14 ERA-CAPS.EVOREPRO.Evolution of Sexual Reproduction in Plants

The economic importance of seed plants cannot be overstated, as they are our main sources of food, fibre and other
industrial raw materials. However, our capacity to generate sufficient food, animal feed and energy is increasingly
compromised by human population expansion, competition for land use, rapid biodiversity loss and predicted global climate
change. The process of sexual reproduction in higher plants is of particular importance for the aim of increasing crop yields,
overcoming hybridization barriers and selecting and fixing quality traits. Before we can develop tools to manipulate plant
reproduction in our favour we must achieve a deeper understanding of the basic mechanisms underlying gamete
development and double fertilization mechanisms in angiosperms.
The project will deliver the first comprehensive view of the molecular evolution of plant sexual reproduction and will provide
insights into the origins of double fertilization in flowering plants. In addition, gene expression data and the networks
generated will be valuable in understanding the evolution of biological pathways and gene function prediction beyond the
focus on reproduction in this project. In parallel, the work on crop species will identify genes useful to the agricultural
industry to enable precision control of plant reproduction, to overcome hybridization barriers and to promote better breeding
schemes by improving hybrid seed production.

Research during the past five years has delivered tremendous new insights into gamete physiology and the mechanisms
involved in fertilization in Arabidopsis. This progress has established the view that gametes are hyper-differentiated cell
types with highly specific transcriptional profiles. Importantly, we lack any knowledge on the origin of mechanisms that
predate double fertilization. Here, we propose to use emerging models, representing key stages in plant evolution, to
provide insight into the ancestral mechanisms of gamete differentiation and fertilization. We will establish gene co-function
networks for the liverwort Marchantia, the moss Physcomitrella and the extant basal flowering plant Amborella. These will
be complemented with co-function networks from Arabidopsis and the important crops maize, tomato and rice. These
networks will be used to study the conservation of gene co-function networks governing male and female gametogenesis,
pollen tube growth and fertilization mechanisms in flowering plants. Moreover, these investigations will provide novel
molecular markers of fertility in crops. We will also directly test the function of established regulators required for male
gamete development, as well as those newly identified from our network analyses.The expected findings will allow the
identification of mechanisms targeted by environmental stresses during sexual reproduction in crops and will assist in the
selection of stress-resistant cultivars. The reprogramming of chromatin modifications is an established feature of sexual
reproduction in animals and data generated in this project will provide the first comprehensive map of the occurrence of
chromatin reprogramming in plant gametes and fertilization products. In summary, the outputs of the EVOREPRO project will provide a deeper understanding of the evolution of sexual reproduction of econonomically important plant species.

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