Progress 08/01/08 to 07/31/11
Outputs
OUTPUTS: Soybean cyst nematode reduced U.S. soybean yields 93.98 million bushels during 2007, 171.9 million bushels during 2008, and 120.1 million bushels during 2009. Soybean cyst nematode reduced U.S. soybean yields more than any other disease each year since 1996. Soybean cyst nematode caused more yield suppression than any other disease in the top eight soybean producing countries during 2006. We developed one productive early group V conventional soybean line, S05-11482 that has broad resistance to SCN HG types or races. This line has shown resistance to SCN races 1, 2, 3, 5, and 14 and has shown resistance to reniform nematode Rotylenchulus reniformis. S05-11482 also shows good resistance to root knot nematode (Meloidogyne incognita) and frogeye leaf spot (Cercospora sojina). We recently released germplasm line S02-2259 was recently released. It is a late group 5 maturity and was released to breeders for use in crossing for soybean improvement. It is resistant to SCN HG type 0 (race 3) based on greenhouse tests at Portageville and Columbia, MO. S02-2259 is also resistant to stem canker, bacterial pustule and some races of frogeye leaf spot. It will be useful as a parent because it combines high yield potential and disease resistance with 25% of its pedigree derived from plant introductions that are not known to be present in the current gene pool for cultivar development. We increased seeds of a conventional line, SS01-3769, with SCN resistance. This line is ready for release. It is a late maturity group III, is tolerant to Phytophthora root rot, and it has good resistance to sudden death syndrome. Two F2:3 populations derived from the Magellan x PI438489B and Magellan x PI567516C crosses were genotyped with 250 SSR and 20 SNP markers to confirm putative QTL and identify novel QTL/genes. In the Magellan x PI438489B population, we have identified and mapped two known QTLs (rhg1 and Rhg4 loci) on LG G and A2. In addition, we also mapped putative QTLs on LG C1, J, and K. We are currently utilizing F7 recombinant inbred line (RIL) of this population to confirm mapped QTLs and develop near-isogenic lines (NILs) for fine-mapping and positional cloning. Soybean cyst nematodes produce secreted CLAVATA3 ⁄ ESR (CLE)-like peptides effector proteins as peptide mimics of plant CLEs to developmentally reprogram root cells to form specialized feeding cells called syncytia. Immunologic, genetic and biochemical approaches were used to reveal the localization and site of action of H. glycines-secreted CLE proteins in planta. The site of action and mechanism of delivery of CLE effectors to host plant cells by the nematode had not been established. Genetic and biochemical analysis confirmed the requirement of the variable domain in planta for host-specific recognition and revealed a novel role in trafficking cytoplasmically delivered CLEs to the apoplast in order to function as ligand mimics. We further determined that variable domain I of nematode CLEs directs post-translational targeting of CLE peptides to the extracellular space. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The soybean cyst nematode (SCN) is the most serious pest of soybean in the United States. The ecological adaptability of this nematode is such that it can apparently thrive and damage soybean wherever this host can be cultivated, a statement that cannot be made for any other soybean pathogen. It spread from two states in 1954 to all soybean producing states by 2006. In 2008, soybean producers nationally lost more than $1.72 billion due to this pest alone. Scientists in Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, North Carolina, Ohio, Oklahoma, South Dakota, and Wisconsin now view SCN as their soybean farmers' worst enemy. Since 2000, the University of Missouri SCN Research Team has developed 19 soybean varieties with resistance to SCN, developed and released 8 soybean breeding lines resistant to SCN, and identified 118 soybean lines that have SCN resistance from the world collection of about 16,000 lines. The genes responsible for SCN resistance in two wild soybean lines commonly used as parents when developing high yielding SCN resistant soybean cultivars have been mapped (finger printed) by the University of Missouri team using molecular methods. This discovery will greatly enhance use of these lines in developing SCN resistant varieties by all soybean breeders in the USA. The benefits from this research are being realized in Missouri and all other states where SCN reduces soybean yield. In Missouri alone, this research has resulted in $50 million greater farm profits each year since 1999.
Publications
- Vuong, T., Sleper, D., Shannon, G., Wu, X., and Nguyen H. 2011. Confirmation of quantitative trait loci for resistance to multiple-HG types of soybean cyst nematode (Heterodera glycines Ichinohe). Theoretical Applied Genetics 123: submitted.
- Wang, J., Joshi, S., Korkin, D., and Mitchum, M.G. 2010. Variable domain I of nematode CLEs directs post-translational targeting of CLE peptides to the extracellular space. Plant Signaling and Behavior 5:12, 1-3. Addendum to New Phytologist 187, 1003-1017.
