Category

Plant Science

Oct 25
2
stoma

How Plants React to Fungi

By | News, Plant Science

Plants are under constant pressure from fungi and other microorganisms. The air is full of fungal spores, which attach themselves to plant leaves and germinate, especially in warm and humid weather. Some fungi remain on the surface of the leaves. Others, such as downy mildew, penetrate the plants and proliferate, extracting important nutrients. These fungi can cause great damage in agriculture.

The entry ports for some of these dangerous fungi are small pores, the stomata, which are found in large numbers on the plant leaves. With the help of specialised guard cells, which flank each stomatal pore, plants can change the opening width of the pores and close them completely. In this way they regulate the exchange of water and carbon dioxide with the environment.

Chitin covering reveals the fungi

The guard cells also function in plant defense: they use special receptors to recognise attacking fungi. A recent discovery by researchers led by the plant scientist Professor Rainer Hedrich from Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany, has shed valuable light on the mechanics of this process.

“Fungi that try to penetrate the plant via open stomata betray themselves through their chitin covering,” says Hedrich. Chitin is a carbohydrate. It plays a similar role in the cell walls of fungi as cellulose does in plants.

Molecular details revealed

The journal eLife describes in detail how the plant recognizes fungi and the molecular signalling chain via which the chitin triggers the closure of the stomata. In addition to Hedrich, the Munich professor Silke Robatzek from Ludwig-Maximilians-Universität was in charge of the publication. The molecular biologist Robatzek is specialized in plant pathogen defense systems, and the biophysicist Hedrich is an expert in the regulation of guard cells and stomata.

Put simply, chitin causes the following processes: if the chitin receptors are stimulated, they transmit a danger signal and thereby activate the ion channel SLAH3 in the guard cells. Subsequently, further channels open and allow ions to flow out of the guard cells. This causes the internal pressure of the cells to drop and the stomata close – blocking entry to the fungus and keeping it outside.

Practical applications in agricultural systems

The research team has demonstrated this process in the model plant Arabidopsis thaliana (thale cress). The next step is to transfer the findings from this model to crop plants. “The aim is to give plant breeders the tools they need to breed fungal-resistant varieties. If this succeeds, the usage of fungicides in agriculture could be massively reduced,” said Rainer Hedrich.

Read the paper: eLife

Article source: University of Würzburg

Author:  Robert Emmerich

Image credit: Michaela Kopischke

Oct 23
1
forest_umd_chinese_academy_study_of_fungi_effect

Scientists Discover Interaction Between Good and Bad Fungi Drive Forest Biodiversity

By | Forestry, News, Plant Science

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.

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Oct 15
1
plants in petri dishes

New key protein function found in plants that will help develop drought-resistant crops

By | News, Plant Science

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.

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Oct 11
1
flower-almond or peach

The sequence of the almond tree and peach tree genomes makes it possible to understand the differences of the fruits and seeds of these closely related species

By | Agriculture, Fruits and Vegetables, News, Plant Science

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.

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Oct 08
1
lettuce genome

Lettuce Mitochondrial Genome is Like a Chopped Salad

By | News, Plant Science

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.

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Oct 03
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This is a view of the Kellogg Biological Station Long Term Ecological Research site in early summer

Global change is triggering an identity switch in grasslands

By | News, Plant Science

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