Progress 05/01/10 to 04/30/13
Outputs
Target Audience: The resultsgenerated by this project were targeted to professionals plant pathologists, mycologists, and wetland ecologists. In addition, these finding will useful to costal land trusts,state parks that contain salt marshes.vegetable and ornamental grower groups. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? I mentored two high school students on this proposal. Both students completed their projects andmade presentations to their classrooms ontheir activities, accomplimishment and conclusions. How have the results been disseminated to communities of interest? I presented presentations to professional societies, community colleges, coastal land trusts,and community groups. I also presented posters displays at our annual Plant Science Day in August, 2013. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Major Activities We conducted several large scale fractal surveys in corn fields in Southbury, CT and North Grosvenor, CT where we detected over 12 species of Fusarium. F. graminearum was the dominate species, was found 33% of the time, and was composed of two mycotoxin producing chemotypes. The 15-Adon chemotype composed approximately 70% of the isolates of F. graminearum whereas the more toxic chemotype called 3-Adon was found 30% of the time. The profile differed greatly from the salt marsh where over 80% of the isolates fell into two large Fusarium groups, F. palustre, a recently described species that is moderately virulent on the marsh grass, Spartina alterniflora, and species that fell into the F. incarnatum-equiseti species complex.We also compared the species profile between ornamental monocots (Ruscus and Lirope) and asparagus, and we found theprofile on all three hosts was similar and composed of F. oxysporum. F. solani, and F. proliferatum. Specific objectives We showed that the salt marsh Fusarium species, F. palustre and F. incarnatum isolated from Spartina alterniflora were more saline tolerant than the genetically similarterrestrial species, F. sporotrichioides and F. equiseti , respectively,isolated from corn stubble. We discovered that F. palustre produced DONmycotoxins in levels comparable to terrestrial species. Pathogenicity tests usingF. oxysporum. F. solani, and F. proliferatum was highly variable on Ruscus and Liriope and appeared to require a predisposing stressor (wet soils, heat stress) to cause the levels of root rots observed in the field. In addition, the species found on these hosts were not closely related to each other as evidenced by genotyping of gene sequences or byvegetative compatibility testing. On the contrary, populations of F. oxysporum on dicots, such as tomato, tend to be more closely related to each other. For example, Race 3 of the Fusarium wilt pathogen on tomato, F. oxysporum f. sp. lycopersici, that appeared in New England in 2012 probably evolved from Race 2, which explains the similar genetic background. Significant results achieved As a result of the salt marsh survey, we identified a new species of Fusarium. This species (F. palustre) was implicated in a dieback that wasalso recently shown to be the cause the decline of native Phragmites reed grass in China. Evidence that the fungus had been introduced to Phragmites on introduced Spartina alterniflora highlighted the unintentional consequence of invasive species. Management strategies for ornamental monocots and asparagus need to focus more on reducing plant stress. Although host resistance and sanitation are still very important, our finding suggest the pathogens are ubiquitous and do not appear to be highly specialized.Therefore,strategies aimed at avoidance may be difficult and ineffective. Key outcomes We concluded that salt marsh species of Fusarium have adapted to saline conditions better than species found in terrestrial habitats. These findings suggest that these species most likely evolved in the marsh and were not recently introduced. The Fusarium composition that lead to root rots of monocot ornamentals do not appear to be specialized pathogens, but may persist in most soils, but plant stress leads to an increase in disease incidence. Management strategies that focus relieving the stresses are more important than efforts to suppress the levels of Fusarium species in the soil.
Publications
- Type:
Book Chapters
Status:
Published
Year Published:
2012
Citation:
Elmer, W. H. 2012. Fusarium Biology and Epidemiology, Pages 11-19, In: Fusarium wilts of greenhouse vegetable and ornamental crops. Eds., Angelo Garibaldi, Jaacov Katan, and M. Lodovica Gullino. APS Press ST. Paul, MN.
Elmer, W. H. 2012. Cultural Management of Fusarium , Pages 67-84, In: Fusarium wilts of greenhouse vegetable and ornamental crops. Eds., Angelo Garibaldi, Jaacov Katan, and M. Lodovica Gullino. APS Press ST. Paul, MN.
Elmer, W. H., and Daughtrey, M. L 2012. Fusarium wilt of cyclamen, Pages 213-219, In: Fusarium wilts of greenhouse vegetable and ornamental crops. Eds., Angelo Garibaldi, Jaacov Katan, and M. Lodovica Gullino. APS Press, St. Paul, MN.
