| Mutant Symbol |
Allele or Genotype |
Mutant Gene |
Phenotype Detail |
Symbiotic Phenotype Brief |
Mutagenesis Method |
Mutant Class |
WT Strain or Line |
|---|
| TR89 | TR89 | dmi2 | TR89 belongs to mycorrhizal phenotype 3. Phenotype 3 showed these typical appressoria (thick lens-shaped with no intercellular hyphae developing from them) and normal appressoria leading to the formation of arbuscules on the same root system. For all the mutants belonging to mycorrhizal phenotype 3, the mycorrhizal fungus G. intraradices forms significantly much more typical AM structures than G. mosseae. They were scored as Nod- at 5 weeks, but developed a single or several nodules 10 weeks after sowing in greenhouse culture, in the presence of S. meliloti and absence of mineral nitrogen. For this reason, they were then classified as Nod+-. The few nodules were pinky, normally shaped and have nitrogen-fixing ability, as confirmed by the fact that plants became green again at the end of flowering. | Nod+-Myc+- | gamma rays | Nod+- | Jemalong J5 | | TRV9 | TRV9 | dmi2 | TRV9 belongs to mycorrhizal phenotype 3. Phenotype 3 showed these typical appressoria (thick lens-shaped with no intercellular hyphae developing from them) and normal appressoria leading to the formation of arbuscules on the same root system. For all the mutants belonging to mycorrhizal phenotype 3, the mycorrhizal fungus G. intraradices forms significantly much more typical AM structures than G. mosseae. They were scored as Nod- at 5 weeks, but developed a single or several nodules 10 weeks after sowing in greenhouse culture, in the presence of S. meliloti and absence of mineral nitrogen. For this reason, they were then classified as Nod+-. The few nodules were pinky, normally shaped and have nitrogen-fixing ability, as confirmed by the fact that plants became green again at the end of flowering. | Nod+-Myc+- | gamma rays | Nod+- | Jemalong J5 | | TR25 | dmi2-1 | dmi2 | Nod-; defective in calcium spiking; with induced touch response, the mutant showed root hair tip swelling (Has) but blocked for branching (Hab-), no root curling (Hac-) in response to live bacteria, lack cortical cell division; blocked in the induction of ENOD11 and ENOD40; dramatically reduced induction of RIP1; Recessive; A more recent paper by Esseling et al., 2004 showed that when care is taken not to induce touch response, the mutant root hairs respond morphologically like the wild type to nod factor. Root hairs are more sensitive to medium refreshment than wild-type root hairs, and they still have the property to reorient their growth axis when challenged with NF (Nod factor), which is a prerequisite for root hair curling. Multifaceted three dimensional curls in which bacteria were entrapped, as well as infection threads, were absent in dmi2-1 root hairs (Inf-). Root hairs make two-dimensional 180 curls but do not entrap bacteria in a three-dimensional pocket because curling stops when the root hair tip touches its own shank. According to Morandi et al. 2004 paper, TR25 belongs to mycorrhizal phenotype 3 (Myc+-). Phenotype 3 showed typical thick lens-shaped appressoria with no intercellular hyphae developing from them and normal appressoria leading to the formation of arbuscules on the same root system. For all the mutants belonging to mycorrhizal phenotype 3, the mycorrhizal fungus G. intraradices forms significantly much more typical AM structures than G. mosseae. | Calcium flux+, Calcium spiking-, Has+, Hab-(touch response), Hab+(no touch response), Enod gene expression-, Ccd-, Hac-(touch response), Hac+(no touch response), Inf-, Nod-, Myc+- | gamma rays | Nod- | Jemalong J5 | | TR26 | dmi2-2 | dmi2 | Nod-; defective in calcium spiking; root hair tip swelling (Has) but are blocked for branching (Hab-); block in the induction of ENOD11 and ENOD40; dramatically reduced induction of RIP1; lack cortical cell division; no infection threads (Inf-); no root curling (Hac-) in response to live bacteria; Recessive. According to Morandi et al. 2004 paper, TR26 belongs to mycorrhizal phenotype 3 (Myc+-). Phenotype 3 