400 Million Years of Food Transport in Plants: unearthing the origin, diversity and genetic toolkit of vasculature

Plants transport sugars around their bodies in the specialised tissue termed the phloem. The phloem is essential for plant life and underpins the growth and survival of all economically important plants, whether crop or forest species. Given how important the phloem is for plant life it might be predicted that we would have a good understanding of its evolution.

However, despite the vital role the phloem plays in living species our understanding of phloem evolution is rudimentary. Key questions remain unanswered including: (i) when did the phloem originate, (ii) how has its structure, function and genetic toolkit evolved over the past 400 million years, (iii) how has phloem evolution been driven by climate change?

In this project we are answering these major questions and fundamentally increasing our understanding of phloem evolution over geological time. To achieve this we are working on three specific objectives: 1. Defining the origin of the phloem in land plants

2. Revealing major evolutionary innovations in phloem structure and function in relation to climatic change through geological time. 3. Characterising the genetic innovations that underpinned the diversification of the phloem

In the initial stage of the Future Leaders Fellowship we have made substantial progress to achieving these objectives and are poised to make new discoveries that will change our understanding of phloem evolution. In the renewal phase of the Fellowship we will continue on our path to achieve these objectives and answer the overarching questions about phloem evolution.

We will greatly expand on our objective to characterise the genetic innovations that underpinned the diversification of the phloem, with a broad scale approach to characterise the expression of genes involved in phloem development in ferns and lycophytes and aim to discover novel regulators of the phloem development in lycophytes.

Collectively the outcome of the project will make a step change in our understanding of phloem evolution over the last 400 million year and demonstrate the added benefit of taking an interdisciplinary approach, combining studies of living plants, fossils and genetic networks together to answer major questions in plant evolution.