Saturday, July 20, 2024

 

Korean War Anniversary: What We’ve Chosen to Forget about the “Forgotten War”


American soldiers on foreign soil fighting to prop up an army of unmotivated conscripts. Savage bombings. Widespread use of napalm. Massacres of civilians by both the US Army and the allied army we’re propping up. Three million killed, and a larger proportion of civilian deaths than World War II. Lies upon lies about the background of the war and the enemy. What Bruce Cumings, former chair of the history department at the University of Chicago, describes as “Gooks, napalm, rapes, whores, an unreliable ally, a cunning enemy, fundamentally untrained G.I.’s fighting a war their top generals barely understood, fragging of officers, contempt for the know-nothing civilians back home, devilish battles indescribable even to loved ones, press handouts from… headquarters apparently scripted by comedians or lunatics, an ostensible vision of bringing freedom and liberty to a sordid dictatorship run by servants of… imperialism.”

At one point early in this war, the US Army feared that guerrilla fighters were disguising themselves as civilian peasants, and opened fire on them. “Fire on everything, kill ’em all”, one US Army veteran says they were told. “Over the course of a three-day barrage of gunfire and air strafing, hundreds of… civilians were killed,” one account reads. “Survivors recall a stream under the bridge running red with blood and 7th Cavalry veterans recall the near constant screams of women and children.” The US Army stonewalled, and journalists were pressured not to report the full story if at all.

The two paragraphs above are apt descriptions of the Vietnam War and the 1968 My Lai Massacre respectively. Except they are neither descriptions of the Vietnam War nor of My Lai, but instead of the Korean War and the No Gun Ri Massacre carried out by American troops in South Korea in late July 1950.

As a history educator, I’m always surprised at how my students–juniors and seniors in the Los Angeles Unified School District–know almost nothing about the Korean War. A few boys recognize it from their Call of Duty video games, a few others might have heard of the North Korean dictatorship’s bombastic threats, but of the Korean War itself, which ended 71 years ago this week, they know next to nothing.

Part of the problem is the textbooks we are given to use. Neither our US History book, the AP US History book, nor the World History book provide any substantive background to the war. We’re only told, as the regular US History textbook tells us, that “North Korean forces swept across the 38th parallel in a surprise attack on South Korea.” This is distortion by omission.

During WWII, the US and the Soviet Union agreed that, upon Japan’s surrender, Korea, which had been a Japanese colony since 1910, would be divided at the 38th parallel into a Northern, pro-Soviet sector and a Southern, pro-American sector.

The US installed Korean exile Syngman Rhee, who had lived in the US from 1912 to 1945, as the leader of South Korea. Rhee’s government and police force, and almost all leaders of South Korea’s Army, had served the colonial Japanese regime.

The Soviets installed the Korean communists into power, led by Kim Il Sung, who fought a guerrilla war against fascist Japan’s colonial occupation of Korea. The communists had credibility and support because of their long struggle to win Korea’s independence from Japan.

The US History textbook tells us that two Koreas then developed—“one communist and one democratic.” Actually, the “democratic” Rhee regime was brutal, authoritarian, corrupt, unpopular, and widely seen as an artificial creation of the US.

Rhee perpetrated horrific massacres of pro-Communist South Koreans, including the Jeju Massacre (1948-1949), in which up to 30,000 Koreans were killed, and the murder of 100,000 to 200,000 suspected Korean communists in the Bodo League massacre. For years, South Korea falsely claimed this crime was committed by North Korea.

Cumings, author of The Korean War: a History, refers to the US-backed regime’s “atrocious massacres…our ostensibly democratic ally was the worst offender, contrary to the American image of the North Koreans as fiendish terrorists.”

The megalomaniacal Rhee on numerous occasions proclaimed his determination to conquer the communist North. Ignoring American warnings not to provoke a war, Rhee foolishly launched military raids across the border, leading to the deaths of 8,000 South Korean soldiers and thousands of North Korean fighters. At the same time, North Korean-backed communist guerrillas launched guerrilla attacks in South Korea.

