Breaking News
January 17, 2019 - New evidence shows how fever alters immune cells
January 17, 2019 - Researchers find new class of blood pressure-regulating peptides in vampire bat venom
January 17, 2019 - Promega to exhibit new Maxwell RSC48 platform at 2019 Festival of Genomics
January 17, 2019 - Study pinpoints immune cells that could be key to tackling hypertension
January 17, 2019 - Couples Intervention May Aid Partners of Diabetes Patients
January 17, 2019 - Your weight history may predict your heart failure risk
January 17, 2019 - Explore a cornucopia of accomplishments in prematurity research
January 17, 2019 - New study identifies four characteristics that predict severity of postpartum depression
January 17, 2019 - New, scalpel-free treatment for reducing Parkinson’s tremor gets FDA approval
January 17, 2019 - Neurobiologists uncover key component of how the human brain marks time
January 17, 2019 - LifeTime receives fund to develop a plan to embed its vision for healthier future
January 17, 2019 - New NSF funded study may help physicians decrease brain injury deaths
January 17, 2019 - Ham bones contain peptides that could have cardioprotective effects
January 17, 2019 - Research finds how Candida albicans adapt to low oxygen levels to cause infection
January 17, 2019 - Cobra Biologics announces appointment of Dr Darrell Sleep as Director of Innovation
January 17, 2019 - Cellular protein that interacts with viruses appears to enable infection process of Zika virus
January 17, 2019 - Opioids Now More Deadly for Americans Than Traffic Accidents
January 17, 2019 - Women who start periods early are at greater risk of cardiovascular problems
January 17, 2019 - The brain-circuitry clash that keeps you from diving into that plate of ribs when you’re dining with royalty
January 17, 2019 - Poo transplant can successfully treat patients with ulcerative colitis
January 17, 2019 - Study suggests key role for glial cells in Parkinson’s disease
January 17, 2019 - Educational videos in clinical settings increase HPV vaccination rates among adolescents
January 17, 2019 - Better understanding of aggressive brain tumour
January 17, 2019 - Why is life expectancy in the U.S. going down? A Q&A
January 17, 2019 - The Electronics Industry Sees Money In Your Health
January 17, 2019 - Hypertension drug may improve effectiveness of ovarian cancer treatment
January 17, 2019 - Scientists reveal key mechanism in worms that controls cell’s response to stress
January 17, 2019 - How Patch Clamp Technology Can Benefit Ion Channel Research
January 16, 2019 - Researchers cultivate organoids that perfectly mimic blood vessels
January 16, 2019 - Sound Pharmaceuticals Advances Phase 2 Hearing Loss Clinical Trial in Cystic Fibrosis
January 16, 2019 - Unraveling the genetic causes of skin cancer
January 16, 2019 - Higher percentages of saturated fat in low-carb diets may not harm cholesterol levels, new analysis suggests
January 16, 2019 - Using bottled or tap water impacts health benefits of green tea
January 16, 2019 - Best trained alert dogs have potential to improve Type 1 diabetes patients’ quality of life
January 16, 2019 - States with lower incidence of melanoma have higher mortality rates
January 16, 2019 - Pollution on the London Underground found to be dangerously high
January 16, 2019 - Breast cancer cells in mice coaxed to turn into harmless fat cells
January 16, 2019 - Study connects the genetic background of autistic spectrum disorders with stem cell dysfunction
January 16, 2019 - When activated, ‘social’ brain circuits inhibit feeding behavior in mice | News Center
January 16, 2019 - How Exercise May Help Keep Our Memory Sharp
January 16, 2019 - Researchers identify a key regulator that stops excessive inflammation
January 16, 2019 - TGF-beta signaling pathway in uterine cells protects against cancer
