Saturday, July 16, 2011

Candidatus Phytoplasma pini, it makes brooms for the witches

It is neither a virus nor a bacterium, but it has characteristics of both microorganisms. It would be because an intermediate step, a link in the evolution. It cannot live on independent way since the bacteria do but necessarily it needs to live within the cytoplasm of a vegetal cell, because it lacks independent cellular membrane and metabolic and reproductive system and takes advantage enzymes and the organules of the vegetal cell to survive and to be perpetuated. It is a special plasmid more evolved and different from the plasmids that parasitize the bacterias and leavenings, adapted to the parasitization of the cells of the coniferous of the Pinus sort.

 Broom of sorceresses or Graft of sorceresses on a Pinus halepensis in an immense forest of Jimena de la Frontera in Cadiz. These malformations, true plant tumors, are caused by the infection by the plasmid Candidatus Phytoplasma pini.

Until not long ago the ignorance was so great on this strange microorganism that not even had binomial scientific name like the rest of alive beings of the Earth. The international scientific community in the end has agreed itself and it has given a name to it formed by three words, Candidatus Phytoplasma pini. The Candidatus word is applied in front of the scientific name to indicate that it is a microorganism perfectly characterized and studied but impossible to cultivate, since always lives inside cells and it cannot be isolated. 

Same broom of sorceresses previous seen from more close.

Structure of the ramifications of previous broom of sorceresses. The plasmid brings about a dwarfing growth shortening the branches that grow crowded together, so that those that are inside the broom are dried for want of light. Due to the maze that forms they cannot fall and they exaggeratedly increase the weight of the ill branch, being able to get to break itself and to fall. Needles also grows much more short and pineapples are completely normal but much more small, like their seeds, which in spite of the parasitization are perfectly viable. 

These vegetal plasmids or phytoplasmas cannot be seen nor be isolated like individual beings, it is only possible to see and to analyze the effects of its parasitization on the plants. They cannot either disperse by themselves of active way, but they need a vector to infect the plants and to propagate. For it insects, acaruses, nematodes, birds, etc use… that transmit the plasmid of plant to plant by means of the tiny ones hurt which they cause to the plants when feeding on them. The contagion also can cause it the man through contaminated tools, like for example scissors to prune, hand saws, power saws, axes, etc… And finally an ill tree can propagate the infection through rubbing of its branches with the branches of the neighboring trees.

Graft of sorceresses or Broom of sorceresses completely spherical on a Pinus halepensis of the ancient Arab village of Castellitx, pertaining to the municipality of Algaida located in center of the Island of Majorca.

Another Broom of sorceresses very compact in the same Majorcan village of Castellitx in the end of one long branch of a Pinus halepensis.

Near image of the previous ill branch. It clearly has a very healthful aspect with needles of an alive green color and numerous pineapples.

The scientists, to know if a branch is ill, must analyze their cells using sophisticated methods of genetic engeneering, as it is the PCR (polymerase chain reaction), through which are able to isolate and to identify some specific genes of this plasmid, like the gene 16S rRNA. 

Broom of sorceresses on Pinus canariensis of the canary municipality of Santiago del Teide located in the South end of the Island of Tenerife.

The plasmid Candidatus Phytoplasma pini, once has been able to penetrate in the cells of the phloem of a sensible tree, it integrates its genome in the nucleus of the parasitized vegetal cell, so that the infected cell happens to be controlled by the DNA of the plasmid. So it is the degree of nuclear integration that the pinions produced by the small pineapples of broom of sorceresses, if they are seeded, germinate without problems but the growth of small plant is very slow and after enough years it becomes a dwarfed pine, a true natural Bonsai. It is possible that throughout million years of parasitization of some plants by virus or plasmids new species have formed that at the moment have already the stable good genome with a total integration of the DNA of the guest and the parasite.

Young Aleppo pine, parasited in its entirety by the Candidatus Phytoplasma pini in a forest of pine, mastic and olive in Majorcan municipality of Bunyola.

With the advances more and more sophisticated of the study of the genome surely there will be many surprises and they are very probable that the viral or plasmidic origin of a great number of species and subspecies, as much animal as vegetal or bacterial are discovered. In fact the transgenic plants and animal " created" by the scientists to obtain new beings with "profitable" characteristics for the man they follow the same principle that the broom of sorceresses: cows with the integrated gene of the human insulin in its genome that produce milk with insulin, rice with the gene of resistance to the drought coming from a cereal of the desert that allows its successful land culture with little rains, pigs with several genes of its genome replaced by human genes whose organs could be profiteers for transplants without bringing about rejection in the receiver, fluorescent mice with the gene of a marine crustacean, goats with several genes of its genome replaced by vegetal genes whose milk contains "good" fats without injurious cholesterol for the human arteries, etc...

Another graft of sorceresses on a Pinus canariensis in the National Park of La Caldera de Taburiente, located in the Island of La Palma.

The nurserymen look for by far interest these brooms of sorceresses. With its seeds they make establishments of dwarfed pines and with its ill branches they graft healthy pines that they grow as small graft of sorceress. As much as others they reach high prices in the world of the coniferous collectors to be seeded in particular gardens like true botanical peculiarities. Also the fans to the art of the Bonsai know very well these brooms of sorceresses, with whose seeds and grafts of branches they secure gorgeous units of Bonsais that by their slowest growth on approval put their masters and their patience.

Nevertheless sometimes it happens that from the center of the branches of one of these dwarfed pines, coverall of the obtained ones by graft, emerges a vigorous normal branch completely heals and the rest of the graft is ended up drying, as if suddenly the pine had cured itself by its own means. Until the moment the explanation is not known these spontaneous healings.

There are many other Phytoplasmas, each of them specific of a certain vegetal species, like the Candidatus Phytoplasma aurantifolia, that affects the lime tree, the Candidatus Phytoplasma fraxini, that affects the ash, the Candidatus Phytoplasma castaneae, that affects the chestnut tree, the Candidatus Phytoplasma mali, that affects the apple tree, the Candidatus Phytoplasma oryzae, that affects the rice, the Candidatus Phytoplasma ziziphi, that affects to jujube tree and the Candidatus Phytoplasma trifolii, that affects to the legumes of the Trifolium sort. All these phytoplasmas cause vegetal malformations similar to broom of sorceresses of the pines. 

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