- Contact: Pat Bailey, UC Davis News Service, (530) 752-9843, pjbailey@ucdavis.edu
The study is published in the early edition of the week of Feb. 20 Proceedings of the National Academy of Sciences.
“Many disease-causing microbes can evade one defensive action by a host plant, but we believe that most microbes would have difficulty overcoming a combination of two immune-system defenses,” said the lead researcher Abhaya Dandekar, professor in the Department of Plant Sciences at UC Davis.
He and his colleagues tested this hypothesis on Xylella fastidiosa, the bacteria responsible for Pierce's disease in grapevines. Strains of the bacteria also attack and damage other host plants, including citrus, stone fruits, almonds, oleander, and certain shade trees, such as oaks, elms, maples and sycamores.
The findings further strengthen UC Davis’ standing as a world leader in the science of plant improvement through advances in genetics, genomics, plant breeding and biodiversity.
First noted in California near Anaheim around 1884, Pierce's disease in grapevines is now known to exist in 28 California counties. From 1994 to 2000, the disease destroyed more than 1,000 acres of northern California grapevines, causing $30 million in damages. There is currently no known cure for Pierce’s disease.
In grapevines, Xylella fastidiosa is carried from plant to plant by half-inch-long insects known as sharpshooters. The bacteria infect and clog the plant’s water-transporting tissue, or xylem. Grapevines with Pierce's disease develop yellow and brown leaves and die within a few years.
To block such infections, the researchers engineered a hybrid gene by fusing together two genes that are responsible for two key functions of the plant’s innate immune response: recognizing Xylella fastidiosa as a bacterial invader and destroying its outer membranes, causing the bacteria to die.
The researchers then inserted this hybrid gene into grapevines.
They found that sap from plants genetically engineered with the hybrid gene effectively killed Xylella fastidiosa in the laboratory. And grapevines engineered to carry the hybrid gene had significantly less leaf scorching and xylem clogging, indicating resistance to Pierce’s disease.
The Los Alamos National Laboratory, New Mexico, and the U.S. Department of Agriculture collaborated on the project. Funding came from the state Department of Food and Agriculture’s Pierce’s Disease Program, the U.S. Department of Energy and the U.S. Department of Agriculture.
- Contact: Brenda Dawson, (530) 754-3914, bldawson@ucdavis.edu
“Rangeland has always been a passion for me – rangeland and livestock,” he said. “I like what grows there. I like the relationships. I’ve always understood it. I don’t care if it’s public land or private land, if it’s rangeland, I’m all in.”
McDougald earned a bachelor’s degree in agriculture from California State University, Fresno and a master’s degree in range management from UC Davis. He spent the first 10 years of his career as a rangeland manager for the Forest Service, then joined UC Cooperative Extension in 1978 as an advisor in Madera County for livestock and natural resources. He is currently also the director of UC Cooperative Extension in Madera County and the manager of the nearby San Joaquin Experimental Range.
McDougald’s family has deep roots in Madera County. On a drive from his Madera office to the San Joaquin Experimental Range, he points across the street and explains that his mother’s family donated land for the historic county courthouse, built in 1900. He discusses his family’s involvement in the local beef and timber industries. And before we arrive at the experimental range, we drive by the entrance to his family’s ranch, which has been home to seven generations of McDougalds.
“I’ve always had an interest in the ranch – and I would have come back no matter what – but I was lucky. I was able to come back to the ranch and work here in Madera too,” McDougald said. “This has been my office since the day I started working for UC Cooperative Extension.”
One of the major accomplishments in McDougald’s career has been helping to establish residual dry matter standards, which measure dry plant material left over from the current year’s growth as a way to gauge the health of rangeland.
Mel George, UC Cooperative Extension specialist in the Plant Sciences department at UC Davis, explained that these standards are an alternative to the range condition method, a once commonly used method, which George says didn’t work in California.
“Neil was instrumental in taking these new ideas – residual dry matter standards – to the Forest Service,” George said. “And then every federal agency of any consequence, when it comes to land management, also adopted these standards for local, state and federal lands in California.”
Today the range condition method has been replaced throughout the West with a more comprehensive set of metrics, but residual dry matter standards continue to be used by land managers in California as one way to quickly and simply evaluate rangeland, George explained.
McDougald also helped develop mountain meadow standards, determine values of rangeland loss in wildfires, and establish a system to determine livestock-carrying capacity for rural lands under the Williamson Act. These science-based standards assist in evaluating the health of rangelands and often support continued use of land for grazing.
Each year, McDougald’s seasonal routine mimics the historic movement of cattle in the area.
“In the spring, we work in annual grasslands because it’s beautiful,” he said. “And when it gets hot in the summertime, I go straight to the mountain meadows. It allows me to look at both annuals and perennials – that’s the fun part of it for me. I get to know all the cool-season plants.”
