Comment from Pamela Ronald, University of California, Davis

I am writing to urge you to NOT list all pathovars of Xanthomonas oryzae on the USDA select agent list. I urge you to continue to support the safe use of Xanthomonas oryzae pv. oryzae for experimental purposes in California and the US. There is no evidence of an agricultural risk in working with this pathogen under controlled conditions, which has been done worldwide for 40 years. Furthermore, after over 20 years of experimental work with X. oryzae pv. oryzae in California and elsewhere in the US, researchers have a perfect safety record. This is not surprising because researchers follow strict protocols to prevent unintended release. Furthermore, conditions and practices of rice production in California (direct seeding; the absence of hurricanes/typhoons; high humidity; etc) are not conducive to the development or spread of the disease. International travel and trade pose a much larger risk of introducing invasive plant pests into agricultural crops as compared to research activities. One of the aims of Xoo research is to mitigate this risk by garnering knowledge and tools for disease prevention, diagnosis, and effective response. If we limit the study of pathogen/host systems that are not in the US at present, our ability to implement crop protection means in response to disease outbreaks will be severely limited. Therefore, continued public research into the interaction of X. oryzae pv. oryzae with rice is a critical component of US biosecurity. It is widely recognized by the leading US funding agencies (NIH, NSF, USDA) that the X. oryzae pv. oryzae /rice interaction is one of the best-developed systems for investigating plant-microbe interactions. Rice and X. oryzae pv. oryzae are genetically tractable, the rice and X. oryzae pv. oryzae genomes are sequenced, and rice is a model for studies of all cereals. Many important discoveries that increase our understanding of how all plants resist disease have resulted from studies of X. oryzae pv. oryzae /rice interaction. In addition, useful products have been developed such as rice carrying the disease resistance gene Xa21. Rice disease resistance genes are very similar to those present in other plants and in animals. Therefore, discoveries gained from studies of the X. oryzae pv. oryzae /rice interaction have had and will continue to have a broad impact in agriculture and medicine. Much of this discovery is driven by the research programs of scientists working in the US. As a reflection of the high quality of this research using rice and X. oryzae pv. oryzae as a model system, numerous papers have been published in leading scientific journals such as Science and Nature. For example, work from my laboratory on X. oryzae pv. oryzae has been cited over 1000 times in the scientific literature. X. oryzae pv. oryzae studies have also been widely acclaimed in the US newspapers (e.g., Wall Street Journal and New York Times) as well as in the rest of the world. With knowledge gained through studies of X. oryzae pv. oryzae, improved rice and other plant varieties can be developed through traditional breeding or genetic engineering. For example, sheath blight, caused by Rhizoctonia solani, is one of the most common and devastating rice diseases in the world. In the US, yield losses of 50% can occur from this disease. Complete genetic resistance to sheath blight has not been identified in cultivated rice. As a result, in the southern growing region of the US alone, ~ $24 million was spent for fungicide to control sheath blight disease in 2003. Reducing fungicide use on rice would significantly reduce production costs and would enhance development of environmentally benign rice production systems. For these reasons, the USDA recently funded a 5-year, $5 million program to help develop new methods for disease control; much of the funding has gone to research involving X. oryzae pv. oryzae because this is a model for understanding other diseases. It was not clear whether the suggestion to list Xoo as a select agent was based on doubts about the importance of this research specifically in California or in the US as a whole but there are many reasons why California is a critical site for such study. X. oryzae pv. oryzae research addresses diseases such as blast, a fungal disease of rice, which was identified in California for the first time in September 1996 and has recurred every year since, as well as stem rot and aggregate sheath spot. These are all prevalent and important diseases in California and all California cultivars are susceptible to these diseases. Information gained on disease resistance to X. oryzae pv. oryzae can be used to address these important problems. In fact though research using X. oryzae pv. oryzae we have already identified genetic factors that potentially control resistance to other diseases and have introduced these factors into rice breeding programs. Furthermore, blast, stem rot and aggregate sheath spot are the three qualifying diseases for purposes of the conditional burn program, which began September 1, 2001. To obtain a permit to burn rice straw, rice growers must inspect their fields and determine if they have a "significant and quantifiable disease." Therefore if we can increase the resistance to these diseases we will not only increase yields but we will reduce air pollution in the Central Valley of California. Xanthomonas species also affect virtually all other US crops, including citrus, beans, grapes, strawberries, and cotton. With what we learn from study of X. oryzae pv. oryzae may allow development of strategies to control other species in the group such as X. axonopodis pv. citri a citrus pathogen. The Florida US citrus is valued at $8.5 billion. Although X. axonopodis pv. citri directly reduces fruit quality and yield, the impact is worsened because the presence of citrus canker in an area triggers immediate quarantine restrictions, disrupting the movement of fresh fruit. Rice plant genomics is becoming an increasingly sophisticated science and, as a result, becoming more difficult for the end users - and even more so for the general public - to understand. In an effort to actively and effectively communicate the science and potential of rice plant genomics to all segments of society, highly experienced teams composed of molecular biologists and educators are needed in every state to coordinate the education, extension and outreach efforts. If research facilities are closed in particular states (which would be necessitated by the dramatic increased cost of research that would result if Xoo is placed on the select agents list) , researchers will be forced to move operations - resulting in the most knowledgeable and productive scientists leaving the state and providing a competitive advantage to researchers in China, India and other countries where X. oryzae pv. oryzae research is a high priority. As far as I can ascertain, the plant pathology community has not had input into the designation of this pathogen as a select agent. I would therefore like to invite you to meet with representatives of the American Phytopathological Society (APS) to assess the risk, provide reasonable guidelines for minimizing risk and discuss the rationale and ramifications of the decision for the benefit of the public research community. By engaging all stakeholders in assessing the risks and benefits of research on exotic diseases ? growers, state representatives, funding agencies, and scientists ? the USDA-APHIS will be able to maximize the best approaches to safeguard our agriculture. We encourage you to engage such stakeholders as you make science-based policy decisions about whether to limit research on certain diseases. I am grateful for the time you have taken to read this communication, and look forward to a positive response. Respectfully, Pamela Ronald Professor of Plant Pathology, Chair, Plant Genomics Program University of California, Davis