I feel honored so many people are trying so hard to insult me and what not... Now if you only spent half that time trying to understand the real issue...you might have something to contribute...
stop wasting your time with this thread unless you can contribute... pics of your grow and exp are always a good start...
Certified Arm Chair Experts do some more reading
Thanks for sharin
SS .
Other issues including Phytoplasmas and Mycoplasma like organisms (MLOs) ............................ 200
Even this old couple knows what the word is... someone should buy this book and do some homework...
Thanks for sharin
SS .
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322544/
Current View on Phytoplasma Genomes and Encoded Metabolism
Phytoplasmas are specialised bacteria that are obligate parasites of plant phloem tissue and insects. These bacteria have resisted all attempts of cell-free cultivation. Genome research is of particular importance to analyse the genetic endowment of such bacteria. Here we review the gene content of the four completely sequenced ‘Candidatus Phytoplasma' genomes that include those of ‘Ca. P. asteris' strains OY-M and AY-WB, ‘Ca. P. australiense,' and ‘Ca. P. mali'. These genomes are characterized by chromosome condensation resulting in sizes below 900kb and a G + C content of less than 28%. Evolutionary adaption of the phytoplasmas to nutrient-rich environments resulted in losses of genetic modules and increased host dependency highlighted by the transport systems and limited metabolic repertoire. On the other hand, duplication and integration events enlarged the chromosomes and contribute to genome instability. Present differences in the content of membrane and secreted proteins reflect the host adaptation in the phytoplasma strains. General differences are obvious between different phylogenetic subgroups. ‘Ca. P. mali' is separated from the other strains by its deviating chromosome organization, the genetic repertoire for recombination and excision repair of nucleotides or the loss of the complete energy-yielding part of the glycolysis. Apart from these differences, comparative analysis exemplified that all four phytoplasmas are likely to encode an alternative pathway to generate pyruvate and ATP.
Thanks for sharin
SS .
http://www.ag.ndsu.edu/pubs/plantsci/pests/eb-31.pdf
Plant Diseases
Develop and Management
Thanks for sharin
SS .
http://www.fasebj.org/cgi/content/meeting_abstract/26/1_MeetingAbstracts/800.1
Tetracycline Therapy Against Phytoplasma Causing Yellowing Disease of Date Palms
An outbreak of phytoplasma microorganisms was observed in date palms grown in Kuwait. Phytoplasma are widespread prokaryotic microorganisms that infect palm trees, ornamentals and some horticultural crops. It sometimes causes lethal yellowing diseases in palm trees, which also multiplies in the host plant grown in tissue culture and spread infections by insect vectors. The presence of phytoplasma was detected by using both transmission and scanning electron microscopy. Fluorescence microscopy was used to detect DNA contents of the causal microorganism. Tetracycline therapy was carried out as a further evidence for the presence of the phytoplasma and as an attempt to control the disease. Infected young palms treated with tetracycline-HCl at early stages of the phytoplasmal infection showed remission of the yellowing symptoms. We show in this work that by injecting the infected young palm trees with tetracycline antibiotic the treated plants were recovered. The use of antibiotic treatment is valuable for the control of yellows disease in date palms especially in the areas where the pathogen is endemic and causes extreme crop losses. Companies producing date palm trees in tissue culture and growers will especially benefit from this knowledge in the development of control strategies for yellow diseases that are caused by phytoplasma.
Thanks for sharin
SS .
http://msue.anr.msu.edu/news/phytoplasma_aster_yellows_identified_on_michigan_soybeans
Phytoplasma (aster yellows) identified on Michigan soybeans
Stunted plants with bud proliferation.
Phytoplasmas are specialized bacteria that lack a cell wall. They often cause plant deformity symptoms such as witches broom or yellowing. Phytoplasmas live and reproduce inside plant phloem tissue and are moved from host-to-host via phloem-feeding insect vectors. Sap-feeding insects can become infected with a phytoplasma when feeding upon an infected host; the phytoplasmas are then thought to colonize and reproduce within the insect vector. There is no known seed transmission of phytoplasmas.
Given the specialized and obligate (requiring a living host) lifestyle of phytoplasmas, it has not yet been possible to culture phytoplasmas which makes them difficult to study. Fortunately, current DNA techniques do provide us with tools to identify and characterize these organisms.
We currently know little about the distribution or prevalence of this disease, and although accurate yield loss estimates are not available, we have clearly seen that this disease is very capable of causing yield loss. Phytoplasmas are not known to be readily seed-treated and no rescue treatments are available.
