How plants sound the alarm about danger. Hormones are more complex than previously thought. Understanding their roles and interactions may ultimately result in better plant protection practices
Team led by Salk scientists provides a detailed picture of how plant hormones communicate through gene regulation
LA JOLLA—Just like humans and other animals, plants have hormones. One role of plant hormones is to perceive trouble—whether an insect attack, drought or intense heat or cold—and then signal to the rest of the plant to respond.
A multicenter team led by current and former investigators from the Salk Institute is reporting new details about how plants respond to a hormone called jasmonic acid, or jasmonate. The findings, which were published in Nature Plants on March 13, 2020, reveal a complex communication network. This knowledge could help researchers, such as members of Salk's Harnessing Plants Initiative, develop crops that are hardier and more able to withstand assault, especially in an era of rapid climate change.
“This research gives us a really detailed picture of how this hormone, jasmonic acid, acts at many different levels,” says Professor Joseph Ecker, co-corresponding author and Howard Hughes Medical Institute investigator. “It enables us to understand how environmental information and developmental information is processed, and how it ensures proper growth and development.”
The plant used in the study was Arabidopsis thaliana, a small flowering plant in the mustard family. Because its genome has been well characterized, this plant is a popular model system. Scientists can take what they learn in A. thaliana and apply it to other plants, including those grown for food. Jasmonic acid is found not only in A. thaliana but throughout the plant kingdom.
“Jasmonic acid is particularly important for a plant's defense response against fungi and insects,” says co-first author Mark Zander, a staff researcher in Ecker's lab. “We wanted to precisely understand what happens after jasmonic acid is perceived by the plant. Which genes are activated and deactivated, which proteins are produced and which factors are in control of these well-orchestrated cellular processes?”
The researchers started with plant seeds grown in petri dishes. They kept the seeds in the dark for three days to mimic the first few days of a seed's life, when it is still underground. “We know this growth stage is super important,” says co-first author and co-corresponding author Mathew Lewsey, an associate professor at La Trobe University in Melbourne, Australia, who previously worked in Ecker's lab. The first few days in the soil are a challenging time for seedlings, as they face attacks from insects and fungi. “If your seeds don't germinate and successfully emerge from the soil, then you will have no crop,” Lewsey adds.
After three days, the plants were exposed to jasmonic acid. The researchers then extracted the DNA and proteins from the plant cells and employed specific antibodies against their proteins of interest to capture the exact genomic location of these regulators. By using various computational approaches, the team was then able to identify genes that are important for the plant's response to jasmonic acid and, moreover, for the cellular cross-communication with other plant hormone pathways.
Two genes that rose to the top in their degree of importance across the system were MYC2 and MYC3. These genes code for proteins that are transcription factors, which means that they regulate the activity of many other genes—or thousands of other genes in this case.
“In the past, the MYC genes and other transcription factors have been studied in a very linear fashion,” Lewsey explains. “Scientists look at how one gene is connected to the next gene, and the next one, and so on. This method is inherently slow because there are a lot of genes and lots of connections. What we've done here is to create a framework by which we can analyze many genes at once.”
“By deciphering all of these gene networks and subnetworks, it helps us to understand the architecture of the whole system,” Zander says. “We now have this very comprehensive picture of which genes are turned on and off during a plant's defense response. With the availability of CRISPR gene editing, these kinds of details can be useful for breeding crops that are able to better withstand attacks from pests.”
Another noteworthy aspect of this work is that all of the data from the research has been made available on Salk's website. Researchers can use the site to search for more information about genes they study and find ways to target them.
Joint research conducted by The Nature Conservancy and the Kunming Institute of Botany, Chinese Academy of Sciences calculated the carbon-storing power of global soils and showcased approaches like agroforestry designed to capitalise on untapped potential.
A critical, nature-based approach to mitigating climate change has been right at our feet all along, according to a new study revealing that soil represents up 25% of the total global potential for natural climate solutions (NCS) – approaches that absorb CO2 from the atmosphere and lock it into landscapes, including forests, croplands and peatlands.
