Understanding plant diseases to ensure food security
Population projections indicate that there will be nine billion people to feed by 2050. That is a large number, and every grain of wheat counts. About a fifth of the calories consumed by humans globally comes from wheat, and when the resistance to a cereal disease like a rust fungus fails, crop losses follow, causing epidemics in places like Africa and Asia. Controlling rusts by genetics in the future must be done in a more stable manner than it is now, because we are currently expending too large of an effort with too many failures. For example, developing countries are suffering much crop loss in an unpredictable fashion; other countries, like the US, are relying too heavily on pesticides. Dr. Scot Hulbert, Cook Chair for Cropping Systems Pathology at Washington State University, develops genetic approaches to control crop diseases while reducing the use of pesticides. By engineering crop resistance to pathogens, Dr. Hulbert hopes to improve food security in the US and in other countries.
The easiest and most efficient way to control serious losses to plant diseases is by planting disease resistant crop varieties, but plant pathogenic microbes evolve very rapidly to overcome each new variety. Specifically focusing on wheat, Dr. Hulbert is therefore researching why some sources of resistance are more durable than others, and furthermore, looking for methods to engineer durable resistance. Dr. Hulbert also collaborates with several wheat breeding programs around the country and at international centers, as the breeding teams are important for getting his results into the farmers' hands and fields. Supported by the USDA’s AFRI program to characterize cereal rust effectors, Dr. Hulbert’s team has an interdisciplinary mix of basic plant and fungal biology, as well as direct applications in crop improvement, not only for environmental but also for economic purposes.
Current areas of research include:
- What are the mechanisms that the fungus uses to overcome plant defenses? In his previous work, Dr. Hulbert identified several components or processes that the pathogen uses to promote its virulence on plants. Generally, the resistance is mediated by genes that recognize the pathogen, or components of the pathogen, like a protein that mounts to a defense response that protects the crop from fungus. Therefore, if the fungus learns to lose the protein, then the plant defense system can no longer recognize the pathogen and becomes vulnerable to the epidemic. Dr. Hulbert and his team are continuing to study the tactics of the rust fungus to prevent it from breaking down plant resistance.
- Are there features of the pathogen that can be recognized by plant defenses that are more difficult to alter by evolution? By identifying the target that the resistance gene could detect, Dr. Hulbert hopes to strengthen the resistance in crops and render it more durable.
- Are there plant resistance genes that confer resistance to the pathogen that aren’t based on pathogen recognition? This part of the research considers engineering resistance genes that may function by other methods than recognizing a pathogen component. Dr. Hulbert and his team have developed gene silence approaches; silencing essential genes in the pathogens can prevent them from developing in the plants. They have also found resistance genes that aren’t based on pathogen recognition that seem to increase the defense of the plants.
Dr. Scot Hulbert grew up on a family farm that specialized in seed production of vegetables. He became interested in crop improvement, or plant breeding, after seeing the advantages and disadvantages of different varieties. He became very interested in how different varieties seemed to be more resistant to different pests and required fewer pesticides. He also met several plant breeders and seed specialists from international seed companies when they checked their production fields. The realization that people actually made these different vegetable varieties, and the alternative prospects of long hours on a tractor for the rest of his life, led Dr. Hulbert to a career in plant genetics and pathology.
In addition to plant biology, Dr. Hulbert really enjoys being involved in national and international world agriculture, traveling and looking at agriculture in different parts of the world. He loves to meet scientists in developing countries working on such problems, and trade ideas and genetic material.
For more information, visit http://plantpath.wsu.edu/people/faculty/hulbert/