas bacteria and one or more Bacillus-based Novozymes products; this collaboration is funded by Novozymes for the period March 2016 - February 2018; Dr. Fidele Akum was hired in 2016 as a postdoc on the project; - we continued our long-standing collaboration with Dr. Stéphane Uroz at INRA Nancy (France) on collimonads in forest soils (which previously led to the discovery of C. arenae Cal35), resulting in a joint publication in the journal Scientific Reports in June 2016; - we continued a parallel project on the interactions of Collimonas with fungal spores; this project is carried out by Sandra Mosquera, who is co-supervised by Dr. Leveau and Dr. Ioannis Stergiopoulos; - we completed or initiated several other projects that meet the overall goal of this Hatch project (i.e. "contribute to the development of novel products and practices that protect or improve the health, yield, and quality of plants with economic value to the state of California") but that do not involve Collimonas; targeted crops include strawberry, pistachio, and citrus, as explained below; - we published our results on the ability of iron-chelating agents (bacteria or organic compounds) to halt the growth of the bacterial pathogen Xanthomonas fragariae on strawberry plants; - we developed molecular tools to detect bacteria belonging to the genus Rhodococcus; this was done in collaboration with Dr. Florent Trouillas on a project that examines the role of Rhodococcus species in the condition known as Pistachio Bushy Top Syndrome; - we invested heavily in the microbiome-based early detection of infection of citrus trees with the CLas bacterium that causes citrus greening; funding for this research comes from the Citrus Research Board. <br><br><b>Publications</b><br>
Target Audience
Target audiences for this project in the period under review included various stakeholders, i.e. scientists, students, and agrotech companies. More specifically, these audiences were: 1) Attendants at the following meetings or events: -2015 August 1-5, 'Antifungal properties of California Collimonas isolates and their use in synergy-based biocontrol of Fusarium wilt of tomato', presented by my student Hung Doan at the 2015 annual meeting of the American Phytopathological Society, Pasadena CA. -2015 August 31, 'Synergy-based biocontrol of plant-pathogenic fungi', Novozymes symposium, Davis campus. -2015 September 17, 'Biocontrol of plant-pathogenic bacteria and fungi', JH Biotech annual meeting, Planet Hollywood, Las Vegas NV. 2) Students in ENT 135: Introduction to Biological Control and SAS 13: Disease and Society, taught in 2015 on the UC Davis campus. 3) Visitors to our new Leveau lab website (http://leveau.ucdavis.edu).
Changes / Problems
Nothing Reported
Training & Professional Development
I trained several students as part of the Collimonas project in my laboratory, including Nilesh Maharaj, Hung Doan and Sandra Mosquera (all PhD students in Plant Pathology at UC Davis) and Tatiana Cuellar (visiting PhD student from the Universidad EAFIT, Medellin, Colombia).
Dissemination Streams
Results were disseminated through presentations at scientific meetings, in classes or through presentations to students at UC Davis, or to professionals at biotech companies. More details are listed under 'Target Audience'.
Next Reporting Steps
Our work on the Collimonas/Bacillus-based synergism against fungal pathogens will continue as part of the collaborative 2-year project with Novozymes Inc. I also have been and will be expanding into other diseases of economic impact to the state of California. These include bacterial diseases such as angular leaf spot of strawberry (work that was initiated in 2015 by Junior Specialist Peter Henry, now PhD student in the Gordon/Leveau lab) and pistachio bushy top syndrome (Junior Specialist Kaitlyn Kelly in my lab, in collaboration with Flo Trouillas, Department of Plant Pathology, UC Davis). Both projects will become part of (and fit the mission of) this AES project, which is to expose and exploit bio-based services for sustainable protection of California crops. <br><br>
<br>What was accomplished under these goals? The main goal of this project continues to be the development of novel products and practices that protect or improve the health, yield and/or quality of plants with economic value to the state of California. Specifically, the project is about the exploitation of naturally occurring microorganisms and their activities to prevent or reduce infectious diseases of important crops. The focus in the project so far has been on fungal disease of processing tomatoes and the use of Collimonas bacteria to protect these plants from Fusarium wilt. Previously, we discovered that a mixture of Collimonas and a commercially available Bacillus-based biocontrol product was able to reduce Fusarium wilt symptoms on tomato plants in the greenhouse and in a field setting. Accomplishments during the time period under review: 1) In the summer of 2015, we repeated the 2014 field experiment and confirmed that the Collimonas/Bacillus mixture was able to reduce Fusarium-induced vascular discoloration in field-grown tomato plants (work of Hung Doan). We also submitted samples for analysis of the microbial populations on the roots of Collimonas/Bacillus-treated and untreated plants under field conditions; these results are pending (work of Nilesh Maharaj). A manuscript detailing these results is being prepared for submission. 