- Wrather, A., Shannon, G., Balardin, R., Carregal, L., Escobar, R., Gupta, G. K., Ma, Z., Morel, W., Ploper, D., and Tenuta, A. 2010. Diseases effects on soybean yields in the top eight soybean-producing countries in 2006. Online. Plant Health Progress doi:10.1094/PHP-2010-0125-01-RS.
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Progress 08/01/09 to 07/31/10
Outputs
OUTPUTS: Soybean cyst nematode reduced U.S. soybean yields 93.98 million bushels during 2007 and 171.9 million bushels during 2008. The value of this loss to SCN in 2008 was $1.71 billion. Soybean cyst nematode reduced U.S. soybean yields more than any other disease each year since 1996. Next in decreasing order of total U.S. yield loss in 2008 were seedling diseases, Phytophthora root and stem rot, and charcoal rot. We have determined that H. glycines uses molecular mimicry of plant CLE peptide signals as a mechanism for plant parasitism. This is a remarkable adaptation by an animal to developmentally reprogram host plant cells for its own parasitic advantage. The functional conservation of H. glycines and plant CLE proteins is restricted to the C-terminal CLE motif. However, sequences outside the CLE motif are also required for nematode CLE function in planta and were found to have dual roles in cellular targeting and host-specific recognition of nematode CLE proteins. What specifies H. glycines host range and whether there is a genetic basis for this host specificity is not known. Thus, host-specific H. glycines CLE peptide recognition may help explain the molecular mechanism controlling host-range specificity of H. glycines. Moreover, a correlation between the presence of specific CLE sequences in H. glycines populations correlates with their ability to reproduce on resistant soybean germplasm, suggesting that H. glycines may be using CLE peptide mimicry as a mechanism for virulence. We have investigated the role of salicylic acid (SA), a key signaling molecule in plant resistance to biotrophic pathogens for a role in Rhg4-mediated resistance to H. glycines. Studies measuring endogenous SA levels in response to nematode infection and parasitic success on transgenic plants compromised for SA production or on soybean roots following exogenous application with SA, suggest that SA plays a role in basal resistance, but may not play a major role in R gene-mediated resistance to H. glycines. These studies are still ongoing. In an effort to mine new resistance sources, a subset of 650 new PIs (MG III-IV) of the USDA Soybean Germplasm Collection have been evaluated for resistance to six SCN HG types in the greenhouse. Among these, over 30 PIs had high or moderate resistance to single or multiple HG types. A total of 38 new crosses have been made to develop new mapping populations. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The soybean cyst nematode (SCN) is the most serious pest of soybean in the United States. The ecological adaptability of this nematode is such that it can apparently thrive and damage soybean wherever this host can be cultivated, a statement that cannot be made for any other soybean pathogen. It spread from two states in 1954 to all soybean producing states by 2006. In 2008, soybean producers nationally lost more than $1.72 billion due to this pest alone. Scientists in Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, North Carolina, Ohio, Oklahoma, South Dakota, and Wisconsin now view SCN as their soybean farmers' worst enemy. Since 2000, the University of Missouri SCN Research Team has developed 19 soybean varieties with resistance to SCN, developed and released 8 soybean breeding lines resistant to SCN, and identified 118 soybean lines that have SCN resistance from the world collection of about 16,000 lines. The genes responsible for SCN resistance in two wild soybean lines commonly used as parents when developing high yielding SCN resistant soybean cultivars have been mapped (finger printed) by the University of Missouri team using molecular methods. This discovery will greatly enhance use of these lines in developing SCN resistant varieties by all soybean breeders in the USA. The benefits from this research are being realized in Missouri and all other states where SCN reduces soybean yield. In Missouri alone, this research has resulted in $50 million greater farm profits each year since 1999.
Publications
- Shannon, J. G., J. Lee, J. A. Wrather, D. A. Sleper, M. A. R. Mian, J. P. Bond, and R. T. Robins. 2009. Registration of S99-2281 soybean germplasm line with resistance to frogeye leaf spot and three nematode species. J. Plant Registrations 3:94-98.
- Wang, J., A. Replogle, S. Joshi, D. Korkin, R.S. Hussey, T.J. Baum, E.L. Davis, X. Wang, and M.G. Mitchum. 2010. Dual roles for the variable domain in protein trafficking and host-specific recognition of Heterodera glycines CLE effector proteins. New Phytologist 187(4):In Press.
- Lu, S-W., S. Chen, J. Wang, H. Yu, D. Chronis, M.G. Mitchum, and X. Wang. 2009. Structural and functional diversity of CLAVATA3/ESR (CLE)-like genes from the potato cyst nematode Globodera rostochiensis. Mol. Plant-Microbe Int. 22:1128-1142.
- Sindhu, A., T.M. Maier, M.G. Mitchum, R.S. Hussey, E.L Davis, and T.J. Baum. 2009. Effective and specific in planta RNAi in cyst nematodes: expression interference of four parasitism genes reduces parasitic success. Journal of Experimental Botany 60:315-324.
