2012 Annual Report
1a.Objectives (from AD-416):
Evaluate the impact of soil environmental factors on the behavior (including disease suppression and colonization of plant surfaces) of biological control agents (BCAs). Evaluate the impact of interactions resulting from the combination of BCAs with other biologically or chemically based control measures on the performance of BCAs. Develop strategies to enhance compatibility between BCAs combined with other BCAs or cover crops in biologically based disease control strategies directed at controlling Pythium ultimum, Phytophthora capsici, and Meloidogyne incognita on cucumber and pepper. Develop strategies for combining chemical pesticides with biologically based disease control methods in integrated pest control strategies directed at controlling P. ultimum, P. capsici, and M. incognita on cucumber and pepper.
1b.Approach (from AD-416):
Use basic microbiology techniques to determine soil factors that negatively impact performance of biological control agents. Use techniques from molecular biology, biochemistry, and basic microbiology to identify genes to use as reporters for environmental conditions that negatively impact biological control performance. Multi-disciplinary collaboration in growth chamber and greenhouse studies will determine impacts of cover crops and chemical controls on performance of biological control agents.
A manuscript written by scientists at USDA-ARS, Beltsville in collaboration with scientists at the Oil Crops Research Institute, Wuhan, People's Republic of China, regarding the development of formulated biological control agents for suppression of soilborne diseases of oilseed rape was accepted for publication. A manuscript evaluating natural variations of proteins in soybean seeds using a proteomic approach was accepted for publication. A manuscript written by scientists at USDA-ARS, Corvallis in collaboration with scientists at Rutgers University and USDA-ARS, Beltsville that detailed the impact of the cucumber seed environment on expression of genes in biological control bacteria, including genes involved in stress responses and biological control, was submitted for publication. Work determining the role of the regulatory protein Vfr of Pseudomonas fluorescens Pf-5 in colonization of plant roots in various soil-types was completed by scientists at USDA-ARS, Beltsville in collaboration with scientists at USDA-ARS, Corvallis and Rutgers University. It was found that Vfr plays a critical role in colonization of cucumber roots in most soils. A manuscript regarding this work is being prepared. Work investigating extracts of beneficial bacteria with regard to suppression of Pythium ultimum on cucumber was completed. It was found that only ethanol extracts from Serratia marcescens N4-5 when coated onto cucumber seed controlled this pathogen. Extracts from several Burkholderia spp. isolates and other S. marcescens isolates were ineffective. Experiments have been initiated to determine the possibility of combining ethanol extracts from isolate N4-5 with biological control fungi for control of multiple diseases of cucumber. A number of cold-tolerant Trichoderma isolates have been isolated that have demonstrated antagonism toward the plant pathogens Rhizoctonia solani and Fusarium culmorum in vitro and in growth chamber pot studies with cucumber and wheat plants. These isolates were isolated and tested in collaborative work by scientists at the All-Russian Research Institute of Phytopathology, Bolshiye Vyazyomy, Russia and at USDA-ARS, Beltsville.
Hu, X., Roberts, D.P., Maul, J.E., Emche, S.E., Liao, X., Gao, X., Gao, Y., Mckenna, L.F., Buyer, J.S., Liu, S. 2011. Formulations of the endophytic bacterium Bacillus subtilis Tu-100 suppress Sclerotinia sclerotiorum on oilseed rape and improve plant vigor in field trials conducted at separate locations. Canadian Journal of Microbiology. 57(7): 539-546.
Baker, C.J., Kovalskaya, N.U., Mock, N.M., Owens, R.A., Deahl, K.L., Whitaker, B.D., Roberts, D.P., Hammond, R., Averyanov, A.A. 2012. An internal standard technique for improved quantitative analysis of apoplastic metabolites in tomato leaves. Physiological and Molecular Plant Pathology. 78:31-37.
Natarajan, S.S., Xu, C., Garrett, W.M., Lakshman, D.K., Bae, H. 2011. Assessment of the natural variation of low abundant metabolic proteins in soybean seeds using proteomics. Journal of Plant Biochemistry and Biotechnology. 21:30-37.