In hot weather, trees “sweat” to cool down by releasing water from their leaves or needles and then replacing it with water from the soil. But during long periods of high temperatures, trees may release more water than they can replace. To strengthen forests against heat stress and other environmental hazards, scientists have suggested adding fungi to the soil. 

Soil fungi living on tree roots are called ectomycorrhizal fungi. They help trees absorb water by expanding their root networks, and trees help the fungi by providing them with sugars for energy. This beneficial partnership is known as symbiosis. Scientists at Fujian Agriculture and Forestry University in China tested whether symbiosis with ectomycorrhizal fungi could help the pine trees Pinus massoniana survive warmer temperatures. 

For their experiment, the researchers grew pine seedlings with and without ectomycorrhizal fungi in a greenhouse under different temperature conditions. First, they grew fungi called Cenococcum geophilum for 45 days on a gel-like substance called agar. At the same time, they grew the pine seedlings for 30 days, then transferred them into pots with natural soil. 

After 15 days in the pots, the researchers spread the gel-like agar containing the fungi over small 1 x 1 centimeter (cm) areas of the pine root tips to introduce the fungi to the seedlings, a process called inoculation. They assumed that the fungal network would expand from the starting area to colonize new root tips as the seedlings grew. The team’s inoculations included 6 different C. geophilum strains and 1 fungi-free control. To simulate heat stress, the researchers replicated each of the 7 inoculations at 25°C (77°F) and 35°C (95°F). They repeated each inoculation condition in 3 pots with 3 seedlings, for a total of 126 seedlings. 

After 60 days, the researchers harvested the pine seedlings and used a microscope to count how many of their root tips had fungi. They divided the number of root tips with fungi by the total number of root tips to calculate a colonization rate. They considered seedlings with a colonization rate of 80% or higher to have successfully formed a symbiotic relationship with the fungi. Then, the researchers analyzed seedlings with an 80% colonization rate to investigate their symbiotic partnerships.

The team observed that pine seedlings grown under heat stress at 35°C were 24% to 59% smaller than those grown at 25°C, and their needles were yellow instead of a healthy green. However, the seedlings that formed a symbiotic relationship with the ectomycorrhizal fungi were greener and 80% heavier than the control seedlings. 

Investigating the trees further, the team measured 3 chemical compounds related to plant stress, including malondialdehyde (MDA), proline, and nitric oxide. Plants release MDA when damaged, so high MDA levels mean a plant is struggling. In contrast, plants release proline and nitric oxide to repair cells or hold water, so high amounts of these compounds mean a plant is healing.

To measure MDA and proline levels in the pine needles, the researchers mixed them with different acids that change color depending on the sample’s MDA or proline content. To measure nitric oxide, the researchers mixed the needles with a protein that converts the compound into a chemical that changes color. They found that inoculated seedlings at 35°C had about 30% to 40% less MDA, 15% to 30% more proline, and 150% more nitric oxide in their roots than the control seedlings. 

Finally, the researchers measured changes in gene activity in the inoculated pine seedlings. They identified active genes by analyzing RNA molecules from the pine seedling roots with a process called RNA sequencing or transcriptomics. They found that inoculating the seedlings with ectomycorrhizal fungi activated more genes related to root strength, water retention, cell defense, and general plant protection than were activated in the control seedlings. 

By combining chemical analyses with growth measurements, the team concluded that a symbiotic partnership with the ectomycorrhizal fungi helped the pine seedlings survive heat stress. They demonstrated that through prolonged heat, inoculated seedlings maintained greener needles and lower levels of stress chemicals. They suggested that ectomycorrhizal fungi could be an ecological tool to help trees stay hydrated in a warming world. They recommended that future researchers conduct field trials with inoculated trees to translate these findings into forest management strategies. 

The post Fungi help pine trees survive heat stress appeared first on Sciworthy.

Nature provides an array of tools for how to navigate the unknown—even in the dark.

From scuba-diving lizards to cliff-climbing goats, nature's organisms have always been able to overcome impossible odds.

Nature is a reminder that nothing is normal, yet everything belongs.

Electric vehicles (EVs) use high-powered rechargeable batteries to store electrical energy that powers their motors. Most EV batteries use a specific mixture of metals to hold the battery’s charge, called nanoscale lithiated nickel manganese cobalt oxides, aka NMC materials. NMC materials can store a large amount of energy, making them ideal for batteries, but the metals themselves can be toxic in soil and water if the batteries are not properly recycled.  

NMC batteries leave behind a specific combination of toxic metals, so researchers can study how bacteria respond to this waste when it enters the environment. By understanding how bacteria adapt to toxic metals, scientists hope to predict how new technologies like EV batteries will affect the environment. 

In 2019, a team of researchers from the University of Minnesota reported that a common soil bacterium called Shewanella oneidensis can rapidly evolve resistance to NMC materials, but they didn’t know how. True beneficial gene evolution usually develops over thousands of generations, but Shewanella oneidensis adapted much more quickly. The team recently conducted a follow-up study to determine the genetic mechanisms behind this bacterium’s unique metal resistance.

They started by analyzing the complete DNA sequences of 33 Shewanella colonies that were resistant to either pure NMC waste or individual metals like nickel and cobalt, using a process called whole-genome sequencing. They expected to find DNA mutations in genes that control how bacteria take up and expel toxic metals that would give the resistant Shewanella an advantage in surviving NMC metal toxicity. However, they didn’t find any DNA mutations in metal-related genes. Instead, they found that a specific DNA region was duplicated 10 to 15 times in all 33 NMC-resistant or metal-resistant colonies. This result suggested to the researchers that a temporary adaptation, not true gene evolution, was responsible for the bacteria’s metal resistance. 

