BTT EAGER: Investigating Genetic, Epigenetic and Environmental Control of Meiotic Recombination using Fluorescent Crossover Reporters in Tomato

大多数农作物食品，包括种子、谷物、水果和蔬菜，都是植物有性繁殖的结果。成功的繁殖需要双亲染色体的相互作用。植物育种者利用相同类型的染色体相互作用来创造有利性状的新组合。北卡罗来纳大学教堂山分校的科彭哈弗实验室与他们的合作者一起，剑桥大学的亨德森实验室之前开发了一种强大的技术，用于检测和量化与芥菜相关的模式植物物种中的这些染色体相互作用。在这个项目中，科彭哈弗和亨德森实验室将把这项技术推广到一种商业作物番茄上。然后，他们将使用这项技术来测量遗传、表观遗传和环境因素对影响这些染色体相互作用的数量和基因组分布的影响，以了解推动植物繁殖的基本生物学机制，并确定加速作物育种的有效途径。科彭哈弗和亨德森实验室将以开放获取的形式发布他们的发现，并将他们开发的遗传资源提供给研究人员和工业同行。此前，Copenhaver和Henderson实验室开发了一种直观的分析方法，用于直接测量拟南芥配子中的减数分裂重组频率。他们的分析被称为FTL系统，使用了一系列携带转基因的品系，这些转基因编码在四重体(Qrt)突变背景中表达的花粉特异荧光蛋白，这使得在高等植物中进行四分体分析成为可能。在这个项目中，他们将把FTL系统转化为茄子(番茄)。利用番茄FTL系统，他们将测试CRISPR/Cas9在recq4解旋酶同源物中诱导的突变是否会导致基因组范围的超重组。他们还将测试CRISPR/Cas9诱导的基因突变是否可以改变具有不同染色质环境的特定染色体区域周围的重组频率，这些基因介导了DNA甲基化和小RNA生物发生等表观遗传机制。先前在拟南芥上的工作表明，暴露在高和低温度下可以显著调节重组频率。科彭哈弗和亨德森实验室将测试类似的环境操作是否可以改变番茄链球菌的重组频率。该项目将为两名博士后研究员提供培训，并为科彭哈弗和亨德森实验室的本科生提供独立研究经验。研究结果将以开放获取的格式发表，所有遗传资源将提供给研究和工业同行。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Most crop foods, including seeds, grains, fruit and vegetables, are the result of plant sexual reproduction. Successful reproduction requires the interaction of parental chromosomes. The same kind of chromosomal interactions are used by plant breeders to create new combinations of favorable traits. The Copenhaver lab at The University of North Carolina at Chapel Hill together with their collaborators, the Henderson lab from the University of Cambridge previously developed a powerful technique for detecting and quantifying these chromosome interactions in a model plant species related to the mustard plant. In this project the Copenhaver and Henderson labs will extend that technology into a commercial crop species tomato. They will then use that technology to measure the effects of genetic, epigenetic and environmental factors on influencing the number and genomic distribution of these chromosome interactions in order to understand the fundamental biological mechanism that drive plant reproduction, as well as to identify fruitful avenues for accelerating crop breeding. The Copenhaver and Henderson labs will publish their findings in open-access formats, and make the genetic resources they develop available to researchers and industrial colleagues. Previously, the Copenhaver and Henderson labs developed a visual assay for measuring meiotic recombination frequencies directly in the gametes of Arabidopsis thaliana. They assay, called the FTL system, employs a collection of lines harboring transgenes encoding pollen-specific fluorescent proteins expressed in the quartet (qrt) mutant background, which enable tetrad analysis in a higher plant. In this project they will translate the FTL system into Solanum lycopersicum (tomato). Using the tomato FTL system they will test whether CRISPR/Cas9 induced mutations in recq4 helicase homologs result in genome wide hyper-recombination. They will also test whether CRISPR/Cas9 induced mutations in genes that mediate epigenetic mechanisms such as DNA methylation and small RNA biogenesis can alter recombination frequencies around specific chromosomal domains with distinct chromatin environments such as centromeres. Prior work in Arabidopsis, suggests that exposure to high and low temperatures can significantly modulate recombination frequencies. The Copenhaver and Henderson lab will test whether similar environmental manipulation can alter recombination frequencies in S. lycopersicum. The project will provide training for two postdoctoral fellows as well as independent research experiences for undergraduates in both the Copenhaver and Henderson lab. The research findings will be published in open-access formats, and all genetic resources will be made available to both research and industrial colleagues.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.