• Scientists identify the mystery killer behind Ireland's potato famine

    Illustrated London News

    Starving people searching for potatoes in a stubble field during the Great Famine (1845-1852) which was caused by the failure of the Irish potato crop and British government inaction.

    By Alan Boyle, Science Editor, NBC News

    Scientists have finally figured out exactly what strain of potato blight led to the deaths of more than a million people in Ireland during the Great Famine of the mid-19th century — and it's not the usual suspect.

    For decades, researchers assumed that a particular strain of Phytophthora infestans, known as US-1, made the leap from the Americas to mainland Europe, and then to Ireland in the 1840s. Selective breeding and fungicides have made US-1 less of a threat than it was a century and a half ago, but it and other strains of blight continue to pose a threat to potato crops around the world. Blight can still turn seemingly healthy potatoes into black, stinking balls of mush, just as it did in 19th-century Ireland.

    An international team of scientists took on the task of tracing the roots of late blight through genetics, and to flesh out the story, they deciphered the genomes for 11 strains of blight preserved in Germany's Bavarian State Collection for Botany and London's Kew Gardens. The dried potato plants containing the blight pathogens were saved in herbaria — that is, collections of preserved plants — by 19th-century scientists who had no idea they could yield that kind of scientific data.

    What the researchers found surprised them: The genetic signature of the blight that was extracted from the Irish potato plants did not match up exactly with US-1. Instead, the blight represented a closely related but previously unknown strain that has now been designated HERB-1.

    The study of blight evolution is to be published in the open-access journal eLife.

    Roots of the blight
    By mapping the genetic differences between the 19th-century samples and 15 modern-day strains of blight, the scientists could reconstruct the pathogen's evolution over the centuries. They determined that the blight originated in Mexico's Toluca Valley. The species' genetic diversity increased markedly in the 16th century, around the time that Spanish explorers settled the New World. That era marked the wider spread of potato varieties, and probably hastened the evolution of Phytophthora infestans as well.

    Kew Gardens

    This potato specimen from the Kew Gardens' herbarium was collected in 1847, during the height of the Irish famine. The legend reads "Botrytis infestans" because it was not known yet that Phytophthora does not belong to the mildew-causing Botrytis fungi.

    The similarities between US-1 and HERB-1 suggest that they both made their appearance in the early 19th century, not long before the first major outbreak of the blight in Europe. "Probably they both came out of the United States," said one of the study's authors, Sophien Kamoun, a researcher at the Sainsbury Laboratory in Britain.

    HERB-1 spread to Europe first, and soon made its way to Ireland, where potatoes were the staple crop for millions of poor farmers. "The potatoes at the time were very susceptible to blight," Kamoun told NBC News. More than a million people died between 1845 and 1852, and at least that many emigrated to friendlier locales. Even today, Ireland's population level has not returned to the pre-famine high of 8 million.

    US-1's rise came in the 20th century, after the introduction of new potato varieties that were resistant to HERB-1. Eventually, US-1 became the dominant blight strain, and HERB-1 faded away. "We think HERB-1 is most likely extinct," Kamoun said.

    Delving into DNA
    The research illustrates how useful herbaria can be for resolving decades-old questions about centuries-old plants. "The degree of DNA preservation in the herbarium samples really surprised us," Johannes Krause of the University of Tübingen said in a news release about the study. It also illustrates how quickly evolution can produce new strains of pathogens, Kamoun said.

    "The molecular clock turned out to be shorter than perhaps we expected," he said.

    The study's lead author, Kentaro Yoshida of the Sainsbury Lab, said the study suggests that crop breeding methods play a role in the molecular evolution of pathogens.

    "Perhaps this strain became extinct when the first resistant potato varieties were bred at the beginning of the 20th century," Yoshida said. "What is for certain is that these findings will greatly help us to understand the dynamics of emerging pathogens."

    More about plant problems:

    Alan Boyle is NBCNews.com's science editor, and the great-grandson of Michael Boyle, who migrated from Ireland to America at the height of the Irish potato famine in 1847.

    Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • How plants respond to positive vibes: 'Talking' mechanism is a mystery

    UWA

    The University of Western Australia's Monica Gagliano studies how plants communicate with each other.