McDougald has brought this rangeland experience to address various aspects of natural resource management. In 1986, he was the first advisor assigned to work for the Integrated Hardwood Range Management Program, where his work focused on effective grazing in oak woodlands, forage production under oak canopies and monitoring grasslands. He later added a focus on rangeland water quality to his expertise, as a regional watershed advisor looking at beef cattle and pack stock. As part of a UC Cooperative Extension team, he assessed possible risks to water quality and then developed management practices to mitigate or reduce those risks.
His plans for retirement include some travel, more fishing and continuing to manage rangelands for his family’s ranch and the San Joaquin Experimental Range. The university has granted McDougald emeritus status so he will also finish up the research projects he has currently under way.
The U.S. Department of Agriculture is funding the $25 million, coast-to-coast project, to which UC Davis is providing expertise in livestock health, foodborne disease and consumer food marketing.
The project, announced Jan. 23 by the USDA, aims to reduce the occurrence of and public health risks associated with Shiga toxin-producing E. coli. The research effort is led by the University of Nebraska, Lincoln.
UC Davis researchers collaborating in the project include James Cullor, a professor in the School of Veterinary Medicine; Christine Bruhn, a food science marketing specialist and director of the Center for Consumer Research; and Terry Lehenbauer, director, and Sharif Aly, assistant professor, both of the Veterinary Medicine Teaching and Research Center in Tulare.
Cullor and his colleagues in the veterinary school's Dairy Food Safety Laboratory -- in Davis and Tulare -- will conduct research aimed at reducing the microbial counts on cattle hides during processing, looking for ecologically responsible methods for enhancing food safety. They also will test radiofrequency technologies, which use electrical currents oscillating at specific frequencies to inactivate E. coli on beef carcasses during processing.
Bruhn will collaborate with North Carolina State University and Kansas State University to reduce health risks associated with undercooked hamburgers. The researchers will encourage television food programs to include safe food-handling practices and messages.
In addition, Bruhn will work with health care professionals to raise the number of food-handling messages directed toward consumers who are at increased risk for foodborne illness, especially children and people with diabetes. She also will investigate consumer interest in the use of irradiation or high-pressure technologies to enhance the safety of ground meat.
Lehenbauer, Aly and their colleagues at the Veterinary Medicine Teaching and Research Center will participate in animal research needed for understanding the epidemiology and ecology of non-Shiga toxin-producing E. coli, after information from preliminary studies is used to develop the scientific protocols for these animal-sampling projects. The research team will focus on dairy cattle, including male Holstein cattle that are being raised for beef production
Other participants are the University of Delaware, New Mexico State University, Texas A&M, Virginia Tech, the University of Arkansas, the USDA's Agricultural Research Service, and a consortium of government, academic and industry scientists and food safety professionals.
- Posted By: Sandra Willard
- Contact: Brenda Dawson, (530) 754-3914, bldawson@ucdavis.edu
“I was the little tag-along with my older sister until I was old enough to join, then I was a 4-H member for nine years, then a volunteer through college, and since college I have been a 4-H staff member,” Gregory said.
Gregory, the 4-H youth development advisor and county director of UC Cooperative Extension Kings County, retired Dec. 31, 2011, after 37 years of service in the University of California Division of Agriculture and Natural Resources.
Gregory’s career started as a 4-H advisor in Kern County in 1974, after earning a bachelor’s degree in Spanish from San Diego State University. She later earned a master’s degree in education from California State University, Bakersfield. In 1991, she began working as a UC 4-H youth development advisor for Kings County and became the UC Cooperative Extension director for the county in 2004.
Carol Collar, a UC Cooperative Extension farm advisor in Kings County, described Gregory as a “very service-oriented” team player.
“Here in Kings County, the 4-H program is very highly valued. She provided excellent leadership and support to leverage volunteer resources for the 4-H program,” Collar said. “Peggy really worked at providing all youth — not just those in the traditional 4-H programs, but all youth — with essential elements in youth development.”
Gregory partnered with various organizations to provide development opportunities for youth in Kings County. One such project was Teen Teams in 2008, which trained at-risk high school students to lead fun, hands-on science activities with younger children in elementary after-school programs. Community collaborators for this program included former NFL player Dameane Douglas and Hanford police officers.
“The program was great because it gave kids who had self-esteem issues a sense of worth by telling them, ‘You're going to teach, and you're going to lead those younger kids,’” said Hanford Police Chief Carlos Mestas. “I like the fact that it brought together different groups of people who wouldn’t normally cross paths for this very, very positive program.”
Through Teen Teams and similar programs, Gregory has trained more than 50 at-risk teens to lead science projects with elementary school students in this rural community.
Gregory worked with volunteer development throughout her career, as a critical component of youth development programs and part of her career’s overarching philosophy.
