PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

To wilt or not to wilt

UC Riverside researchers identify new process that explains why tomatoes are susceptible to a disease-causing fungus

To wilt or not to wilt
2014-10-24
(Press-News.org) RIVERSIDE, Calif. – Plant breeders have long identified and cultivated disease-resistant varieties. A research team at the University of California, Riverside has now revealed a new molecular mechanism for resistance and susceptibility to a common fungus that causes wilt in susceptible tomato plants.

Study results appeared Oct. 16 in PLOS Pathogens.

Katherine Borkovich, a professor of plant pathology and the chair of the Department of Plant Pathology and Microbiology, and colleagues started with two closely related tomato cultivars: "Moneymaker" is susceptible to the wilting fungus Fusarium oxysporum whereas "Motelle" is resistant. In their search for what makes the two different, the researchers focused on microRNAs, small molecules that act by regulating the expression of a variety of genes, including genes involved in plant immunity.

They treated roots from the two cultivars with water or with a solution containing F. oxysporum and looked for microRNAs that were increased in response to the fungus in Moneymaker (where they would inhibit resistance genes) or decreased in Motelle (where they would allow expression of resistance genes). They identified two candidate microRNAs whose levels went down in Motelle after treatment with the fungus.

Because microRNAs inhibit their targets by binding to them, computer searches can find target genes with complementary sequences. Such an "in silico" search for targets of the two microRNAs identified four candidates in the tomato genome, and all four resembled known plant resistance genes.

"When we compared the levels of the four potential targets in the two cultivars after exposure to the fungus, we found that all four were up-regulated in response to F. oxysporum—but only in Motelle; the levels in Moneymarker were unchanged," said Borkovich, the corresponding author of the study.

To test whether up-regulation of the target genes was indeed what made Motelle resistant, Borkovich and her colleagues employed a virus-induced gene silencing (VIGS) system that can down-regulate specific genes in tomato. After exposure to F. oxysporum, disease symptoms, including leaf wilting, were seen in VIGS Motelle plants that silenced any one of the four genes. Although the symptoms were not as severe as in Moneymaker plants, this suggested that all four targets contribute to resistance.

"Taken together," Borkovich and her coauthors conclude, "our findings suggest that Moneymaker is highly susceptible, because its potential resistance is insufficiently expressed due to the action of microRNAs." Moreover, "because the four identified targets are different from the only known resistance gene for F. oxysporum in tomato," they say, "there is much to learn about the immune response to an important pathogen family that infects numerous crop plants."

Borkovich was joined in the research by Shouqiang Ouyang (first author of the research paper), Gyungsoon Park, Hagop S. Atamian, Jason Stajich and Isgouhi Kaloshian at UC Riverside; and Cliff S. Han at Los Alamos National Laboratory.

"Next, we would like to find out if any of the microRNAs we identified are conserved in additional plant species that are infected by other F. oxysporum strains," Borkovich said. "We are interested, too, in identifying the proteins and genes in the fungus that are important for regulating expression of these microRNAs in one cultivar but not the other. In other words, what is it about the fungus that the plant is sensing?"

INFORMATION:

The research was supported by seed funding to Borkovich, Kaloshian and Han from the Los Alamos National Laboratory-UC Riverside Collaborative Program in Infectious Disease. The purpose of the seed project was to explore the molecular basis of plant diseases caused by microorganisms.

The University of California, Riverside (http://www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.


[Attachments] See images for this press release:
To wilt or not to wilt To wilt or not to wilt 2 To wilt or not to wilt 3

ELSE PRESS RELEASES FROM THIS DATE:

Overweight kids misinterpret asthma symptoms, potentially overuse medication

2014-10-24
ORLANDO, Fla. – New research shows obese children with asthma may mistake symptoms of breathlessness for loss of asthma control leading to high and unnecessary use of rescue medications. The study was published online in the Journal of Allergy and Clinical Immunology (JACI), the official scientific journal of the American Association of Allergy, Asthma and Immunology. "Obese children with asthma need to develop a greater understanding of the distinct feeling of breathlessness in order to avoid not just unnecessary medication use, but also the anxiety, reduced quality ...

Growing a blood vessel in a week

2014-10-24
Just three years ago, a patient at Sahlgrenska University Hospital received a blood vessel transplant grown from her own stem cells. Suchitra Sumitran-Holgersson, Professor of Transplantation Biology at The Univerisity of Gothenburg, and Michael Olausson, Surgeon/Medical Director of the Transplant Center and Professor at Sahlgrenska Academy, came up with the idea, planned and carried out the procedure. Missing a vein Professors Sumitran-Holgersson and Olausson have published a new study in EBioMedicine based on two other transplants that were performed in 2012 at Sahlgrenska ...

Receiving gossip about others promotes self-reflection and growth

2014-10-24
Gossip is pervasive in our society, and our penchant for gossip can be found in most of our everyday conversations. Why are individuals interested in hearing gossip about others' achievements and failures? Researchers at the University of Groningen in the Netherlands studied the effect positive and negative gossip has on how the recipient evaluates him or herself. The study is published in Personality and Social Psychology Bulletin. In spite of some positive consequences, gossip is typically seen as destructive and negative. However, hearing gossip may help individuals ...

