It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, March 02, 2024
Genetic research revealed several new fern species in tropical America
DANAEA UBATUBENSIS, ONE OF THE RECENTLY DESCRIBED FERN SPECIES, IS KNOWN ONLY FROM A SMALL AREA OF COASTAL RAINFOREST IN BRAZIL. A LARGE PROPORTION OF THE SPECIES IN THE AREA ARE ENDEMIC.
Researchers have clarified the evolutionary history of a previously poorly known group of ferns from the tropical rainforests of America using DNA methods. The study discovered many new fern species, 18 of which have now been given official names and species descriptions.
The Amazon Research Team of the University of Turku in Finland has conducted long-term studies on the flora and vegetation of Amazonian rainforests to gain a better understanding of species distribution and evolutionary history. The researchers have collected data from both Amazonia and other parts of tropical America. Now, they have traced the evolutionary history of the fern genus Danaea using DNA analyses.
"Studying the evolutionary relationships between species reveals factors that can lead to the differentiation of species traits and ultimately to the evolution of new species," says Doctoral Researcher Venni Keskiniva. "This type of information helps us understand the drivers behind the high biodiversity observed in tropical regions," Keskiniva continues.
The study revealed that there are many more species in the genus Danaea than previously thought, and as part of their revision, the researchers described 18 species that were new to science.
Genetics helped to distinguish between tricky species
In the study, the researchers combined DNA methods with solid field experience. Many of the new species were found in tropical rainforests in areas that had previously been studied little or not at all.
"However, some new species were growing right under the researchers’ noses, for example on Barro Colorado Island, which is one of the most intensively researched rainforests in the world. Two of our new species were found practically in the backyard of a research station," says Professor Hanna Tuomisto. "The plants had of course been seen, but they were thought to belong to a common species that grows throughout tropical America."
The recently published study shows that there are no such widespread species in the genus Danaea. Researchers have just been unable to distinguish between similar-looking species.
In the 1990s, it was estimated that the total number of Danaea species wass 20–30, and that many of them were very widespread. Today, there are about 80 named species, with a further 20 or so still awaiting confirmation. This means that the number of species is much higher, but their ranges are smaller than previously thought.
"At first, we were surprised to see that different individuals of a known species were placed in completely different parts of the family tree. Then we noticed that they formed groups that differed not only in DNA but also in appearance and area of occurrence. This led us to conclude that they were different species," explains Keskiniva.
Danaea ferns are notorious for being difficult to identify. Therefore, the researchers from the University of Turku also published an online identification key. This will help other researchers gather information on the ecology and species richness of tropical forests.
Several species are already endangered at the time of discovery
The ferns of the genus Danaea represent a very old evolutionary line, already differentiated from other plants in the Carboniferous Period. At that time, their ancestors formed vast fern forests, the fossilised remains of which later became coal.
As a result of the burning of the coal and other fossil fuels, the climate of tropical rainforests is becoming hotter and drier. This is threatening the future of species adapted to high humidity, such as Danaea ferns. The researchers estimate that six of the now described 18 species are already endangered.
"Suitable habitats for rainforest species have been reduced due to direct human activity, such as deforestation" says Tuomisto. "The situation is especially bad in the rainforests of the Atlantic coast, Andean montane forests, and parts of the Pacific coast and Central America. These areas are rich in endemic species, but the forests have been reduced to fragments. For understanding and protecting the biodiversity of tropical forests, it is important to realise that species distributions are narrower than used to be thought".
Danaea ampla, one of the new fern species recently described, was found in Panama on Barro Colorado Island, which is one of the most intensively researched rainforest sites in the world.
CREDIT
Photographer: Hanna Tuomisto
JOURNAL
Willdenowia - Annals of the Botanic Garden and Botanical Museum Berlin-Dahlem
Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species
Targeting seed microbes to improve seed resilience
Analysis of seed endophytes in the wild crop fonio reveals the seed microbiome as a potential target for sustainably enhancing crop resilience to climate stress.
Fonio (Digitaria exilis), a type of millet, is the oldest indigenous crop in West Africa and one of the fastest maturing cereals. Despite its low yield, the combination of quick maturation and drought tolerance and its ability to thrive in poor soils make it a useful model for understanding how cereals can adapt to future climate change conditions.
