Linking biochemistry and genetics in celery to taste and flavour perceived by consumers: developing a more acceptable product

芹菜因其独特的风味和口感，成为一种受欢迎的新鲜食品。它最初是适应沼泽条件，因此它倾向于产生中空的茎和叶柄。作物的驯化导致选择更多的可食用品种，减少了苦味和强烈的味道。芹菜是饮食中维生素C、K、钠和钾的良好来源（USDA, 2012），对结直肠癌有很强的保护作用（Jinfu et al., 1991）。它富含类黄酮和酚类物质（Lin et al., 2007）；后者的氧化导致采收后切割表面褐变。芹菜中主要的风味化合物是邻苯酞，其次是萜烯。Van Wassenhove等人（1990）使用GCMS发现33种化合物存在于所有四种被测试的焯水芹菜中。该项目的目的是开发育种系和相关的分子标记，以提高芹菜的采后性能和风味属性。项目计划。A L Tozer有限公司共有52条生产线可供该项目使用。我们将选择30个涵盖多样性的品种，并在雷丁的受控环境中进行种植。我们将使用GCMS测定挥发性化合物（如萜烯和邻苯酞）的风味特征，使用LCMS测定非挥发性化合物（如酚类和糖）的风味特征。从这些数据中，我们将选择6条极端线=里程碑1（第9个月）。我们将进行感官小组来评估选定的极端线，从而验证生物化学与人类感知的对比=里程碑2（第12个月）。我们将开始生成基于亲本的图谱种群，这些亲本代表了生物化学和风味感知的广度。如果第一次杂交是在第一年进行的，那么我们应该在第三年=第3个里程碑（第30个月）时达到F2代。这六个极端品系将在第二年在西班牙和英国种植，从而测试不同环境，土壤类型和季节对选择的生化和感官特性的影响。这项工作将有助于评估环境对芹菜风味的影响=里程碑3（第24个月）。在第三年，该项目将检查不同植物发育/田间保存时间的风味和生物化学变化，从而提供有关哪些品系可能具有季节性和感官稳定性的信息=里程碑4（第36个月）。消费者小组将用来评估亲本芹菜品系的喜好（或其他）。亲本代的转录组测序将用于组装芹菜基因组。里程碑5（第40个月）在第4年，该项目将与G公司合作，通过他们的商业加工生产线加工来自亲本系和绘制种群F2代的芹菜。将分析采后质量（硬度、重量减轻、褐变、茎空化）和风味生物化学，并将其用作可绘制的特征=里程碑6（第45个月）。这些特征将提供广泛的QTL，并可能与基于转录组的标记相关联，Tozer可以在博士任期结束后对其进行改进和推进。即使无法找到基于转录组的标记，该项目仍将提供生物化学与理想风味特征之间的强烈联系，从而可以开发基于代谢物特征的新品系。

Celery characteristicsCelery Apium graveolens var. secalinum is popular as a fresh product due to its characteristic flavour and texture. It was originally adapted to marshy conditions, hence its tendency to produce hollow stems and petioles. Domestication of the crop has resulted in the selection of more edible varieties with reduced bitter and strong flavours. Celery is a good source of Vitamins C, K, sodium, and potassium in the diet (USDA, 2012) and has a strong protective effect against colorectal cancer (Jinfu et al., 1991). It is rich in flavonoids and phenolics (Lin et al., 2007); oxidation of the latter causes postharvest browning of cut surfaces. Key flavour compounds in celery are phthalides, and to a lesser degree the terpenes. Van Wassenhove et al (1990) found 33 compounds using GCMS that were present in all four varieties of blanching celery tested. The aim of the project is to develop breeding lines and associated molecular markers that can give rise to a celery variety with improved postharvest performance and flavour attributes. Project plan.A L Tozer Ltd have 52 lines in total available to the project. We will select 30 lines that cover the diversity and grow them in controlled environment at Reading. We will determine flavour profiles of volatile compounds e.g. terpenes and phthalides using GCMS and non-volatile compounds such as phenolics and sugars using LCMS. From these data we will select 6 extreme lines = Milestone 1 (month 9).We will conduct sensory panels to evaluate the selected extreme lines, thus validating the biochemistry against human perception = Milestone 2 (month 12).We will start to generate mapping populations based on linked parents that represent the breadth of biochemistry and flavour perceptions. If the first crosses are made in year 1 we should be at F2 generation by year 3 = Milestone 3 (month 30). The six extreme lines will be grown in Spain and the UK in year 2, thus testing the impact of different environments, soil types and seasons on the biochemical and sensory properties of the selections. This work will enable evaluation of the environmental impact on celery flavour = Milestone 3 (month 24).In year three the project will examine changes in flavour and biochemistry at different plant development/field holding times, thus providing information on which lines are likely to impart seasonal and sensory stability = Milestone 4 (month 36). Consumer panels will be used to assess liking (or otherwise) of the parental celery lines.Transcriptome sequencing of the parental generations will be used to assemble a celery genome. SNPs will be scored in the F2 population and a working map will be produced = Milestone 5 (month 40)In year 4 the project will collaborate with G's to process celery from the parental lines and in the F2 generation of the mapping population through their commercial processing line. Postharvest quality (firmness, weight loss, browning, stem hollowing) and flavour biochemistry will be analysed and used as traits that can be mapped = Milestone 6 (month 45). These traits will give broad QTL, and possible association with transcriptome based markers that Tozer can refine and take forward beyond the life of this PhD. Even if transcriptome based markers cannot be found the project will still provide strong associations between biochemistry and desirable flavour profile, such that development of new lines based on metabolite profile will be possible.