CNAS

CNAS in the News

 

California homeowners can help stave off exotic citrus disease

California citrus growers and scientists, gravely concerned by confirmation this week that the Asian citrus psyllid is making its way northward, are asking all Californians to be on the look out for signs of the pest on backyard, apartment complex, community garden and public park citrus trees.

 Helping authorities put the brakes on Asian citrus psyllid is in the best interest of the entire state. The psyllid imperils California's $1.1 billion citrus industry because it can transmit Huanglongbing (HLB, also known as citrus greening disease), considered the world's most devastating citrus disease. Trees with the disease are stunted, sparsely foliated, and may bloom off-season. There is twig dieback, leaf and fruit drop. The fruit that remains becomes bitter, lopsided, small and hard. Once a tree is infected with HLB, it cannot be saved. To date, none of the psyllids captured in Southern California was carrying the bacteria that cause HLB.

Asian citrus psyllid was first detected in California in early 2008 in San Diego and Imperial counties. The pest is believed to have been introduced from northern Mexico. The adult psyllids recently found in Orange and Los Angeles counties were in traps hanging in backyard trees. The University of California, California Department of Food and Agriculture, USDA and the citrus industry have worked closely to quarantine the affected areas and try to eradicate the pest.

Californians can help by monitoring for the Asian citrus psyllid. According to UC citrus entomologist Beth Grafton-Cardwell, the insect's presence isn't too hard to spot during the late summer and fall citrus flush.

Pin-head-sized psyllid adults, mottled brown in color, can live anywhere on the tree, typically on the underside of leaves. But the earlier stages -- known as nymphs -- congregate on the light green, tender new citrus leaves and shoots. These tiny, bright yellowish-orange flightless insects leave behind tell-tale signs of their presence. While feeding, the nymphs extract large amounts of plant sap. They excrete the sap as honeydew, which can turn leaves and fruit black from sooty mold, or they make white waxy tubules that look like bits of instant noodles. The leaves become twisted and curled and, in severe cases, the shoots die back.

"If homeowners take a close look at the new growth on their citrus trees, if there is an Asian citrus psyllid infestation, they will be able to see signs with the naked eye," Grafton-Cardwell said. "But it's easier to see with a magnifying glass."

 A suspected Asian citrus psyllid infestation should be reported immediately to the county agricultural commissioner or the CDFA hotline at (800) 491-1899.

Video: Detecting the Asian citrus psyllid

["flashvars":"file=http://cnas.ucr.edu/videos/DetectingACP_13544.flv&width=320&height=240&repeat=none&resizing=false","src":"http://transcodeit.com/resources/players/3.15/mediaplayer.swf","align":"left"]

Asian citrus psyllid is established in parts of Florida, Georgia, South Carolina, Louisiana, Texas, Hawaii and Mexico. It also occurs in Belize, Brazil, Cuba, the Caribbean, China, India, Afghanistan, Saudi Arabia and other parts of the world. The pest is typically introduced into new areas when it is carried by people on fruit or plant material.

 "People in California can help us fight Asian citrus psyllid, and prevent the introduction of other pests, by not bringing citrus trees or other plants or fruit into the state from other parts of the United States or other countries," Grafton-Cardwell said.

 In Florida, the Asian citrus psyllid was found before symptoms of HLB were observed. Authorities believe numerous illegally imported citrus trees infected with HLB were already growing in Florida backyards. The disease went unnoticed for years because there was no insect to spread it from tree to tree. However, in 1998, Asian citrus psyllid made its way to the Sunshine State. In short order, the pest and the disease swept into all of Florida's 31 citrus-growing counties. Currently, HLB is killing 10 percent of Florida trees every year.

 The potential for very rapid spread of HLB isn't the only thing the California industry has learned from the Florida experience. When trees started dying, Florida didn't have enough disease-free citrus stock available to replace them.

