Physiology and Molecular Evolution of Photoprotection in Allopolyploids

多倍体是整个基因组在二倍体基础上的增殖。这在开花植物中是一个特别重要的遗传过程，许多栽培植物（如小麦、玉米、棉花、大豆）都是多倍体。多倍体可以导致深刻的基因组变化，甚至超越复制基因组中的所有基因。多倍体对生理、解剖学和生物化学的影响早已为人所知，但很少有研究试图将表型与分子水平的变化联系起来，以了解植物如何在自然群体中实现对多倍体的综合反应。这些研究是理解多倍体为什么在植物中如此普遍，以及为什么多倍体通常被认为比它们的二倍体祖先更具适应性或更成功的关键。该项目将研究最近形成的甘氨酸多倍体物种（包括栽培大豆）的光保护——植物避免过度光能伤害的重要生理过程。这些物种在过去的5万年中通过杂交和基因组加倍（异源多倍体）形成。产生它们的二倍体物种已经被确定。叶绿素荧光测定将用于比较多倍体物种与其二倍体祖先的光保护。在分子水平上，将确定由两个二倍体祖细胞贡献的基因拷贝自多倍体物种形成以来如何在序列和表达上发生变化，以及DNA序列、剂量和/或表达模式的变化是否与光保护表型相关。更广泛的影响。该项目具有广泛的意义和影响，因为它将阐明多倍体这一普遍存在的遗传现象对植物适应性所必需的生理过程的影响，并将其与光保护基因的变化联系起来。此外，该项目还包括对研究生和本科生的培训，并与康奈尔大学正在进行的高中教师拓展计划有关。

Polyploidy is the multiplication of the entire genome beyond the diploid level. It is a particularly important genetic process in flowering plants, and many cultivated plants (e.g., wheat, maize, cotton, soybean) are polyploid. Polyploidy can lead to profound genomic changes, even beyond duplicating all of the genes in the genome. Polyploidy has long been known to affect physiology, anatomy, and biochemistry, but few studies have sought to connect phenotype with changes at the molecular level to understand how plants achieve an integrated response to polyploidy in natural populations. Such investigations hold the key to understanding why polyploids are so prevalent among plants, and why polyploids often have been considered more adaptable or more successful than their diploid progenitors.This project will study photoprotection - an important physiological process by which plants avoid damage from excess light energy - in several recently formed polyploid species of Glycine, the genus that includes the cultivated soybean. These species formed by hybridization and genome doubling (allopolyploidy) within the last 50,000 years. The diploid species that gave rise to them have been identified. Chlorophyll fluorescence assays will be used to compare photoprotection in the polyploid species with their diploid progenitors. At the molecular level, it will be determined how the gene copies contributed by the two diploid progenitors have changed in sequence and expression in the polyploidy species since their formation, and whether changes in DNA sequence, dosage, and/or expression patterns correlate with photoprotection phenotype.Broader Impacts. This project is of broad significance and impact because it will elucidate the effects of a ubiquitous genetic phenomenon, polyploidy, on a physiological process essential to plant fitness, and will connect this to changes in the genes underlying photoprotection. In addition, the project involves training graduate and undergraduate students and is linked to an ongoing high-school teacher outreach program at Cornell.