Mechanisms of celery seed morphological dormancy, longevity and quality

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The overall aim of the project is to gain a deeper understanding of the underpinning mechanisms of vegetable seeds with morphological dormancy and from there to develop applied solutions for improving their quality. This project is therefore be at the very core of agriculture and food security of primary crop production. The student will be exposed to commercial application of world-class bioscience research - providing solutions for sustainably enhancing agricultural production. This PhD project is in collaboration with Tozer Seeds and is using celery seeds as a vegetable model for morphological dormancy. Tozer Seeds is an independent British vegetable breeding company located in Surrey that aims to provide consistent high quality seeds and services for the international market. Celery seed is one of their key products - they were the first company to develop a F1 hybrid variety - however, there are problems with celery seed quality. This problem can only be solved with knowledge of the underpinning mechanisms of morphological dormancy. This is a class of dormancy in which an underdeveloped tiny embryo is embedded into abundant living endosperm tissue. In order to germinate, the tiny embryo must first grow in size on the expense of the endosperm, but how this is achieved mechanistically is not yet known. This class of dormancy is very different to the many vegetable seeds with physiological dormancy of the Brassicaceae and Solanaceae families for which knowledge of the underpinning mechanisms exists. Morphological dormancy is the typical dormancy class for carrot, celery and other species of the Apiaceae family. The student will first conduct a morphological (microscopy, seed size fractions) and physiological (ambient conditions for seed imbibition with temperature and water as focus) investigation of morphological dormancy and its release with different genotypes. This will deliver the quantitative framework and target tissues for the biomechanical analysis combined with hormone and transcriptome profiling to elucidate the underpinning molecular mechanisms of morphological dormancy, its release, subsequent seed germination, and seedling establishment. This knowledge is instrumental for subsequently analysing the hormonal, epigenetic, and gene expression mechanisms underlying after-ripening storage, longevity and aging of celery seeds, as well as their importance for the production of sturdy and uniform seedlings. The possibilities of the Seed Biology team at RHUL and the collaboration with the company Tozer will provide superb training possibilities and will equip the student with skills that exploit novel ways of working. This studentship aims to establish celery as a model for seeds with morphological dormancy, and to develop diagnostic assays that identify molecular markers, critical for improving celery seed quality and breeding.