Growers and crop consultants should be aware of the disease. Possible cases can be reported to Martin Chilvers ([email protected]) for investigation and plant samples can be submitted to MSU Diagnostic Services.
Thanks for sharin
SS .
http://www.realagriculture.com/2012...ore-unanswered-questions-about-aster-yellows/
Some Answers but More Unanswered Questions About Aster Yellows
It’s the nasty phytoplasma that took many Prairie farmers by surprise in 2012 — aster yellows. Carried on the aster leafhopper, aster yellows can infect over 200 species but took a particularly heavy toll on canola this year. The irony is, canola isn’t even a preferred food source, as the leafhopper tends to prefer grasses. Still, some fields were hit with 25% and much higher infection, causing significant economic losses to an already struggling crop.
The kicker with aster yellows is that there really is no viable control option — it’s not a fungus so fungicides are useless against it, and the insects that carry it come up in waves with every south wind, so spraying isn’t cost effective. There are also very few cultural controls a farmer can implement to avoid or decrease infection.
Tiffany Martinka, agronomy specialist for eastern Saskatchewan with the Canola Council of Canada, outlines the few things farmers can do about aster yellows. Although the insects that carry the phytoplasma don’t typically overwinter, the phytoplasma itself does. The phytoplasma can over winter in the roots of perennial weeds and shrubs. This may explain why weedy fields seemed to show a higher incidence of infection. So cleaner fields may lead to lower incidence.
Martinka notes that this year was really unprecedented, and that the problem could have been even worse than we realize. “There were many plants that were testing positive for aster yellows but weren’t showing symptoms. For every one plant showing symptoms over twice as many were testing positive but with no visual symptoms.”
The small comfort in all this, if there is one, is that while there’s very little farmers can do to control the pest, it’s not often an issue. This year’s specific wind patterns are the likely culprit to the high levels and wide geographic area of infection. It’s unlikely farmers will be faced with the same levels next year.
Thanks for sharin
SS .
http://www.potatogrower.com/2014/05/natural-relief
Natural Relief?
Salicylic acid’s potential for crop protection
Published in the May 2014 Issue — Published online: May 02, 2014 —
Willow trees are well-known sources of salicylic acid, and for thousands of years, humans have extracted the compound from the tree’s bark to alleviate minor pain, fever and inflammation.
Now, salicylic acid may also offer relief to crop plants by priming their defenses against a microbial menace known as “potato purple top phytoplasma.” Outbreaks of the cell-wall-less bacterium in the fertile Columbia Basin region of the Pacific Northwest in 2002 and subsequent years inflicted severe yield and quality losses on potato crops. The Agricultural Research Service identified an insect accomplice—the beet leafhopper, which transmits the phytoplasma to plants while feeding.
Carefully timed insecticide applications can deter such feeding. But once infected, a plant cannot be cured. Now, a promising lead has emerged. An ARS-University of Maryland team has found evidence that pre-treating tomato plants, a relative of the potato, with salicylic acid can prevent phytoplasma infections or at least diminish their severity.
Treating crops with salicylic acid to help them fend off bacteria, fungi and viruses isn’t new, but there are no published studies demonstrating its potential in preventing diseases caused by phytoplasmas.
Wei Wu, a visiting scientist, investigated salicylic acid’s effects, together with molecular biologist Yan Zhao and others at ARS’s Molecular Plant Pathology Laboratory in Beltsville, Md. “This work reached new frontiers by demonstrating that plants could be beneficially treated even before they become infected and by quantifying gene activity underlying salicylic acid’s preventive role,” said Robert E. Davis, the lab’s research leader.
For the study, published in the July 2012 Annals of Applied Biology, the team applied two salicylic acid treatments to potted tomato seedlings. The first application was via a spray solution four weeks after the seedlings were planted. The second was via a root drench two days before phytoplasma-infected scions were grafted onto the plants’ stems to induce disease. A control group of plants was not treated.
In addition to visually inspecting the plants for disease symptoms, the team analyzed leaf samples for the phytoplasma’s unique DNA fingerprint, which turned up in 94 percent of samples from untreated plants but in only 47 percent of treated ones. Moreover, ymptoms in the treated group were far milder than in untreated plants. In fact, analysis of mildly infected treated plants revealed phytoplasma levels 300 times below those of untreated plants, meaning that the salicylic acid treatment must have suppressed pathogen multiplication. Significantly, the remaining 53 percent of treated plants were symptom- and pathogen-free 40 days after exposure to the infected scions.
