NodMutDB

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since 4/20/2004

Last updated 10/01/09

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Mutant Detail

Mutant Detail:

Mutant Symbol	TR26
Allele Symbol	dmi2-2
Gene and Mutation Location	DMI2 (NORK) (Single nucleotide (T) deletion causing frame shift and early translational termination in the extracellular domain)
Symbiotic Phenotype Brief	Calcium flux+, Calcium spiking-, Has+, Hab-, Enod gene expression-, Ccd-, Hac-, Inf-, Nod-, Myc+-
Phenotype Detail	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.
Single gene targeted?	yes
Extra Information	A recent paper by Esseling et al., 2004 showed that when care is taken not to induce touch response, the dmi2 mutant root hairs respond morphologically like the wild type to nod factor. TR26 was previously described as Myc- (Catoira et al. 2000), Morandi et al. 2004 observed a Myc+- phenotype. This different result may be attributed to (1) the use of a very "efficient" inoculum in this new experiment, especially G. intraradices, which gives a very rapid and intense colonisation thus facilitating visualisation of arbuscules, (2) the fact that, in previous observations, the "search image" was different, since the concept of [Myc-/+] had not been defined.
Mutagenesis Method	gamma rays
Mutant Class	Nod-
Allelism	not allelic to dmi1, dmi3 or nsp1, determined by complementation test
The earliest development stage known to be affected	Calcium spiking
Wildtype Line	Jemalong J5
External Link	http://www.genome.clemson.edu/affiliated_cugi/medicago/genelist.html

References:

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
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

Curation Information:

Data entered by	Chunhong Mao (05/06/2004)
Updated/Verified by	Chunxia Wang (07/26/2004), Jing Qiu (12/02/2004), Chunhong Mao (12/06/2004)
Final verification status	verified by Chunhong Mao (12/06/2004)