Supervisors: Dr Samuel Brockington (Principal Supervisor), with Prof. Beverley Glover
Reference Code: B104
The colonization of land by plants is a milestone in the history of life, fundamental to subsequent organismal evolution and global environmental change. Water availability is one of the major limitations to terrestrial plant production. Consequently, terrestrial colonization by plants is associated with a suite of evolutionary adaptations that increase absorption of water and control water loss. These key land plant innovations include an extended root system, symbiotic fungal associations, internal conducting systems, a system of air pores or stomata, and the formation of an external waterproof cuticle. All of these key land plant innovations are currently subject to intensive genetic research in early land plants, to understand what key genetic changes were responsible for the origin and evolution of these essential adaptations. However some of these traits such as the waxy cuticle probably arose earlier in the algal precursors to land plants, in the organisms called Charophytes. But very little is known about the pre-adaptation of algae to life on land.
The objective of this studentship is better understand one of the both important biological events in the earth’s history, namely the colonization of land by the land plants. The student will address this topic by examining the potential pre-adaption of algae to life on land utilizing the Charophyte algae, which are the closest relatives to land plants. The project will involve a comprehensive range of approaches and a range of wet and dry lab techniques includinbg bioinformatics, phylogenetics, next-generation sequencing, morphological characterization, and physiological assays.
The student will be involved in cultivating and analyzing algae in different growth conditions, perform a range of molecular genetic techniques including RNA extraction, cDNA construction, Illumina library construction, and gene cloning. The student will also take bioinformatic approaches to analyse next generation sequencing data including gene assembly, annotation, gene alignment and phylogenetic reconstruction.
Specific project related tasks include:
- Cultivation of several species of Charophyte algae in a variety of aquatic to sub-aerial environments.
- Developmental and physiological analysis of Charophyte algae using electron microscopy in order to examine the effects of the sub-aerial environment of the formation of cuticle, and altered morphogenesis in response to dehydration.
- Next generation sequencing by Illumina, and analysis of transcriptomes in algae exposed to the sub-aerial environment versus algae grown in aquatic conditions.
- Real-time PCR and gene expression analyses to confirm expression differences detected by next generation sequencing.
- Phylogenetic analysis to determine the relationship between desiccation genetic programs in algae and their counterparts in land plants.
- Functional analysis of dehydration-resistance genes and their algal counterparts in the early land plant Marchantia
You will receive training in cultivation of charophyte algae in association with the Cambridge Botanic Gardens, you will be trained in basic molecular biology techniques as well as bioinformatics processes and pipelines by Dr Samuel Brockington. Next generation sequencing, assembly, and analysis will be done in collaboration with in-house bioinformaticians, and in association with collaborators in the United States.
- Kenrick P, and Crane P (1997) The origin and early evolution of plants on land. Nature 389 33-39
- Graham LE, et al. (2012) Aeroterrestrial Coleochaete (Streptophyta, Coleochaetales) models early plant adaptation to land American Journal of Botany 99:130-144