January 16, 2019 - MD Anderson Cancer Center collaborates with Dragonfly for new immunotherapy drug clinical trials
January 16, 2019 - Drug Repurposing May Provide More Psychiatric Tx Options
January 16, 2019 - A new brain imaging study challenges the dominant theoretical model of autism spectrum disorders
January 16, 2019 - GoFundMe CEO: ‘Gigantic Gaps’ In Health System Showing Up In Crowdfunding
January 16, 2019 - Induced neuronal cells derived from fibroblasts are similar to neurons in the brain
January 16, 2019 - New study finds link between childhood abuse and suicide in later life
January 16, 2019 - Lifestyle and health factors that are good for the heart can also prevent diabetes
January 16, 2019 - Scientists take another step in understanding bacteria that cause Salmonella epidemic
January 16, 2019 - Look to Your Aunts, Uncles and Parents for Clues to Your Longevity
January 16, 2019 - Study finds ADHD drugs are unlikely to cause cardiac damage in children who take them
January 16, 2019 - Call The Midwife! (If The Doctor Doesn’t Object)
January 16, 2019 - Changes in hippocampal structural connectivity differentiate responders of electroconvulsive therapy
January 16, 2019 - Study sheds light on the deadly venom of Mojave rattlesnakes
January 16, 2019 - University of Nebraska to develop new drugs that prevent and counteract effects of radiation exposure
January 16, 2019 - Sugar-based stent makes precarious sewing process easier
January 16, 2019 - FDA-approved drug hampers cancer metastasis in animal model, shows study
January 16, 2019 - Memories of past meals influence future food intake in rats
January 16, 2019 - Low-level cannabis use can change the adolescent brain
January 16, 2019 - MTC in Rouen acquires Robocath’s R-One robot for future healthcare practitioner training
January 16, 2019 - OSSIO granted FDA 510(k) market clearance for OSSIOfiber Bone Pin Family
January 16, 2019 - Childhood body composition may play a role in future respiratory health
January 16, 2019 - Outdated commissioning methods are failing mental health services in the UK, reveals report
January 16, 2019 - Unconventional immune cells trigger disturbed cytokine production in human spondyloarthritis
January 16, 2019 - Patients Turn To GoFundMe When Money And Hope Run Out
January 16, 2019 - Researchers develop novel viral identification method
January 16, 2019 - Study proposes improvements in pharmacological study of cognitive function enhancers in schizophrenia
January 16, 2019 - Study points to potential new biomarker and drug target for amyotrophic lateral sclerosis
January 16, 2019 - Differences in geographic origin of genes may affect mitochondrial function
January 16, 2019 - Study analyzes vaccine-preventable infections in children who receive solid organ transplants
January 16, 2019 - MiRagen Announces New Clinical Data in Patients With Three Different Types of Blood Cancers Treated With Cobomarsen
January 16, 2019 - Scientists uncover why knee joint injury leads to osteoarthritis
January 16, 2019 - Salk team uses new model to study health effects of AMP-activated protein kinase
January 16, 2019 - Research reveals novel approach to suppressing chemotherapy-induced tumor growth
January 16, 2019 - Researchers reveal how fasting leads to better overall health
January 16, 2019 - Deprivation and neglect in early childhood have impact on cognitive functioning in adolescence, shows study
January 16, 2019 - Training Students to use Imaging Techniques: NMR and EPR
January 16, 2019 - Nerve transfer surgery restores arm movement in children with acute flaccid myelitis
January 16, 2019 - Exelixis Announces U.S. FDA Approval of Cabometyx (cabozantinib) Tablets for Previously Treated Hepatocellular Carcinoma
Researchers report novel findings on plant hormone