Representing the first time soil's total global potential for carbon-mitigation across forests, wetlands, agriculture and grasslands together has been catalogued, the study – led by scientists from The Nature Conservancy alongside Conservation International, Woods Hole Research Centre, University of Aberdeen, Yale University and the Kunming Institute of Botany, Chinese Academy of Sciences(KIB/CAS) – provided a timely reminder in this critical 'super year' for nature not to neglect the power of soils and the many benefits these ecosystems can deliver for climate, wildlife and agriculture.
Published in the journal Nature Sustainabilityentitled "The role of soil carbon in natural climate solutions". the research also argued that a lack of clarity to date regarding the full scale of this opportunity and how to best capitalise on it has restricted investment.
"While momentum continues to build behind the role nature can play in the global response to climate change, soils have historically enjoyed less of the limelight as a 'natural climate solution' compared with, say, forests or mangroves. Our study is designed to redress this situation," said lead author Dr. Deborah Bossio, The Nature Conservancy's Lead Soil Scientist. "By highlighting the full carbon-mitigation potential of soils across a range of landscapes, but also – crucially – exploring practical mechanisms that already exist for accelerating the uptake of these comparatively untapped approaches, including their integration into burgeoning carbon markets. This is particularly important for agriculture sector, for which more effective management of soils represents the single biggest contribution this industry can make towards mitigating climate change."
"Soils and improved soil management have a tremendous potential to store carbon. Agroforestry, and more generally just including more trees in the agricultural landscape, has been shown to be one of the most important approaches to increasing soil organic carbon with substantial global mitigation potential. In addition, highlighting the complimentary beneficial impacts available from improved agricultural production practices aimed at improving soil health, both the increased on-farm bio-diversity and livelihood diversification can enhance farm and ecosystem resilience," said co-author Dr. Robert Zomer of the KIB/CAS.
Demonstrating that soil carbon represents up to 25% of total global NCS potential, the paper also estimated that 40% of this potential will be delivered by protecting existing soil carbon reserves, while 60% will come from rebuilding stocks depleted by practices such as over-intensive arable agriculture and the draining of peatlands.
Breaking these data down further, the researchers also showed the share of total NCS potential that soil represents across various, climate-critical landscapes – from a relatively diminutive 9% of forest mitigation potential, through 47% for agricultural lands and grasslands, right up to 72% of total carbon sequestration potential in wetland landscapes.
The study also showed that agroforestry systems can have significant positive impacts on soil organic carbon across specific geographies. Moreover, the majority of other soil carbon pathways tend to be "no regrets" practices that deliver soil fertility, climate resilience and provide other ecosystem services alongside climate mitigation.
"We already know that nature has a powerful role in mitigating runaway climate change," said Prof. XU Jianchu from KIB/CAS, who was not associated with the study. “This study showed the NCS provide pathways for sustainable development that have both climate mitigation and livelihood improvement potential. It is essential that soil health become a central pillar of agricultural production, not just for climate mitigation, but also for both environmental and food security."
- Author: Cheryl Reynolds
Online training courses and webinars available from
UC Statewide Integrated Pest Management Program
This spring if you are looking for options to obtain your continuing education units (CEUs) and not sure where to get them, why not check out the online options that the UC Statewide IPM Program (UC IPM) has to offer. For license and certificate holders from the California Department of Pesticide Regulation (DPR) with last names beginning with the letters A through L, 2020 will be the year to renew.
UC IPM currently offers 16 online courses for DPR credit. Many of the courses are also accredited by the California Structural Pest Control Board (SPCB), Certified Crop Advisor (CCA), Western Chapter of the International Society of Arboriculture (WCISA), or Arizona Department of Agriculture.
If you are looking for CEUs in the Laws and Regulations category, check out these courses:
- Proper Pesticide Use to Avoid Illegal Residues (2.0 Pesticide Laws & Regs)
- Proper Selection, Use, and Removal of Personal Protective Equipment (1.5 Pesticide Laws & Regs)
- Providing IPM in Schools and Child Care Settings(1.0 Other and 0.5 Pesticide Laws & Regs)
Some of our courses do require a fee and are being offered at an early-bird price through October 31st. These courses can be purchased individually, or they can be purchased as a 4-course bundle for a special price of $85—a total discount of $20 versus purchasing each course separately.