Nutritionally, fonio is comparable to other millets, says KAUST researcher Naheed Tabassum, but yields are much lower than the major cereal crops rice, maize and wheat. Tabassum believes fonio could complement staple crops amid climate change and desertification challenges.
Tabassum and colleagues, led by Heribert Hirt and Simon Krattinger, have investigated the potential to improve fonio by manipulating its association with soil microbes.[1]
Plants grown in arid conditions associate and interact with bacteria that help them combat abiotic challenges. Hirt and his group are experts on plant-microbe interactions and their role in plant growth and development, nutrient uptake and protection against biotic stress.
“Plants evolve in close interaction with microbial partners, which is crucial for their survival and fitness,” says Hirt. “As seeds are the bottleneck for vertical transmission (from the mother plant) of potentially beneficial microbial communities, we tried to unravel the role of the fonio seed microbiome in various abiotic conditions.”
Their study investigated the bacterial seed endophyte diversity in 126 fully sequenced genetic groups of fonio accessions from distinct locations in West Africa.
The role of endophytic bacteria in seeds has been linked to plant growth and protection, yet the specific mechanisms remain to be explained in detail. The results of this study suggest that seed-associated endophytes support plant growth promotion through nutrient availability and assimilation. Previous studies have shown that seed endophytes produce biocontrol inhibitors to protect from pathogens.
When they analyzed the seed microbiomes, the researchers found that fonio millet has diverse heritable seed endophytic taxa. “Despite finding diverse microbiomes in fonio from distinct geographical locations, all fonio plants share a set of microbes, a so-called core microbiome, which probably plays important functions in the general metabolism of this cereal,” says Hirt.
To test whether environmental factors influenced the composition of the seed microbiomes, the researchers gathered meteorological and soil data (precipitation, temperature, pH and soil structure) at the collection sites. They found a correlation between several of these parameters and microbial diversity, indicating that environmental factors may affect microbial composition and transgenerational transmission.
“The seed coat and storage tissue represent distinct microhabitats,” explains Tabassum. “The vertical transmission of microbiota to fortify the progeny of a plant species opens a new technological application in crop breeding.”
“Seed microbe engineering could be used for targeted metabolites or to produce antimicrobial compounds to improve plant biomass and yield under stresses,” she says.
The recently published study provides a proof of concept to explain the composition and diversity of the seed-associated microbiomes of fonio from a number of locations.
In what they believe is a world first, the team performed genome-wide association studies (GWAS) of the 126 fonio accessions to identify genetic loci associated with seed endophyte diversity. This led to the identification of a number of known and novel genes that appear to influence the diversity of the microbial communities in different fonio accessions, suggesting that different fonio groups also genetically regulate the composition of their seed microbiomes.
“Although seed microbiome research is in its infancy, our work shows that it has great potential to advance our understanding of the plant-microbiome-environment interaction and in seed microbiome engineering of crops,” says Hirt.
“This study identified the seed microbiome as a potential target for enhancing crop resilience to climate stress in a sustainable way,” he concludes.
Naheed is a postdoctoral fellow in Heribert Hirt's Darwin 21 research group. Naheed's research interests focus on plant defense signaling, plant-microbe interactions and microbiome.
THE NEWLY DISCOVERED PLANT RELICTITHISMIA KIMOTSUKIENSIS PROBABLY DIVERGED AT AN EARLY STAGE IN THE EVOLUTION OF THE WHOLE FAMILY AND RETAINS ANCESTRAL CHARACTERISTICS. THIS HISTORY IS REFLECTED IN THE PLANT’S NAME.
A new species and genus of fairy lantern, tiny glass-like white plants that feed on fungi, has been discovered in Japan. In the country renowned for its extensive flora research, the discovery of a new plant genus is extremely rare and has not occurred in almost 100 years.
Fairy lanterns, or Thismiaceae as they are known to botany, are very unusual plants found mainly in tropical but also in subtropical and temperate regions. First of all, they are not green and do not engage in photosynthesis, but rather feed on fungal mycelia in the ground. As a consequence, they are often hidden under fallen leaves and only for a brief period produce above-ground flowers that look like glasswork. The Japanese name for Thismia, one of the major groups within this family, is “Tanuki-no-shokudai,” which means “raccoon dog’s candleholder” and refers both to their shape and their underground lifestyle. However, they are also extremely rare and difficult to find. “At present, approximately 100 species within the family have been identified, nearly half of which are known only from their first discovery, sometimes from a single specimen,” explains Kobe University botanist SUETSUGU Kenji, who is an internationally renowned expert on non-photosynthetic plants.
