In a recent post about lemon shape being affected by high temperatures
a grower sent an image of what I thought was a blurred view of something that was circled. I responded saying that I couldn't make it out, and a better image should be sent.
The grower resent the image, but this time it was about the long yellow thing in the background that was being asked about. The tree is planted next to a chile pepper plant and the question was whether the shape was affected by the chile proximity.
The grower had never seen anything like it before and I haven't either. But rack it up to the high temperature wave during flowering and the rapid fruit growth period and hormones gone amuck. if temperature extremes become more common, unusual fruit shapes will likely become more common.
Now we know
A team of researchers, including two from the University of California, Riverside, has identified the genes responsible for the hallmark sour taste of many citrus fruits. Published Tuesday, Feb. 25 in Nature Communications, the research could help plant breeders develop new, sweeter varieties.
Modern citrus varieties have been bred over thousands of years to generate a broad palette of sour and sweet-tasting fruits. Analyses of their pulp reveals that a single chemical element--hydrogen--is largely responsible for the difference between sour and sweet-tasting varieties, which usually have similar sugar content. The pulp from sour fruits contains more hydrogen ions, giving it a lower pH and a tangy taste that is recognized by acid-sensitive cells in our taste buds. Conversely, pulp from sweeter varieties contains fewer hydrogen ions and tastes less acidic.
Ronald Koes and colleagues at the University of Amsterdam in the Netherlands set out to untangle how some citrus varieties wind up with more acidic juice than others, a process that until now has remained a mystery. Their interest stemmed from a previous study showing that higher acidity in purple petunia flowers resulted in more petal pigmentation.
Intrigued by the Faris variety of lemon tree, which produces branches bearing both sweet and sour fruits, and white and purple-tinged flowers, Koes' team turned to UCR plant scientists Mikeal Roose and Claire Federici. Using the university's vast Citrus Variety Collection, which preserves over 1,000 living citrus and related fruit varieties, Roose and Federici selected the Faris lemon and 20 other citrus fruits ranging from wincingly sour to sugary sweet for Koes' team to analyze.
By studying the expression of genes related to those controlling acidity in petunias, Koes' team identified two citrus genes, CitPH1 and CitPH5, that are highly expressed in sour varieties and weakly expressed in sweet-tasting varieties. The CitPH1 and CitPH5 genes encode transporter proteins that pump hydrogen ions into the vacuole, a large storage compartment inside juice cells, thus increasing their overall acidity.
Next, the team turned its attention to genes that control the levels of CitPH1 and CitPH5 in juice cells. While down-regulation of CitPH1 and CitPH5 in sweeter tasting varieties arose multiple times independently in different varieties, the researchers found that mutations in genes for a handful of transcription factors (proteins that help turn specific genes on and off) were responsible for reduced expression of CitPH1 and CitPH5, and therefore a sweeter taste.
Roose, a professor of genetics in UCR's College of Natural and Agricultural Sciences, said the findings could help breeders develop better-tasting citrus fruits. However, he said breeding varieties with severe mutations in the transcription factors such as those studied in the "acidless" citrus would be "overkill," producing sugary citrus fruits with none of their popular acidic kick. Instead, plant scientists should look to target mutations that have a less dramatic effect on the production and activity of transporter proteins.
"By understanding the mechanism acidification of fruit cells, we can now look for related genes that might reduce the expression of CitPH1 and CitPH5 just enough to engineer or select for new, sweeter varieties," Roose said.
Hyperacidification of Citrus fruits by a vacuolar
proton-pumping P-ATPase complex
Nature Communicationsvolume 10, Article number: 744 (2019)
Ever in search of new crops and especially those that require little or no water, a recent notice in a Peruvian newspaper promotes a "new" crop that the local tourist industry is finding attractive:
What do you think?
Corryocactus brevistylus BK09424.1 “Sanky”
Attractive Trichocereus peruvianus-like columnar cactus from southern Peru. Stems 10–20′ tall, spines up to 9″ long! Yellow tubular flowers and softball size fruit. Fruit purchased at one of the large traditional markets in Lima city. The flesh of the huge fruit is amazingly sour, as acidic as a lemon. Considered a liver and kidney tonic. We blended the pulp with a little honey-water to make a delicious and refreshing sanky-ade. More tolerant of cold and aridity than any lemon tree, could substitute in areas where lemons can't grow. Z8b
Seed packet $4
4-6″+ plant 3 years old $12.50
Or if Sanky doesnt fit the bill, how about growing Rumpa?
Virulent Newcastle's Disease is Still at Large
NOTICIA: Enfermedad de Newcastle Virulento
El Departamento de Alimentos y Agricultura de California y el Departamento de Agricultura de los Estados Unidos estan investigando una incidencia de la enfermedad de Newcastle virulento que fue encontrada el 18 de mayo 2018 en una bandada de pollitos de corral de traspatio de exhibicion en el condado de Los Angeles, California. Este es el primer caso de la enfermedad de Newcastle virulento (VND), antes conocido como enfermedad de Newcastle exotica, en los Estados Unidos desde el 2003. Como es temprano en la invetigación, es posible que más casos pueden ocurrir.