The researchers wanted to know more about the duplicated DNA region in metal-resistant Shewanella, so they focused on 2 gene duplication mechanisms that might serve as temporary adaptations in Shewanella. The first mechanism directly duplicates DNA regions to create extra copies of a gene, via a process called gene duplication amplification. The second mechanism moves DNA segments, called mobile genetic elements, into different DNA sections to create extra copies of a gene. 

To test whether either of these mechanisms was causing the gene duplication in Shewanella, the team grew the bacteria in different liquid media containing only cobalt, only nickel, or cobalt and nickel together. The researchers used a technique that measures the exact amount of DNA in a given sequence, called quantitative polymerase chain reaction (qPCR), to calculate how many duplicated DNA regions were in each genome sequence. They found that neither cobalt nor nickel alone triggered DNA duplication. But the bacteria grown in the media with cobalt and nickel together had 8 additional copies of the DNA region. This suggested that something about the combination of nickel and cobalt triggered gene duplication. 

To determine whether this gene duplication only occurred with nickel and cobalt, the team substituted copper and zinc for nickel in the growth media. They exposed Shewanella cells to different combinations of these metals using a grid pattern in a 96-well plate, a technique called a checkerboard assay. Then they repeated the qPCR process to measure the duplicated DNA region. They found that no other combinations of metals triggered gene duplication, suggesting that nickel and cobalt are especially toxic together, and that the gene duplication responds to this combined toxicity.

Finally, the researchers identified the function of the duplicated DNA region. They found that one of the genes within the region turned on a special protein that pushes metal ions and other toxins out of the cell, called an efflux pump protein. The team hypothesized that this efflux pump protein was responsible for removing cobalt and nickel from the bacteria’s cells. To test this theory, they grew modified Shewanella cells without the efflux pump gene in media containing cobalt, nickel, or cobalt and nickel together. They found that the modified bacteria grew well in the nickel-only treatment, but didn’t grow in the cobalt-only or combined treatments, which indicated that the efflux pump protein is necessary for Shewanella to resist cobalt toxicity. 

Based on their experiments, the team concluded that nickel and cobalt together trigger a gene duplication event in Shewanella oneidensis. This gene duplication event increases the number of efflux proteins in Shewanella that can expel cobalt and underlies its unique NMC resistance. They suggested that future researchers study temporary adaptations similar to gene duplication in bacteria to track how they respond to electronic waste and other new technologies.

The post How do bacteria adapt to toxic metal waste? appeared first on Sciworthy.

A new study by Chester Zoo and Nottingham Trent University scientists revealed that just over a third (38%) of more than 230 householders in Cheshire and North Wales were willing or able to introduce more wildlife-friendly features to their gardens.

Five baby orangutans abandoned in an Indian forest have exposed a "massive" exotic wildlife trade, with traffickers smuggling increasingly rare species into the country, experts say.

When most Australians say 'spring is in the air,' they're speaking metaphorically, as the days become longer and warmer.

Understanding the migration pathways of sharks and rays is key to conserving some of the world's most endangered marine species, according to new University of Queensland research.

A rare Australian sea lion (Neophoca cinerea) on Kangaroo Island has been confirmed to have died from highly pathogenic H5N1 bird flu. The sea lion had recently been attacked by a shark, weakening it. Testing revealed that the virus caused its death. Another dead sea lion is being tested.

In recent years, numerous attempts have been made to use artificial intelligence to decipher the communication of bats, whales, birds and other animals. However, a new study led by a team of researchers from Tel Aviv University points to a fundamental problem with this approach: AI models focus on the physical properties of a sound, but this does not mean they understand the meaning attributed to it by the animal receiving it.

In recent years, numerous attempts have been made to use artificial intelligence to decipher the communication of bats, whales, birds and other animals. However, a new study led by a team of researchers from Tel Aviv University points to a fundamental problem with this approach: AI models focus on the physical properties of a sound, but this does not mean they understand the meaning attributed to it by the animal receiving it.

A research team at the Max Planck Institute for Chemical Ecology discovered a previously unknown strategy by which certain fungi neutralize spruce defense compounds. These fungi are introduced into trees by bark beetles, and their success makes it easier for bark beetles to invade the trees.

Critically endangered Sumatran elephants are being pushed closer to the brink as wildfires raze vast swaths of their habitat on the western island of Sumatra, Indonesian conservation group Geopix told AFP on Wednesday.

Saccharina latissima, or sugar kelp, is one of the dominant species in Maine's kelp forests, providing food, habitat and clean water to support a rich marine ecosystem. It is also the bedrock of the state's burgeoning kelp aquaculture industry, which relies on the annual harvest of reproductive tissue from the wild.

Indonesian authorities are working to repatriate five baby orangutans allegedly trafficked to India, where they were found motherless in a forest, Jakarta's forestry ministry told AFP on Friday.

What the elusive polar bear can teach us about the difference between solitude and loneliness.

The globe is full of unknown species. But is it really possible to find a completely new animal species in the middle of the largest city in the United States?

The Hammerschmiede clay pit near Pforzen in the eastern Allgäu is famous for its wealth of finds: Besides fossils of two early anthropoid apes, the remains of numerous vertebrate species have been uncovered in 11.6-million-year-old river sediments—but until now, very few birds.

The Hammerschmiede clay pit near Pforzen in the eastern Allgäu is famous for its wealth of finds: Besides fossils of two early anthropoid apes, the remains of numerous vertebrate species have been uncovered in 11.6-million-year-old river sediments—but until now, very few birds.