Synchronization of crop seed germination

点击翻译按钮获取中文摘要

In order to ensure the survival of their offspring, many organisms employ a bet-hedging strategy whereby they produce a large number of progeny having different behavioural characteristics. This approach ensures that a subset of their progeny survive regardless of unexpected fluctuations in their environment. Seed germination in plants also follows this bet-hedging strategy. While seeds are resistant to harsh environmental conditions, seedlings are not, and this makes the correct timing of germination critical for the future survival of plants. Plants have evolved noise-generating mechanisms to create variable behaviour within the individual seeds they produce in order to alter the timing of their germination responses to the environment. In this way at least a fraction of their progeny are ensured survival regardless of future climatic conditions.While this is a powerful adaptive trait for the survival of plants in natural ecological settings, the asynchronous germination of seeds represents an obstacle to agriculture. The vast majority of food production begins with the planting of a seed, and the rapid and uniform establishment of seedlings in the field is key determinant of future yield. Non-uniform germination leaves gaps in the field which increases herbicide use, and asynchronous crop development lowers yield following single-pass mechanical harvesting. Robust and synchronous germination underpins the sale of high quality seed in the £52 billion annual global seed trade. Climate change and variable weather further exacerbates uniformity issues, which continue to persist.This project seeks to uncover the mechanistic basis of variability generation and bet hedging in model and crop seeds, and to leverage this information to synchronise the germination of seed populations. This will be done together with industrial partner Rijk Zwaan through a mutually beneficial interaction.We have previously developed a powerful predictive mathematical model that captures the relationships between hormones in seeds which determine when they germinate. Using this model, the preferential use of alternating temperatures to promote seed germination was accurately predicted (Topham et al. 2017, PNAS). This project will extend the use of this model to identify mechanisms that lead to the creation of variable germination-controlling hormone abundance in individual seeds. By identifying how variability in generated within individual seeds, targeted strategies to mitigate these noise-generating mechanisms will be utilized in order to harmonize the hormone content, and in turn germination, of seed populations. Initial proof of concept studies will be performed in the model species Arabidopsis, and together with Rijk Zwaan this will be extended to the crop species lettuce where agronomically limiting issues in germination synchronization are present. By the conclusion of the project this same germplasm will be modified to have enhanced synchronization in their germination profile.A second aspect to this project involves the development of a vital high throughput germination monitoring system. The expression of genes in individual seeds can be monitored dynamically, and used to predict the future timing of germination following early events. In this way the variability in seed populations can be quantified, and this system can be used to sort seeds having similar germination characteristics. This represents both a powerful scientific tool and agricultural technology to generate populations with synchronized germination behaviour.This project will address a key scientific questions relating to variability and bet hedging which also have a direct and powerful relevance to modern food production systems and industry. Following state of the art modelling and biological approaches and an industrial partnership, the development of strategies and germplasm enhancing the synchronization of crop seed germination will be provided.