    By Alan Boyle, Science Editor, NBC News


    Studies show that basil gives a boost to chili peppers, while fennel is a real bummer. The effect has been seen even when the plants are sealed off from each other with sheets of black plastic. So does that mean that the plants are "talking" to each other through subtle vibrations? That's the kind of talk that sparks a debate — not between the plants, but between humans.

    The latest study, reported in the open-access journal BMC Ecology, looked at potential communication between basil plants and chili pepper seeds. It's one of a series of experiments conducted by Monica Gagliano and Michael Renton of the University of Western Australia.

    "Our results show that plants are able to positively influence growth of seeds by some as-yet unknown mechanism," Gagliano said in a news release from BioMed Central, the journal's publisher. "Bad neighbors, such as fennel, prevent chili seed germination in the same way."

    Fennel plants release chemicals into the air and soil that are detrimental to most other plants, including chili peppers. Last year, Gagliano and her colleagues set up mini-gardens to study the interaction between the plants more closely. They were surprised to find that chili seeds germinated more quickly when the fennel plant was sealed off with plastic to block the transfer of those nasty chemicals. It was almost as if the baby chilis sensed that a villainous plant was nearby, and grew up faster so they'd have a better chance of fending off the fennel.

    The new study looks at the flip side of plant interaction: Unlike fennel, basil is a "good neighbor" for chili plants because basil plants release chemicals that discourage weed growth. Gagliano and her colleagues found that to be the case for chili seedlings. The seeds germinated at a higher rate, even if the basil plant was sealed off with the black plastic. That led Gagliano and Renton to conclude that the seeds could still sense the presence of a friendly plant when they couldn't get the standard chemical signals.

    How could this be?

    "We believe that the answer may involve acoustic signals generated using nanomechanical oscillations from inside the cell which allow rapid communication between nearby plants," Gagliano said in the news release.

    That surmise seems to fit with other findings on plant communication. Corn roots, for example, give off regular clicking sounds in the range of 220Hz (which corresponds to an A below middle C). Gagliano and her colleagues found that when young corn roots are suspended in water, they tend to lean toward the source of a continuous 220Hz tone transmitted through the water. The researchers suggested that acoustic signals could knit plants into an underground network of friends and foes.

    But as Gagliano points out, no one has yet identified the precise mechanism by which one plant hears what another plant is saying. That's one of the reasons why other researchers haven't wholeheartedly embraced the idea that plants are talking to each other.

    "Although the idea of plants communicating by sound is intriguing, there is still a long way to go before we know whether, and if so to whom, the woods sing!" the University of Leiden's Carel ten Cate wrote last December in the journal Behavioral Ecology.

    Duke University's Dan Johnson, who is studying how trees respond to drought, said it's "too early to tell" whether plants truly respond to each other's sounds.

    "We have been detecting these acoustic signals for almost 50 years," Johnson told NBC News. "The idea of using those signals for communication is incredibly interesting, and there is potentially some growing support for it. But we're a good ways away from strong support for acoustic signaling between plants. ... I'm glad that somebody's working on it, but I think it's too early to say."

    More about plant communication:

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • Lady Gaga immortalized in ferns

    Duke University reports on the new fern genus, named after Lady Gaga.

    By Alan Boyle, Science Editor, NBC News


    Lady Gaga is already a huge name in the music world, but now she's a scientific name as well — thanks to fans at Duke University who named an entire genus of ferns after the gender-bending pop star.

    Nineteen species in Central and South America, Mexico, Arizona and Texas belong to the newly designated genus Gaga, the researchers report in a paper published by Systematic Botany. The genus is a grouping of closely related species that was split off from an earlier named genus known as Cheilanthes on the basis of subtle differences (for example, the number of spores per sporangeum) as well as DNA analysis.

    The new genus' 19 species include two new ones: Gaga germanotta was found in Costa Rica and has a species name that pays tribute to the family of the artist, whose birth name was Stefani Germanotta. The species name for Gaga monstraparva, a newfound type of Mexican fern, honors Gaga's fans. ("Monstra parva" is Latin for "Little Monster," Gaga's term of endearment for her followers.)

