18-BTT: Epi-TOM: The development and characterization of an EpiRIL TOMato population

番茄(Solanum Lycopersicum)是世界上最重要的商业水果作物，全球净产值估计超过500亿美元[www.fao.org]。根据番茄的消费量(新鲜的和加工的)，番茄产品在人类饮食中发挥着至关重要的作用，提供必要的矿物质、维生素和促进健康的生物活性植物化学物质。目前，标记辅助选择(MAS)已成为提供消费者性状和农艺性状得到改善的新品种/杂交种的选择方法。MAS依赖于对自然变异的开发。然而，很明显，在包括番茄在内的许多作物物种中，表型多样性高于仅基于现有遗传变异的预期。对这一现象的一种解释是，在植物物种中出现的新证据表明，稳定的遗传表观遗传变异可以为不依赖DNA序列变化的达尔文进化提供基础。利用模式植物拟南芥，已经创建了含有甲基化嵌合体的遗传相同的重组自交系。这是通过杂交两个遗传相同的品系实现的，只是其中一个亲本的DNA甲基转移酶MET1受损，这是在DNA复制过程中繁殖胞嘧啶甲基化所需的基因。在随后的世代中，甲基化的嵌合体通过自花授粉和单粒种子下降到F8而固定。在番茄中发现了一个与其表观基因组相关的近纯合系的独特外源基因群体，这将构成本项目的基础并提供宝贵的遗传/化学社区资源。群体由115个品系组成。到目前为止，可观察到的表型差异在种群内是明显的(例如，株高和果实大小)，然而，与消费者和农艺性状有关的化学差异的程度有待在拟议的epi-tom项目的范围内进行评估。该项目将提供关于表观遗传变异对复杂基因组中化学/表型的作用的重要信息，这些信息可用于阐明具有表观遗传基础的新的数量性状(表观QTL)。

Tomato (Solanum lycopersicum) is the most important commercial fruit crop in the world with an estimated global net production value well in excess of $50bn [www.fao.org]. On the basis of volume consumed (fresh and processed) tomato products play a crucial role in the human diet, providing essential minerals, vitamins and health promoting bioactive phytochemicals. Presently Marker Assisted Selection (MAS) has been the method of choice to deliver new varieties/hybrids with improved consumer and agronomic traits. MAS is reliant on the exploitation of natural variation. However, it has become apparent that in many crop species including tomato, phenotypic diversity is higher than that expected based on the available genetic variation alone. One explanation for this phenomena is the emerging evidence in plant species that stable inherited epigenetic variation can provide a basis for Darwinian evolution independent of DNA sequence changes.Using the model plant Arabidopsis, genetically identical recombinant inbred lines harbouring mosaics of methylation (epiRILs) have been created. This has been achieved by crossing two genetically identical lines with the exception that one of the parents is impaired in DNA methyltransferase MET1, a gene required for propagating cytosine methylation during DNA replication. In subsequent generations mosaics of methylation are fixed by self-pollination and single seed descent to F8. a unique epiRIL population in tomato of near homozygous lines with respect to their epigenomes, which will form the foundation of the current project and provide a valuable genetic/chemical community resource. The population consists of 115 lines. To date observable phenotypic differences are evident within the population (e.g. plant height and fruit size) However, the extent of chemical variation linked to consumer and agronomic traits awaits assessment within the remit of the proposed epi-TOM project. The project will deliver important information on the role of epigenetic variation on chemo/phenotypes in a complex genome, which can be exploited for the elucidation of novel quantitative traits with an epigenetic basis (epi-QTL).