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H2020Individual fellowship2021–2023

miR156evo · The role of the miR156-SPL genetic network during land plant evolution: a comparative analysis of sporophyte development in divergent plant lineages

Horizon 2020 — Marie Skłodowska-Curie Actions

Duration
2021-11-01 → 2023-10-31
EU contribution
€212,934
Participants
1
Scheme
MSCA-IF

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Results in brief

The role of the miR156-SPL genetic network during land plant evolution: a comparative analysis of sporophyte development in divergent plant lineages

Plants first colonised land ~470–515 million years ago. Prior to this the Earth’s terrestrial surface was an extremely inhospitable place, largely devoid of life. The arrival of plants on land from aquatic algal ancestors changed both the Earth’s surface and atmosphere, enabling a huge explosion in terrestrial life. The expansion of land plants initiated the development of soils on a previously barren landscape and led to atmospheric oxygen concentrations that could support animal life. The ‘greening’ of Earth changed the course of evolution and was essential to the emergence of vertebrate animals including humans. Understanding the nature of early land plants is thus fundamental to understanding our own evolutionary history. The land plants we live among and depend on today look very different to the ancestral green alga that first colonised the land. Green algae have basic body plans that are usually restricted to two-dimensions with limited apical growth (i.e. directional proliferative growth facilitated by the self-renewing activity of undifferentiated stem cells). Furthermore, the diploid stage of the life cycle is brief with meiosis occurring immediately following fertilisation. On the other hand, land plants grow in complex 3D structures with extensive apical growth and prolonged diploid development prior to meiosis. What, then, were the critical innovations that led to the establishment of plants on land? With this fundamental question in mind, the aim of this project was to elucidate the ancestral role of a key genetic network in land plants. To do this we carried out a comparative analysis of gene function in a vascular plant (the flowering plant Arabidopsis) and a bryophyte (the moss Physcomitrium), which arose following an ancient divergence in land plant evolution. Sustained apical growth is a defining feature of vascular plants and the establishment of elaborate shoot systems with delayed reproductive development enabled their extraordinary evolutionary success. In contrast, mosses undergo more transient apical growth prior to rapid reproductive development. In Arabidopsis, a well-studied genetic network regulates apical growth and promotes developmental transitions. However, the role of this module in plant evolution remains to be determined. Excitingly, early results suggest that this network has an ancestral role in regulating developmental transitions in plants and that the appearance of the network shortly after plants colonised the land was a critical event in plant evolution.

Data: CORDIS, © European Union

Project objective

An ancient divergence in land plant evolution gave rise to the vascular plant (e.g. Arabidopsis) and bryophyte (e.g. moss) groups. Prolonged apical growth is a defining feature of vascular plants and the establishment of elaborate shoot systems with delayed reproductive development enabled their extraordinary evolutionary success. In contrast, mosses undergo transient apical growth prior to rapid reproductive development. In Arabidopsis, the microRNA miR156 represses members of the SPL family of transcription factors that inhibit apical growth and promote developmental transitions. However, the role of the miR156-SPL module in plant evolution remains to determined. SPL genes evolved before plants colonised land, whereas miR156 arose during early plant evolution. It is possible, therefore, that miR156 was a critical innovation in land plant evolution that facilitated the elaboration of vascular plant forms. My Proposal will test this hypothesis by taking a comparative developmental approach. Using gain and loss-of function genetic techniques I will characterise the role of miR156 and SPL genes in moss sporophyte development, specifically, their effects on apical growth and reproductive development. In Arabidopsis, I will test how SPL genes regulate apical growth using reporter genes assays, advanced imaging and genome-wide surveys of SPL-targets. Finally, I will test the importance of intercellular signaling to apical growth in moss and Arabidopsis by blocking connections between cells. This Fellowship will provide training from a world-leading expert in cutting-edge techniques that are critical to my long-term research objectives. It will allow me to extend my research portfolio by asking fundamental biological questions in a new experimental system (moss) within a highly stimulating scientific environment. The training and outstanding professional development opportunities provided by the University of Bristol will be vital to achieve my career ambitions.

Original text from CORDIS.

Participants

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Data: CORDIS, © European Union