- Type:
Book Chapters
Status:
Awaiting Publication
Year Published:
2014
Citation:
Elmer W. H. 2014. Diseases of asparagus. In Diseases of Temperate Vegetable Plants, CABI, Ed. Ray George (In Press).
- Type:
Book Chapters
Status:
Awaiting Publication
Year Published:
2014
Citation:
Elmer, W. H., and Datnoff, L. E. 2014, Plant Health Management: Mineral Nutrition and Suppression of Plant Disease, pages xxx, In: Encyclopedia of Agriculture and Food Systems Ed. R. James Cook Elsevier, Oxford, UK (In Press).
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
Elmer, W. H. 2014. A tripartite interaction between Spartina alterniflora, Fusarium palustre and the purple marsh crab (Sesarma reticulatum) contributes to Sudden Vegetation Dieback of salt marshes in New England. Phytopathology 103: Accepted
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Huang, C-H, Roberts, G. L. R., Elmer, W. H., and Datnoff, L. E. 2013. Population structure of Fusarium oxysporum f. sp. radicis-lycopersici in Florida inferred from vegetative compatibility groups and microsatellites. European Journal of Plant Pathology 136:509-521.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Elmer, W. H., and McGovern, R. J. 2013. Epidemiology and management of Fusarium wilt of China aster. Plant Disease 97: 530-536 http://dx.doi.org/10.1094/PDIS-05-12-0445-RE.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: The fungal genus Fusarium is diverse with over 200 species reported. Although many species persist as saprophytes, almost every plant species is colonized endophytically by at least one Fusarium species. Many of these species are specific to their host and can cause diseases. In Connecticut, the species F. avenaceum, F. graminearum, F. proliferatum, and F. subglutinans, along with members of the F. oxysporum species complex and the F. solani species complex, are found most frequently. In 2011, a new species (F. palustre) was discovered on Spartina alterniflora in the salt marshes in CT where Sudden Vegetation Dieback (SVD) occurred. F. palustre is closely associated with S. alterniflora and has a greater tolerance for salinity than terrestrial species. Its center of origin is not known. A 2012 survey of salt marshes in Shanghai, China, found F. palustre was a major colonist of S. alterniflora. However, since S. alterniflora was introduced to China in the 1960's, it may have been introduced along with its host. A recent survey of salt marshes in Argentina where S. alterniflora is native is currently being assayed to determine if F. palustre can be found. These geographically distinct populations will be used to determine the level of genetic diversity. These findings, thus far, have been presented at state, regional, national, and international conferences. This project has been used to mentor two high school students at New Haven Sound School. The pathogenic relationships among members of the F. oxysporum species complex that cause root rots and wilts was also studied. The epidemiology of the China aster wilt disease was shown to be the result of infested seed lots. Simple sterilization procedures can eliminate this destructive pathogen. Cross pathogenicity with other plants in the Asteraceae was not observed. Fusarium populations on Liriope, Ruscus, and asparagus were tested for cross pathogenicity. We were unable to demonstrate pathogenicity of any isolates on healthy Ruscus and concluded those isolates were endophytes that may only cause damage on compromised plants. Pathogenicity tests on Liriope were delayed due to problems in germinating seeds and obtaining clean plant material, but a new plant source has been identified. On tomato, wilt caused by F. oxysporum f. sp. lycopersici (FOL) was observed in New Hampshire on resistant cultivars. Cultivars resistant to Race 2 and to both Race 2 and Race 3 were grown along with susceptible Bonnie Best and inoculated with test isolates and an isolate of Race 2. Wilt and vascular discoloration were observed on plants resistant to Race 2, but race 3-resistant tomatoes remained healthy, demonstrating the appearance of Race 3 in New England. The experiment is being repeated. A new disease of bloodroot caused by F. oxysporum previously reported in Guilford, CT in 2011, has recently appeared in New Hampshire. It is not known if it is the same strain of F. oxysporum or if another genotype has emerged. Isolates have been obtained and are being compared to the