360-million-year-old Irish fossil provides oldest evidence of plant self-defense in wood
IMAGE: MICROSCOPIC OBSERVATION OF A SECTION OF DEVONIAN FOSSIL WOOD CONTAINING TYLOSES AND DETAIL OF AN AREA SHOWING SEVERAL TYLOSES (ARROWS) PRODUCED BY PARENCHYMA CELLS (P) INSIDE A CONDUCTOR CELL (C); SCALE: 0.05 MM (50 ΜM). PHOTOS: A-L DECOMBEIX. view more
CREDIT: A-L DECOMBEIX.
An international team of scientists, co-led by Dr Carla J. Harper, Assistant Professor in Botany in the School of Natural Sciences at Trinity, has discovered the oldest evidence of plant self-defence in wood in a 360-million-year-old fossil from south-eastern Ireland.
Plants can protect their wood from infection and water loss by forming special structures called “tyloses”. These prevent bacterial and fungal pathogens from getting into the heartwood of living trees and damaging it. However, it was not previously known how early in the evolution of plants woody species became capable of forming such defences.
Published today in Nature Plants is the oldest evidence of tylosis formation from Late Devonian (360-million-year-old) fossil wood from the Hook Head Peninsula area, Co. Wexford, Ireland.
These plants lived well before the time of the dinosaurs or even flying insects. They formed the first primeval forests, when plants ruled the continents, accompanied by microorganisms, fungi, and early relatives of spiders, millipedes and centipedes.
Dr Harper and her team, including Dr Anne-Laure Decombeix (CNRS, France), Dr Cyrille Prestianni (Uni. Liège, Belgium), Trinity Botany PhD student Thibault Durieux (co-advised by Harper and Decombeix), Merlin Ramel (INRAe, France), and Prof Michael Krings (BSGP, Munich, Germany and Trinity SNS Visiting Research Associate), discovered tyloses in the fossilised wood of an extinct group of plants known as the Archaeopteridalean progymnosperms. These plants are particularly important as they were the first trees to resemble those we see today, with a large woody trunk, branches, and complex root systems.
The team has now discovered that these primitive trees were also able to form tyloses to protect their wood. What is particularly exciting is that Ireland is one of the few places in the world where such details can be observed in plants from this remote time period. This means that the fossils from Co. Wexford give unique insights into this important period in plant evolution.
Dr Harper said: “Fossil wood is an example of an anatomically preserved fossil: plant remains that have been infiltrated by a water rich in minerals, preserving their tissues in three dimensions. These fossils allow us to study very fine details of extinct plant anatomy, down to the cellular level. This type of preservation, in general, is rare but occurs in certain fossil deposits in Ireland.
“Continuing fieldwork in Irish Devonian localities will yield new fossils that will increase our understanding of the diversity and biology of extinct plants. Overall, Ireland’s rich plant fossil history – an untapped resource – plays a key role in answering exciting research questions and raises many more.”
Ireland has long been known as the Emerald Isle due its famous rolling green hills—but such discoveries help us to understand how and when this “greening” began.
Dr Harper said: “By studying these fossil plants and their past environments, we can get powerful insights into the history of plant physiological processes that still occur today, and into both current and future ecosystems of Ireland and the world.”
The journal article can be read on the publisher's website.
To learn more about this research see a new blog post on the Nature website.
This research was funded by the Irish Research Council Ulysses 2021 Grant 17056, Irish Research Council and French Ministry of Foreign Affairs and a Trinity College Dublin Ph.D. Provost Award.
JOURNAL
Nature Plants
METHOD OF RESEARCH
Experimental study
New study uncovers Colorado’s spicy ancient history of chili peppers
A case of “the chicken or the chili pepper?" and coming to grips with a new timeline
Peer-Reviewed PublicationIMAGE: CU BOULDER’S ROCÍO DEANNA AND ABEL CAMPOS IDENTIFIED THIS CHILI PEPPER FOSSIL IN THE CU BOULDER MUSEUM OF NATURAL HISTORY COLLECTIONS BY THE UNIQUE SHAPE OF ITS CALYX TEETH: SPIKES ON THE END OF THE FRUITING STEM THAT HOLD ON TO THE PEPPER. view more
CREDIT: R. DEANNA
Botanists and paleontologists, led by researchers from the University of Colorado Boulder, have identified a fossil chili pepper that may rewrite the geography and evolutionary timeline of the tomato plant family.
The team’s findings, published last month in the journal New Phytologist, show that the chili pepper tribe (Capsiceae) within the tomato, or nightshade (Solanaceae), family is much older and was much more widespread than previously thought. Scientists previously believed that chili peppers evolved in South America at most 15 million years ago, but the new research pushes that date to at least 50 million years ago—and suggests that chili peppers were in fact present in North America at that time.
Rocío Deanna, a postdoctoral researcher in ecology and evolutionary biology, and Abel Campos, an undergraduate double majoring in evolutionary biology and molecular, cellular and developmental biology, weren't planning to rewrite history when they met up one afternoon at the CU Boulder Museum of Natural History in 2021. Yet among a group of specimens in its collections gathered from the Green River Formation—geological treasure trove in northwestern Colorado and southwestern Wyoming—Deanna spotted a specific, solanaceous trait embedded in one fossil: little spikes on the end of a fruiting stem.
“At first, I thought ‘No way! This can’t be true,’” said Rocío Deanna, lead author of the study. “But it was so characteristic of the chili pepper.”
After they discovered two of these fossils in the CU Boulder collections, Deanna and Campos, a co-author of the study, found one more from the chili pepper tribe in collections at the Denver Museum of Nature and Science. All three fossils are from the Green River Formation in Colorado: the CU specimens from Garfield County and the DMNS fossil from Rio Blanco County.
These chili pepper fossils from the Eocene geological epoch (34 to 56 million years ago) match the timeline of another nightshade fossil found in the Esmeraldas Formation in Colombia, revealing that the family was already distributed across all of the Americas by as early as 50 million years ago.
“The family is way older than we thought,” said Deanna, also a faculty member at the National University of Cordoba.
A chili pepper fossil from the CU Boulder collections.
CREDIT
S. Manchester
A fruit-fossil history
The nightshade family comprises 3,000 species and almost 100 different genera, including chili peppers. The ancient chili pepper was technically a fruit—and a berry, at that. While tomatoes and peppers are commonly associated with vegetables, they have seeds on the inside, which officially categorizes them as fruits.
The researchers cannot be sure of the chili’s exact shape or color, but it was probably on the smaller end compared to modern day chili peppers. And like its relatives, it could have been quite spicy, according to Deanna.
Deanna and Campos identified the fossil by the unique shape of its calyx teeth: spikes on the end of the fruiting stem that hold on to the pepper, like those which hold a gemstone in a ring.
“The world has maybe 300,000 plant species. The only plants with that kind of calyx is this group of 80 or 90 species,” said Stacey Smith, senior author of the paper and associate professor of evolutionary biology at CU Boulder.
Paleontologists collected the CU Boulder fossil from the Green River Formation in the 1990s. But its exact identity remained a mystery for years, in part because there are only a handful of “solanologists,” botanists who study the nightshade family, in the world. When Deanna found these Colorado-based fossils, she had just returned from a global search for tomato family fossil specimens, only to find some “just ripe for the picking” right on campus.
“A lot of discoveries happen decades after the specimens have been collected,” said Smith. “Who knows how many other new fossil species are sitting in any of these museums? They're just waiting for the right eyes to look at them.”
Rocío Deanna, a postdoctoral researcher in ecology and evolutionary biology, examines a chili pepper fossil in the CU Boulder collections.
CREDIT
R. Deanna
Trickle-down evolution
These chili pepper fossils were around during the Eocene, a geologic epoch that lasted from about 34 to 56 million years ago as the continents drifted toward their present positions. During this balmy time in Earth’s history, carbon dioxide levels ranged between 700 and 900 parts per million (twice as high as they are today), and palm trees grew as far north as Alaska. Because little to no ice was present on Earth, sea level was as much as 500 feet higher than it is today.