 In California, all new trees are produced by nurseries with disease-free budwood from the UC Riverside Citrus Clonal Protection Program, which maintains a block of disease-free trees at the UC Lindcove Research and Extension Center in Exeter. (Budwood is small citrus cuttings that nurseries use to propagate new trees.) For decades, the parent trees were maintained in a field at Lindcove, but the increasing threat of another citrus disease, citrus tristeza virus, prompted UC to move true-to-type, disease-free trees into a screenhouse in the late 1990s to protect the trees from aphids, which spread tristeza. Three years ago, as tristeza virus pressure intensified, plans were made to expand the screenhouse, a move especially fortuitous now that another pest is threatening California citrus trees.

The original screenhouse houses 500 potted and 100 in-ground trees representing 379 commercially important varieties. More than 200 of these citrus varieties are registered with the CDFA for budwood distribution.

 The expansion, which is under construction, will hold an additional 250 in-ground trees, according to Georgios Vidalakis, director of UC Riverside Citrus Clonal Protection Program.

 "To keep out Asian citrus psyllid, the new screenhouse will have finer mesh than the old one and the existing screenhouse will be rescreened," Vidalakis said.

 

Chemistry Professor Yadong Yin wins prestigious award

Yadong Yin, assistant professor of chemistry, has been named a Cottrell Scholar - an honor that carries with it an award of $100,000 to further his research and teaching. The awards recognize faculty who excel in both teaching and research, and are among the most prestigious fellowships for beginning faculty in the sciences.

The award is given by the Research Corporation for Science Advancement (RCSA), one of the country's first foundations. The Arizona-based RCSA aids basic research in the physical sciences (astronomy, chemistry, and physics mainly) at U.S. and Canadian colleges and universities.

Yin received the award for his proposal titled "Self-Assembly of Superparamagnetic Colloids to Field-Responsive Photonic Crystals." In this project, Yin will study the self-assembly of nanostructures for photonic materials with magnetically tunable optical properties. Applications include novel display units, signage, and reusable electronic paper

The primary focus of Yin's research is to understand the formation mechanism and physical and chemical properties of nanostructured materials, and use these nanostructures to design and fabricate novel electronic, photonic and biomedical devices and other functional materials. He joined UCR in 2006.

Each year about 30 Cottrell Scholars attend a conference, usually in the second week of July, to share ideas about teaching and for discussions with noted scientists who have been recognized as outstanding teacher-scholars. Yin will use a portion of his award to support his travel to the conference.

Chemist Frederick Gardner Cottrell founded and endowed the RCSA in 1912 with the patent rights to his invention, the Cottrell electrostatic precipitator. The award honors his generosity as a benefactor of science through the RCSA and his lifetime devotion to helping young scientists get their start.

 

 

CNAS Professor Receives Top Scientific Honor

 

Entomologist Alexander Raikhel is elected member of the prestigious National Academy of Sciences

Alexander Raikhel is a professor of entomology at UC Riverside. (Photo credit: UCR Strategic Communi- cations.)

 

 

Professor of Entomology Alexander Raikhel has been elected a member of the National Academy of Sciences (NAS) for his excellence in original scientific research.

Membership in the NAS is one of the highest honors given to a scientist or engineer in the United States. Raikhel will be inducted into the academy next April during its 147th annual meeting in Washington, D.C.

Raikhel, elected along with 71 others, brings the number of current UCR faculty elected to NAS to three. Four additional UCR faculty members who received the honor are deceased; one faculty member who received the honor when he was at UCR is now at UC Irvine.

"Dr. Raikhel’s election to the National Academy of Sciences is a wonderful tribute to his standing in his field," said Thomas Baldwin, the dean of UCR's College of Natural and Agricultural Sciences. "This is a well-deserved honor and a tremendous source of pride for the entire college and university."

There are currently just over 2,000 active NAS members. Among the NAS's renowned members are Albert Einstein, Robert Oppenheimer, Thomas Edison, Orville Wright, and Alexander Graham Bell. More than 180 living NAS members have won Nobel Prizes.

