Mapping and analysis of genetic loci controlling quality traits in broccoli

增加水果和蔬菜的消费被强调为改善国民健康的必要条件。西兰花是英国最受欢迎的绿色蔬菜，被认为营养丰富，是维生素和矿物质的极好来源。西兰花和其他芸苔属蔬菜也含有有价值的化合物，已被证明对人类健康有积极影响。绿色蔬菜如花椰菜对供应商和消费者来说是一个问题，因为它们的保质期短，表现为变黄和枯萎。此外，有价值的营养素和风味的损失开始，只要作物收获，这种质量损失可能不一定与任何可见的标准。在这个项目中，我们的目标是解决这个问题，首先通过识别遗传标记，这将是有用的植物育种创造一个改进的花椰菜作物。其次，通过详细分析具有不同保质期特征的品系中发生的分子变化，这将使我们能够了解正在发生的许多事件。这将增进我们对这些事件的控制的了解，并为今后的改进指明更具体的目标。我们已经确定了两种西兰花，它们显示出非常不同的保质期特征。这些已经被杂交以创建一个群体，该群体可用于鉴定与有用的质量属性（例如变黄时间或良好的营养含量）相关的染色体基因座。将识别与有用的品质性状相关的遗传标记，这些将有助于改良西兰花系的育种。该项目的工业合作伙伴先正达公司将利用已确定的遗传标记，将与优良品质相关的染色体区域引入其优良育种系，以创造新的改良作物品种。分子技术的快速发展使植物科学家能够全面了解植物在发育过程中或对胁迫的反应中发生的分子变化。我们一直在使用这样的技术在拟南芥叶片衰老的研究，并已确定了许多基因和途径，参与调节发生在一个叶子，因为它变黄的降解事件。在这个项目中，我们扩展到一个实际问题的分析，在作物收获后衰老过程中发生的分子事件的检查。我们已经显示出西兰花小花衰老和拟南芥叶片衰老之间的密切相似性，并且我们可以应用于分析的西兰花的重要先验知识和广泛的遗传和分子资源。花椰菜与拟南芥的密切关系允许直接与拟南芥研究中已经获得的基因表达和代谢产物组成的数据进行比较。模式植物拟南芥已经被完全测序，所以我们知道所有的基因在这个生物体中的位置。芸苔属植物的序列正在进行中，很可能在本项目的生命周期内完成。这些序列信息，加上芸苔属和拟南芥之间的相似性，可能使我们能够确定控制我们正在研究的性状的可能候选基因。这对今后更有针对性的改进方法很重要。

Increased consumption of fruit and vegetables has been emphasised as essential to improve the health of the nation. Broccoli is the most popular green vegetable consumed in the UK and is recognised as being rich in nutrients and an excellent source of vitamins and minerals. Broccoli and other Brassica vegetables also contain valuable compounds that have been shown to have a positive effect on human health. Green vegetables such as broccoli are a problem to suppliers and consumers because of their short shelf life, which is exhibited by yellowing and wilting. In addition, loss of valuable nutrients and flavour begin as soon as the crop is harvested and this quality loss may not necessarily be linked to any visible criteria. In this project we aim to address this problem, first by identifying genetic markers that will be useful to plant breeders to create an improved broccoli crop. Secondly, by a detailed analysis of the molecular changes taking place in the lines with differing shelf life characteristics which will allow us to understand the many events that are taking place. This will improve our knowledge of the control of these events and indicate more specific targets for future improvements. We have identified two lines of broccoli that show very different shelf life characteristics. These have been crossed to create a population that can be used to identify the chromosomal loci linked to useful quality attributes such as yellowing time or good nutrient content. Genetic markers linked to useful quality traits will be identified and these will assist in the breeding of improved broccoli lines. Syngenta, the industrial partner in this project, will use the genetic markers identified to introduce chromosomal regions linked to good quality into their elite breeding lines to create new, improved crop varieties. Rapid advances in molecular techniques have allowed plant scientists to obtain a holistic view of molecular changes that are occurring in plants, during development or in response to stress. We have been using such techniques in the study of Arabidopsis leaf senescence and have identified many genes and pathways that are involved in regulating the degradative events that occur in a leaf as it yellows. In this project, we extend this to the analysis of a practical problem, the examination of the molecular events that take place during post harvest senescence in a crop.. We have shown close similarities between broccoli floret senescence and Arabidopsis leaf senescence and we have significant prior knowledge and extensive genetic and molecular resources for broccoli that we can apply to the analysis. The close relationship of broccoli to Arabidopsis allows direct comparison with the data on gene expression and metabolite composition that is already available from Arabidopsis studies. The model plant Arabidopsis has been fully sequenced so we know where all the genes are in this organism. The sequence of brassica is ongoing and is likely to be completed in the lifetime of this project. This sequence information, together with the close similarities between Brassica and Arabidopsis, may allow us to identify likely candidate genes that control the traits that we are studying. This will be important for more targeted improvement approaches in the future.