And it was a success... like a flower!

It is the common ancestor of some 300,000 species of flowering plants that we know today. An international study coordinated by Hervé Sauquet a teacher-researcher at the Ecology, Systematics and Evolution Laboratory (Paris-Sud University/CNRS/AgroParisTech) has just released an image of the flower that is the ancestor of all flowering plants that would have appeared over the last 140 million years.

It is difficult to imagine a world without flowers. However, this is what has long proven to be the reality on Earth as flowering plants only arrived late on in the evolution of the plant world. Whilst the first plants appeared about 420 million years ago, flowering plants, also called Angiosperms (1), waited almost another 300 million years to unfurl their petals.

Although they may have arrived late, their appearance ultimately turned out to be a real success since they have spread to all the world’s continents and to the extent that they now account for almost 90% of all plants. All the more so since this colonisation of the planet was accompanied by extreme diversification as there are no fewer than 300,000 different species of flowering plants.

300,000 species but one common ancestor

The origin and the evolution of these flowering plants is one of biology’s great enigmas. To try to solve the mystery, a team of 36 researchers from 13 countries, whose work was coordinated by Hervé Sauquet, teacher-researcher at Paris-Sud University, set about drawing up a model of the first common ancestor of all flowering plants. Due the fragile nature of flowers, fossilised flowers are too rare to be used as truly reliable references, which makes it all the task all the more difficult.

Without any fossils for evidence, the researchers looked towards another means of research: analysing a large database that compiles phenotype information (i.e. the visual appearance) from species of flowers with the latest evolutionary tree of flowering plants, constructed from genetic information from living species. A long-term endeavour since this project, named eFLOWER, lasted almost six years.

The team sampled 800 species which were representative of the diversity of different Angiosperm families. This colossal task has made it possible to solve the enigma of the original flower and has provided a surprising answer: the very first flower, which was probably borne on a small tree or a shrub, was a hermaphrodite and covered in petaloid organs arranged in circles. But, this model doesn’t correspond to any of those put forward during the last 100 years! 

‘No one had really thought about the first stages in the evolution of flowers in this way, and yet a large part of diversity can now be explained in a simple way using the new scenario which has emerged from our models’ says Hervé Sauquet.

A new scenario to explain the evolutionary history of flowering plants

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