The newly reported genome sequence of a water lily sheds light on the early evolution of angiosperms, the group of all flowering plants. An international team of researchers, including scientists at Penn State, used high-throughput next-generation sequencing technology to read out the water lily's (Nymphaea colorata) genome and transcriptome--the set of all genes expressed as RNAs.
The unusual high quality and depth of coverage of the sequence allowed the researchers to assemble the vast majority of the genome into 14 chromosomes and identify more than 31 thousand protein-coding genes. A paper describing the sequence and subsequent analysis appears December 18, 2019 in the journal Nature.
"Water lilies have been an inspiration to artists like Claude Monet because of their beauty and important to scientists because of their position near the base of the evolutionary tree of all flowering plants," said Hong Ma, associate dean for research and innovation, Huck Distinguished Research Professor of Plant Molecular Biology, and professor of biology at Penn State, one of the leaders of the research team.
"I previously contributed to the sequencing and analysis of the genome of Amborella, which represents the earliest branch to separate from other flowering plants, but Amborella lacks big showy colorful flowers and attractive floral scent, both of which serve to attract pollinators in most groups of flowering plants. We were interested in the water lily genome to help us understand how these traits evolved."
Evolutionary comparison of the water lily genome to the genomes of Amborella, other angiosperms, and several gymnosperms--the group of seed-bearing plants that do not produce flowers--confirmed the position of Amborella, which shares some characteristics with the gymnosperms, as the earliest of currently living angiosperms to separate from other flowering plants.
Water lilies were the next branch to diverge from a third branch (Austrobaileyales, which includes star anise) and a fourth very large group called the mesangiosperms, which contains over 99% of living flowering plants.
"If we make an analogy to mammalian evolution, Amborella has a similar position to that of the platypus and other egg-laying mammals," said Ma. "The platypus is a mammal because it feeds its young with milk, but it lays eggs like birds or reptiles.
Amborella, like gymnosperms, has separate male and female plants, but the water lily has male and female reproductive parts within a single flower. This makes the water lily more similar to the vast majority of other flowering plants, so having the genomes of both Amborella and water lily can help us to better analyze the evolutionary transition from gymnosperms to angiosperms."
The researchers used molecular dating to estimate the separation of the family of water lilies (Nymphaeaceae) from other families of related aquatic plants at somewhere between 147 and 185 million years ago, when dinosaurs roamed the earth, with a whole-genome duplication (WGD)/polyploidy event at about the same time. Many of the key genes for flower development retained in this WGD.
The research team also analyzed genes in the water lily genome that are likely important for the generation of molecules for attractive floral scent and color, traits shared with most other angiosperms, but not found in Amborella.
They identified a massive expansion in the number of genes involved in the biosynthesis of floral scent in water lilies; these genes seem to have evolved in parallel with the other angiosperms. They also analyzed the expression of genes involved in flower color between two species of water lily, identifying the key proteins responsible for blue petals.
"Having the water lily genome allows us to explore these important traits in flowering plants and especially among horticultural plants," said Ma. "It's likely that brightly colored flowers and floral scent evolved through an interaction with pollinators and such flowers are ultimately extremely important for the success of flowering plants. Identification of the key synthetic genes of blue petals has important reference value for breeding blue petal varieties."
In addition to Ma, the research team was led by Liangsheng Zhang and Haibao Tang of the Fujian Agriculture and Forestry University in Fuzhou, China; Fei Chen and Feng Chen of Nanjing Agricultural University in Nanjing, China and the University of Tennessee, Knoxville; and Yves Van de Peer of Ghent University in Belgium, and includes 47 authors from 23 institutions.
Life's clockwork: Scientist shows how molecular engines keep us ticking
14.01.2020 | University of North Carolina Health Care
World Premiere in Zurich: Machine keeps human livers alive for one week outside of the body
14.01.2020 | Universitätsspital Zürich
Researchers from the University Hospital Zurich, ETH Zurich, Wyss Zurich and the University of Zurich have developed a machine that repairs injured human livers and keep them alive outside the body for one week. This breakthrough may increase the number of available organs for transplantation saving many lives of patients with severe liver diseases or cancer.
Until now, livers could be stored safely outside the body for only a few hours. With the novel perfusion technology, livers - and even injured livers - can now...
A balloon-borne scientific instrument designed to study the origin of cosmic rays is taking its second turn high above the continent of Antarctica three and a half weeks after its launch.
SuperTIGER (Super Trans-Iron Galactic Element Recorder) is designed to measure the rare, heavy elements in cosmic rays that hold clues about their origins...
One last time on Earth it has been turned on in France in December 2019. The next time the MOMA laser developed by the Laser Zentrum Hannover e.V. (LZH) is going into operation will be on Mars. The ExoMars rover into which the laser is integrated has now successfully passed the thermal vacuum tests at Airbus in Toulouse, France.
For 18 days the ExoMars rover Rosalind Franklin was subjected to thermal vacuum tests at Airbus. There, it had to withstand strong changes in temperature and...
The Atacama Desert in Chile is the oldest and most arid desert on earth. Organisms living in this area have adapted to the extreme conditions over thousands of years. A research team led by Dr Patrick Jung has now discovered and investigated a previously unknown biocoenosis of lichens, fungi, cyanobacteria and algae. It colonises tiny stones, so-called grit and its need for water is satisfied by fog and dew. These organisms also decompose the rock on and in which they live. The scientists believe that this is how they have shaped the landscape of the Atacama Desert. Their study was published in the renowned scientific journal "Gebiology".
Many desert areas have large black spots in the sand. These spots are mineral deposits, so-called desert varnish. In the Atacama Desert, which can be compared...
For the first time, physicists from the University of Würzburg have successfully converted electrical signals into photons and radiated them in specific directions using a low-footprint optical antenna that is only 800 nanometres in size.
Directional antennas convert electrical signals to radio waves and emit them in a particular direction, allowing increased performance and reduced...
07.01.2020 | Event News
19.12.2019 | Event News
03.12.2019 | Event News
14.01.2020 | Life Sciences
13.01.2020 | Physics and Astronomy
13.01.2020 | Life Sciences