| Mutant Symbol |
Allele or Genotype |
Mutant Gene |
Phenotype Detail |
Symbiotic Phenotype Brief |
Mutagenesis Method |
Mutant Class |
WT Strain or Line |
|---|
| MtENOD40-1 RNAi | MtENOD40-1 RNAi | ENOD40-1 | The transcript level of MtENOD40-1 was reduced about 25-fold in RNA isolated from MtENOD40-1 RNAi roots as compared with control roots, while MtENOD40-2 expression was not altered
in MtENOD40-1 RNAi roots. Knock-down of MtENOD40-1 expression led to a 46.4% reduction in the number of nodules. The nodules formed on MtENOD40-1 RNAi plants are spherical and small. Analyses of sections of MtENOD40-1 RNAi nodules showed that in about half of the MtENOD40-1 RNAi
nodules, the zonation of the central tissue cannot be recognized. The majority of these nodules were senescent. Some cells in the proximal part are repopulated by rhizobia. In MtENOD40-1 RNAi nodules, bacteria are released from infection threads, and EM analyses revealed that each bacteroid was surrounded by symbiosome membrane as in the wild type. In contrast to wild-type nodules, bacteroid development was arrested at stage II-III and never developed into bacteroids of stage IV. Further, in cells of the fixation zone, bacteroids undergo premature senescence. Furthermore, in cells of this zone, fusion of symbiosomes leads to the formation of vacuole-like structures with lysis of bacteroids that are trapped inside. The latter is a typical feature for (premature) symbiosis termination. The bacteroid lysis was followed by destruction of mitochondria, as cells contained swollen organelles with degraded matrix and a very low number of cristae. | Inf+Bad+-Nod+- | RNAi | Nod+- | Jemalong A17 | | MtENOD40-1 MtENOD40-2 RNAi | MtENOD40-1 MtENOD40-2 RNAi | ENOD40-1ENOD40-2 | In roots containing pRRsil4012 DNA, the level of the transcript of MtENOD40-1 and MtENOD40-2 is reduced >5-fold compared with the transcript levels of MtENOD40-1 and MtENOD40-2 in control roots. On roots, in which the expression of both MtENOD40-1 and MtENOD40-2 is reduced, the average number of nodules per root is 1.5 (75% reduction). Thus knocking down of the expression of both genes has an additive effect, suggesting that MtENOD40 acts in a dose-dependent manner. Analyses of nodules in which the expression of both MtENOD40 genes is reduced also showed that bacteroid development was blocked at stage II-III. | Inf+Bad+-Nod+- | RNAi | Nod+- | Jemalong A17 |
|
| Authors |
Year |
Title |
Locator |
|---|
| Wan X, Hontelez J, Lillo A, Guarnerio C, van de Peut D, Fedorova E, Bisseling T and Franssen H | 2007 | Medicago truncatula ENOD40-1 and ENOD40-2 are both involved in nodule initiation and bacteroid development | J Exp Bot. |
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