Scientists had assumed that the origins of chili peppers began in South America roughly 10 to 15 million years ago, where they then dispersed over land and water to the other continents. While Colorado today is home to very few native nightshades and no chili peppers, this new discovery hints that a plethora of plants from the tomato plant family may have existed in North America 40 to 50 million years ago, which have since largely disappeared.
But how did these peppers first get to North America? It’s now a case of “the chicken or the chili pepper?”
Experts have theorized that fruit-eating birds, which existed as early as 60 million years ago, may have carried seeds and plants around the world with them in their guts, stuck to their feathers or in the mud on their feet. But these birds also had to be eating something to fuel their journeys—and fleshy berries, or peppers, make the perfect fuel. Birds may have distributed peppers from continent to continent, but peppers may also have been crucial to the success of those same birds.
So the nightshade family could have easily started in North America instead of South America, then dispersed in the other direction—and with this discovery, scientists can no longer say for sure, said Smith.
“These chili peppers, a species that we thought arose in an evolutionary blink of an eye, have been around for a super long time,” said Smith. “We're still coming to grips with this new timeline.”
Additional authors on this publication include: Camila Martínez, Universidad EAFIT and Smithsonian Tropical Research Institute; Steven Manchester, Florida Museum of Natural History, University of Florida; Peter Wilf, Pennsylvania State University; Sandra Knapp, Natural History Museum, London; Franco E. Chiarini, Gloria E. Barboza, and Gabriel Bernardello of the Instituto Multidisciplinario de Biologia Vegetal, IMBIV (CONICET-UNC); Herve Sauquet, National Herbarium of New South Wales and Evolution and Ecology Research Centre, University of New South Wales; Ellen Dean, Center for Plant Diversity, University of California; Andres Orejuela, Grupo de Investigacion en Recursos Naturales Amazonicos – GRAM, Facultad de Ingenierıas y Ciencias Basicas, Instituto Tecnol ogico del Putumayo, and Subdireccion cientıfica, Jardın Botanico de Bogota Jose Celestino Mutis.
Abel Campos, majoring in Ecology & Evolutionary Biology, examines a fossil in the Invertebrate Paleontology department at the University of Colorado Museum of Natural History.
CREDIT
Casey A. Cass / University of Colorado Boulder
JOURNAL
New Phytologist
ARTICLE TITLE
Fossil berries reveal global radiation of the nightshade family by the early Cenozoic
What was the agriculture like in southeast China in Late Neolithic
Peer-Reviewed PublicationIMAGE: 3D MODEL OF MAJOR CHARRED PLANT REMAINS IDENTIFIED AT THE JINGSHUIDUN SITE. (A) LAYER 25, CHENOPODIACEAE CARYOPSIS; (B)LAYER 27, SOLANACEAE CARYOPSIS; (C) LAYER 27, RICE CARYOPSIS; (D) LAYER 32, FABACEAE CARYOPSIS; (E)1–4: LAYER 25, 5: LAYER 26, FOXTAIL MILLET CARYOPSIS view more
CREDIT: HIGHER EDUCATION PRESS LIMITED COMPANY
The emergence and spread of agriculture in the Neolithic had a revolutionary impact on the development of human society, and it provided a solid economic basis for the origin and development of human civilization. In southern China, the original crop was rice, but over time, millet cultivation gradually spread. Affected by these various environmental and social developmental factors, there are still many issues about spatiotemporal detail of agriculture development in southern Anhui Province, China, with most information currently deriving from historical documents and rather limited archeological evidence.
The study, looked at data of the archeobotanical remains at the Jingshuidun site in the mountainous areas of the lower reaches of the Yangtze River in southern Anhui Province. This work was carried out by the research team of Wu Yan, from the Institute of Vertebrate Paleontology and Paleoanthropology, entitled “The history of agriculture in the mountainous areas of the lower Yangtze River since the late Neolithic” is published online in Frontiers of Earth Science on 2022.
