Controlling dormancy and sprouting in potato and onion

马铃薯和洋葱是英国和世界各地的主要作物，消费者和加工商全年都需要它们。由于季节性生产，需要长期储存，在此期间，产品必须保持良好的质量，以供新鲜消费和加工，并处于营养状态。马铃薯块茎和洋葱鳞茎是天然的越冬结构，具有在储存期间恢复生长的趋势，导致发芽的农产品没有吸引力和无法销售，或者由于成分变化如糖水平增加而不适合加工。采用多种策略来延长休眠期并最大限度地减少发芽和浪费，包括低温储存和使用发芽抑制剂，如氯苯胺灵、马来酰肼或乙烯。这种处理并不完全有效，因为即使抑制发芽也可能发生质量劣化，并且立法越来越限制使用许多这些化学品。此外，长期冷藏是一项重大的经济成本，具有巨大的碳足迹。开发替代策略以保持块茎和鳞茎处于休眠状态并长期抑制发芽是行业的首要任务。马铃薯的遗传研究表明，块茎休眠特性的遗传受到几个基因单独或联合作用的影响，但这些基因的身份尚不清楚。尽管取得了实质性进展，但对休眠和发芽的生物学的充分理解尚未出现，这大大阻碍了新的储存策略的开发，以及具有更好休眠和发芽行为的新品种的培育。幸运的是，分子生物学领域的最新进展使我们能够在解决这些问题方面取得重大进展。科学研究揭示了马铃薯和洋葱中几种植物激素的共同作用，包括脱落酸，乙烯，赤霉素和细胞分裂素，调节休眠和萌芽生长，这表明对一种商品的了解有助于我们了解另一种商品。该项目将受益于马铃薯遗传学的重大进展，特别是基因组序列的出版，以及DNA测序技术的巨大发展，现在可以深入分析相对未开发但高度复杂的洋葱基因组。新的、强大的马铃薯遗传资源将使我们能够确定对休眠和发芽施加最大控制的基因的位置和身份。这些资源包括通过杂交高度分化的亲本而开发的大型作图种群。初步研究已经揭示了包含关键基因的基因组区域，这些基因可以驱动作物改良和新的管理方法。组装的研究联盟汇集了詹姆斯赫顿研究所，克兰菲尔德大学，帝国理工学院伦敦和格林威治大学，提供了基因组学，遗传学，分子生物学，生理学，项目成果将包括：（1）确定马铃薯和洋葱中的关键基因，它们的变异形式和支持马铃薯块茎休眠的调控机制，（2）洋葱鳞茎休眠和发芽主基因的全基因组数据的开发，以及（3）马铃薯和洋葱休眠和发芽控制的共享和独特元件的比较，导致阐明关键的生理和分子控制步骤。通过行业代表机构和公司的参与，所产生的信息可以很容易地转化为增强的、针对具体品种的储存制度，从而减少化学品的使用，减少对昂贵的低温储存的依赖。从长远来看，育种者可以利用关键调控基因的知识来培育具有更好休眠特性的马铃薯。

Potato and onion are major UK and worldwide crops required year-round by consumers and processors. Due to seasonal production, long term storage is necessary, during which produce must be maintained with good quality for fresh consumption and processing, and in a nutritious state. Potato tubers and onion bulbs are natural over-wintering structures with a tendency to resume growth during storage, resulting in sprouted produce that is unattractive and unsaleable, or unsuited to processing due to compositional changes such as increased sugar levels. Multiple strategies are used to extend dormancy and minimise sprouting and waste, including low temperature storage and application of sprout suppressants such as chlorpropham, maleic hydrazide or ethylene. Such treatments are not fully effective as quality deterioration may occur even if sprouting is inhibited and legislation increasingly limits use of many of these chemicals. In addition, long-term cold storage is a major economic cost with a substantial carbon footprint.Development of alternative strategies to maintain tubers and bulbs in a dormant state and long-term suppression of sprouting are top industry priorities. Genetic studies in potato have shown that inheritance of tuber dormancy characteristics is affected by several genes acting alone or in combination, but the identity of these genes is unknown. Despite substantial progress, a full understanding of the biology of dormancy and sprouting has not yet emerged, and this substantially hampers development of new strategies for storage, and breeding of new varieties with better dormancy and sprouting behaviours. Fortunately recent advances in the field of molecular biology allow us to make major advances to address these issues. Scientific studies have revealed common roles in potato and onion for several plant hormones including abscisic acid, ethylene, gibberellins and cytokinins, in regulation of dormancy, and sprout growth, suggesting that knowledge of one commodity further our understanding of another. This project will benefit from major advances in potato genetics, especially publication of the genome sequence, as well as huge developments in DNA sequencing technologies which now enable in-depth analysis of the relatively unexplored but highly complex onion genome. New, powerful potato genetic resources will allow us to pinpoint the position and identity of genes that exert the greatest control of dormancy and sprouting. These resources include large mapping populations, developed by crossing highly divergent parents. Preliminary studies have already revealed genomic regions containing key genes that can drive crop improvement and new management methods.The assembled research consortium brings together James Hutton Institute, Cranfield University, Imperial College London and Greenwich University, providing a wealth of experience in genomics, genetics, molecular biology, physiology, agronomy and storage of potato and onion.Project outcomes will include (1) identification of key genes in potato and onion, their variant forms and regulatory mechanisms that underpin potato tuber dormancy, (2) development of genome-wide data on major genes in onion bulb dormancy and sprouting, and (3) comparison of shared and distinctive elements of dormancy and sprouting control in potato and onion, leading to elucidation of key physiological and molecular control steps. Through involvement of industry representative bodies and companies, information generated can readily be translated towards enhanced, variety-specific storage regimes, enabling reduced chemical usage and less reliance on expensive low temperature storage. Knowledge of key regulatory genes can in the longer term be adopted by breeders to develop potatoes with better dormancy characteristics.