To support our disease containment and eradication efforts, the CA State Veterinarian is recommending that all poultry exhibitions that include birds from high-risk counties (Los Angeles, Riverside, San Bernardino, and Ventura) be cancelled. An exhibition is an assembly of birds (including but not limited to poultry) brought to the assembly location for purposes that include public display for any duration. These can be auctions, shops, pet marts, cock fights, petting zoos, or more.
- Over 350 confirmed cases have been reported in Southern California including 4 commercial poultry farms. An additional case in Utah has been reported and is believed to be linked to Southern California.
- Infected flocks have been immediately euthanized to prevent further contamination. Approximately 1,000,000 backyard and commercial birds have been euthanized as a result.
- USDA is announcing confirmed cases weekly. These can be found here: www.aphis.usda.gov/
- Samples are tested by the California Animal Health & Food Safety Laboratory System (CAHFS), and confirmed by the APHIS national lab in Iowa.
- Human infection is rare and can be prevented by properly cooking poultry products and wearing personal protective equipment when handling poultry.
- Please report sick birds or unusual deaths!
- USDA's toll free number:-866-536-7593
- Biosecurity for Birds.
For more information regarding Virulent New Castle Disease, please see below:
Virulent Newcastle Disease is a highly contagious and deadly virus in birds; the virus is found in respiratory discharges and feces. Clinical signs in birds include:
It is essential that all poultry owners follow good biosecurity practices to help protect their birds from infectious diseases such as Newcastle. These include simple steps like washing hands and scrubbing boots before and after entering a poultry area; cleaning and disinfecting tires and equipment before moving them off the property; and isolating any birds returning from shows for 30 days before placing them with the rest of the flock.
For backyard flock owners, biosecurity measures are to use dedicated shoes and clothes when caring for them and not to use/wear those clothes/shoes in other areas.
Additional information on biosecurity can be found at:
- USDA Biosecurity for Birds
- CDFA Backyard Biosecurity for Poultry
- CDFA Disease Prevention Guide for Backyard an Pet Bird Owners
- CPF Biosecurity Workshop Videos
- Thoughts on vaccination against virulent Newcastle Disease (vND) from UC Davis School of Veterinary Medicine-Cooperative Extension
In addition to practicing good biosecurity, all bird owners should report sick birds or unusual bird deaths through California's Sick Bird Hotline at 866-922-BIRD (2473). Additional information on VND and biosecurity for backyard flocks can be found at CDFA's Virulent Newcastle Disease Updates webpage.
Sick or dead backyard birds can be submitted to CAHFS laboratories for post-mortem examination ($20 plus shipping and handling). Information on this program can be found at CDFA's CAHFS Laboratory Necropsy Services for California Backyard Poultry Owners webpage.
Virulent Newcastle disease is not a food safety concern. No human cases of Newcastle disease have ever occurred from eating poultry products. Properly cooked poultry products are safe to eat. In very rare instances people working directly with sick birds can become infected. Symptoms are usually very mild, and limited to conjunctivitis and/or influenza-like symptoms. Infection is easily prevented by using standard personal protective equipment.
Please feel free to share widely.
Next up on Ag Experts Talking is Laurel Wilt Disease which is causing major damage in the native tree populations of the south east United States and the avocado groves in particular. Learn what is being done there and what the potential threat is to California avocados.
What are the upcoming topics and how do I register?
Laurel Wilt (March 20, 2019 from 3-4 pm)
Dr. Monique J. Rivera will present current knowledge of the laurel wilt, the biology and ecology of its vector - Ambrosia beetles, current known location of the disease in the US, Identifying the disease, and the laurel wilt disease prevention in California.Dr. Monique J. Rivera will present current knowledge of the laurel wilt, its biology and spreading. One DPR CE unit (other) and one CCA CE unit (IPM) are pending.
Management of Glyphosate-Resistant Weeds in Orchard Crops (April 24, 2019 from 3-4pm)
Dr. Brad Hanson, cooperative extension specialist, will discuss what is herbicide resistance, current state of resistant weeds in CA permanent crops, identification and lifecycle of key glyphosate-resistant weeds, selection pressure for resistant biotypes and species, herbicide modes of action, and examples of herbicide programs for orchard crops. One DPR CE unit (other) and one CCA CE unit (IPM) are pending.
What Are the UC Ag Experts Talking About?
What is involved in the webinars?
A series of 1 hour webinars, designed for growers and Pest Control Advisors, will highlight various pest management and horticultural topics for citrus and avocados. During each session, a UC Expert on the subject will make a presentation and entertain write-in questions via chat during and/or after the presentation. As we develop this program, we may expand to other crops.
Topics: pests and diseases of citrus, avocado and other crops
Are there Continuing Education units?
When the subject discusses pest or disease management, continuing education units will be requested from DPR (1 unit per session). Participants will pre-register, participate in the webinar and be awarded the unit. The sessions will be recorded and hosted on this web site for future study. However, continuing education units will be awarded only to the participants who attend the live version of the webinar.
Who is involved?
This webinar series is brought to you by Ben Faber (UC ANR Ventura Advisor) and Dr. Beth Grafton-Cardwell (Depart of Entomology UC Riverside Extension Specialist) with the technical support of Petr Kosina (UC IPM Contect Development Supervisor) and Cheryl Reynolds (UC IPM Interactive Learning Developer).