"This extraordinary honor recognizes Dr. Raikhel's groundbreaking contributions to understanding mosquito physiology, particularly the molecular and genetic basis of events in the mosquito's reproductive cycle that are linked to utilizing a blood meal to develop eggs, and to transmission of human diseases such as malaria and dengue," said Ring Cardé, chair of UCR's Department of Entomology.

Raikhel was raised and educated in the Soviet Union. He obtained his M.S. in zoology from Leningrad (St. Petersburg) University and his Ph.D. in biological sciences from the Zoological Institute of the Russian Academy of Sciences. He and his family immigrated as political refugees to the United States in 1979.

He is recognized internationally for his significant contributions to insect science and vector biology. A leader in insect and mosquito reproduction and immunity, he is the author or coauthor of more than 150 research papers in international peer-reviewed scientific journals and books.

At UCR, his research focuses on genetic studies of blood-feeding arthropods, especially mosquitoes, which are responsible for transmitting many different diseases to animals and humans. His accomplishments include being among pioneers of genetic engineering of disease-resistant mosquitoes for the purpose of mosquito control.

Raikhel has deciphered in great molecular detail a chemical chain reaction and genes which prompts disease-spreading mosquitoes to produce and mature their eggs. Manipulation of this process may be key to controlling the mosquito populations responsible for the spread of disease.

His laboratory also uncovered how a female mosquito's first blood meal triggers its reproductive system to produce eggs, a finding that could lead someday to new ways of controlling disease-spreading mosquito populations.

His research team recently identified a pathway by which the mosquito's immune system recognizes some pathogens and protects the mosquito from disease.

Raikhel came to UCR's Department of Entomology in January 2002 from Michigan State University. He is a recipient of many awards, including a Distinguished Faculty Award from Michigan State University and the Entomological Society of America Recognition Award in Insect Physiology, Biochemistry and Toxicology. In 2002, he received a prestigious ten-year, $4.3 million research merit grant from the National Institutes of Health to carry out research on mosquito reproduction.

Raikhel was thrilled and humbled by his election to the NAS.

"I am delighted to see that the NAS recognizes the importance of insect science and vector biology by honoring a researcher in this field," he said. "I am deeply grateful to members of my laboratory, past and present, who contributed to my success and recognition. My thanks go also to my beloved family, Natasha, Eugene, Vincent, Iris and Eli, for their love and support."

The NAS is a private, nonprofit honorific society of distinguished scholars engaged in scientific and engineering research, dedicated to the furthering science and technology and to their use for the general welfare. Established in 1863, the academy has served to "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon to do so by any department of the government.

 

>

Standing room only at first Science Lecture Series talk

(Above) Gene-carrying members of the audience hold up their colored alleles, symbolized by paper plates, as instructed by Prof. of Genetics Norman Ellstrand (below) during his talk, "The Dance of the Genes: How Biological Evolution Works." It was the first of the Spring 2009 Science Lecture Series on "The Science of Evolution: Life, Earth, Universe," presented by the College of Natural and Agricultural Sciences and the Science Circle to a standing-room-only audience of 500 at the University Theatre on April 2.

For other photographs taken at the Science Lectures, click HERE.

 

 

Researchers Find Earliest Evidence for Animal Life

CNAS professor and his colleagues discover fossil animal steroids that date back to more than 635 million years ago

An international team of scientists from UC Riverside, the Massachusetts Institute of Technology and other institutions has found the oldest evidence for animals in the fossil record. The researchers examined sedimentary rocks in south Oman, and found an anomalously high amount of distinctive steroids that date back to 635 million years ago, to around the end of the last immense ice age.

The steroids are produced by sponges - one of the simplest forms of multicellular animals. sponges (Love Lab)The researchers argue that the discovery of the sponges is evidence for multicellular animal life beginning 100 million years before the Cambrian explosion, a well-studied and unique episode in Earth history that began about 530 million years ago when, as indicated by the fossil record, animal life diversified rapidly. The discovery can help scientists reconstruct Earth's early ecosystems and explain how animal life may have first evolved on the planet.