showed typical thick lens-shaped appressoria with no intercellular hyphae developing from them and normal appressoria leading to the formation of arbuscules on the same root system. For all the mutants belonging to mycorrhizal phenotype 3, the mycorrhizal fungus G. intraradices forms significantly much more typical AM structures than G. mosseae. | Calcium flux+, Calcium spiking-, Has+, Hab-, Enod gene expression-, Ccd-, Hac-, Inf-, Nod-, Myc+- | gamma rays | Nod- | Jemalong J5 | | P1 | dmi2-3 | dmi2 | Nod-; leaky for calcium spiking; root hair tip swelling (Has) but are blocked for branching (Hab-); block in the induction of ENOD11 and ENOD40; dramatically reduced induction of RIP1; lack cortical cell division; no infection threads (Inf-); no root curling (Hac-) in response to live bacteria; Myc (+/-, leaky)phenotype; Recessive. A recent paper by Esseling et al., 2004 showed that when care is taken not to induce touch response, the mutant root hairs respond morphologically like the wild type to nod factor. | Calcium flux+, Calcium spiking+-, Has+, Hab-, Enod gene expression-, Ccd-, Hac-, Inf-, Nod-, Myc +/- ( leaky) | EMS | Nod- | Jemalong A17 | | R38 | dmi2-4 | dmi2 | Nod-; defective in calcium spiking; root hair tip swelling (Has) but are blocked for branching (Hab-); block in the induction of ENOD11 and ENOD40; dramatically reduced induction of RIP1; lack cortical cell division; no infection threads (Inf-); no root curling (Hac-) in response to live bacteria; Myc+ phenotype; Recessive | Calcium flux+, Calcium spiking-, Has+, Hab-, Enod gene induction-, Ccd-, Hac-, Inf-, Nod-, Myc+ | EMS | Nod- | Jemalong A17 |
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| Authors |
Year |
Title |
Locator |
|---|
| Ane JM, Levy J, Thoquet P, Kulikova O, de Billy F, Penmetsa V, Kim DJ, Debelle F, Rosenberg C, Cook DR, Bisseling T, Huguet T and Denarie J | 2002 | Genetic and cytogenetic mapping of DMI1, DMI2, and DMI3 genes of Medicago truncatula involved in Nod factor transduction, nodulation, and mycorrhization | Mol Plant Microbe Interact. 15(11):1108-18 | | Catoira R, Galera C, de Billy F, Penmetsa RV, Journet EP, Maillet F, Rosenberg C, Cook D, Gough C and Denarie J | 2000 | Four genes of Medicago truncatula controlling components of a nod factor transduction pathway | Plant Cell. 12(9):1647-66 | | Endre G, Kereszt A, Kevei Z, Mihacea S, Kalo P and Kiss GB | 2002 | A receptor kinase gene regulating symbiotic nodule development | Nature. 417(6892):962-6 | | Esseling JJ, Lhuissier FG and Emons AM | 2004 | A nonsymbiotic root hair tip growth phenotype in NORK-mutated legumes: implications for nodulation factor-induced signaling and formation of a multifaceted root hair pocket for bacteria | Plant Cell. 16(4):933-44 | | Mitra RM, Shaw SL and Long SR | 2004 | Six nonnodulating plant mutants defective for Nod factor-induced transcriptional changes associated with the legume-rhizobia symbiosis | Proc Natl Acad Sci U S A. 101(27):10217-22 | | Morandi D, Prado E, Sagan M, and Duc G | 2004 | Characterisation of new symbiotic Medicago truncatula (Gaertn.) mutants, and phenotypic or genotypic complementary information on previously described mutants. | Mycorrhiza | | Sagan M, Morandi D, Tarenghi E and Duc G | 1995 | Selection of nodulation and mycorrhizal mutants in the model plant Medicago truncatula (Gaertn.) after gamma-ray mutagenesis | Plant Science. 111(1):63-71 | | Sagan M, de Larembergue H and Morandi D | 1998 | Genetic analysis of symbiosis mutants in Medicago truncatula | Elmerich C, Kondorosi A, Newton WE (eds) Biological nitrogen fixation for the 21st century. Kluwer, Dordrecht, pp 317?318 | | Shaw SL and Long SR | 2003 | Nod factor elicits two separable calcium responses in Medicago truncatula root hair cells | Plant Physiol. 131(3):976-84 | | Wais RJ, Galera C, Oldroyd G, Catoira R, Penmetsa RV, Cook D, Gough C, Denarie J and Long SR | 2000 | Genetic analysis of calcium spiking responses in nodulation mutants of Medicago truncatula | Proc Natl Acad Sci U S A. 97(24):13407-12 |
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