Medical costs for stroke survivors stay high 10 years on

2014-10-24
New data shows that healthcare and personal costs to support survivors of stroke remains high 10 years on. The Monash University research, published today in the journal Stroke, is the first to look at the long-term costs for the two main causes of stroke; ischemic where the blood supply stops due to a blood clot, and hemorrhagic, which occurs when a weakened blood vessel supplying the brain bursts. Previous studies based on estimating the lifetime costs using patient data up to 5 years after a stroke, suggested that costs peaked in the first year and then declined ...

Three-dimensional metamaterials with a natural bent

2014-10-24
Metamaterials, a hot area of research today, are artificial materials engineered with resonant elements to display properties that are not found in natural materials. By organizing materials in a specific way, scientists can build materials with a negative refractivity, for example, which refract light at a reverse angle from normal materials. However, metamaterials up to now have harbored a significant downside. Unlike natural materials, they are two-dimensional and inherently anisotropic, meaning that they are designed to act in a certain direction. By contrast, three-dimensional ...

Global boom in hydropower expected this decade

2014-10-24
An unprecedented boom in hydropower dam construction is underway, primarily in developing countries and emerging economies. While this is expected to double the global electricity production from hydropower, it could reduce the number of our last remaining large free-flowing rivers by about 20% and pose a serious threat to freshwater biodiversity. A new database has been developed to support decision making on sustainable modes of electricity production. It is presented today at the international congress Global Challenges: Achieving Sustainability hosted by the University ...

For brain hemorrhage, risk of death is lower at high-volume hospitals

2014-10-24
October 24, 2014 – For patients with a severe type of stroke called subarachnoid hemorrhage (SAH), treatment at a hospital that treats a high volume of SAH cases is associated with a lower risk of death, reports a study in the November issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health. After adjustment for other factors, the mortality rate after SAH is about one-fifth lower at high-volume hospitals, according to the report by Dr. Shyam Prabhakaran ...

Roman-Britons had less gum disease than modern Britons

2014-10-24
The Roman-British population from c. 200-400 AD appears to have had far less gum disease than we have today, according to a study of skulls at the Natural History Museum led by a King's College London periodontist. The surprise findings provide further evidence that modern habits like smoking can be damaging to oral health. Gum disease, also known as periodontitis, is the result of a chronic inflammatory response to the build-up of dental plaque. Whilst much of the population lives with mild gum disease, factors such as tobacco smoking or medical conditions like diabetes ...

'Swingers' multiple drug use heightens risk of sexually transmitted diseases

2014-10-24
These so called 'swingers' need to be offered more tailored interventions by sexual health services to help encourage safer sexual practices and prevent the spread of sexually transmitted infections (STIs). Swingers are described as heterosexuals who, as a couple, practise mate swapping or group sex, and/or visit sex clubs for couples. Recreational drug use is associated with high-risk sexual behaviour or sexually transmitted infections and previous studies on the association between drug use and STI focused on women and on men who have sex with men, but there is little ...

Were clinical trial practices in East Germany questionable?

2014-10-24
Clinical trials carried out in the former East Germany in the second half of the 20th century were not always with the full knowledge or understanding of participants with some questionable practices taking place, according to a paper published online in the Journal of Medical Ethics. Moreover, the country agreed to the trials due to impending bankruptcy there and Western pharmaceutical companies took advantage of the situation, said researchers who have studied documents from the time. The German Democratic Republic (GDR), known as East Germany, was a state within ...

LAST 30 PRESS RELEASES:

Hidden chemistry of Earth’s core revealed by how it froze

IRB Barcelona researchers uncover a new strategy to tackle obesity by activating brown fat

Biological ‘moonshot’ accelerates efforts to genetically map life on Earth

New papers reveal how gut-brain interactions shape eating behaviors

Meal timing in later life may matter for health and longevity

“Cracks in the system” driving high suicide rates for autistic people

Biodegradable PET alternative bioproduced at unprecedented levels

NTU Singapore scientists develop cooling sunscreen from pollen

Efficient ethane separation from natural gas using ZIF-8 slurry

Flying blind: aviation experts call for more pilot training amid poor general aviation safety record

Unraveling the complex relationship between trade openness and carbon emissions in Asia

Towards a new era of global agricultural ecology and environmental science

Durham University scientists pioneer new drone swarm technology

New research reveals insights into linkage between menopause and cardiovascular health

Durham University scientists map stress response system in plants

Weight-loss drug semaglutide reduces cocaine use in rats: Suggests possible first pharmacological treatment for human cocaine dependency

Are probiotics worth the cost to prevent infection after a colon removal surgery?

Mizzou at the forefront of using hydrogen energy safely

New design framework makes it easier to create custom shock-absorbing materials

Ochsner Health honored by AMA for Joy in Medicine

New meta-analysis demonstrates that access to the GeneSight test can significantly improve response and remission rates for patients with depression

UCLA receives $7.1M federal grant to expand psychotherapy treatment for chronic pain

One dose of antibiotic treats early syphilis as well as three doses

Researchers identify single antibody behind life-threatening reaction to common blood thinner

Don’t sweat it: New device detects sweat biomarker at minimal perspiration rate

Not so sweet: Some sugar substitutes linked to faster cognitive decline

Antibody-making cells reveal new function in response to flu infection

CCNY physicists make quantum emitter discovery in diamonds

SwRI and Copeland win R&D 100 Award for innovative oil-free compressor

Loneliness is bad for health and wealth in the U.K.

[Press-News.org] To wilt or not to wilt
UC Riverside researchers identify new process that explains why tomatoes are susceptible to a disease-causing fungus