"Our findings suggest that the evolution of multicellular animals began earlier than has been thought," said Gordon Love, an assistant professor of Earth Sciences, who led the research group.. "Moreover, sponges live on the seafloor, growing initially in shallow waters and spreading, over time, into deeper waters, implying the existence of oceanic environments which contained dissolved oxygen near the shallow seafloor around 635 million years ago." Study results appear in the Feb. 5 issue of Nature. Prof. Gordon Love According to Love, the climatic shock of the extensive glacial episodes of the Neoproterozoic era (1000-542 million years ago) likely caused a major reorganization of marine ecosystems, perhaps by irrevocably altering ocean chemistry.

"This paved the way for the evolution of animal feeders living on the seafloor," he said. "We believe we are converging on the correct date for the divergence of complex multicellular animal life, on the shallow ocean floor between 635 and 750 million years ago." The steroids that Love and his colleagues observed in the Omani rocks are essential biochemicals present in the cell membranes of the sponges, and help provide the membranes with structural support. The sponges are a few millimeters in size, immobile, and were filter feeders existing on the seafloor.

The sponge findings emerged from a project Love was working on at MIT (with Roger Summons, a professor of geobiology) in collaboration with Petroleum Development Oman. Using state-of-the-art techniques, he and his colleagues analyzed 64 Neoproterozoic-Cambrian sedimentary rock samples from the South Oman Salt Basin (SOSB), a region known for some of the best preserved rocks in the world. The researchers also established a robust stratigraphic and temporal framework for the SOSB rocks as part of their analysis.

Next, Love and his colleagues plan to screen other Neoproterozoic sedimentary rocks for animal steroids just before and through the Sturtian and Marinoan glaciations, the greatest ice ages known to have occurred on Earth during 850 to 635 million years ago. "We aim to investigate the environmental context by which multicellular animal life became viable and flourished," he said.

Love obtained his Ph.D. in chemistry from the University of Strathclyde (Scotland). He was a recipient of the prestigious Natural Environment Research Council Postdoctoral Fellowship to carry out organic geochemical research at the University of Newcastle (England). He joined UCR's Department of Earth Sciences in January 2007 after a postdoctoral appointment at the Massachusetts Institute of Technology.

Love has co-authored 50 research papers in international peer-reviewed scientific journals on petroleum geochemistry, geobiology, cosmochemistry, solid state nuclear magnetic resonance (NMR) spectroscopy and analytical chemistry.

Eleven CNAS faculty and alumni named 2008 AAAS Fellows

Eight of the 13 UC Riverside researchers and all three of the UCR alumni who have been named Fellows of the American Association for the Advancement of Science (AAAS) for 2008 are affiliated with the College of Natural and Agricultural Sciences. They are:

Also receiving AAAS honors were Steven Brint, professor of sociology; Jie Chen, professor of electrical engineering; Mart Molle, professor of computer science and engineering; and Yushan Yan, professor of chemical and environmental engineering.

All the 486 2008 AAAS Fellows will be announced in the Dec. 19 issue of Science. New fellows will be presented with an official certificate and a gold and blue (representing science and engineering, respectively) rosette pin on Feb. 14 during the annual meeting of the AAAS in Chicago.

The tradition of AAAS Fellows began in 1874. Currently, members can be considered for the rank of Fellow if nominated by the steering groups of the AAAS's sections; by three current Fellows; or by the association's chief executive officer.

The AAAS is the world's largest general scientific society. Founded in 1848, the association includes about 262 affiliated societies and academies of science, serving 10 million individuals.

CNAS Scientist to Explore How Vegetation Affects Urban Heat Islands

Collaborative project with Arizona State University researchers examines urban residents' vulnerability to heat.

Darrel Jenerette, a landscape ecologist at UC Riverside, is on a team led by Arizona State University researchers that will be investigating human vulnerability to deadly heat exposure.