With both sides threatening to unify the country by force, the North invaded on June 25, 1950.

Even though the US-Soviet division of Korea gave the South twice the population of the North, the North quickly overran the South. As historian James Stokesbury explains, the masses of conscript South Korean soldiers had little loyalty to the Rhee regime, and soon retreated or defected en masse to the North.

Two days after the invasion, Rhee’s regime abandoned the capital, Seoul, detonating the Hangang Bridge over the Han River in an effort to slow down the North Korean advance. Thousands of refugees were crossing the bridge at the time, leading to hundreds of deaths.

After General Douglas MacArthur’s brilliant landing at Inchon, United Nations forces–90% of whom were American–pushed north towards the Chinese border, spurring China to enter the war. After major Chinese advances, the war ended in a stalemate.

Ignored in our textbooks are the horrific results of the US air war. Air Force General Curtis LeMay, head of the US Strategic Air Command during the Korean War, explained, “[W]e killed off…20 percent of the population…We…burned down every town in North Korea.”

Former Secretary of State Dean Rusk recalled “we were bombing every brick that was standing on top of another, everything that moved.”

In August 1951, war correspondent Tibor Meráy saw “complete devastation between the Yalu River and the capital…[there were] no more cities in North Korea.”

According to the Asia-Pacific Journal:

By the fall of 1952, there were no effective targets left for US planes to hit. Every significant town, city and industrial area in North Korea had already been bombed. In the spring of 1953, the Air Force targeted irrigation dams on the Yalu River, both to destroy the North Korean rice crop and to pressure the Chinese, who would have to supply more food aid to the North. Five reservoirs were hit, flooding thousands of acres of farmland, inundating whole towns and laying waste to the essential food source for millions of North Koreans.

U.S. planes dropped more bombs on the Korean peninsula— 635,000 tons — and more napalm — 32,557 tons — than against Japan during World War II. Yet, incredibly, the word “bomb” does not appear once in the US History textbook’s section on the Korean War.

Cumings says the US “carpet-bombed the north for three years with next to no concern for civilian casualties.”

Nor is there any mention of napalm in our texts. Then-British Prime Minister Winston Churchill condemned the US’ widespread use of napalm as being “very cruel,” saying the US was “tortur[ing] great masses of people” by “splashing it all over the civilian population.” He explained, “Napalm ought not to be used in the way it is being done by the American Forces.”

Nor do our texts mention No Gun Ri or other massacres perpetrated by the American forces. Former Associated Press international correspondent Charles Hanley, author of The Bridge at No Gun Ri: A Hidden Nightmare from the Korean War, explains:

[T]he story of No Gun Ri was shocking when it emerged in 1999, but within the following decade it became clear that events like this were quite commonplace during the Korean War, and it is in some ways what war is all about.

The Associated Press explains that revelations about No Gun Ri “led to an outpouring of other accounts of alleged mass killings of southern civilians by the U.S. military in 1950-51, particularly air attacks. A South Korean investigative commission counted more than 200 cases on its docket by 2008, but the commission was disbanded by a new conservative government in 2010 before it could confirm more than a handful.”

The US History textbook spends 458 words on the conflict between President Truman and General MacArthur and tells us the war cost the US $67 billion and 54,000 killed (actually 36,574). Students are then asked to consider “whether fighting the Korean War was worthwhile” in light of “the loss of American lives” and “fear of communism.” Not once is there mention of the three million Koreans killed, mostly civilians, nor of the 600,000 Chinese killed.

The World History textbook we use is little better, though it does acknowledge that the South Korean government was “undemocratic.” The AP US History textbook, to its credit, acknowledges Korean civilian casualties caused by the American air war as well as the undemocratic nature of the South Korean government, but we’re still given no sense of the horrors perpetrated by the South Korean government nor of why North Korea invaded South Korea.

