International Research Fellowship Program: Towards Conservation and Sustainable Use: Genetic Diversity and Reproductive Mode of the Endangered Himalayan Fungus O. sinensis

国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该项目的奖项提供了联合研究的机会，并提供了使用国外独特或互补的设施、专业知识和实验条件的机会。这一奖项将支持凯瑟琳·布什利博士与姚一建博士在中国微生物研究所为期24个月的研究奖学金。冬虫夏草是一种濒危、特有、珍贵的药用真菌，寄生于喜马拉雅鬼蛾Thitarodes(异名：Hepialus)。真菌和寄生飞蛾的组合，在藏语中被称为“冬虫夏草”，在汉语中被称为东冲夏草，在中国和藏医药中已经被收获和药用了至少三个世纪。然而，在过去的十年里，市场价值增加了近十倍，导致了更多的收获和过度开采。该项目解决了中华按蚊在1)系统学、2)遗传多样性、3)生殖生物学和4)生态学方面的几个基本科学知识空白，目前这些空白阻碍了评估增加捕捞对种群生存能力的影响和制定可持续利用战略的努力。多位点序列数据集正被用来更好地划定中华按蚊的物种边界，群体遗传标记(微卫星和SNPs)正在被开发来表征遗传多样性在亚群体内和亚群体之间的分布。本研究还将有助于通过克隆交配型基因座更好地了解中华对虾的生殖生物学，以确定中华对虾是同源(自交)还是异源(异交)。此外，还通过估计异交率、利用基于序列的标记估计随机交配和重组率以及分析位于云南省的四个野外种群中国的精细空间遗传变异模式，研究了自然种群的生殖生物学和孢子传播。该项目的科学影响包括划定系统发育物种和表征这种经济上重要的真菌的遗传多样性和繁殖生物学。这项研究的结果将有助于保护工作以及扩大对自然界中昆虫病原真菌的生态学和空间分布的了解，这对它们在农林中作为生防剂的开发具有应用价值。这项工作的更广泛的影响包括对博士后和本科生的高级培训和国际合作，建立中国冬虫夏草生物学科学专家与美国之间新的关系，并通过各种途径向中国和美国的科学家和公众传播与保护中华虫草有关的知识：1)在同行评议的期刊上发表文章，2)与密切参与资源管理的当地收割机分享知识；3)为来自几个喜马拉雅国家的研究人员主办一次关于中华虫草可持续利用的国际研讨会。

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Kathryn Bushley to work with Dr. Yijian Yao at the Institute of Microbiology in China. Ophiocordyceps sinensis (synonym: Cordyceps sinensis) is an endangered, endemic, and highly valued medicinal fungus which parasitizes species of the Himalayan ghost moth Thitarodes (synonym: Hepialus). The combination of fungus and parasitized moth, called Yartsa gunbu ("winter-worm, summer-grass") in Tibetan or dongchong xiacao in Chinese, has been harvested and used medicinally in both Chinese and Tibetan Medicine for at least three centuries. Within the last decade, however, a nearly tenfold increase in market value has led to increased harvest and overexploitation. This project addresses several fundamental gaps in scientific knowledge of the 1) systematics, 2) genetic diversity, 3) reproductive biology, and 4) ecology of O. sinensis which currently hamper efforts to assess the impacts of increased harvesting on population viability and to develop strategies for sustainable use. Multilocus sequence datasets are being used to better delimit species boundaries of O. sinensis and population genetic markers (microsatellites and SNPs) are being developed to characterize the distribution of genetic diversity both within and between subpopulations. This research will also contribute to a better understanding of the reproductive biology of O. sinensis by cloning the mating type locus to determine whether O. sinensis is homothallic (selfing) or heterothallic (outcrossing). Reproductive biology and spore dispersal in natural populations are also being investigated by estimating the outcrossing rate, evaluating random mating and rates of recombination using sequence based markers, and analyzing patterns of fine scale spatial genetic variation in four field populations located in Yunnan province, China. The scientific impacts of this project include delimiting phylogenetic species and characterizing the genetic diversity and reproductive biology of this economically important fungus. Results of this research will contribute to conservation efforts as well as expand knowledge of the ecology and spatial distribution of insect pathogenic fungi in nature which has applications towards their development as biocontrol agents in agriculture and forestry. The broader impacts of this work include advanced training and international collaboration for the postdoctoral fellow and undergraduate students, the forging of new relationships between scientific experts in Cordyceps biology from China and the U.S., and dissemination of knowledge relevant to conservation of O. sinensis to scientists and the general public in both China and the U.S. through a variety of means: 1) publication in peer reviewed journals, 2) sharing of knowledge with local harvesters intimately involved in managing the resource, and 3) hosting of an international symposium on sustainable use of O. sinensis for researchers from several Himalayan nations.