In addition to offering online courses, UC IPM also hosts a monthly webinar series sponsored by
the Citrus Research Board. The UC Ag Experts Talk webinar series is designed for growers and pest control advisers. It includes presentations on various pest management and horticultural topics, primarily for citrus and avocados. The next webinar will be held on April 8th from 3 PM until 4 PM with Dr. Elizabeth Grafton-Cardwell, UC Riverside Department of Entomology and Extension Specialist, speaking about citricola scale. This webinar has been approved for one hour of Other CEUs from DPR and 1 hour of IPM units from CCA. Registration is currently open. View past webinars on the YouTube UC Ag Expert Talk Playlist. CEUs are only available for attending the live webinar.
DPR always encourages license and certificate holders to avoid the last-minute rush and renew early to ensure your license will be renewed by January 1st. Take advantage of UC IPM's online courses and webinar series to get a jump start on your renewal today!
New technique has potential
to protect citrus from HLB
Citrus greening, also called Huanglongbing (HLB), is devastating the citrus industry. Florida alone has experienced a 50 to 75 percent reduction in citrus production. There are no resistant varieties of citrus available and limited disease control measures.
Some scientists think it is possible that orange juice could one day become as expensive and rare as caviar. In an effort to prevent this, three plant pathologists at the University of California-Berkeley and United States Department of Agriculture conducted research into ways to boost citrus immunity and protect the valuable fruit against citrus greening.
Because the bacteria that causes citrus greening cannot be grown in a lab, scientists have to find novel ways to conduct experiments. The University of California-Berkeley/USDA team looked at many different strains of the bacteria that cause citrus greening to see if they could identify peptides (a compound of two or more amino acids) that would trigger immune responses.
"This was a long list, so we narrowed it down by selecting small peptides that were a bit different in their peptide sequence, which might imply that the bacterium had made those sequence changes so that they wouldn't be recognized by the plant immune system," explained Jennifer D. Lewis, group leader of the research team. "Then we further narrowed that list to peptides from strains that caused disease in citrus."
Through this research, they showed that two peptides could trigger immune responses in multiple plant species, including citrus. These peptides may play a role in preventing or reducing yield loss from citrus greening.
According to Lewis, "We thought it was particularly interesting that some of the peptides predicted to elicit a response, could actually trigger immune responses in multiple plant species. This suggests that the immune response to these peptides is conserved across species."
The University of California has put together a series of publications on addressing COVID-19 in the home and the workplace. They can be found at: COVID-19 Guidelines
The individual articles are below:
Take Care and Stay well.
And from CDFA:
BEST PRACTICES GUIDELINES
Food producers and manufacturers have been required by longstanding federal and state laws and regulations to prevent anyone who is sick or has a communicable disease from handling, processing or preparing food for human consumption. Thus, industries handling food and agricultural commodities are well practiced at this important and general principle of food safety and hygiene. It is important to follow recommendations as set forth by the CDC as well as those outlined below:
- Maintain diligence in good hygiene, monitor for employee illness, and adhere to social distancing guidelines as possible.
- Adhere to your Sanitation Standard Operating Procedures (SSOP), ensuring that those supervising staff and operations are vigilant in their oversight.
- Ensure adequate frequency of cleaning and sanitizing per CDC Environmental Cleaning and Disinfection guidance.
- Adhere to cleaning and sanitizing frequency of restroom and other high contact areas.
- Consider ways for employees to easily identify themselves (business card, company ID badge) outside of business operations for ease in transportation to and from work while adhering to local ordinances.
According to both the U.S. Centers for Disease Control (CDC) and the United States Department of Agriculture (USDA) there is currently no evidence to support transmission of COVID-19 associated with food or food packaging. The CDC is also reporting that, in general, because of poor survivability of the coronavirus on surfaces, there is likely a very low risk of spread from food products or packaging that are shipped over a period of days or weeks at ambient, refrigerated, or frozen temperatures.
Labor is a vital component to the food supply, from farm to fork. California has among the highest standards for food safety, which includes worker health and hygiene standards supported by labor laws that are very specific about paid sick leave for those individuals that may be affected by COVID-19 and unable to work.
Transportation: Governor Newsom's Executive Order on transportation “to allow timely delivery of vital goods” is also an important part of this discussion.
For additional information and FAQs please visit:
Photo: San Luis Obispo landscape