Researchers credit salicylic acid with triggering “systemic acquired resistance,” a state of general readiness against microbial or insect attack. Using quantitative polymerase chain reaction procedures, the team also identified three regulatory defense genes whose activity was higher in treated plants than in untreated ones.
Why salicylic acid had this effect isn’t known. Other questions remain as well, including how treated plants will fare under field conditions. Nonetheless, such investigations could set the stage for providing growers of potato, tomato and other susceptible crops some insurance against phytoplasmas in outbreak-prone regions.
Thanks for sharin
SS .
http://www.reichmansales.com/products/product.php?id=56
Actigard 50W® Fungicide
Does anybody have a link to order this stuff?
Thanks for sharin
SS .
http://www.researchgate.net/publica...Ca2_influx_is_involved_in_sieve-tube_blockage
Phytoplasma-triggered Ca2+ influx is involved in sieve-tube blockage.
ABSTRACT Phytoplasmas are obligate, phloem-restricted phytopathogens that are disseminated by phloem-sap sucking insects. Phytoplasma infection severely impairs assimilate translocation in host plants and might be responsible for massive changes in phloem physiology. Methods to study phytoplasma-induced changes thus far provoked massive, native occlusion artifacts in sieve tubes. Hence, phytoplasma/phloem relationships were investigated here in intact Vicia faba host plants using a set of vital fluorescent probes and confocal laser scanning microscopy. We focused on the effects of phytoplasma infection on phloem mass-flow performance and evaluated if phytoplasmas induce sieve-plate occlusion. Apparently, phytoplasma infection brings about Ca2+ influx into sieve tubes leading to sieve-plate occlusion by callose deposition and/or protein plugging. In addition, Ca2+ influx may confer cell wall thickening of conducting elements. In conclusion, phytoplasma effectors may cause gating of sieve-element Ca2+ channels leading to sieve-tube occlusion with presumptive dramatic effects on phytoplasma spread and photoassimilate distribution.
Very interesting.... Blocking of trace elements
Thanks for sharin
SS .
stop wasting your time with this thread unless you can contribute... pics of your grow and exp are always a good start...
Certified Arm Chair Experts do some more reading
Thanks for sharin
SS .
http://otokehort.com/yahoo_site_admin/assets/docs/CFCRVTOC.12123027.pdfOther issues including Phytoplasmas and Mycoplasma like organisms (MLOs) ............................ 200
Even this old couple knows what the word is... someone should buy this book and do some homework...
Thanks for sharin
SS .
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322544/
Current View on Phytoplasma Genomes and Encoded Metabolism
Phytoplasmas are specialised bacteria that are obligate parasites of plant phloem tissue and insects. These bacteria have resisted all attempts of cell-free cultivation. Genome research is of particular importance to analyse the genetic endowment of such bacteria. Here we review the gene content of the four completely sequenced ‘Candidatus Phytoplasma' genomes that include those of ‘Ca. P. asteris' strains OY-M and AY-WB, ‘Ca. P. australiense,' and ‘Ca. P. mali'. These genomes are characterized by chromosome condensation resulting in sizes below 900kb and a G + C content of less than 28%. Evolutionary adaption of the phytoplasmas to nutrient-rich environments resulted in losses of genetic modules and increased host dependency highlighted by the transport systems and limited metabolic repertoire. On the other hand, duplication and integration events enlarged the chromosomes and contribute to genome instability. Present differences in the content of membrane and secreted proteins reflect the host adaptation in the phytoplasma strains. General differences are obvious between different phylogenetic subgroups. ‘Ca. P. mali' is separated from the other strains by its deviating chromosome organization, the genetic repertoire for recombination and excision repair of nucleotides or the loss of the complete energy-yielding part of the glycolysis. Apart from these differences, comparative analysis exemplified that all four phytoplasmas are likely to encode an alternative pathway to generate pyruvate and ATP.