The study site of Jingshuidun (31°48 '3"N, 117°11′ 50" E), located at the intersection of the lower reaches Yangtze River Plain and the mountainous area in southern Anhui Province, preserves thick archeological strata and a rare superpositional relationship of multiple occupational periods, allowing for the study of cultural stages and archaeobotany.
The authors noted that macrobotanical remains and phytoliths of domesticated rice are present in layers at the Jingshuidun site dated to 4874–4820 cal. yr B.P. (middle-late Liangzhu Period) and 2667–2568 cal. yr B.P. (late Western Zhou Dynasty to the early Spring and Autumn Period). Moreover, macrobotanical remains and phytoliths from the site document the earliest remains of foxtail millet (Setaria italica) in southern Anhui Province, from a layer dating to the late Western Zhou Dynasty and the early Spring and Autumn Period (2667–2568 cal. yr B.P.). These results suggest that the people occupying the Jingshuidun site used single rice farming as far back as 4874–4820 cal. yr B.P., and they began to plant millet by at least 2667–2568 cal. yr B.P., documenting the spread of millet agriculture to the southern area by that time.
The study also showed that there were many traces of carbonized millet remains in layers dated to 2667–2568 cal. yr B.P. in the Jingshuidun site, which is the earliest direct dating of millet remains in southern Anhui. Evidence of macrobotanical remains at the Jingshuidun site shows that dry cultivation techniques from northern China had spread to southern Anhui by 2667–2568 cal. yr B.P., and that mixed cultivation of rice and millet occurred. It may be caused by the migration of ancient people and the change of climate.
The analyses of their study on macrobotanical remains and phytoliths also formed the basis for the reconstruction of the subsistence economy of ancient humans at the Jingshuidun site from the late Neolithic to early historical times. They can obtain a clearer picture of the development of rice and millet agriculture in the southern Anhui Province region, as well as the spread of millet cultivation, when combined their dates with that of the previous archeobotanical work. It provides new evidence for further understanding of agricultural development and the transmission route of Millet in southern Anhui since the late Neolithic period.
Cite this article
Wang, J., Chen, X., Zhang, G. et al. The history of agriculture in the mountainous areas of the lower Yangtze River since the late Neolithic. Front. Earth Sci. (2022). https://doi.org/10.1007/s11707-021-0956-z
About Researcher
Wu Yan, young professor. Innovative research achievements have been made focusing on the use of phytolith methods to carry out the origin and spread of agriculture, the utilization of ancient human plants and the feeding habits and evolution of herbivores.
About Frontiers of Earth Science
Frontiers of Earth Science publishes original, peer-reviewed, theoretical and experimental frontier research papers as well as significant review articles of more general interest to earth scientists. The journal features articles dealing with observations, patterns, processes, and modeling of both innerspheres (including deep crust, mantle, and core) and outerspheres (including atmosphere, hydrosphere, and biosphere) of the earth. Its aim is to promote communication and share knowledge among the international earth science communities.
About Higher Education Press
Founded in May 1954, Higher Education Press Limited Company (HEP), affiliated with the Ministry of Education, is one of the earliest institutions committed to educational publishing after the establishment of P. R. China in 1949. After striving for six decades, HEP has developed into a major comprehensive publisher, with products in various forms and at different levels. Both for import and export, HEP has been striving to fill in the gap of domestic and foreign markets and meet the demand of global customers by collaborating with more than 200 partners throughout the world and selling products and services in 32 languages globally. Now, HEP ranks among China's top publishers in terms of copyright export volume and the world's top 50 largest publishing enterprises in terms of comprehensive strength.
The Frontiers Journals series published by HEP includes 28 English academic journals, covering the largest academic fields in China at present. Among the series, 13 have been indexed by SCI, 6 by EI, 2 by MEDLINE, 1 by A&HCI. HEP's academic monographs have won about 300 different kinds of publishing funds and awards both at home and abroad.
JOURNAL
Frontiers of Earth Science
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
The history of agriculture in the mountainous areas of the lower Yangtze River since the late Neolithic
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