2) We have conducted experiments into the mechanistic nature by which Collimonas bacteria inhibit the germination of fungal spores and have been able to show that this inhibition relies on physical contact of the bacteria with the spores, and on the involvement of bacterially-produced chitinases and antifungal compounds (work of Sandra Mosquera). A manuscript is being prepared in collaboration with Ioannis Stergiopoulos in the Department of Plant Pathology. 3) I have dedicated quite a bit of time and effort in 2015 working towards a research collaboration with Novozymes Inc. to study the mechanism that underlies the Collimonas/Bacillus synergism against fungal disease on plants. This has culminated into a research agreement between my lab and Novozymes Inc. that was signed recently and will start in March of 2016 to last for a 2 year period. <br><br><b>Publications</b><br>
Target Audience
Target audiences for this project included various stakeholders, including scientists, students, agrotech companies, commodity groups, farm advisors, and growers. More specifically, these audiences were: 1) Attendants at these meetings or events: - December 5, 2013: 2013-2014 California Processing Tomato Research Proposal Meeting, UC Davis campus - January 23, 2014: presentation of the Lab Leveau research program to representatives from Monsanto, UC Davis campus - February 25, 2014: presentation of the Lab Leveau research program to attendants at the 2014 UCCE Advisor Workshop, hosted by the UC Davis Entomology & Nematology Department and Plant Pathology Department, UC Davis campus - March 12, 2014: 60th Annual Conference on Soilborne Plant Pathogens, Dominican University of California, San Rafael, CA - June 25, 2014: presentation of the Lab Leveau research program to representative from BASF, UC Davis campus - June 30, 2014: presentation of the Lab Leveau research program to representatives from BioConsortia, UC Davis campus - July 22, 2014: presentation of the Lab Leveau research program to representatives from Novozymes, UC Davis campus 2) Students in these classes: SAS 13: Disease and Society, PLP 201A: Advanced Plant Pathology, PLP 298: Advanced Plant Pathology Lab 3) readers of the articles that we published in various peer-reviewed journals (see the section Products).
Changes / Problems
Nothing Reported
Training & Professional Development
We trained several students as part of the Collimonas project in our laboratory. These include Sandra Mosquera (PhD student in Plant Pathology at UC Davis), Je-Jia Wu (PhD student visiting from Ching Hsung University (NCHU, Taichung, Taiwan), in addition to a number of undergraduate students rotating through the lab.
Dissemination Streams
Results were disseminated through peer-reviewed journal articles, presentations at scientific meetings, in classes or through presentations to students at UC Davis or on other campuses or to professionals at several biotech companies. More details are listed under 'Target Audience'.
Next Reporting Steps
We will continue our work on objective a), with emphasis on a mechanistic understanding of the impact of Collimonas on spore germination and of the phenomenon of biocombicontrol (i.e. two bacterial strains mixed together prevent plant disease, whereas either one by itself has no or much less effect). We will also start with experiments that address objective b). <br><br>
<br>What was accomplished under these goals? The supporting objectives of this proposal are as follows: a) to uncover the mode of action that underlies Collimonas biocontrol activity in planta and in synergy with commercial biofungicides; b) to quantify and improve the shelf-life and soil persistence of Collimonas strains with biocontrol potential. For objective a), we have been studying the interaction of Collimonas bacteria with fungal spores to quantitatively describe the ability of Collimonas to prevent or slow down spore germination. We have used knockout mutants of Collimonas to identify genes that are involved in this interaction. We also have set up a microbox assay that allows rapid screening of Collimonas strains for ability to prevent, either alone or in synergy with other biocontrol agents, the development of disease symptoms caused by the fungus Fusarium oxysporum f. sp. lycopersici on tomato. In addition, we sequenced the entire genome sequence of California soil isolate Collimonas arenae Cal35, which now allows for the first time a comparative genomics approach to the bacterial genus Collimonas. <br><br><b>Publications</b><br>