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How plant hormones control root growth

By | News, Plant Science

Plant roots can grow without limit. To do so, they need to balance the production of new cells via cell division and elongation. Plant hormones known as brassinosteroids play a key role in this balancing act. New work unravels how brassinosteroid production is localized in plant roots for optimal growth patterns.

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Tree species diversity is no protection against bark beetle infestation

By | Forestry, News

In recent years, foresters have been able to observe it up close: First, prolonged drought weakens the trees, then bark beetles and other pests attack. While healthy trees keep the invaders away with resin, stressed ones are virtually defenseless. Freiburg scientist Sylvie Berthelot and her team of researchers from the Faculty of Environment and Natural Resources and the Faculty of Biology are studying the importance of tree diversity on bark beetle infestation. They are investigating whether the composition of tree species affects bark beetle feeding behavior. The team recently published their findings in the Journal of Ecology.

In a 1.1 hectare experimental set-up in Freiburg, six native deciduous and coniferous tree species from Europe and six deciduous and coniferous tree species from North America were each planted in different mono- and mixed plots. After the severe drought in the summer of 2018, the Sixtoothed spruce bark beetle mainly attacked the native species: the European spruce and the European larch. “We were surprised that the beetles exhibited only a slight interest in the exotic conifer species, such as the American spruce,” Berthelot says.

While measuring the infestation, the researchers found that the position within the experimental site was also crucial. The trees at the edge were attacked the most. Therefore, Berthelot suspects that the bark beetle entered the testing plot from outside. “In addition, environmental influences weaken the unprotected outer trees more, so they are more susceptible.”

At the same time, the likelihood of which trees the bark beetles will attack changes the more tree species there are. Until now, the researchers assumed that tree diversity reduces the infestation of insect pests such as the bark beetle. But their experiment shows that “increasing tree diversity can reduce the risk of bark beetle infestation for species that are susceptible to high infestation rates, such as larch and spruce. But the risk for less preferred species such as pine or exotic trees may increase with tree diversity, as beetles, once attracted, also attack these trees,” Berthelot says. Although the study indicates that non-native tree species are less attacked because the bark beetles are unfamiliar with these species. “However, this effect may weaken over the years,” she said. As a result, the risk of infestation in mixed forests is redistributed among tree species rather than reduced for all.

Read the paper: Journal of Ecology

Article source: Albert-Ludwigs-Universität Freiburg

Image: Aerial view of the IDENT tree diversity experiment near Freiburg before (left) and after (right) the 2018 drought and bark beetle infestation. Credit: aerial photos by K. R. Kovach, Sixtoothed spruce bark beetle photo by U. Schmidt.

Terpen-tales: The mystery behind the unique fragrance of the lovely lavender

By | Agriculture, News, Plant Science

Even the mention of lavender evokes the distinct fragrance of the flower. This beautiful flower has been used to make perfumes and essential oils since time immemorial. The aesthetics of the flower have captured the imagination of hundreds, worldwide. So, what makes this flower so special? What are the “magical” compounds that gives it its unique fragrance? What is the genetic basis of these compounds? These questions have long puzzled scientists.

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Preventing the spread of plant pandemics

By | News, Plant Health, Plant Science

Plant diseases don’t stop at national borders and miles of oceans don’t prevent their spread, either. That’s why plant disease surveillance, improved detection systems, and global predictive disease modeling are necessary to mitigate future disease outbreaks and protect the global food supply, according to a team of researchers.

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​​Mapping Citrus Microbiomes: The First Step to Finding Plant-Microbiome Treasures ​

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

Due to their complexity and microscopic scale, plant-microbe interactions can be quite elusive. Each researcher focuses on a piece of the interaction, and it is hard to find all the pieces let alone assemble them into a comprehensive map to find the hidden treasures within the plant microbiome. This is the purpose of review, to take all the pieces from all the different sources and put them together into something comprehensive that can guide researchers to hidden clues and new associations that unlock the secrets of a system.

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Scientists uncover how resistance proteins protect plants from pathogens

By | News, Plant Science

In plants, disease resistance proteins serve as major immune receptors that sense pathogens and pests and trigger robust defense responses. Scientists previously found that one such disease resistance protein, ZAR1, is transformed into a highly ordered protein complex called a resistosome upon detection of invading pathogens, providing the first clue as to how plant disease resistance proteins work. Precisely how a resistosome activates plant defenses, however, has been unclear.

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The legume family tree: massive molecular study uncovers clues to the evolution and diversification of essential plant family

By | Agriculture, Botany, News, Plant Science

The most comprehensive study of the family tree for legumes, the plant family that includes beans, soybeans, peanuts, and many other economically important crop plants, reveals a history of whole-genome duplications. The study also helps to uncover the evolution of genes involved in nitrogen fixation—a key trait likely important in the evolutionary spread and diversification of legumes and vital for their use as “green manure” in agriculture.

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