CT strains. PARTICIPANTS: The main investigator on this project is Dr. Wade H. Elmer of the Department of Plant Pathology and Ecology at The Connecticut Agricultural Experiment Station (CAES). Participants included Dr. Robert E. Marra of CAES, who has an interest in the population genetics of F. palustre, Dr. Ann Chase of Chase Gardens, Mt. Aukum, CA, and Mr. Tom Dudek, Michigan State Extension, Michigan State University and Lorraine Graney, Bartlett Tree Co., provided the diseased plant material and will continue to participate in the project by locating new infected plants. We have other collaborations with Dr. Frank Caruso of the Cranberry Research Station at the University of Massachusetts. Mr. Peter Thiel, CAES, provided technical support for this project. TARGET AUDIENCES: These findings are targeted to scientific groups, such as plant pathologists, mycologists, wetland ecologists, and environmentalists. They are also important for stakeholders that have an interest in diseases of ornamental plants, vegetables, and salt marsh habitats, such as coastal townships, communities, state parks, and property owners. This research is of interest to grade, middle, and high school students for science projects. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Soilborne diseases are conservatively estimated to cost US agriculture between 10-20% of the attainable yield for most crops resulting in an economic loss of over 250 billion dollars for 2011 alone. Diseases caused by species of Fusarium represent a sizeable fraction of these losses and also include human health threats from mycotoxin-contaminated grains. Experimentation to better understand their ecology, pathology, and epidemiology is warranted. This information helps lay the framework for understanding how species may selectively colonize one principal host and/or niche. It also demonstrates the value of surface-sterilizing China aster seed since Fusarium wilt can eliminate up to half of the plants during a season. Our discovery that F. palustre can tolerate high saline conditions suggests it evolved in salt marsh habitat. The collaboration with Dr. Robert Marra will provide evidence as to its overall diversity and may lend support to where the fungus originated. Salt marshes are the most productive ecosystems on the planet so understanding the cause of the SVD is very important to protect the marshes along Connecticut's Long Island Sound. Cross pathogenicity among isolates in the F. oxysporum species complex is generally rare, but when it does occur, it is paramount that growers know what the alternate hosts are. Identifying hosts that may share common pathogens can aid growers in planning rotation strategies.
Publications
- Elmer, W. H., and McGovern, R. J. 2013. Epidemiology and management of Fusarium wilt of China asters. Plant Disease http://dx.doi.org/10.1094/PDIS-05-12-0445-RE
- Elmer, W. H., and Marra, R. E. 2012. First report of crown rot of bloodroot (Sanguinaria canadensis) caused by Fusarium oxysporum in the United States. Plant Disease 96:1577. http://dx.doi.org/10.1094/PDIS-11-11-1008-PDN.
- Elmer, W. H., Useman, S., Schneider, R. W., Marra, R. E., LaMondia, J. A., Jimenez-Gasco, M., Mendelssohn, I. A., and Caruso, F. L. 2013. Sudden Vegetation Dieback in Atlantic and Gulf Coast salt marshes. Plant Disease (http://dx.doi.org/10.1094/PDIS-09-12-0871-FE.
- Geiser, D. M., Aoki, T., Bacon, C. W., Baker, S. E., Bhattacharyya, M. K., Brandt, M. E., Brown, D. W., Burgess, L. W., Chulze, S., Coleman, J. J., Correll, J. C., Covert, S. F., Crous, P. W., Cuomo, De Hoog, G. S., Di Pietro, A., Elmer, W. H., Epstein, L., Frandsen, R. J. N., Freeman, S., Glenn, A. E., Gordon, T. R., Hammond-Kosack, K. E., Hanson, L. E., del Mar Jimenez-Gasco, M., Kang, S., Kistler, C., Kuldau, G. A., Leslie, J. F., Logrieco, A., Lu, G., Lysoe, E., Ma, L., McCormick, S. P., Migheli, Q., Moretti, A., Munaut, F., O'Donnell, K., Pfenning, L., Ploetz, R. C., Proctor, Rehner, S. A., Robert, V. A. R. G., Rooney, A. P., bin Salleh, B., Scandiani, M. M., Scauflaire, J., Steenkamp, E., Suga, H., Summerell, B. A., Sutton, D. E., Thrane, U., Trail, F., Van Diepeningen, A., VanEtten, H. D., Viljoen, A., Waalwijk, C., Ward, T. J., Wingfield, M. J., Xu, J. R., Yang, X. B., Yli-Mattila, T., and Zhang, N. 2013. One Fungus, One Name: Defining the genus Fusarium in a scientifically robust way that preserves longstanding use. Phytopathology (In Press).
