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Nature: Plant biology: Electric defence (2013)

Nature: Plant biology: Electric defence (2013) | Plants | Scoop.it

Herbivory and mechanical wounding in plants have been shown to elicit electrical signals — mediated by two glutamate-receptor-like proteins — that induce defence responses at local and distant sites.

 

The mammalian nervous system can relay electrical signals at speeds approaching 100 metres per second. Plants live at a slower pace. Although they lack a nervous system, some plants, such as the mimosa (Mimosa pudica) and the Venus flytrap (Dionaea muscipula), use electrical signals to trigger rapid leaf movements. Signal propagation in these plants occurs at a rate of 3 centimetres per second — comparable to that observed in the nervous system of mussels. On page 422 of this issue, Mousavi et al. address the fascinating yet elusive issue of how plants generate and propagate electrical signals. The authors identify two glutamate-receptor-like proteins as crucial components in the induction of an electrical wave that is initiated by leaf wounding and that spreads to neighbouring organs, prompting them to mount defence responses to a potential herbivore attack.

 

As sessile organisms, plants have evolved diverse strategies to combat herbivores. These include mechanical defences, such as the thorns found on rose bushes, and chemical deterrents, such as the insect-neurotoxic pyrethrins of the genus Chrysanthemum. However, some plants do not invest in continuous defensive structures or metabolites, relying instead on the initiation of defence responses on demand2. This strategy requires an appropriate surveillance system and rapid communication between plant organs. A key player in orchestrating these reactions is the lipid-derived plant hormone jasmonate, which rapidly accumulates in organs remote from the site of herbivore feeding.

 

Mousavi et al. used thale cress (Arabidopsis thaliana) plants and Egyptian cotton leafworm (Spodoptera littoralis) larvae as a model of plant–herbivore interactions. The researchers placed the larvae on individual leaves and recorded changes in electrical potentials using electrodes grounded in the soil and on the surface of different leaves. The leaf-surface potential did not change when a larva walked on a leaf, but as soon as it started to feed, electrical signals were evoked near the site of attack and subsequently spread to neighbouring leaves at a maximum speed of 9 centimetres per minute. The relay of the electrical signal was most efficient for leaves directly above or below the wounded leaf. These leaves are well connected by the plant vasculature, which conducts water and organic compounds, and is a good candidate for the transmission of signals over long distances.

 

Mousavi et al. 

http://www.nature.com/nature/journal/v500/n7463/full/nature12478.html


Via Kamoun Lab @ TSL, Guogen Yang
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Steve Marek's curator insight, October 7, 2013 12:22 PM

So when can I start using plants to improve my internet bandwidth?

Do mycorrhizae conduct e-signals root to root?

Rescooped by Romano Porras from Business Market Research Reports
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Production and Market of Alpha and Beta-Pinene Industry Report in China

Production and Market of Alpha and Beta-Pinene Industry Report in China | Plants | Scoop.it

As the main component of turpentine, alpha-pinene (pinene) and beta-pinene (pinene) are also important forest chemicals in China.

Get your copy of this report @ http://www.rnrmarketresearch.com/production-and-market-of-alpha-and-beta-pinene-in-china-market-report.html

Since a large amount of pinene is exported annually in recent years, the global economy situation is very important for pinene industry. After global financial crisis in 2008, global economy recovers difficultly, though China takes the lead in economic recovery around the world, with the implementation of massive stimulus package. However, the negative effects of massive stimulus package have appeared since 2010, such as debt crisis, high inflation rate. How much does this affect China’s pinene industry in recent three years? CCM will figure out it in this report.

In 2011, thanks to the great demand from domestic and overseas markets, the pinene production still keeps an uptrend in China. But the price of pinene has changed a lot. In this pinene report, CCM will tell you the details of the changes in the past years and the changing trend in the next five to ten years.

China is still a very important supplier of pinene for the world, and a large quantity of pinene is exported annually while little pinene is imported. In this report, the detailed export situation of pinene (pinene and pinene) in 2010 and 2011 and general information about pinene export before 2009 and Jan. ~July 2012 will be analyzed.

In China, pinene is mainly applied in dihydromyrcene/dihydromyrcenol, synthetic camphor, synthetic borneol and all kinds of synthetic perfume. pinene is mainly applied in synthesized flavors and polymerized terpene resin. In this report, you will find market shares of these two kinds of pinene in 2011 as well as the forecast on pinene consumption in the following five to ten years.

Besides the points above, CCM will also offer an insightful analysis on the following aspects:

- Prices of pinene and pinene in the past and currently
- Supply situation of all pinene producers
- Introduction to major derivatives of pinene and pinene
- Raw material supply for pinene and pinene
- Key influencing factors for the development of pinene and pinene industry in China
- Detailed introduction to major active pinene producers and key pinene export merchants in China


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Rescooped by Romano Porras from Arabidopsis
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Isoprenoid biosynthesis is required for miRNA function and affects membrane association of ARGONAUTE 1 in Arabidopsis (PNAS)

Isoprenoid biosynthesis is required for miRNA function and affects membrane association of ARGONAUTE 1 in Arabidopsis (PNAS) | Plants | Scoop.it

