A new study reveals a complex interplay between soil fungi and tree roots that could be the cause of rare-species advantage. The researchers found that the type of beneficial soil fungi living around tree roots in a subtropical forest in China determined how quickly the trees accumulated harmful, pathogenic fungi as they grew. The rate of accumulation of pathogenic fungi strongly influenced how well the trees survived when growing near trees of the same species.
As their Latin name indicates, pineapples are truly “excellent fruits”—and thanks to a freshly completed genome sequencing project, researchers have gained a new understanding of how human agriculture has shaped the evolution of this and other crops.
Before Europeans arrived in America, longleaf pine savannas sprawled across 90 million acres from present-day Florida to Texas and Virginia. Today, thanks to human impacts, less than 3 percent of that acreage remains, and what’s left exists in fragmented patches largely isolated from one another.
Researchers have discovered a new function of one of the plant’s proteins – BAG4. In their study, they show that this protein takes part in regulating the plant’s breathability, the transporting of potassium to occlusive cells and, therefore, the opening of stomas, the pores located on the leaves and through which the plant breaths. This finding is especially relevant for the development of crops that are more resistant to drought conditions.
Almond and the peach are two well-known tree species, since humans have been eating their fruit (peach) or seed (almond) for thousands of years. New research shows that the movement of the transposons could lie at the origin of the differences between the fruit of both species or the flavour of the almond.
The mitochondrion, “the powerhouse of the cell.” Somewhere back in the very distant past, something like a bacterium moved into another cell and never left, retaining some of its own DNA. For billions of years, mitochondria have passed from mother to offspring of most eukaryotic organisms, generating energy for the cell and playing roles in metabolism and programmed cell death.
Grasslands make up more than 40% of the world’s ice-free land and have sustained humanity and thousands of other species for eons. In addition to providing food for cattle and sheep, grasslands are home to animals found nowhere else in the wild, such as the bison of North America’s prairies or the zebras and giraffes of the African savannas. Grasslands also can hold up to 30% of the world’s carbon, making them critical allies in the fight against climate change.
Climate change is causing grasslands to shift beneath our feet, putting these benefits at risk. Global change — which includes climate change, pollution and other widespread environmental alterations — is transforming grasslands and the plant species in them. A new study from researchers at Michigan State University shows what these changes to grassland plant communities look like, and reveal they are not always in ways scientists expect.
“Here in the Midwest, grasslands have been reduced to less than 1% of what they were at the time of European settlement and understanding what drove these changes is important to managing and restoring these systems” said Kay Gross, a plant ecologist at MSU’s Kellogg Biological Station, or KBS, and one of the authors of the study. “Our research at the KBS Long Term Ecological Research site and Allegan State Game Area had provided important information on these processes, but including our data into this larger synthesis reveals insights that are not apparent in site-specific research.”
The new paper, published in the Proceedings of the National Academy of Sciences, offers the most comprehensive evidence to date on how human activities are changing grassland plants.
The team looked at 105 grassland experiments around the world, including other sites from the National Science Foundation’s Long Term Ecological Research program and other research done at KBS. Each experiment tested at least one global change factor — such as rising carbon dioxide, hotter temperatures, extra nutrient pollution or drought. Some experiments looked at two or more of these factors. The team was led by Kimberly Komatsu, a grassland ecologist at the Smithsonian Environmental Research Center, and included researchers from around the world—including former KBS graduate students Emily Grman and Greg Houseman. Team members contributed data from a wide range of grasslands, and developed analyses to determine whether global change was altering the composition of grasslands, both in the total number and kinds of plant species present.
They discovered grasslands can be surprisingly tough — to a point. And it can take time for these changes to be detected. In general, grasslands resisted the effects of global change for the first decade of exposure. But after 10 years of exposure to a climate change factor, species began to shift. Half of the experiments lasting 10 years or more found a change in the total number of plant species, and nearly three-fourths found changes in the types of species. By contrast, only 20% of the experiments that lasted less than 10 years picked up any species changes at all. Experiments that examined three or more aspects of global change were also more likely to detect grassland transformation.
“I think grasslands are very, very resilient,” said Meghan Avolio, co-author and assistant professor of ecology at Johns Hopkins University. “But when conditions arrive that they do change, the change can be really important.”