Researchers report novel findings on plant hormone

image_pdfDownload PDFimage_print

Jasmonic acid is not just the aromatic odor of the plant Jasminum grandiflorum used in cosmetics and perfume industries. Plants wounded by e.g. chewing herbivores produce jasmonic acid as a defense signal, as a phytohormone to mount their defense responses – this includes for example the formation of toxic substances. They even employ volatile derivatives of jasmonic acid to warn their neighbors to fight the rising threat in time.

Today, an international research team led by the plant biologist Dirk Becker of Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany, report on their novel findings on jasmonic acid effects in the renowned scientific journal Developmental Cell. They found that jasmonic acid also is involved in the quick closure of stomata.

Wounding induces the closure of stomata via jasmonic acid

Stomata are adjustable pores formed by two guard cells in the epidermis of plant leaves. They control the uptake of carbon dioxide crucial for photosynthesis and at the same time the plants’ water balance. The phytohormone abscisic acid (ABA) represents a key signal for stomatal closure. Plants produce ABA during drought stress to save water.

During their experiments on guard cell volume control by biotic stress the team from the JMU Chair of Plantphysiology and Biophysics noticed that mechanical wounding of leaves of the model plant Arabidopsis thaliana quickly triggers stomatal closure, too. Surprisingly, this effect was not restricted to the wounded leaf, but also occurred in neighboring leaves.

“This observation was not reported before and suggested to us that the jasmonate signaling pathway might have been turned-on in the guard cells,” explains Dirk Becker. But how to monitor jasmonic acid signaling in guard cells? Here the Würzburg team received assistance from the plant biologist Antoine Larrieu (Ecole Normale Supérieure Lyon), who had developed a genetically encoded fluorescent sensor for monitoring jasmonate signaling in living cells. He could show that wounding indeed activates the jasmonic acid signaling cascade in guard cells.

From jasmonic acid to a potassium channel

Stomatal closure requires the efflux of anions and potassium mediated by guard cell ion channels. To understand the molecular mechanism that underlie jasmonic acid controlled stomatal closure the Becker team went out searching for mutants that would not respond to jasmonate treatment.

When screening their mutant collection of guard cell ion channels they discovered the K+ channel (GORK) as an essential target of jasmonate induced stomatal closure. In collaboration with the labs from Jörg Kudla (Universität Münster) and Erwin Grill (Technische Universität München) they could identify a calcium dependent protein kinase – the plant specific CBL/CIPK complex – to interact and regulate the activity of the GORK potassium channel. “Wounding induces calcium signals in guard cells and in electrophysiological studies we could demonstrate that the calcium-binding CBL1/CIPK5 complex activates the ion channel”, Dirk Becker states.

Two plant hormones in a molecular crosstalk

The research team further identified the protein phosphatase ABI2 to counteract kinase mediated channel activation, thus representing a negative regulator of jasmonate signaling in guard cells. Becker further explains, “Interestingly, ABI2 is the co-receptor for the plant drought hormone ABA. This is indicating molecular crosstalk between the two phytohormones jasmonic acid and abscisic acid.” Indeed, together with colleagues from the Pedro Rodriguez lab (Universitat Politecnica Valencia) the team could show that Arabidopsis mutants lacking guard cell ABA receptors are also insensitive to jasmonic acid.

With their story the international team of plant biologists led by JMU scientist Dirk Becker has made an important step in understanding the molecular framework that allows plants to respond to wounding stress in guard cells. Leaf turgor and photosynthetic rates correlate with stomatal conductance.

Thus, wounding induced stomatal closure might provide an emergency signal to plants. “Currently we do not know how jasmonic acid addresses the abscisic acid signaling pathway”, Becker says. The Würzburg team now will investigate whether jasmonic acid triggers abscisic acid biosynthesis or whether it acts at the level of abscisic acid perception and sensitivity.

Puzzling observation about Coronatine

Plant pathogenic Pseudomonas bacteria are capable of producing a molecular mimicry of jasmonic acid, known as Coronatine. Plant physiologists commonly use Coronatine as a substitute for jasmonic acid in their experiments.

“In the long term, however”, Becker explains, “Coronatine does just the opposite of jasmonic acid in guard cells: it opens stomata providing an entry pathway for the pathogenic bacteria.” This puzzling observation shall be resolved in future studies by comparing differentially expressed genes in guard cells after jasmonic acid or coronatine treatment.

Source:

https://www.uni-wuerzburg.de/en/news-and-events/news/detail/news/news-about-a-plant-hormone/

Tagged with:

About author

Related Articles