“A good youth development program engages the entire community to support its youth,” she said. “You really can’t have a strong youth development program without a strong community to support it — and obviously part of that is volunteers in the community who are willing to work with young people.”
More than half of Kings County’s population is of Hispanic or Latino origin, and in 2007 Gregory was the principal investigator of a project examining civic engagement in Latino communities. The project culminated in the ANR publication, “Recommendations for Working in Partnership with Latino Communities.”
Dave Campbell, UC Cooperative Extension specialist in community studies with the UC Davis Human and Community Development Department, said the outcomes of the study were eye-opening.
“The project expanded the range of our thinking about different modes of engaging with the diverse communities in our state,” he said. “Peggy was really the driving force in getting this project going, and it stemmed from really deep-seated, personal and professional interest she had in the project’s questions.”
Gregory also helped create the state’s first mandatory 4-H volunteer orientation and continued to work on volunteer development and policy for 4-H throughout her career.
Though Gregory said she is taking a break from 4-H after 53 years, she has been granted emeritus status and has offered to mentor 4-H staff and volunteers.
- Author: Jeannette E. Warnert
Mahacek was an industrious youngster. In addition to participation in 4-H projects in electricity, woodworking, cooking and raising cattle, he worked on the family farm and managed a 120-home newspaper route for 6 years. His earnings from the paper route and selling the animals he raised in 4-H went towards his college education.
Mahacek earned a bachelor’s degree in industrial arts at San Jose State University in 1974. He considered a career as a high school shop teacher, but ultimately chose a path that allowed him to extend the benefits he derived from 4-H with youth of subsequent generations. He was named the 4-H Youth Development advisor for Merced County in 1976. In 2005, Mahacek added administrative duties to his job, when he was named director of UC Cooperative Extension in Merced County.
During his career, Mahacek placed an emphasis on mechanical sciences and engineering projects. His work included development of curricula and activities in science processes, robotics, computers, GIS/GPS, bio-security and environmental issues, such as watersheds and wildlife habitats.
In 1988, Mahacek was a member of the team that developed the 4-H SERIES (Science Experiences and Resources for Informal Educational Settings) curriculum, which was funded by the National Science Foundation and Kellogg. SERIES was the first comprehensive pragmatic science education curriculum to join 4-H’s traditional projects. In 2004, Mahacek served on the national leadership team for 4-H SET (Science, Engineering and Technology), a program that succeeded SERIES. SET aims to enhance young people’s interest in developing the knowledge and skills needed for the 21st century’s technically oriented careers.
The crowning achievement of his career was the development of the 4-H Junk Drawer Robotics curriculum in 2011. The curriculum shows how to engage children in building robotic devices with rubber bands, Popsicle sticks, medicine dispensers and bamboo skewers – the kinds of things people already have around the house. The robotics program develops skills that go beyond science and engineering. The children learn communications, teamwork and critical thinking.
“Junk drawer robotics is hands-on as well as heads-on,” Mahacek said. “We’re getting kids to be innovative, to come up with ideas themselves. When they come up with their own designs, and then build them, they have internalized the concepts much more than if they are just following directions.”
Junk drawer robotics is one part of a three-track robotics curriculum. The other tracks are virtual robotics, in which participants build virtual robots on computers, and robotics platforms, which employs commercial robot building kits for materials. The package of robotics programs was the No. 1 selling 4-H curriculum in the nation in 2011.
Mahacek received many honors for his contributions to 4-H and UC Cooperative Extension. In 1988 he received distinguished service awards from the state and national 4-H associations. The Merced County Farm City Ag Business Committee presented him its Agri-Education Award in 1992. When his daughter, Anne, was part of UC Merced’s first graduating class in 2008, Mahacek, his wife Susan and Anne received the UC Merced Student Affairs Parent-Family Recognition Award. Last year, Mahacek received the “Hands-On Heroes Award” at the Merced County Children’s Summit.
Mahacek said the 4-H program has evolved during his tenure, but it has not changed its core objectives.
“We went from being a predominantly ag program to including many other topics. Our members used to live in just rural settings, but now they come from the suburbs and urban neighborhoods,” Mahacek said. “But we’re still promoting the concept of working together and gaining confidence by learning practical skills.”
He said 4-H is fundamentally different from programs that focus specifically on developing self-esteem.
“In 4-H, we teach kids positive things to do and make and it builds their self-esteem when they have these abilities and capabilities,” Mahacek said.
All three of Mahacek’s children were active 4-H members, achieved 4-H All Star status – the highest county honor – and pursued higher education and careers in science and engineering.
In retirement, Machacek plans to visit Europe and, in particular, Southern France, where his middle son is working on an ocean acidification research project. Closer to home, Mahacek also plans to spend more time in his backyard workshop, where he is restoring a 1967 Pontiac Firebird and farm equipment that dates back to the early 1900s.