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Mychorrhiza Helper Bacteria (MHB) are a group of organism that form symbiotic associations with both ectomycorrhiza and arbuscular mycorrhiza . MHB's are diverse and are associated with different bacterial phyla including gram-negative bacteria and gram-positive bacteria .These include some of the most common types of MHB's pseudomonas and plant growth-promoting rhizobacteria . MHB's are found to have specific interaction with mycorrhiza fungi, but not with the plant itself . The bacteria are known to enhance the mycorrhizae's function by helping to increasing the mycorrhizal growth, providing nutrients to the fungus and plant, help with soil conductance, and aid different pathogens .

Contents
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 * 1The Function of Bacteria and the Increase of Roots and Branches
 * 1.1Growth Promoted by Nutrients
 * 1.2Growth Hormones
 * 1.3Bacteria's Interaction with Specific Fungi
 * 2Bacteria and Detoxifying Soil
 * 2.1Bacteria's Role in Detoxifying the Soil
 * 3Specific Types of Bacteria and their Fungi Associations
 * 4Helpers in Symbiotic and Pathogenic Fungi
 * 5References
 * 6External links

The Function of Bacteria and the Increase of Roots and Branches[edit]
Mychorrhiza Helper Bacteria (MHB) are known to have several function when interacting with the roots and growth of fungi. In several studies, it has been found that MHB help to increase and stimulate the growth of different fungi  .The bacteria are known to promote the growth of the plant through different mechanisms and the environment.

Growth Promoted by Nutrients[edit]
Plants and fungi need nutrients in order to survive and grow. However, the nutrients that the plant needs to survive is often unavaliable in the soil because it cannot be digested. Some mychorrhiza helper bacteria are known to help with breaking down the nutrients to a more usable form that the plant can use . MHB's can obtain inorganic and organic nutrients in the soil through a process known as mineral-weathering . This is a direct process to help the the cycling of nutrients in the soil . There is a diverse group of bacteria that are able to participate in the mineral- weathering process. Some are from the genus of Pseudomonas, Burkholderia, and Collimonas .

Similarly, some of the MHB's are capable of only breaking down and obtaining certain forms of nutrients to help with the growth of the plant and mychorriza. One MHB is the plant growth promoting rhizobacteria (PGPR). The bacteria help to fix nitrogen . It was shown that the rhizobacteria help to promote the growth of the hyphal branching and induce the survival of the plant and fungus  .

MHB's also help to obtain unavailable phosphorous from the soil . Phosphate solubilizing rhizobacteria are the most common MHB to help with phosphorous uptake  . The bacteria work in phosphorous limited conditions to help the mycorrhiza establish, grow, and inoculate the plant, thus promoting the overall the nutrition the fungus and plant needs to grow and survive .

Growth Hormones[edit]
It has been proposed that MHB induce growth hormones which help the mycorrhiza interact with the lateral roots in the soil . In a study by Kaska, Myllayla, and Cooper they found that there was a high presence of ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and auxin inhibitor when the lateral roots of the plant were growing in the presence of MHB bacteria. This was inferred that the hormone could possibly be produced by the MHB to help create a more symbiotic association between the plant and the mychorriza . The increase of root formation was also found when Pseudomonas putida produced ACC and was inoculated with the arbuscular mychorriza, Gigaspora rosea, on a cumber plant. The inoculation of both the MHB and the fungus allowed for the increase in root elongation and growth in the soil, similar to the previous study. The introduction of growth hormones produced by MHB was only discovered recently, and need to be studied further to understand more behind how MHB helped with the symbiotic relationship and root growth.

Bacteria's Interaction with Specific Fungi[edit]
MHB are known to have specific association with a fungus, but not the roots of the plant .The specificity of MHB has been found in both arbuscular and ectomycorrhiza. There are currently many biological studies on the specificity of MHB to fungi because researchers are looking to improve the growth of the fungus and receive more beneficial outcomes.However, the researchers have encountered only certain bacteria are responding to specific mycorrhiza fungi groups. This has been found that only the indigenous AM fungi of the clover plant could grow in the presence Pseudomonas putida, but the plant could grow with the presence of multiple bacteria .

It has been hypothesized that the rhizosphere helper bacteria, in the soil, have developed the specific fungal traits due to the competition of colonization on the fungus  . Due to the high ratio of bacteria to fungus in the soil, these bacteria need to develop the mechanism in order for colonization on a fungus for resources. Thus, it makes is plausible that MHB's developed a differentiation to select for certain fungi. This allows the MHB to chose which fungus they will aid in growth of the mychorriza to gain nutrients from the plant, and possibly the bacteria itself . More research is still needed in order to understand how the actual mechanism works when a MHB help promote the growth of both the roots, plant, and fungus.

Bacteria and Detoxifying Soil[edit]
Mycorrhiza Helper Bacteria (MHB) help mycorrhiza establish symbiotic associations in stress and metal toxic environments . In the harsh environments the bacteria help to acquire more nitrogen and phosphorous  . This is used to help the mycorrhiza and plant to gain nutrients the need in order to grow and survive.

