Evolution in action: New Plant species in the Swiss Alps

Date:
October 6, 2020
Source:
University of Zurich
Summary:
A new plant species named Cardamine insueta appeared in the region
of Urnerboden in the Swiss alps, after the land has changed from
forest to grassland over the last 150 years. The inheritance of two
key traits from its parent plants enabled the newly emerged species
to grow in a distinct environmental niche, as researchers now show.



FULL STORY ==========================================================================
A new plant species named Cardamine insueta appeared in the region of Urnerboden in the Swiss alps, after the land has changed from forest to grassland over the last 150 years. The inheritance of two key traits from
its parent plants enabled the newly emerged species to grow in a distinct environmental niche, as researches from the University of Zurich now show.


==========================================================================
The emergence of a new species is generally thought to occur over
long periods of time. But -- as the example of the plant Cardamine
insueta shows - - evolution can also happen quite quickly. C. insueta,
a new bittercress species first described in 1972, has only recently
emerged in Urnerboden, a small alpine village in central Switzerland. It evolved just within the past 150 years due to environmental changes in
the surrounding valley: when the local people cleared the forest and
turned it into pasture land.

New plant species allows to observe 'evolution in action' "C. insueta
proves to be an exceptional case to directly analyze the genetic traits
and environmental responses of a new species. In other words: to observe 'evolution in action', a main topic of the university's corresponding University Research Priority Program," says Rie Shimizu-Inatsugi from
the Department of Evolutionary Biology and Environmental Studies at
the University of Zurich (UZH). The plant biologists were now able to
unravel the genetic mechanisms underlying the plant's evolution.

C. insueta developed from two parent species with specific ecological
habitats: while C. amara grows in and beside water streams, C. rivularis inhabits slightly moist sites. The land-use conversion from forest to
grassland induced the hybridization of the two progenitors generating
the new species that is found in-between the parents' habitats with
temporal water level fluctuation.

"It is the combination of genetic traits from its parents that enabled
the new species to grow in a distinct environmental niche," says Shimizu-Inatsugi. In fact, C. insueta inherited one set of chromosomes
from C. amara and two sets of chromosomes from C. rivularis. It therefore contains three sets of chromosomes making it a so-called triploid plant.

Inheritance of two key parental traits enabled the survival To
characterize the responses to a fluctuating environment, the research
team used high-throughput sequencing to analyze the time-course gene
expression pattern of the three species in response to submergence. They
found that the gene activity responsible for two parent traits were
key for the survival of the new species in the novel habitat. First,
C. insueta can clonally propagate through leaf vivipary, meaning it
produces plantlets on the surface of leaves that can grow into new
plants. It inherited the ability for asexual vegetative reproduction
from C. rivularis. Since C. insueta is sexually sterile, it would not
have been able to survive without this trait.

Second, C. insueta inherited the submergence tolerance from C. amara,
since the genes responsible for this trait were active in both
species. "The results show that C. insueta combined advantageous patterns
of parental gene activity to contribute to its establishment in a new
niche along a water-usage gradient.

Depending on the environmental situation, the plant activates different
set of genes it inherited from its two parent species." says Rie Shimizu-Inatsugi.

Funding This work is mainly funded by the University Research Priority
Program "Evolution in Action: From Genomes to Ecosystems," the Swiss
National Science Foundation, Japan Science and Technology Agency, and
the Human Frontier Science Program.


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


========================================================================== Journal Reference:
1. Jianqiang Sun, Rie Shimizu-Inatsugi, Hugo Hofhuis, Kentaro Shimizu,
Angela Hay, Kentaro K. Shimizu, Jun Sese. A Recently Formed Triploid
Cardamine insueta Inherits Leaf Vivipary and Submergence Tolerance
Traits of Parents. Frontiers in Genetics, 2020; 11 DOI: 10.3389/
fgene.2020.567262 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201006091244.htm

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