Genomics of adaptation to agriculture in Striga hermonthica, a plant parasite of cereals

本行动资助2017财年美国国家科学基金会国家植物基因组计划生物学博士后研究奖学金。该奖学金支持奖学金获得者在主办实验室的研究和培训计划，该奖学金获得者还提出了扩大生物学参与的计划。该奖学金的主办机构是宾夕法尼亚州立大学，赞助科学家是杰西·拉斯基博士。农业杂草对农业生产力构成严重威胁，在气候变化的条件下，杂草的侵害可能加剧。为了更好地了解生物和非生物胁迫源之间的相互作用，本项目研究了紫独脚金对不同寄主作物和非生物环境的特化机制。寄生独脚金对撒哈拉以南非洲的粮食生产构成了最大的生物限制，并破坏了玉米、高粱、小米和水稻等重要经济谷物的产量。更广泛的影响包括产生新的基因组和表型资源，以加强抗性作物品种的开发，培训本科生，以及针对非洲科学家的独脚金生物信息学研讨会。培训目标包括统计进化基因组学、古代DNA测序、定量遗传学和实验植物-寄生虫相互作用。该项目的主要目标是更好地了解作物-寄生虫在不同非生物环境中相互作用的进化。首先，通过对过去150年间从东非和西非不同原产宿主收集的200个植物标本进行定向外显子组测序，确定寄主专门化和本地适应的基因组特征。将确定显示与环境和原产寄主统计关联的位点，并通过跟踪区域寄主作物产量随时间变化的等位基因变异。对于第二个目的，非生物胁迫对宿主范围的影响将进行实验评估。对高粱、谷子和玉米3种重要寄主作物60个基因型的20个寄主种群在氮素和水分限制条件下的种子萌发、早期寄主寻找行为和寄主抗性进行了定量研究。项目期间产生的基因组和表型资源将通过在线数据库（NCBI; project Unity, http://phenome-networks.com）和一个专门的项目网站公开访问，包括教学材料、代码和分子协议。

This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2017. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The host institution for the fellowship is Pennsylvania State University and the sponsoring scientist is Dr. Jesse Lasky. Agronomic weeds pose a serious threat to agricultural productivity, and weed infestations may intensify under changing climates. To better understand interactions between biotic and abiotic stressors, this project investigates mechanisms of specialization to different host crops and abiotic environments in purple witchweed (Striga hermonthica). Parasitic witchweeds constitute the greatest biotic constraint to food production in sub-Saharan Africa and devastate yields of economically important cereals such as maize, sorghum, millet, and rice. Broader impacts include generation of new genomic and phenotypic resources to enhance development of resistant crop varieties, training of undergraduate students, and workshops in witchweed bioinformatics targeted to African scientists. Training objectives include statistical evolutionary genomics, ancient DNA sequencing, quantitative genetics, and experimental plant-parasite interactions.The main goal of this project is to better understand evolution of crop-parasite interactions across diverse abiotic environments. First, genomic signatures of host-specialization and local adaptation will be identified, using targeted exome sequencing of 200 herbarium specimens collected within the past 150 years from different hosts of origin across East and West Africa. Loci will be identified that exhibit statistical associations with environment and host of origin, with allelic variation that tracks change in regional host crop production over time. For the second aim, effects of abiotic stress on host range will be experimentally evaluated. Seed germination, early host-seeking behavior, and host resistance will be quantified under nitrogen- and water-limitation for 20 parasite populations across 60 genotypes of three agriculturally important host crops: sorghum, millet, and maize. Genomic and phenotypic resources generated during the project will be publicly accessible through online databases (NCBI; Project Unity, http://phenome-networks.com) and a dedicated project website including instructional materials, code, and molecular protocols.