Bacteria's Role in Detoxifying the Soil[edit]
There have been multiple studies concluding that MHB help to prevent the uptake of toxic metals. The contaminated soils included the heavy metals of Lead, Zinc, and Cadmium. In all of the studies it was found that the bacteria helped to decrease the amount of metals that were taken up by the plant through a blockade mechanism . The blockade of the toxic metals by the bacteria allows the fungus to form a stronger symbiotic association with the plant, and promote the growth of both. Thus, MHB have an underlying mechanism to help the plant survive in harsh, and previously unsuited environments.

Helpers in Symbiotic and Pathogenic Fungi[edit]
MHB have developed mechanisms to positively interact with mycorrhizal fungi because of their beneficial effects aiding in fungi growth . In the presence of a pathogenic fungi, most studies show that these MHB aid in fighting off the pathogens . However, there has been a few cases where they had neutral or negative effects on fungi. One study showed that in the presence of an infection, the MHB increased colonization of a type of fungal pathogen theorizing that it may be a defense mechanism . Another suggestion is that they may be neutral or inhibitory if they are interacting with a non-symbiotic fungi or plant-fungus combination .

The main effect of MHB is aiding in fungal infections of plant roots .

Rough Draft before Pearl Edited it sources and actual paper is on user page

= Mychorrhiza Helper Bacteria[edit] = Mychorrhiza Helper Bacteria (MHB) are a group of organism that form symbiotic associations with both ectomycorrhiza and arbuscular mycorrhiza . MHB's are diverse and are associated with different bacterial phyla including gram-negative bacteria and gram-positive bacteria .These include some of the most common types of MHB's pseudomonas and plant growth-promoting rhizobacteria . MHB's are found to have specific interaction with mycorrhiza fungi, but not with the plant itself . The bacteria are known to enhance the mycorrhizae's function by helping to increasing the mycorrhizal growth, providing nutrients to the fungus and plant, help with soil conductance, and aid different pathogens .

II. The Function of Bacteria and the Increase of Roots and Branches.
a. Gigaspora margarita and the association with Candidatus Glomeribacter gigasporarum helped to enhance the growth of the mycorrhizae.
 * 1) To increase surface area.

III. Detoxifying Soil and Helper Bacteria
a. Reduce the Heavy Metals.
 * 1) Improved Soil Conductance.

b. pH

c. Gather nutrients.

2. Common in ectomycorrhizal.

IV. Specific Types of Bacteria and Their Fungi Association.
1.     Nitrogen fixing bacteria

a.  Certain Bacteria help to fix nitrogen so the plant can get the nitrogen that it needs.

2.   Rhizosphere microbial communities.

3. Candidatus in Arbuscular mycorrhizae.

4. Many other specific kinds that are listed in the Tarkka paper that I want to analyze, and research more on.

V. Helpers in Symbiotic and Pathogenic Fungi.
MHB have developed mechanisms to positively interact with mycorrhizal fungi because of their beneficial effects aiding in fungi growth. In the presence of a pathogenic fungi, most studies show that these helper bacteria aid in fighting off the pathogens. However, there has been a few cases where they had neutral or negative effects on fungi. One study showed that in the presence of an infection, the helper bacteria increased colonization of a type of fungal pathogen theorizing that it may be a defense mechanism. Another suggestion is that they may be neutral or inhibitory if they are interacting with a non-symbiotic fungi or plant-fungus combination.

The main effect of MHB is aiding in fungal infections of plant roots.

b.  Ectomycorrhizal

i.   Stagonospora- Pathogenic Strain.

VI. Conclusion/ Summary
I may need to narrow it down more, or add more content.

Resources:
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 * 1) Barriuso, J., Solano, B. R., Santamaría, C., Daza, A., & Mañero, F. G. (2008). Effect of inoculation with putative plant growth-promoting rhizobacteria isolated from Pinus spp. on Pinus pineagrowth, mycorrhization and rhizosphere microbial communities. Journal of Applied Microbiology, 105(5), 1298-1309. doi:10.1111/j.1365-2672.2008.03862.x
 * 2) Goodwin, S. B. (n.d.). Resistance in wheat to septoria diseases caused by Mycosphaerella graminicola (Septoria tritici) and Phaeosphaeria (Stagonospora) nodorum. Disease resistance in wheat, 151-159. doi:10.1079/9781845938185.0151
 * 3) Khan, A. G. (n.d.). Microbial Dynamics in the Mycorrhizosphere with Special Reference to Arbuscular Mycorrhizae. Plant-Bacteria Interactions, 245-256. doi:10.1002/9783527621989.ch13
 * 4) Lumini, E., Bianciotto, V., Jargeat, P., Novero, M., Salvioli, A., Faccio, A., & ... Bonfante, P. (2007). Presymbiotic growth and sporal morphology are affected in the arbuscular mycorrhizal fungus Gigaspora margarita cured of its endobacteria. Cellular Microbiology, 9(7), 1716-1729. doi:10.1111/j.1462-5822.2007.00907.x
 * 5) Pivato, B., Offre, P., Marchelli, S., Barbonaglia, B., Mougel, C., Lemanceau, P., & Berta, G. (2008). Bacterial effects on arbuscular mycorrhizal fungi and mycorrhiza development as influenced by the bacteria, fungi, and host plant. Mycorrhiza, 19(2), 81-90. doi:10.1007/s00572-008-0205-2
 * 6) Tarkka, M. T., & Frey-Klett, P. (2008). Mycorrhiza Helper Bacteria. Mycorrhiza, 113-132. doi:10.1007/978-3-540-78826-3_6