It is important to remember that misleading or faulty textbooks don’t simply miseducate students, they miseducate their teachers as well. History is a vast subject and any teacher, particularly younger or less experienced teachers, will have areas of history they’re unfamiliar with. In such cases, teachers rely upon the textbook and its related materials–if the textbook does not tell the full truth about an historical event, often the teacher will not be able to either.

The Korean War is often dubbed the “Forgotten War”, and there’s some truth to this, but the real issue is what the American educational establishment has chosen to forget about the “Forgotten War”.Facebook

Glenn Sacks teaches social studies at James Monroe High School in the Los Angeles Unified School District. His columns on education, history, and politics have been published in dozens of America's largest publications. Read other articles by Glenn.

Engineering: Tool predicts rogue waves up to 5 minutes in advance


CRUCIAL FOR SHIPS


SCIENTIFIC REPORTS



A new tool that can be used to predict the emergence of unusually large and unpredictable waves at sea — known as rogue waves — up to five minutes into the future is presented in a study published in Scientific Reports. The authors suggest that the tool could be used to issue advance warnings to ships and offshore platforms to enable those working on them to seek shelter, perform emergency shutdowns, or manoeuvre to minimise the impacts of approaching rogue waves.

The tool developed by Thomas Breunung and Balakumar Balachandran consists of a neural network that has been trained to distinguish ocean waves that will be followed by rogue waves, from those that will not. The authors trained the neural network using a dataset consisting of 14 million 30 minute-long samples of sea surface elevation measurements from 172 buoys located near the shores of the continental United States and the Pacific Islands. They used their tool to predict the emergence of rogue waves using a separate dataset consisting of 40,000 sea surface elevation measurements from the same buoys.

The authors found that their tool was able to correctly predict the emergence of 75% of rogue waves one minute into the future and 73% of rogue waves five minutes into the future. The tool was also able to predict the emergence of rogue waves near two buoys not included within the datasets used in training with 75% accuracy one minute into the future. This highlights that the tool may be capable of predicting rogue waves at new locations.

The authors suggest that the accuracy and advance warning time of their tool’s forecasts could be further improved by incorporating water depth, wind speed, and wave location data. Future research could also enable the heights of upcoming rogue waves or the times at which they may emerge to be predicted, they add.

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Article details

Prediction of freak waves from buoy measurements

DOI: 10.1038/s41598-024-66315-3

Corresponding Authors:

THE ANCIENT LOWLY

Archivist explores Troy's invisible workers


Laborers at early archaeological sites often received no recognition for their contributions, expert says


UNIVERSITY OF CINCINNATI

Troy 

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VISITORS TO TROY LISTEN TO A LECTURE ABOUT THE UNIVERSITY OF CINCINNATI'S EXCAVATIONS IN 1934.

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CREDIT: UC CLASSICS




While poring over nearly century-old photos documenting the University of Cincinnati’s historic excavation at Troy, archivist Jeff Kramer was struck by just how many people worked behind the scenes for years to contribute to its success.

The archivist and research associate in UC’s Department of Classics created a digital archive of pictures and documents from UC archaeologist Carl Blegen’s influential 1930s project that identified nine periods of reconstruction and evidence of a great battle and fiery devastation that some historians said was suggestive of the ransacking of Troy.

But in the four double volumes published on the project, the workers who made the team’s discoveries possible are mentioned briefly and only once, Kramer said. While this omission was hardly unusual in the early days of archaeology, Kramer said it ignores their important contributions to our understanding of ancient civilizations.

“All the big excavations owe their results to these individuals who are unheralded and unacknowledged,” he said. “They’re not given their due. They’re simply not mentioned.”

One worker in particular stood out in the extensive documentation from the seven-year project:  an Albanian laborer named Emin Kani Barin who went by Kani. Kramer wrote about him and the broader question of acknowledging the invisible workers of archaeology in a paper published in the journal Bulletin of the History of Archaeology.