Suetsugu has long-standing collaborations with local botanists who have access to secluded areas all over Japan. He says, “The dedication of Japanese amateur researchers to revealing the hidden flora of these regions has been crucial in identifying species unknown to science.” And so, when he was sent a specimen of a fairy lantern that a hobby botanist had found and that a local expert thought represented a new species of the genus of Tanuki-no-shokudai, he knew he had to investigate. However, it soon became clear “that this plant was not included in any of the existing genera (such as Thismia) because of its unique features, and it became necessary to obtain additional individuals for further examination.” So, he went to Kimotsuki in Kagoshima Prefecture, where the discovery had been made, but could not find any other samples. However, a year later he tried again and got lucky: They found four more plants, all in the same narrow area.
The Kobe University expert now published his analysis in the scientific Journal of Plant Research. Based both on morphological and genetic analysis, the team concluded that the plant is not only a new species, but in fact different enough from Tanuki-no-shokudai to be a different genus — the next level of relationship above species. The researchers think the plant probably diverged at an early stage in the evolution of the whole Thismiaceae family and retains characteristics that are common to the family but have been lost in the Thismia genus. This is the reason Suetsugu chose the name “Mujina-no-shokudai,” or “badger’s candleholder”: “Mujina” is an old Japanese word for a badger, but sometimes has also been used for the raccoon dog which it resembles but is different from. Thus, the name reflects the plant’s relationship with Thismia. The Latin name Relictithismia kimotsukiensis is similar, as it can be translated as “Thismia relict of Kimotsuki.”
“Japan is one of the regions in the world where botanical surveys are most advanced, making the discovery of new plant species extremely rare, and the discovery of a new genus even more so,” says Suetsugu. In fact, the last discovery of a new vascular plant concurrently identified as a separate genus was the discovery of Japonolirion in 1930, almost 100 years ago. Suetsugu explains, “This research might suggest that many other new species may be hiding in regions previously thought to be well-studied and underscores the critical need for ongoing exploration and investigation of the planet’s flora both abroad and at home.”
A plant that feeds on fungi and is so limited in its local spread is also exceptionally vulnerable to environmental change. This motivates Suetsugu to deepen his research, saying, “A segment of our future research will be dedicated to ecological studies aimed at deciphering the interactions between Relictithismia and its fungal hosts, in addition to assessing the impact of environmental alterations on these associations.”
One of the most intriguing unique characteristics of the newly described Relictithismia kimotsukiensis is that its stamens (the male part of the plant) touch the stigma (the female part), thus facilitating self-pollination. This adaptation is likely advantageous for a plant that lives under fallen leaves in dark forests where pollinators are scarce.
Members of the family Thismiaceae feed on fungal mycelia in the ground. As a consequence, they are often hidden under fallen leaves and only for a brief period produce above-ground flowers that look like glasswork.
The analysis of the newly discovered Relictithismia kimotsukiensis showed that it is different enough from all known genera of Thismiaceae to warrant its classification as an entirely new genus. “Our expertise in various aspects of botany enabled us to merge traditional taxonomic methods with modern molecular techniques, offering a comprehensive approach to our research,” says Kobe University botanist SUETSUGU Kenji.
CREDIT
TAGANE Shuichiro
This study was supported by the PRESTO program (grant JPMJPR21D6) of the Japan Science and Technology Agency, the JSPS KAKENHI (grant 21K06307) and the Environment Research and Technology Development Fund (grant JPMEERF20204001) of the Ministry of the Environment, Japan. It was conducted in collaboration with an independent researcher and researchers from Kyoto University and the Kagoshima University Museum.
Kobe University is a national university with roots dating back to the Kobe Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with nearly 16,000 students and nearly 1,700 faculty in 10 faculties and schools and 15 graduate schools. Combining the social and natural sciences to cultivate leaders with an interdisciplinary perspective, Kobe University creates knowledge and fosters innovation to address society’s challenges.
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