DISSERTATION RESEARCH: The Evolution of Plant Drought Tolerance and Gene Function Across Historic Frequency Gradients

本研究将探讨拟南芥野生种群中可能参与干旱适应的基因的功能。干旱是大自然的一种？世界上最具破坏性的力量，每年影响数百万人。然而，作为对植物种群进行强选择的媒介，它们对理解基本的进化过程也很有价值，比如发现与适应有关的基因。此外，在干旱的背景下研究植物进化可能会产生开发耐旱作物所需的关键知识。利用基于遥感数据的全球历史干旱频率图，确定了经历非常不同的干旱频率的人群。从这些群体之间的遗传差异的数据，20个基因被确定，将研究其分子和表型效应。这项工作有望对基因功能的进化产生关键的洞察力，并确认耐旱性状的基因。研究这些基因的结果可能对提高作物耐旱性的育种计划具有重要价值。此外，该项目将涉及指导本科生和高中生，包括来自科学领域代表性不足的群体的个人。 历史干旱频率显着预测重要的耐旱性状，开花时间和水分利用效率，在自然加入的拟南芥。该项目将研究功能等位基因缺失对20个与开花时间或水分利用效率有关的基因的影响。基于T-DNA基因敲除的反向遗传学方法将用于在共同的基因组背景中人工诱导这些基因的突变。该项目将量化这些假设基因对开花时间和水分利用效率的影响大小。它还将使用RNAseq表征对全基因组表达谱和非生物信号级联的影响。

This research will investigate the function of genes possibly involved in drought adaptation in wild populations of the plant Arabidopsis thaliana. Droughts are one of nature?s most devastating forces, affecting millions of people each year. Yet as agents of strong selection on plant populations, they are also valuable for understanding basic evolutionary processes, such as discovering the genes involved in adaptation. Furthermore, studying plant evolution in the context of drought may produce the critical knowledge needed to develop drought tolerant crops. Using a global map of historic drought frequency based on remote sensing data, populations were identified that experience very different drought frequencies. From data on genetic differences among those populations, 20 genes were identified that will be studied for their molecular and phenotypic effects. This work is expected to yield key insight into the evolution of gene function, and to confirm genes underlying drought tolerance traits. The results of studying these genes may be of great value to breeding programs working to improve drought tolerance in crop species. In addition, the project will involve mentoring both undergraduate and high school students, including individuals from groups that are underrepresented in the sciences. Historic drought frequency significantly predicts important drought tolerance traits, flowering time and water use efficiency, among natural accessions of Arabidopsis thaliana. The project will investigate the effects of loss of function alleles on 20 genes involved in flowering time or water use efficiency. A reverse genetics approach based on T-DNA gene knockouts will be used to artificially induce mutations in these genes in a common genomic background. The project will quantify the effect sizes of these hypothesized genes on flowering time and water use efficiency. It will also characterize effects on whole genome expression profiles and abiotic signaling cascades using RNAseq.