“These are the people who put shovels in the ground and swung the picks. They were the ones who pulled the artifacts out of the ground,” he said.

Troy was the backdrop for one of Greek mythology’s most dramatic stories: the Trojan War between the Greeks and Trojans and the ransacking of Troy mentioned in Virgil’s Aeneid.

Stories of Troy in Homer’s Iliad and Odyssey tell of the mythic figures Odysseus, Hector, Ajax and Achilles, cut down by an arrow to his heel. And its legends persist today, particularly that of the Trojan horse sculpture within which the Greeks allegedly hid to gain entry to the fortified city.

The ancient cities of Troy were first unearthed in the 1870s and studied again in expeditions over the next 20 years before UC’s Blegen arrived on the site in the early 1930s.

“This was an unbelievably vast undertaking,” Kramer said.

Despite the Great Depression, amateur archaeologist and heiress Louis Taft Semple funded the expedition. She was wife to William T. Semple, the head of UC’s Department of Classics, and niece to President William Howard Taft, who served as dean of UC’s College of Law.

Semple and his wife took part in the excavations throughout the project. When they were away, Blegen kept Semple apprised of developments via telegram, including this 1936 update: “Digging begun, still believe in Helen.”

Kramer said this was a cheeky reference to Helen of Troy, “the most beautiful woman in the world,” according to legend, whose abduction by Paris launched the Trojan War.

In 1914 another war had erupted across Europe. Kani’s family had sent him to Canada, where he learned English. He later moved to Akron, Ohio, where as a teenager he worked at a tire-rubber plant. He had a knack for languages and learned English, Polish and Russian from his factory co-workers.

After the war, he returned to Albania to find it fundamentally changed, Kramer said. 

With the local economy in shambles, Kani and his new wife and child fled to Greece. But they found no refuge there. Instead, they were deported to Turkey as part of the 1923 compulsory population exchange in which Greece forcibly expelled more than 400,000 Muslims while Turkey deported an estimated 2 million Greek Orthodox Christians in what amounted to mutual ethnic cleansing.

“This compulsory population exchange resulted in a great deal of poverty in both countries,” Kramer said.

When Kani applied to work at Troy, Blegen wrote in his excavation log, he was “particularly ragged, unshaved, and seedy-looking.” But “employee No. 62,” as he was identified in the excavation records, quickly made himself indispensable to the project, Kramer said.

Kani helped Blegen translate instructions to the worker refugees. He was assigned with other skilled workers to mend pots broken over the millennia. He demonstrated such prowess that by his third year he was training others in the painstaking process of rebuilding the pots from tiny fragments.

In 1935 Kani was promoted to foreman where he took over bookkeeping duties and was entrusted with purchasing supplies. He also supervised the construction of the site guardhouse, a pottery room annex, a railway storeroom and a prefabricated house Blegen shipped from the United States.

And because of his knack for languages, he served as tour guide to visitors at the site when the UC representatives were not available.

Kramer said while just one photo of the workers was published in Blegen’s scholarly works documenting the excavation, Kani shows up in dozens of other photos the expedition captured of the archaeological site and daily life at Troy.

“If you look at the photos, you see he was everywhere. His energy was boundless,” Kramer said. “And in the daily journals, it’s clear when they needed something to be done they would call on Kani and his response was, ‘On it.’”

More than that, Kramer said, the photos and documents and Blegen’s later address to the Cincinnati Literary Club where he calls Kani the dig’s most important worker show a genuine fondness.

“It showed not just his interest in Kani’s story but also their friendship,” Kramer said.

Eric Cline, a professor at George Washington University, said the work of laborers was often overlooked in published scholarship because of class bias.

“It was a very colonialist attitude but common for the day,” he said.

Allison Mickel, an associate professor at Lehigh University, examined the unrecognized work of archaeology laborers in her 2021 book “Why Those who Shovel are Silent.”

“Archaeological excavations are, in many ways, microcosms of broader power structures in science and society,” she said.