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Within the fungal genus Fusarium, over 200 species have been described. The majority of these species are associated with a plant disease. In Connecticut, the pathogenic species commonly found on economically important crops are F. avenaceum, F. graminearum, F. proliferatum, and F. subglutinans, along with members of the F. oxysporum species complex and the F. solani species complex. Many species may have developed a selective advantage for the habitats in which they live. Recently, a new pathogenic species (F. palustre) was discovered in the salt marshes in Connecticut where a dieback of smooth cordgrass (Spartina alterniflora) occurred. Salinities in salt marsh average around 25-30 mM NaCl, but can reach as high as 100 mM in microhabitats. Fusarium palustre may have a greater level of tolerance for the harsh saline conditions in a salt marsh than similar species isolated from terrestrial plants. One similar species, F. sporotrichioides, is found on corn. These two species were compared for tolerance to salinity. Three cultures of F. sporotrichioides from cornfields in Connecticut were compared to three cultures of F. palustre for their radial growth on NaCl-amended agar. It was observed that at higher saline conditions (54 mM NaCl), the F. palustre isolates from the salt marsh were significantly more tolerant to salinity than F. sporotrichioides indicating a selective advantage for salt marsh species. Another objective for this project was to understand the relationships among Fusarium strains that cause root rots on related hosts such as asparagus, Ruscus spp., and Liriope spp. The genetic structure of these isolates is not clear, but a rich database is now available in Genbank for the tef1 sequences, which allows researchers to determine genetic relatedness. We have hypothesized that the populations found on Ruscus spp. and Liriope spp. will be very similar to the populations found on asparagus and that there will be many isolates that are pathogenic on multiple hosts. To test this, infected Ruscus and Liriope were obtained from commercial fields in California and Michigan where root rot symptoms were present. Isolations from diseased Ruscus onto selective agar and identification yielded exclusively F. solani, but from Liriope the species F. solani, F. oxysporum, F. subglutinans, and F. proliferatum were recovered. Again in 2011, we were unable to demonstrate pathogenicity on Ruscus. New pathogenicity tests on Liriope were delayed due to problems with obtaining plant material. In another system, F. oxysporum was isolated from a woodland wildflower called bloodroot and was shown to be pathogenic on healthy plants. Interestingly, this isolate yielded sequences for the tef1 gene that were identical to the tomato wilt pathogen, F. oxysporum f. sp. lycopersici (FOL). However, when both isolates were tested on tomato seedlings, only the tomato wilt Fusarium caused disease indicating there is more diversity in the FOL complex than previously thought. PARTICIPANTS: The main investigator on this project is Dr. Wade H. Elmer of the Department of Plant Pathology and Ecology at The Connecticut Agricultural Experiment Station (CAES). Participants included Dr. Robert E. Marra of CAES, who assists in molecular analyses on the isolates. Dr. Francis J. Ferrandino also participated in the sampling of corn. Dr. Ann Chase of Chase Gardens, Mt. Aukum, CA, and Mr. Tom Dudek, Michigan State Extension, Michigan State University provided the diseased plant material and will continue to participate in the project by locating new infected plants. We have other collaborations with Dr. Frank Caruso of the Cranberry Research Station at the University of Massachusetts. Mr. Peter Thiel, CAES, provided technical support for this project. TARGET AUDIENCES: These findings are targeted to scientific groups, such as plant pathologists, mycologists, wetland ecologists, and environmentalists. They are also important for stakeholders that have an interest in diseases of ornamental plants, vegetables, and salt marsh habitats, such as coastal townships, communities, state parks, and property owners. These findings are also of interest to grade school children. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Understanding how Fusarium species are adapted to different host systems will begin to lay the framework for understanding how species may selectively colonize one principal host and/or niche. Salt marshes are the most productive ecosystems on the planet so understanding the cause of the dieback is very important to protect the marshes along Connecticut's Long Island Sound. The propensity for F. palustre to tolerate high saline conditions may have allowed it a selective advantage for the salt marsh habitat. This discovery could explain why so few species of Fusarium are recovered from Spartina plants. As saline conditions increase during periods of drought, F. palustre's ability to tolerate excessive salinity may have allowed it to competitively colonize and incite disease, which in turn, contributed to the dieback. Cross pathogenicity among isolates in the F. oxysporum species complex is generally rare. Identifying hosts that may share common pathogens can aid in understanding whether or not similar genetic traits are present. Many gene sequences like the tef1 gene were thought useful in not only identifying strains of Fusarium but might identify pathogenic formae speciales in Fusarium. Our findings suggest that, in some circumstances, the tef1 gene is not specific for pathogenicity.
Publications
- Elmer, W. H., LaMondia, J. A., and Caruso F. L. 2011. Association between Fusarium spp. on Spartina alterniflora and dieback sites in Connecticut and Massachusetts. doi.org/10.1007/s12237-011-9448-9.
- Elmer, W. H., and Marra, R. E. 2011. New species of Fusarium associated with dieback of Spartina alterniflora in Atlantic salt marshes. Mycologia 103:806-819. doi: 10.3852/10-155.
- Elmer, W. H., and Marra, R. E. 2011. Fusarium crown rot of bloodroot (Sanguinaria canadensis) in Connecticut caused by Fusarium oxysporum. Plant Disease (In press).
