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，估计全球净产值远远超过500亿美元[www.fao.org]。根据消费量（新鲜和加工），番茄制品在人类饮食中起着至关重要的作用，提供必需的矿物质，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）已成为提供具有改善的消费者和农艺性状的新品种/杂交种的选择方法。MAS依赖于对自然变异的利用。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可用遗传变异的预期。对这种现象的一种解释是，在植物物种中出现的证据表明，稳定的遗传表观遗传变异可以为达尔文进化论提供一个基础，而不依赖于DNA序列的变化。这是通过杂交两个遗传上相同的品系来实现的，除了其中一个亲本在DNA甲基转移酶MET 1中受损，该基因是在DNA复制期间传播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种子遗传到F8而固定。番茄中一个独特的epiRIL群体，其表观基因组接近纯合系，这将构成当前项目的基础，并提供有价值的遗传/化学社区资源。人口由115行组成。到目前为止，在种群中可观察到的表型差异是明显的（例如株高和果实大小），然而，与消费者和农艺性状相关的化学变异程度有待于在拟议的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数量性状（epi-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).