Study clarifies kinship of important plant group

Date:
August 5, 2020
Source:
University of Bonn
Summary:
Asterids comprise around 100,000 flowering plants, from heather to
tomatoes. Up to now, their family relationships had not yet been
fully clarified. A new study has now somewhat closed this knowledge
gap. It is the world's most detailed phylogenetic analysis ever
conducted for asterids.



FULL STORY ========================================================================== Asterids comprise around 100,000 flowering plants, from heather to
tomatoes. Up to now, their family relationships had not yet been fully clarified. A new study by the University of Bonn, Pennsylvania State
University (USA) and Fudan University (China) has now somewhat closed
this knowledge gap. It is the world's most detailed phylogenetic analysis
ever conducted for asterids. The results of the study have been published
in the journal Molecular Biology and Evolution.


========================================================================== Evolution is a process of gradual change. As a rule, organisms therefore
differ from each other more markedly the longer it has been since their developmental paths separated. This association is even more apparent
in their genes than in their external appearance. A comparison of the
genetic make-up of numerous species therefore makes it possible to
reconstruct their family tree.

This is precisely what the researchers involved in the study did. "For a
total of 365 different species, we analyzed an average of over 1,000 genes
each that are active in these plants," explains Prof. Dr. Maximilian
Weigend from the Nees Institute for Biodiversity of Plants at the
University of Bonn. "This makes our study of the asterid group the
largest such study on this plant group to date." Among the asterids
are such diverse species as coffee, heather or even the water hawthorn,
which is found in Madagascar and resembles a water fern. In total,
the group comprises around 100,000 species, or almost a quarter of all flowering plants worldwide. Their appearance and the ecological niches
they occupy vary accordingly.

Uncertain tiles in the family tree mosaic The group is divided into a
number of orders, each of which is in turn broken down into different
plant families. The position of many of these subgroups in the family
tree has been a matter of debate. If the family relationships were a
mosaic, the position of many of the tiles would still be uncertain.



==========================================================================
The current study has now changed this to some extent. "We selected the
species studied to cover all plant orders and almost all families of
asterids," Weigend stresses. "Subgroups whose ancestry is still unclear
were particularly well represented." This enabled the researchers
to clarify a number of open questions, such as the position of the Boraginaceae, which includes for instance forget-me-nots.

However, new questions arose in other areas -- the researchers now know
at which points in the mosaic they have to sequence the genome of other
plants in order to clarify remaining questions. The study is therefore an important step on which those involved in the project and other working
groups can now build.

A large part of the species studied originates from Bonn 99 of the
210 newly studied plants come from the University of Bonn's Botanic
Gardens. "Due to its high quality, DNA from living plants allows much
more precise conclusions than that obtained from herbarium specimens
that have been stored in museums for decades," says Weigend. "You would
have to travel to more than 40 different countries to collect the samples
here used from the wild and would probably be busy for years." The living collections in botanic gardens are an increasingly important resource
for research and development, since modern methods can be used to answer
ever new questions, the researcher emphasizes. "At the same time, it's
becoming more and more difficult to legally to obtain access to plant
material from other countries, which further underlines the importance of
the collections." Sequencing many hundreds of genes in over 200 species generates a huge amount of data. Evaluating these by computer places
enormous demands on software and hardware. "The sequences were evaluated primarily by our partners at Pennsylvania State University and Fudan University," explains Maximilian Weigend. "Such large-scale investigations
can nowadays only be carried out in international collaborations."
The results make it possible to understand the evolution of flowering
plants more precisely than before. The botanist stresses that although
this is basic research, it also has tangible practical implications --
for example, if one wants to understand how plants have reacted to
changing climatic conditions in the past and therefore also what the
impact of current or future changes in environmental conditions might
be. "In addition, many important crops used by humans are asterids,
from potatoes to kiwis and coffee," he explains.

Many species also produce important agents that could be the basis for
future drugs. And if you are looking for an alternative to a plant-based
agent, it is best to take a look at a related species. Weigend: "This is another reason why it's important to know the family tree of asteroids
in as much detail as possible."

========================================================================== Story Source: Materials provided by University_of_Bonn. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Hong Ma, Maximilian Weigend, Ji Qi, Michael W Frohlich, Mathew
Rees, Yi
Hu, Chien-Hsun Huang, Yezi Xiang, Federico Luebert, Taikui Zhang,
Caifei Zhang. Asterid phylogenomics/phylotranscriptomics uncover
morphological evolutionary histories and support phylogenetic
placement for numerous whole genome duplications. Molecular Biology
and Evolution, 2020; DOI: 10.1093/molbev/msaa160 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200805110122.htm

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