Mickel said archaeology projects today are far more inclusive and typically include members of the community as valued partners in all stages of the project’s planning and execution.

“Luckily, I think a lot of archaeologists are really interested in building a more inclusive archaeology because that is the bedrock of better science,” she said.

After the excavation concluded in 1938, Kani continued to correspond with Blegen, noting that he had taken a job with the British American Tobacco Co.

Kramer said the  tale of Kani’s life spanning continents, war, love, loss and tragedy was emblematic of this volatile time in world history.

“He was caught up in this stream that was so highly representative of what was being faced by millions of people,” Kramer said. “So I saw how remarkable his life was but also how his life reflected what was going on in Greece and Turkey at that time.”

 

TROY (IMAGES)

QUANTUM CHEMISTRY

Come closer: titanium-48’s nuclear structure changes when observed at varying distances

A 100-year-old physics mystery may be close to being solved as a new study reveals structural changes in titanium-48’s nucleus




OSAKA METROPOLITAN UNIVERSITY

Structural changes in titanium-48 

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THE NUCLEAR STRUCTURE OF TITANIUM-48 CHANGES FROM A SHELL MODEL STRUCTURE TO AN Α-CLUSTER STRUCTURE BASED ON THE DISTANCE FROM THE CENTER OF THE NUCLEUS.

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CREDIT: OSAKA METROPOLITAN UNIVERSITY




The world around us is made up of particles invisible to the naked eye, but physicists continue to gain insights into this mysterious realm. Findings published in Physical Review C by Osaka Metropolitan University researchers show that the nuclear structure of an atom likely changes depending on the distance the protons and neutrons are from the center of the nucleus.

OMU graduate student Maito Okada, Associate Professor Wataru Horiuchi, and Professor Naoyuki Itagaki from the Graduate School of Science compared calculations using theoretical models with existing experimental data to determine whether titanium-48, the most common isotope of titanium with 22 protons and 26 neutrons, has a shell model structure or an α-cluster (alpha cluster) structure.

While shell models are symmetric, α-cluster structures are thought to have an alpha particle at the outer region of the nucleus, making an asymmetrical configuration. An α-particle is the same as helium with 2 protons and 2 neutrons. In alpha decay, this particle is emitted; for example, titanium-48 becomes calcium-44 if such decay occurs.

The OMU team calculated the collision effect of high-energy accelerated protons and α-particles on titanium-48. This was based on a theory of nuclear reactions in which the impact of protons on a nucleus reflects the structure near the surface of the target nucleus, while the collision of α-particles on a nucleus reflects the structure of the outer regions.

The results suggest that titanium-48 changes from a shell model structure to an α-cluster structure depending on the distance from the center of the nucleus.

“These results upend the conventional understanding of nuclear structure and can be expected to provide clues to the α-decay process that occurs in heavy nuclei, which has not been solved for nearly 100 years,” Professor Horiuchi enthused, referring to the Gamow theory on nuclear decay. “In the future, we would like to extend the results obtained through this research to take on the challenge of solving issues related to heavier nuclei.”

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About OMU

Established in Osaka as one of the largest public universities in Japan, Osaka Metropolitan University is committed to shaping the future of society through “Convergence of Knowledge” and the promotion of world-class research. For more research news, visit https://www.omu.ac.jp/en/ and follow us on social media: XFacebookInstagramLinkedIn.

 

Wetland wonders unfold: Aerial systems shed light on ecosystem services


JOURNAL OF REMOTE SENSING
Study area in southeastern NC showing the 8 collection locations across 4 coastal counties. 

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STUDY AREA IN SOUTHEASTERN NC SHOWING THE 8 COLLECTION LOCATIONS ACROSS 4 COASTAL COUNTIES.

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CREDIT: JOURNAL OF REMOTE SENSING





A cutting-edge study revolutionizes coastal wetland mapping by integrating unmanned aerial systems with light detection and ranging (LiDAR) and multispectral sensors. This innovative approach provides detailed elevation data and vegetation analysis, enabling highly accurate classifications of diverse wetland types. The research advances conservation by offering a scalable, efficient, and cost-effective method that is instrumental in climate change mitigation strategies and informs policy-making for coastal resilience.