To the scientists’ surprise, the identity of grassland species can change drastically, without altering the number of species. In half the plots where individual plant species changed, the total amount of species remained the same. In some plots, nearly all the species had changed.
For the team, this is a sign of hope that most grasslands could resist the experimentally induced global changes for at least 10 years. And that maybe grasslands are changing slowly enough that we can prevent catastrophic changes in the future.
However, time may not be on our side. In some experiments, the current pace of global change transformed even the “control plots” that were not exposed to experimentally higher global change pressures. Eventually, many of those plots looked the same as the experimental plots.
“Working collectively to understand how climate change is affecting grasslands is critical so that we can better restore and manage this important habitat that we and many other species depend on,” Gross said. “Long-term experiments and data sets are crucial for these efforts.”
Read the paper: Proceedings of the National Academy of Sciences
Article source: Michigan State University
Image credit: Kevin Kahmark, Michigan State University
A team of scientists with two disparate sets of expertise – in plant biology and protein structural chemistry – have unraveled the atomic basis of how optimal numbers of stomata are made in leaves.
An international team succeeded in assembling the first sequence of the pea genome. This study will, in addition to increasing knowledge of this genome compared to that of other legumes, help to improve traits of interest for peas, such as disease resistance, regularity of yield and nutritional value.
Over-fertilization of agricultural fields is a huge environmental problem. Excess phosphorus from fertilized cropland frequently finds its way into nearby rivers and lakes. A resulting boom of aquatic plant growth can cause oxygen levels in the water to plunge, leading to fish die-offs and other harmful effects.
Researchers from Boyce Thompson Institute have uncovered the function of a pair of plant genes that could help farmers improve phosphate capture, potentially reducing the environmental harm associated with fertilization.
The work was published in Nature Plants.
The discovery stems from Maria Harrison’s focus on plants’ symbiotic relationships with arbuscular mycorrhizal (AM) fungi. Harrison is the William H. Crocker Professor at BTI and an adjunct professor in Cornell University’s School of Integrative Plant Science.
AM fungi colonize plant roots, creating an interface where the plant trades fatty acids for phosphate and nitrogen. The fungi also can help plants recover from stressful conditions, such as periods of drought.
But feeding the AM fungi with fatty acids is costly, so plants don’t let this colonization go unchecked.
To discover how plants control the amount of fungal colonization, Harrison and Lena Müller, a postdoctoral scientist in her lab, looked at genes that encode short proteins called CLE peptides in the plants Medicago truncatula and Brachypodium distachyon.
CLE peptides are involved in cellular development and response to stress, and they are present throughout the plant kingdom, from green algae to flowering plants.
The researchers found that two of these CLE genes are key modulators of AM fungal symbiosis. One gene, called CLE53, reduces colonization rates once the roots have been colonized. Another gene, CLE33, reduces colonization rates when there is plenty of phosphate available to the plant.
“Being able to control fungal colonization levels in plant roots and maintain the symbiosis even in higher phosphate conditions might be useful to a farmer,” Harrison said. “For example, you may want the other beneficial effects of AM fungi, like nitrogen uptake and recovery from drought, as well as further uptake of phosphate”
“You might be able to achieve these benefits by altering the levels of these CLE peptides in the plants,” Harrison added.
Müller found that the CLE peptides act through a receptor protein called SUNN. In collaboration with Harro Bouwmeester and Kristyna Flokova of the University of Amsterdam, she found that the two CLE peptides modulate the plant’s synthesis of a compound called strigolactone.
Plant roots exude strigolactone into the soil, and the compound stimulates AM fungi to grow and colonize the root. Once the roots are colonized or there is plenty of phosphate, the CLE genes suppress the synthesis of strigolactone, thus reducing any further colonization by the fungi.
“In the early 2000’s, researchers found that plants had a way to measure and then reduce colonization,” Müller said. “But until now, nobody really understood the molecular mechanism of that dynamic.”
The researchers’ next steps will include figuring out the molecules that turn on the CLE genes in response to colonization and high phosphate levels.
Müller also plans to compare the two CLE peptides from this study with additional CLE peptides that have different functions.
“The CLE peptides are all so similar but they have completely different functions,” Müller said. “It will be very interesting to see why that is.”
Read the paper: Nature Plants
Article source: Boyce Thompson Institute
Image: Boyce Thompson Institute