- Author: Rachel Rattner
- Contributor: Therese Kapaun
Rachel Rattner is beginning her 5th year in the Plant Biology Ph.D program at UC Riverside working under Dr. Mikeal Roose. She is working on a research project that investigates the significance of small RNA molecules in grafted citrus and their impact on citrus fruit quality. Small RNAs are molecules that are found in plants naturally and are a rapidly growing area of study in many species. Their role in the regulation of gene expression has been shown to be of importance in many aspects of plant growth and development, as well as being involved in reactions to various environmental stresses. Previous research has suggested that small RNAs may be species-specific and are able to move across the graft union. Citrus rootstocks have long been known to influence fruit quality traits. This project utilizes the Lane Late navel rootstock orchard at Lindcove REC planted in 1991 to examine the potential genetic cause of these differences. The trial consists of 230 navel orange scions on 29 different rootstocks. By comparing genetic sequences of small RNAs in the roots and fruit of different trees, Rachel will correlate changes in gene expression with differences in fruit quality traits.
These photos depict samples of fruit and roots of the Lane Late navels at Lindcove REC. Juice vesicles and young roots are collected throughout the growing season to capture changes in gene expression throughout fruit development. The samples are quickly frozen on dry ice in the field to preserve the integrity and current state of the RNA molecules present at the time of collection.
- Author: Elizabeth E Grafton-Cardwell
Kris Tollerup, UC IPM Advisor stationed at the Kearney Ag Center, is initiating a study on insecticide treatments for leaffooted bug in pomegranate at Lindcove. According to Kris, leaffooted bug populations are normally lowered by cold winter temperatures, but we did not have cold temperatures this past winter. The result is that there are plenty of test subjects available on the pomegranates at Lindcove!
- Author: Therese Kapaun
Each year the Lindcove Research and Extension Center tests every field tree for citrus tristeza virus (CTV), with funding from the California Citrus Nursery Board. This plant virus can be found in citrus trees worldwide, and certain strains of CTV can kill trees while other strains cause mild or no disease symptoms. The virus is phloem-limited, and transmitted by winged forms of cotton aphids, which are common at certain times of the year in the San Joaquin Valley. No cure is known for trees diseased by CTV, and those found to be infected at the Center are removed in order to protect the research plantings from infection.
The Center utilizes the direct tissue blot immunoassay (DTBIA) method of sampling, and Therese Kapaun processes the blots in-house using DAS-ELISA. Briefly, four leaf samples are taken from each tree, and the leaf stems are snipped off at a cross section and quickly pressed onto a nitrocellulose membrane. Leaves are discarded on the ground, and the sampling moves to the next tree. The pressings from about 150 trees can typically fit onto a membrane the size of a 3" X 5" card. Membranes can be stored for weeks in a refrigerator if necessary, and laboratory processing can be performed in batches, taking less than four hours per batch. Results can be dramatic, as blots containing the virus will stain a dark purple color, and are usually visible without magnification.
A five minute training video of our CTV field testing methods can be viewed on YouTube by clicking here.
- Author: Roberta Barton
California 4-H Food Smart Families is recruiting teens to serve as volunteer leaders for nutrition programs in Fresno County and Tulare County. Programs will launch at school sites and afterschool locations this fall.
Teens will volunteer as mentors, role models and teachers motivating youth to make healthier eating choices and to engage in more physical activity. With support from University of California Agriculture and Natural Resources Research and Extension Center staff, teens will deliver established nutrition education lessons to help youth and families learn how to shop for and cook nutritious meals on a budget.
Teen leaders must be 15-18 years of age and will be required to attend free training. Interested and enthusiastic teens can apply by submitting a letter of application to Roberta Barton, Community Educator, at rbarton@ucanr.edu. For further information, call (559) 646-6509.
- Author: Elizabeth Fichtner
- Contributor: Therese Kapaun
University of California Cooperative Extension (UCCE) in Tulare County and the Lindcove Research and Extension Center (LREC) co-hosted three College of the Sequoias (COS) interns enrolled in the SURGE (Student Undergraduate Research Group Experience) program. Student research programs are completed under the academic mentorship of UCCE Advisors, while LREC provides the land and laboratory infrastructure to achieve research goals. Elizabeth Fichtner, UCCE Farm Advisor covering nuts, olives, and prunes, initiated the partnership with COS in 2014, and was joined in 2015 by Allison Ferry-Abee, UCCE Farm Advisor covering viticulture.
Yelena Martinez, a COS Chemistry major, was the first SURGE intern hosted by UCCE and LREC. Yelena's 2014 project focused on plant physiology and the potential for plant growth regulator treatments to mitigate alternate bearing in olive. Since completion of her internship, Yelena has worked as a Student Assistant in Fichtner's research program and has additionally worked for LREC on the annual citrus tristeza survey. Yelena plans to transfer to a 4 year university in 2016 to complete her BS in chemistry.
Stephanie Doria and Edra Lona, 2015 SURGE interns, are conducting research in the new plant pathology laboratory at LREC. Both students' projects address replant issues associated with pistachio bushy top syndrome, a newly recognized disease caused by a plant pathogenic bacterium. Stephanie was a Biology major at COS and is transferring to UC Davis to complete her BS in Evolution, Ecology, and Biodiversity. Edra was a RN/Biology major at COS and is transferring to Fresno State to complete her BS in Microbiology. Since completing their SURGE projects, both students have joined Fichtner's research program as Student Assistants and will continue working at LREC until the commencement of the fall semester.
