Abstract
The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.
| Original language | English (US) |
|---|---|
| Article number | 491 |
| Journal | Frontiers in Plant Science |
| Volume | 6 |
| Issue number | JULY |
| DOIs | |
| State | Published - Jul 1 2015 |
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Keywords
- Effector proteins
- Nodulation
- Rhizobia
- Signal exchange
- Symbiosis
- Type III secretion system
- Type IV secretion system
- Type VI secretion system
Cite this
Secretion systems and signal exchange between nitrogen-fixing rhizobia and legumes. / Nelson, Matt; Sadowsky, Michael J.
In: Frontiers in Plant Science, Vol. 6, No. JULY, 491, 01.07.2015.Research output: Contribution to journal › Review article
}
TY - JOUR
T1 - Secretion systems and signal exchange between nitrogen-fixing rhizobia and legumes
AU - Nelson, Matt
AU - Sadowsky, Michael J
PY - 2015/7/1
Y1 - 2015/7/1
N2 - The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.
AB - The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.
KW - Effector proteins
KW - Nodulation
KW - Rhizobia
KW - Signal exchange
KW - Symbiosis
KW - Type III secretion system
KW - Type IV secretion system
KW - Type VI secretion system
UR - http://www.scopus.com/inward/record.url?scp=84936946915&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84936946915&partnerID=8YFLogxK
U2 - 10.3389/fpls.2015.00491
DO - 10.3389/fpls.2015.00491
M3 - Review article
C2 - 26191069
AN - SCOPUS:84936946915
VL - 6
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
SN - 1664-462X
IS - JULY
M1 - 491
ER -