Plant and metazoan microRNAs (miRNAs) guide ARGONAUTE (AGO) protein complexes to regulate expression of complementary RNAs via base pairing. In the plant Arabidopsis thaliana, the main miRNA effector is AGO1, but few other factors required for miRNA activity are known. Here, we isolate the genes defined by the previously described miRNA action deficient (mad) mutants, mad3 and mad4. Both genes encode enzymes involved in isoprenoid biosynthesis. MAD3 encodes 3-hydroxy-3-methylglutaryl CoA reductase (HMG1), which functions in the initial C5 building block biogenesis that precedes isoprenoid metabolism. HMG1 is a key regulatory enzyme that controls the amounts of isoprenoid end products. MAD4 encodes sterol C-8 isomerase (HYDRA1) that acts downstream in dedicated sterol biosynthesis. Using yeast complementation assays and in planta application of lovastatin, a competitive inhibitor of HMG1, we show that defects in HMG1 catalytic activity are sufficient to inhibit miRNA activity. Many isoprenoid derivatives are indispensable structural and signaling components, and especially sterols are essential membrane constituents. Accordingly, we provide evidence that AGO1 is a peripheral membrane protein. Moreover, specific hypomorphic mutant alleles of AGO1 display compromised membrane association and AGO1-membrane interaction is reduced upon knockdown of HMG1/MAD3. These results suggest a possible basis for the requirement of isoprenoid biosynthesis for the activity of plant miRNAs, and unravel mechanistic features shared with their metazoan counterparts.


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The tannosome is an organelle forming condensed tannins in the chlorophyllous organs of Tracheophyta

The tannosome is an organelle forming condensed tannins in the chlorophyllous organs of Tracheophyta | Plants | Scoop.it

 The presence of the three different chloroplast membranes inside vacuolar accretions that constitute the typical form of tannin storage in vascular plants was established in fresh tissues as well as in purified organelles, using several independent methods. Tannins are polymerized in a new chloroplast-derived organelle, the tannosome. These are formed by pearling of the thylakoids into 30 nm spheres, which are then encapsulated in a tannosome shuttle formed by budding from the chloroplast and bound by a membrane resulting from the fusion of both chloroplast envelopes. The shuttle conveys numerous tannosomes through the cytoplasm towards the vacuole in which it is then incorporated by invagination of the tonoplast. Finally, shuttles bound by a portion of tonoplast aggregate into tannin accretions which are stored in the vacuole. Polymerization of tannins occurs inside the tannosome regardless of the compartment being crossed. A complete sequence of events apparently valid in all studied Tracheophyta is described.


Via Bradford Condon
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Alpha pinene- Import Data india

We provide alpha pinene Import data with HS code, Date, Port Name, Product List. Get buyers and sellers details of alpha pinene.
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Rescooped by Romano Porras from molecular biology
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Science: Paired Plant Immune Receptors (2014)

Science: Paired Plant Immune Receptors (2014) | Plants | Scoop.it

Plants are constantly interpreting microbial signals from potential pathogens and potential commensals or mutualists. Because plants have no circulating cells dedicated to this task, every plant cell must, in principle, recognize any microbe as friend, foe, or irrelevant bystander. That tall order is mediated by an array of innate immune system receptors: pattern-recognition receptors outside the plant cell and nucleotide-binding oligomerization domain (NOD)–like receptors (NLRs) inside the cell. Despite their importance for plant health, how NLRs function mechanistically has remained obscure. On page 299 of this issue, Williams et al. (1) reveal a role for heterodimerization between NLRs and show how the rather limited NLR repertoire of any plant genome might be enhanced by combinatorial diversity.

 

Marc T. Nishimura, Jeffery L. Dangl


Via Nicolas Denancé, Christophe Jacquet, Jose Eduardo Ulloa Rojas
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Rescooped by Romano Porras from Arabidopsis
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Cell - Reprogramming of DNA Methylation in Pollen Guides Epigenetic Inheritance via Small RNA

Cell - Reprogramming of DNA Methylation in Pollen Guides Epigenetic Inheritance via Small RNA | Plants | Scoop.it

Highlights

- Arabidopsis male germline retains symmetric DNA methylation after meiosis

- CHH methylation restored in vegetative nucleus and embryo after fertilization

- CG methylation is lost exclusively in vegetative nucleus from targets of DME and ROS1

- 24 nt siRNA from transposable elements flanking imprinted genes accumulate in sperm

 

Summary

Epigenetic inheritance is more widespread in plants than in mammals, in part because mammals erase epigenetic information by germline reprogramming. We sequenced the methylome of three haploid cell types from developing pollen: the sperm cell, the vegetative cell, and their precursor, the postmeiotic microspore, and found that unlike in mammals the plant germline retains CG and CHG DNA methylation. However, CHH methylation is lost from retrotransposons in microspores and sperm cells and restored by de novo DNA methyltransferase guided by 24 nt small interfering RNA, both in the vegetative nucleus and in the embryo after fertilization. In the vegetative nucleus, CG methylation is lost from targets of DEMETER (DME), REPRESSOR OF SILENCING 1 (ROS1), and their homologs, which include imprinted loci and recurrent epialleles that accumulate corresponding small RNA and are premethylated in sperm. Thus genome reprogramming in pollen contributes to epigenetic inheritance, transposon silencing, and imprinting, guided by small RNA.


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A Quick Review: Photosynthesis In The Chloroplast (Basic Overview)

This is just a short tutorial about the process of photosynthesis in the chloroplast. Since it's for my 7th graders I kept it pretty basic. However, I will a...
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