    It's clear from Duke's news release that Gaga's Little Monsters include the Duke researchers who proposed the new genus name.

    "We wanted to name this genus for Lady Gaga because of her fervent defense of equality and individual expression," said biologist Kathleen Pryer, director of the Duke Herbarium. "And as we started to consider it, the ferns themselves gave us more reasons why it was a good choice."

    Duke pointed out that the ferns go through a stage in which they have somewhat fluid definitions of gender. During their bisexual reproductive stage, the ferns' gametophyte takes on the appearance of a blue-green Gaga costume. Even the DNA analysis turned up a Gaga angle: One of the genus' distinguishing strings of base pairs reads GAGA (guanine-alanine-guanine-alanine).

    Duke University

    One of the costumes Lady Gaga wears for her performances (left) reminded researchers of the color and shape of a gametophyte from the species in the genus Gaga (right).

    But the main motivation for the naming is to pay tribute to a superstar who's been an inspiration.

    "We often listen to her music while we do our research," Pryer said. "We think that her second album, 'Born This Way, is enormously empowering, especially for disenfranchised people and communities like LGBT, ethnic groups, women — and scientists who study odd ferns."

    Lady Gaga is a "remarkable, unexpected, perfect" choice for the scientific tribute, said Duke faculty member Cathy N. Davidson, whose was involved in a MacArthur Foundation initiative that helped the pop star create a national anti-bullying project called the Born This Way Foundation.

    "Encouraging her fans and kids everywhere to be brave, bold, unique, creative and smart is what Lady Gaga is about," Davidson said in Duke's news release. "It's rare that a celebrity so young gives back so much to society."

    There may be future opportunities out there for performers who count botanists among their fans. Pryer, who is president of the American Fern Society as well as the American Society of Plant Taxonomists, points out that genetic analysis may well reorganize the family tree of ferns over the long term — leading to more scientific categories that will need new names.

    Update for 6:20 p.m. ET: In a follow-up phone call, Pryer told me she was inspired to go for a genus named Gaga after seeing the performer's blue-green getup during the broadcast of the 2010 Grammy Awards.

    "When she emerged in what I saw as a fern gametophyte, I just felt that she was speaking to us," Pryer said.

    She and her colleagues had been focusing on ferns for five years or so, and detailed studies of the plants' characteristics as well as DNA readings were leading them to the conclusion that many of the ferns that had been classified as belonging to the genus Cheilanthes really belonged in a separate category. "This is going to come as a shock to some botanists that they can't be called Cheilanthes anymore," she said.

    Lady Gaga's appearance, basically in a fern costume, was the key moment for Pryer. "That was the initial 'Oh, my gosh, it would be wonderful if we could name a genus after her,'" the biologist said. When the research article was submitted to Systematic Botany for review, she and her colleagues sought Gaga's permission to use her name.

    "Within 24 hours, her manager sent us an email and said 'Great,' with a smiley face," Pryer said.

    She noted that U.S. taxpayers, including fans of Lady Gaga, help fund her lab's research through the National Science Foundation. "A lot of 'Little Monsters' are out there supporting the work in this field," Pryer said. Maybe knowing there's a scientific classification out there with Gaga's name on it will inspire the littlest Monsters to pursue careers in science. But in any case, the name will stand as an enduring tribute to a person who's done so much to promote basic human kindness through her music and the Born This Way Foundation, Pryer said.

    "It's a way for us to give a gift," she said. "A forever gift."

    This performance helped inspire the Duke researchers' decision to name a fern genus after Lady Gaga: Lady Gaga performs "Poker Face" and a medley of "Speechless" and "Your Song" with Elton John at the 52nd Annual Grammy Awards on CBS. © 2010 The Recording Academy

    Taylor Kinney tells TODAY's Kathie Lee Gifford and Hoda Kotb that he feels lucky to be dating superstar Lady Gaga and discusses his role as a tough guy lieutenant battling an addiction to pain medication on the new NBC show "Chicago Fire.''

    More celebrity species:

    In addition to Pryer, the authors of "Gaga: A New Fern Genus Segregated from Cheilanthes (Pteridaceae)" include Fay-Wei Li and Michael D. Windham. The research was funded in part by the National Science Foundation.

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.