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Species of the fungus, Fusarium, form the anamorph or asexual stages of Gibberella, Nectria, and Cosmospora teleomorphs. These species cause crown, stem, fruit, and root rots, as well as head blights, stalk rots, and vascular wilts. The causal species commonly found on agronomic crops in Connecticut include F. avenaceum, F. graminearum, F. proliferatum, and F. subglutinans, along with members of the F. oxysporum species complex and the F. solani species complex. The widespread occurrence of root-rotting diseases caused by Fusarium species may be attributed to the ability of these fungi to colonize plant tissue asymptomatically, thus allowing the fungus access to plant tissues, and giving them a selective advantage to infect when conditions for infection become conducive. These opportunistic fungi can then rapidly colonize the tissue upon senescence. Many of these strains may have developed a selective advantage for the habitats in which they live. For example, the newly described species, F. palustre and F. cf. incarnatum, are found 88% of the time on Spartina alterniflora. These particular Fusaria may have a greater level of tolerance for the harsh saline conditions in a salt marsh than similar species isolated from terrestrial plants. On corn, the species F. graminearum (teleomorph Gibberella zeae), F. avenaceum, and F. sporotrichioides are isolated 40%, 10%, and 6% of the time, respectively. Studies to compare and contrast these species for tolerance to salinity and for competitive saprophytic ability on corn and Spartina are planned to test the hypothesis regarding selective advantage and habitat. To date, representative cultures isolated from Maine to Louisiana have been selected and sub-cultured from single spores for this study. Another objective for this project was to understand the relationships among Fusarium strains that cause root rots on related hosts such as asparagus, Ruscus spp., and Liriope spp. It is not clear what the genetic structure of these isolates is, but a rich database is now available for the tef1 sequences in Genbank, which allows researchers to determine genetic relatedness. We have hypothesized that the populations found on Ruscus spp. and Liriope spp. will be very similar to the populations found on asparagus and that there will be many isolates that are pathogenic on multiple hosts. To test this, infected Ruscus and Liriope were obtained from commercial fields in California where root rot symptoms were present. Isolations from diseased Ruscus onto selective agar and identification yielded exclusively F. solani. However, pathogenicity tests found that none of these isolates were virulent on Ruscus. When isolations were made from infected Liriope, several Fusaria were obtained, including F. solani, F. oxysporum, F. subglutinans, and F. proliferatum. Of these, we found that isolates of F. oxysporum gave the highest disease ratings in pathogenicity tests in Liriope. PARTICIPANTS: The main investigator on this project is Dr. Wade H. Elmer of the Department of Plant Pathology and Ecology at The Connecticut Agricultural Experiment Station (CAES). Participants included Dr. Robert E. Marra of CAES, who will assist in molecular analyses on the isolates. Dr. Francis J. Ferrandino also participated in the sampling of corn stubble and with the analysis of spatial patterns. Dr. Ann Chase of Chase Gardens, Mt. Aukum, CA, provided the diseased plant material and will continue to participate in the project by locating new infected plants. We have other collaborations with Dr. Frank Caruso of the Cranberry Research Station at the University of Massachusetts. Mr. Peter Thiel, CAES, provided technical support for this project. TARGET AUDIENCES: These findings are targeted to scientific groups, such as plant pathologists, mycologists, wetland ecologists, and environmentalists. They are also important for stakeholders that have an interest in diseases of ornamental plants, vegetables, and salt marsh habitats, such as coastal townships, communities, state parks, and property owners. These findings are also of interest to grade school children. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
These findings have revealed the species of Fusarium found colonizing the roots of declining Ruscus and Liriope and begin to lay the framework for understanding the genetic relatedness of the various isolates and their ability to act as primary causal agents for the root rots. It also provides new information for growers to help them understand that some stressors, e.g., wet soils, drought, poor nutrition, may help to predispose these plants to root rot. Studies in progress designed to evaluate if Fusarium species isolated from Spartina and corn have developed selective advantages will advance our understanding of the evolutionary relationships between Fusarium spp. and host plant and our understanding of the ecology of Fusaria in different plant communities.
Publications
- Elmer, W. H. 2010. Asparagus in Connecticut and diseases to watch out for. Connecticut Weekly Agricultural Report, June 23, 2010.
- Elmer, W. H. 2010. Asparagus in Connecticut and diseases to watch out for. The Connecticut Agricultural Experiment Station Fact Sheet. http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/pl ant_pathology_and_ecology/asparagus_in_connecticut_06-11-10.pdf.
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