Non Technical Summary
Soybean, one of the world's most valuable oil-seed crops, is also a major source of protein for animal feed and human diets. The U.S. is the world leader in soybean production. In 2010, the total U.S. soybean crop value was over $38.9 billion. It is estimated that the soybean crop would have been 14.4% higher if there were no incidence of diseases. Soybean sudden death syndrome (SDS) is a major disease; and in 2010, it caused crop loss valued $820M. This loss will be exacerbated if SDS continues to spread or if climate extremes create soil conditions conducive to the SDS pathogen, Fusarium virguliforme. There are no effective management tools to control SDS. SDS resistance of soybean lines is partial and governed by many quantitative trait loci. Genes encoding complete SDS resistance are yet to be discovered. Therefore, the need for alternative, complementary SDS resistance encoded by transgenes is crucial to protect this crop. In this project, we will evaluate the feasibility of several genetic approaches to create stable transgenic soybean lines with enhanced resistance to this major disease. These include: (i) suppress the pathogen's growth by expressing synthetic genes in soybeans; (ii) induce SDS resistance by expressing genes from Arabidopsis and maize in soybean; (iii) express synthetic plant antibodies to nullify toxins in soybean; and (iv) express a gene of the SDS pathogen in soybean to promote SDS resistance. SDS resistant lines will then be evaluated against selected SDS pathogen isolates representing five geographical regions, viz., Iowa, Illinois, Indiana, Argentina and Brazil. Selected transgene(s) for enhanced SDS resistance will be incorporated into elite soybean lines. To accomplish these objectives, relevant cutting-edge technologies including a micro-fluidic RNAi assay to identify vital F. virguliforme genes, phase display to identify synthetic plant antibody genes, HiSeq 2000 sequencing of 175 pathogen-isolates, and optical biosensors to identify the strongest toxin-interacting peptides will be applied. Outcomes/impacts: Gains in knowledge are: Our investigation is expected to identify gene(s) of F. virguliforme that are vital for infection and disease development and reveal if suppression of the expression of these genes in the pathogen is feasible by expressing relevant transgenes in soybean. If demonstrated, we would develop an innovative approach to manage SDS. In addition, sequence analyses of 175 SDS pathogen isolates will reveal the molecular complexity of the pathogen. Expected actions are: Incorporation of one or more of the selected transgenes will result in elite soybean lines with enhanced SDS resistance and consequently increased profitability for soybean growers who chose to use this transgenic technology to manage the SDS. Expected changes in conditions are: Our project is expected to result in reduced soybean yield losses from SDS; improved farm economy from growing elite transgenic soybean lines with enhanced SDS resistance; development of a new generation of teachers, educators and scientists, who will contribute towards enhanced crop production for sustainable food security.
Transgenic Approaches in Managing Sudden Death Syndrome in Soybean
Non Technical Summary