The three-year project will examine how variation in the "urban heat island" - a metropolitan area that is much warmer than its surrounding areas - impacts human comfort and health risks, as well as how human decisions lead to this variation.

Jenerette, an assistant professor in the Department of Botany and Plant Sciences, will investigate the moderating effects of vegetation on urban heat islands.

"I will be researching the potential for plants to reduce summer extreme temperatures in the urban heat island of the Phoenix, Ariz., metropolitan region," Jenerette said. "High temperature events injure and kill many people every year and there is the potenDarrel Jenerettetial for heat exposures to increase with the combination of urban heat islands and global climate changes."

Arizona State University's Sharon Harlan, who is leading the team, noted that people in cities are in double jeopardy due to urban heat islands and global climate change - factors that are increasing and intensifying as they interact.

"With the mounting effects of climate change and half the world's population now living in urban areas - one-third of the people in slums - the potential for the increasing frequency and severity of heat waves is cause for grave concern," she said.

According to Jenerette, the research team also will look at the trade-off between water use and how it affects local climate and spatial components (for e.g., the proximity of trees and parks to homes; green pathways for pedestrian movement).

"How does one tree incrementally affect its immediate environment - a yard, a neighborhood, all the way up to the entire region?" he said. "Much of the cooling associated with vegetation comes at a cost for water. With increased restrictions on water throughout the southwestern United States, understanding the consequences of water allocation is essential for making appropriate decisions."

The researchers will seek answers to guide policymakers and planners in bolstering protective measures to prevent heat-related illness and deaths. They also will examine how global environmental change combines with local conditions to affect human vulnerability to climate change.

More than a dozen researchers working in nearly as many scientific disciplines and subdisciplines are involved in the project.

The team will share its findings locally and nationally with city planners and health agencies and provide data to public health officials responsible for developing early warning systems and heat-illness prevention programs.

Jenerette, who received $135,000 of the $1.4 million grant that the National Science Foundation awarded to the researchers, joined UCR in January 2008.

UCR professor is ranked top plant scientist in U.S.

Zhu’s work receives more citations than any other in last decade

Jian-Kang Zhu, a faculty member in the Department of Botany and Plant Sciences at the University of California, Riverside, is the most cited plant scientist in the United States, according to a survey by ScienceWatch for 1997-2007 (sciencewatch.com/dr/sci/08/jun22-08_4/). Zhu’s 5,405 citations—references to his research work in other scholars’ articles—earned him a #4 ranking internationally.

Zhu holds the Jane S. Johnson Chair in Plant Sciences as well as a University of California Presidential Chair and is the former director of the Institute for Integrative Genome Biology. He joined the UCR faculty in 2004, after appointments at the University of Arizona and Auburn University and a postdoctoral fellowship at Rockefeller University, where he was a Life Sciences Research Foundation Fellow.

While at Arizona Zhu was named Researcher of the Year in 2002 by the College of Agriculture and Life Sciences. In 2003 he received the Charles Albert Shull Award from the American Society of Plant Biologists. And in 2004 he was named a Fellow of the American Association for the Advancement of Science, which cited him for his pioneering research in the field of plant stress biology research, work that fundamentally changed the perspective and direction of research in this field. It is this pioneering research that receives so many citations from other scientists around the world.

A UCR alumnus, Zhu received an M.S. in botany from Riverside in 1990 after graduating from Beijing Agricultural University with a B.S. in soils and agricultural chemistry in 1987. He then earned a doctorate at Purdue in plant physiology in 1993.

The long-term goals of his research program, Zhu says, are “to elucidate the signaling pathways used by plants in responding to environmental stresses and to identify key genes for modifying the responses of crops to environmental stresses, which ultimately will lead to major contributions to agriculture and the environment.”

Other news from the College, departments, centers, & institutes

The Advantage

The College's newsletter, The Advantage, is mailed to alumni, donors, friends, faculty, staff, community and corporate partners, and professional colleagues throughout California, the United States, and the world. An archive of past issues in PDF format is available.