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Progress 08/01/08 to 07/31/09
Outputs
OUTPUTS: Soybean cyst nematode (SCN) suppressed US soybean yields 1.71 million bushels during 2008. The greatest suppression in U. S. soybean production due to diseases in 2008 was caused by SCN followed by seedling diseases, Phytophthora root and stem rot, and charcoal rot. Soybean cyst nematode suppressed US soybean yields more than any other disease each year since 1996. The University of Missouri SCN research team developed one productive early group V conventional soybean lines, S05-11482, that has broad resistance to SCN HG types or races. This line has shown resistance to SCN races 1, 2, 3, 5, and 14 and has shown resistance to reniform nematode Rotylenchulus reniformis. S05-11482 also shows good resistance to root knot nematode (Meloidogyne incognita) and frogeye leaf spot (Cercospora sojina). Yield of this line has been equal to a popular group V Roundup Ready cultivar from Monsanto. We evaluated 120 plant introductions with resistance to SCN to determine if they also have resistance to two other nematode species- root knot nematode (RKN) and reniform nematode (RN) and another important disease frogeye leaf spot (FELS). About half (64) of the SCN resistant PI sources showed resistance to RKN. Of the 64 sources with resistance to RKN, 27 also showed resistance to RN. There were 14 SCN PIs that showed resistance to RKN and FELS. Finally, there were 13 SCN sources which showed resistance to all three diseases RKN, RN and FELS. This information will be useful to soybean breeders who want to develop cross resistance to several nematode species and frogeye leaf spot. We increased seeds of a conventional line, SS01-3769, with SCN resistance. This line is ready for release. It is a late maturity group III, is tolerant to Phytophthora root rot, and it has good resistance to sudden death syndrome. PARTICIPANTS: The project investigators were Dr. Melissa Mitchum, Dr. Henry Nguyen, Dr. Dave Sleper, Dr. Grover Shannon, and Dr. Allen Wrather, and all are faculty in the University of Misssouri Division of Plant Sciences. Each work with scientists at other universities, and the funding for their research is from USDA competitive grants, the United Soybean Board, and local state soybean merchandising councils. TARGET AUDIENCES: The results of the research from this project will be of use to university and private industry scientists, crop consultants, and extension personnel around the United States. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Soybean cyst nematode (SCN), Heterodera glycines, has been and remains the most serious pest to soybeans in the United States. The ecological adaptability of this nematode is such that it can apparently thrive and damage soybean wherever this host can be cultivated, a statement that cannot be made for any other soybean pathogen. In 2008, US soybean producers nationally lost an estimated $1.71 billion (1.71 million bushels at $10/bu) due to this pest. Scientists in Arkansas, Delaware, Georgia, Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, North Carolina, Tennessee, and Virginia view SCN as their soybean farmers' worst enemy. The SCN-soybean interaction is extremely complex. New varieties must continually be developed as the nematode adapts to older ones. Since 2000, The University of Missouri SCN Research Team has developed 19 soybean varieties with resistance to SCN, developed and released 8 soybean breeding lines resistant to SCN, and identified 118 soybean lines that have SCN resistance from the world collection of about 16,000 lines. The genes responsible for SCN resistance in two wild soybean lines commonly used as parents when developing high yielding SCN resistant soybean cultivars have been mapped (finger printed) by the University of Missouri team using molecular methods. This discovery will greatly enhance use of these lines in developing SCN resistant varieties by all soybean breeders in the USA. The benefits from this research are being realized in Missouri and all other states where SCN reduces soybean yield. In Missouri alone, this research has resulted in $50 million greater farm profits per year since 1999.
Publications
- Davis, E.L., R.S. Hussey, M.G. Mitchum, and T.J. Baum. 2008. Parasitism proteins in nematode-plant interactions. Current Opinion in Plant Biology 11:360-366. Invited review article.
- Mitchum, M.G. and T.J. Baum. 2008. Genomics of the soybean cyst nematode-soybean interaction. Chapter 17 In: Genetics and Genomics of Soybean (ed, Gary Stacey). Springer, New York, p.321-341. Invited book chapter.
- Wrather, J. A., and S. R. Koenning. 2009. Effects of diseases on soybean yields in the United States 1996 to 2007. Online. Plant Health Progress doi:10.1094/PHP-2009-0401-01-RS.
- Shannon, J. G., J. Lee, J. A. Wrather, D. A. Sleper, M. A. R. Mian, J. P. Bond, and R. T. Robins. 2009. Registration of `S99-2281' soybean germplasm line with resistance to frogeye leaf spot and three nematode species. J. Plant Registrations 2: (In Press).
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