Thanks for sharin
SS .
http://www.ag.ndsu.edu/pubs/plantsci/pests/eb-31.pdf
Plant Diseases
Develop and Management
Thanks for sharin
SS .
http://www.fasebj.org/cgi/content/meeting_abstract/26/1_MeetingAbstracts/800.1
Tetracycline Therapy Against Phytoplasma Causing Yellowing Disease of Date Palms
An outbreak of phytoplasma microorganisms was observed in date palms grown in Kuwait. Phytoplasma are widespread prokaryotic microorganisms that infect palm trees, ornamentals and some horticultural crops. It sometimes causes lethal yellowing diseases in palm trees, which also multiplies in the host plant grown in tissue culture and spread infections by insect vectors. The presence of phytoplasma was detected by using both transmission and scanning electron microscopy. Fluorescence microscopy was used to detect DNA contents of the causal microorganism. Tetracycline therapy was carried out as a further evidence for the presence of the phytoplasma and as an attempt to control the disease. Infected young palms treated with tetracycline-HCl at early stages of the phytoplasmal infection showed remission of the yellowing symptoms. We show in this work that by injecting the infected young palm trees with tetracycline antibiotic the treated plants were recovered. The use of antibiotic treatment is valuable for the control of yellows disease in date palms especially in the areas where the pathogen is endemic and causes extreme crop losses. Companies producing date palm trees in tissue culture and growers will especially benefit from this knowledge in the development of control strategies for yellow diseases that are caused by phytoplasma.
Thanks for sharin
SS .
http://msue.anr.msu.edu/news/phytoplasma_aster_yellows_identified_on_michigan_soybeans
Phytoplasma (aster yellows) identified on Michigan soybeans
Stunted plants with bud proliferation.
Phytoplasmas are specialized bacteria that lack a cell wall. They often cause plant deformity symptoms such as witches broom or yellowing. Phytoplasmas live and reproduce inside plant phloem tissue and are moved from host-to-host via phloem-feeding insect vectors. Sap-feeding insects can become infected with a phytoplasma when feeding upon an infected host; the phytoplasmas are then thought to colonize and reproduce within the insect vector. There is no known seed transmission of phytoplasmas.
Given the specialized and obligate (requiring a living host) lifestyle of phytoplasmas, it has not yet been possible to culture phytoplasmas which makes them difficult to study. Fortunately, current DNA techniques do provide us with tools to identify and characterize these organisms.
We currently know little about the distribution or prevalence of this disease, and although accurate yield loss estimates are not available, we have clearly seen that this disease is very capable of causing yield loss. Phytoplasmas are not known to be readily seed-treated and no rescue treatments are available.
Growers and crop consultants should be aware of the disease. Possible cases can be reported to Martin Chilvers ([email protected]) for investigation and plant samples can be submitted to MSU Diagnostic Services.
Thanks for sharin
SS .
http://www.realagriculture.com/2012...ore-unanswered-questions-about-aster-yellows/
Some Answers but More Unanswered Questions About Aster Yellows
It’s the nasty phytoplasma that took many Prairie farmers by surprise in 2012 — aster yellows. Carried on the aster leafhopper, aster yellows can infect over 200 species but took a particularly heavy toll on canola this year. The irony is, canola isn’t even a preferred food source, as the leafhopper tends to prefer grasses. Still, some fields were hit with 25% and much higher infection, causing significant economic losses to an already struggling crop.
The kicker with aster yellows is that there really is no viable control option — it’s not a fungus so fungicides are useless against it, and the insects that carry it come up in waves with every south wind, so spraying isn’t cost effective. There are also very few cultural controls a farmer can implement to avoid or decrease infection.
Tiffany Martinka, agronomy specialist for eastern Saskatchewan with the Canola Council of Canada, outlines the few things farmers can do about aster yellows. Although the insects that carry the phytoplasma don’t typically overwinter, the phytoplasma itself does. The phytoplasma can over winter in the roots of perennial weeds and shrubs. This may explain why weedy fields seemed to show a higher incidence of infection. So cleaner fields may lead to lower incidence.
Martinka notes that this year was really unprecedented, and that the problem could have been even worse than we realize. “There were many plants that were testing positive for aster yellows but weren’t showing symptoms. For every one plant showing symptoms over twice as many were testing positive but with no visual symptoms.”
The small comfort in all this, if there is one, is that while there’s very little farmers can do to control the pest, it’s not often an issue. This year’s specific wind patterns are the likely culprit to the high levels and wide geographic area of infection. It’s unlikely farmers will be faced with the same levels next year.
Thanks for sharin
SS .
http://www.potatogrower.com/2014/05/natural-relief
Natural Relief?
