The evolution of herbicide resistance

快速的当代进化是一个机会，以研究动态的进化，以应对环境压力。基因拷贝数变异是一种常见但研究不足的遗传变异形式，已成为适应环境胁迫的一种机制，包括植物除草剂抗性的进化。拷贝数变异的起源、其与抗性表型的关系以及拷贝数的上限在植物中还没有很好的理解。此外，基因拷贝数变异和基因组背景之间的潜在相互作用是公认的，但很少研究，特别是在地理范围内。因此，为了进一步了解基因拷贝数进化，我提出了一种定量遗传学方法。我将使用的普遍存在的除草剂，草甘膦，在长穗苋作为一个模型，探索基因拷贝数的进化限制（S）的抗性的演变。5-烯醇式莽草酸-3-磷酸合成酶（EPSPS）基因拷贝数在1 ~>100之间。palmeri。这种作物杂草正在扩大其以前受限制的范围-美国西南部和墨西哥-现在发生在美国各地，并向加拿大边境移动。 我的长期研究目标将促进对拷贝数变异在进化中的作用的理解：抗逆性状的遗传机制、进化起源和进化极限是什么？基因拷贝数变异有多普遍，它在适应环境中的频率有多高？本文提出的短期研究调查了EPSPS拷贝数变异是否解释了整个地理范围内草甘膦抗性的大部分变异，以及其他基因组变异是否有贡献。历史植物样本提供了调查EPSPS拷贝数变异是否早于草甘膦的开发和普遍使用的机会。为了预测EPSPS拷贝数变异的未来轨迹，我们将通过人工选择寻找基因拷贝数的上限来扩展EPSPS拷贝数变异。该计划是一个难得的机会，结合联合收割机调查的历史，当代和未来的演变特点，以应对环境变化。在进化生物学和农业的交叉点拟议的研究计划提供了3个博士，4个硕士和10个理学士HQP的培训机会。对于可持续农业实践的发展，关键是要了解除草剂在农业杂草种群进化中的作用（艾德），以及抗性进化是否有可能加剧，或已达到稳定的极限。该计划将在野外生物学，实验设计，定量遗传学，统计学，基因组学和生物信息学以及口头和书面交流方面培训HQP-为学术，工业和/或政府研究做好准备。

Rapid contemporary evolution is an opportunity to investigate the dynamics of evolution in response to environmental stress. Gene copy number variation, a common but understudied form of genetic variation, has emerged as a mechanism that can play a role in adaptation to environmental stress, including the evolution of herbicide resistance in plants. The origin(s) of copy number variation, its relationship to resistance phenotype, and the upper limit(s) to copy number are not well understood in plants. Moreover, the potential interaction between a gene copy number variant and genomic background is acknowledged but rarely investigated, especially across a geographic range. Therefore, to advance understanding of gene copy number evolution I propose a quantitative genetic approach. I will use the evolution of resistance to the ubiquitous herbicide, glyphosate, in Amaranthus palmeri as a model to explore the evolutionary limit(s) of gene copy number. Copy number of resistance gene EPSPS (5enolpyruvyl- shikimate-3-phosphate synthase) ranges from 1 to >100 in A. palmeri. This crop weed is expanding its previously restricted range - southwest US and Mexico - now occurring across the US and moving toward the Canadian border. My long-term research goals will advance understanding of the role of copy number variation in evolution: What are the genetic mechanisms, evolutionary origin(s) and evolutionary limit(s) of stress resistance traits? How common is gene copy number variation, and how often is it involved in adaptation to the environment? The short-term research proposed here investigates whether EPSPS copy number variation explains the majority of variation in glyphosate resistance across the geographic range, and whether other genomic variation contributes. Historical plant samples provide opportunity to investigate whether EPSPS copy number variation pre-dated the development and ubiquitous use of glyphosate. To forecast the future trajectory of EPSPS copy number variation, we will extend EPSPS copy number variation through artificial selection in search of the upper limit(s) of gene copy number. This program is a rare opportunity to combine investigation of the historical, contemporary and future evolution of a trait in response to environmental change. The proposed research program at the intersection of evolutionary biology and agriculture provides training opportunities for 3 PhD, 4 MSc and 10 BSc HQP. For development of sustainable agriculture practices it is critical to understand the role herbicides play(ed) in the evolution of agricultural weed populations, and whether resistance evolution has potential to intensify, or has reached a stable limit. This program will train HQP in field biology, experimental design, quantitative genetics, statistics, genomics and bioinformatics, as well as both oral and written communication - preparing HQP for academic, industrial and/or government research.