Coastal wetlands, situated at the junction of land and water, are vital ecosystems known for their high productivity. They play a key role in carbon sequestration, storm buffering, and providing habitats for diverse species. However, these critical areas are increasingly threatened by human activities and climate change. The dynamic nature and periodic flooding of wetlands pose significant challenges for traditional monitoring methods. Based on these issues, there is a pressing need for advanced remote sensing techniques to ensure effective conservation and management of these valuable ecosystems.

A team of researchers from Mississippi State University and the University of North Carolina Wilmington conducted a study (DOI: 10.34133/remotesensing.0169) published on July 4, 2024, in the Journal of Remote Sensing. The study focuses on the precision mapping of coastal wetlands using UASs equipped with light detection and ranging (LiDAR) and multispectral sensors. By surveying eight diverse wetland sites in North Carolina, the research aimed to enhance the accuracy and efficiency of wetland classification and mapping.

Using UASs equipped with LiDAR and multispectral sensors, the researchers collected high-resolution elevation data and detailed vegetation imagery across eight diverse wetland sites in North Carolina. Sophisticated machine learning algorithms enabled highly precise classifications of wetland types. Estuarine intertidal emergent wetlands exhibited the highest classification accuracy due to distinct vegetation structures and spectral signatures. Palustrine forested and scrub-shrub wetlands, with their dense and complex vegetation, presented more challenges. The integration of LiDAR and multispectral data proved scalable, efficient, and cost-effective for wetland mapping. This approach significantly advances conservation efforts and informs policy-making for coastal resilience, highlighting the transformative potential of combining advanced remote sensing technologies in environmental monitoring.

Dr. Narcisa Gabriela Pricope, the lead researcher, stated, "Our integrated approach using UAS-derived LiDAR and multispectral data significantly improves the accuracy of wetland mapping. This method not only enhances our understanding of these critical ecosystems but also supports the development of effective conservation strategies."

The innovative use of UASs for wetland mapping has far-reaching implications for conservation and policy-making. The precise data collected can inform strategies to protect coastal wetlands, mitigate climate change impacts, and enhance biodiversity. This research highlights the transformative potential of merging advanced remote sensing technologies in environmental monitoring, paving the way for sustainable management of natural habitats.

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References

DOI

10.34133/remotesensing.0169

Original Source URL

https://doi.org/10.34133/remotesensing.0169

Funding information

This research was funded by the North Carolina Department of Transportation (NCDOT), contract number RP 2020–04, awarded to N.G.P. (lead principal investigator) and J.N.H. in the Department of Earth and Ocean Sciences at the University of North Carolina Wilmington.

About Journal of Remote Sensing

The Journal of Remote Sensingan online-only Open Access journal published in association with AIR-CAS, promotes the theory, science, and technology of remote sensing, as well as interdisciplinary research within earth and information science.

 

The rhythm led by plants is crucial for symbiosis with nutrient-providing bacteria



Discovery that symbiosis with rhizobia in legumes is regulated by oscillating gene expression



NATIONAL INSTITUTES OF NATURAL SCIENCES

The Rhythm Led by Plants is Crucial for Symbiosis with Nutrient-Providing Bacteria 

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SYMBIOSIS WITH RHIZOBIA IN LEGUMES IS REGULATED BY OSCILLATING GENE EXPRESSION

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CREDIT: NIBB



Legumes thrive in low-nitrogen environments by partnering with rhizobia, soil bacteria that convert atmospheric nitrogen into ammonium, a usable form for the plants. These beneficial bacteria are housed in root nodules formed on legume roots. However, the uncontrolled formation of numerous root nodules can impede root function. To prevent this, legumes need to regulate the distribution and number of root nodules, but the precise mechanisms were previously unclear.

Recent research on Lotus japonicus, a model leguminous plant, has unveiled that the interaction between legume roots and rhizobia is characterized by periodic gene expression with a six-hour rhythm. This rhythmic gene expression influences the regions of the root susceptible to rhizobial infection and the distribution of nodules. It was also discovered that the plant hormone cytokinin is crucial for maintaining this gene expression rhythm. This groundbreaking study, published in Science, is a collaborative effort conducted by the National Institute for Basic Biology, Nara Institute of Science and Technology, Hokkaido University, Kwansei Gakuin University, RIKEN, and Aichi University of Education.

When rhizobia infect legume roots, root epidermal cells form infection threads, membranous tube-like structures guiding the bacteria to the inner root tissue where they can fix nitrogen. Rhizobial infection primarily occurs in a narrow root region just behind the root tip, known as the susceptible region. The continuous cell generation at the root tip perpetually creates new susceptible regions. Ideally, infection threads would be evenly distributed throughout the root. However, closer examination reveals a pattern of densely formed infection threads alternating with sparser regions, suggesting intermittent rather than continuous responses to rhizobia. Detailed studies on the dynamic response of roots to rhizobia over time have been lacking.

Using luminescence live-imaging with luciferase as a reporter, the research team observed that NSP1 gene expression, rapidly induced in response to rhizobia and essential for the infection process, exhibited oscillatory patterns at approximately six-hour intervals in the susceptible region. As the root grew, new expression sites appeared apically to the previous oscillation regions. "We noticed that these oscillation regions coincide with areas where infection threads are densely formed, leading us to think that this rhythmic gene expression might be related to the determination of nodule formation sites," said Dr. Takashi Soyano, Associate Professor of the National Institute for Basic Biology, a member of the research team. Consistent with this notion, a large population of root nodules was formed in the oscillation region, suggesting a link between rhythmic gene expression and nodule formation. Other genes essential for early responses during nodule symbiosis also displayed oscillatory expression patterns, marking the first evidence of periodic gene expression in response to rhizobia.

Cytokinin, a key regulator in root nodule symbiosis, maintains this oscillatory gene expression. Genes related to cytokinin biosynthesis, metabolism, and signaling exhibited oscillatory expression after rhizobial inoculation. Luminescence imaging using the cytokinin response marker TCSn revealed oscillatory cytokinin responses, aligning with the timing of active cytokinin content fluctuations.

The study utilized mutants of a cytokinin receptor LHK1 to explore cytokinin's role in gene expression periodicity. In mutants lacking functional LHK1, oscillating intervals of the periodic NSP1 expression were prolonged, expanding the root region where NSP1 expression oscillates. Conversely, in plants transformed with an activated form of LHK1, the induction of NSP1 expression was suppressed, leading to loss of its periodicity. The NSP1 oscillation region coincided with the area forming dense infection threads. The lhk1 loss-of-function mutants exhibited enlarged root segments forming dense infection threads, whereas the active LHK1 reduced infection thread densities. These findings underscore the importance of proper cytokinin response in maintaining the symbiotic oscillation and ensuring appropriate infection thread distribution.

Root nodule symbiosis occurs in the monophyletic nitrogen-fixing clade, including four orders, Fabales, Rosales, Cucurbitales, and Fagales, indicating a shared evolutionary acquisition to interact with nitrogen-fixing bacteria. Among them, the legume family in the order Fabales, where most of the species engaged in root nodule symbiosis, uniquely incorporated the cytokinin pathway as an important regulatory module for the symbiosis. "The discovery of periodic cytokinin responses was unexpected, raising several questions, including the molecular mechanisms that establish this periodicity and how these periodic responses shape the infection regions, " Dr. Soyano said. Addressing these questions is expected to deepen the understanding of the regulatory mechanisms of root nodule symbiosis and advance research on the spatial control of organ development through periodic responses mediated by plant hormones.

Spatio-temporal expression pat [VIDEO]