Salicylic acid’s potential for crop protection
Published in the May 2014 Issue — Published online: May 02, 2014 —
Willow trees are well-known sources of salicylic acid, and for thousands of years, humans have extracted the compound from the tree’s bark to alleviate minor pain, fever and inflammation.
Now, salicylic acid may also offer relief to crop plants by priming their defenses against a microbial menace known as “potato purple top phytoplasma.” Outbreaks of the cell-wall-less bacterium in the fertile Columbia Basin region of the Pacific Northwest in 2002 and subsequent years inflicted severe yield and quality losses on potato crops. The Agricultural Research Service identified an insect accomplice—the beet leafhopper, which transmits the phytoplasma to plants while feeding.
Carefully timed insecticide applications can deter such feeding. But once infected, a plant cannot be cured. Now, a promising lead has emerged. An ARS-University of Maryland team has found evidence that pre-treating tomato plants, a relative of the potato, with salicylic acid can prevent phytoplasma infections or at least diminish their severity.
Treating crops with salicylic acid to help them fend off bacteria, fungi and viruses isn’t new, but there are no published studies demonstrating its potential in preventing diseases caused by phytoplasmas.
Wei Wu, a visiting scientist, investigated salicylic acid’s effects, together with molecular biologist Yan Zhao and others at ARS’s Molecular Plant Pathology Laboratory in Beltsville, Md. “This work reached new frontiers by demonstrating that plants could be beneficially treated even before they become infected and by quantifying gene activity underlying salicylic acid’s preventive role,” said Robert E. Davis, the lab’s research leader.
For the study, published in the July 2012 Annals of Applied Biology, the team applied two salicylic acid treatments to potted tomato seedlings. The first application was via a spray solution four weeks after the seedlings were planted. The second was via a root drench two days before phytoplasma-infected scions were grafted onto the plants’ stems to induce disease. A control group of plants was not treated.
In addition to visually inspecting the plants for disease symptoms, the team analyzed leaf samples for the phytoplasma’s unique DNA fingerprint, which turned up in 94 percent of samples from untreated plants but in only 47 percent of treated ones. Moreover, ymptoms in the treated group were far milder than in untreated plants. In fact, analysis of mildly infected treated plants revealed phytoplasma levels 300 times below those of untreated plants, meaning that the salicylic acid treatment must have suppressed pathogen multiplication. Significantly, the remaining 53 percent of treated plants were symptom- and pathogen-free 40 days after exposure to the infected scions.
Researchers credit salicylic acid with triggering “systemic acquired resistance,” a state of general readiness against microbial or insect attack. Using quantitative polymerase chain reaction procedures, the team also identified three regulatory defense genes whose activity was higher in treated plants than in untreated ones.
Why salicylic acid had this effect isn’t known. Other questions remain as well, including how treated plants will fare under field conditions. Nonetheless, such investigations could set the stage for providing growers of potato, tomato and other susceptible crops some insurance against phytoplasmas in outbreak-prone regions.
Thanks for sharin
SS .
http://www.reichmansales.com/products/product.php?id=56
Actigard 50W® Fungicide
Does anybody have a link to order this stuff?
Thanks for sharin
SS .
http://www.researchgate.net/publica...Ca2_influx_is_involved_in_sieve-tube_blockage
Phytoplasma-triggered Ca2+ influx is involved in sieve-tube blockage.
ABSTRACT Phytoplasmas are obligate, phloem-restricted phytopathogens that are disseminated by phloem-sap sucking insects. Phytoplasma infection severely impairs assimilate translocation in host plants and might be responsible for massive changes in phloem physiology. Methods to study phytoplasma-induced changes thus far provoked massive, native occlusion artifacts in sieve tubes. Hence, phytoplasma/phloem relationships were investigated here in intact Vicia faba host plants using a set of vital fluorescent probes and confocal laser scanning microscopy. We focused on the effects of phytoplasma infection on phloem mass-flow performance and evaluated if phytoplasmas induce sieve-plate occlusion. Apparently, phytoplasma infection brings about Ca2+ influx into sieve tubes leading to sieve-plate occlusion by callose deposition and/or protein plugging. In addition, Ca2+ influx may confer cell wall thickening of conducting elements. In conclusion, phytoplasma effectors may cause gating of sieve-element Ca2+ channels leading to sieve-tube occlusion with presumptive dramatic effects on phytoplasma spread and photoassimilate distribution.
Very interesting.... Blocking of trace elements
Thanks for sharin
SS .
Last edited by a moderator:
