Table 1.
Overview of the Symbiotic Plant Mutants Described in this Reviewa
| Mutant | Phenotypic Characteristics |
|---|---|
| Lotus japonicus | |
| nin | Blocked in Nod factor–induced responses in the inner cell layers, but extensive curling of root hairs. |
| NIN encodes a putative transcription factor. | |
| Medicago sativa | |
| MNNN1008 (nn1) | Blocked in all Nod factor–induced responses. Myc−. |
| Putative ortholog of dmi2 and sym19. | |
| Medicago truncatula | |
| dmi1 | Blocked in all Nod factor–induced responses. Myc−. |
| dmi2 | Blocked in all Nod factor–induced responses. Myc−. Putative ortholog of nn1 and sym19. |
| dmi3 | Blocked in many Nod factor–induced responses, except Ca2+ oscillation for which it shows an |
| increased sensitivity. Myc−. | |
| hcl | Blocked in root hair curling. |
| nsp | Blocked in Nod factor–induced response in the inner cell layers. |
| skl | Ethylene insensitive. An increased number nodule primordia are formed opposite the proto phloem poles. Increased sensitivity to Nod factors in respect to Ca2+ oscillation. |
| Pisum sativum | |
| SYM2 | Controls infection thread formation in relation to Nod factor structure. |
| Occurs as natural variation. | |
| sym8 | Blocked in all Nod factor–induced responses. Myc−. |
| sym9 | Blocked in all Nod factor–induced responses, except Ca2+ oscillation. Myc−. |
| sym10 | Blocked in all Nod factor–induced responses. Myc+. |
| sym19 | Blocked in all Nod factor–induced responses. Myc−. Putative ortholog of nn1 and dmi2. |
| sym30 | Blocked in all Nod factor–induced responses, except Ca2+ oscillation. Myc−. |
a
(Myc+), able to establish a mycorrhizal interaction, and (Myc−), not able to establish a mycorrhizal interaction, for mutants blocked at an early stage of nodulation. For references, see text.