Table 1.
Phenotype of mutants affected at different stages of symbiosis
| Gene mutated | Description | Experiment | |||||
| Rhizosphere* | Root† | Nodules‡ | C2H2 reduction§ | Nodule occupancy¶ | Regrowth from nodules# | ||
| Root-progressive | |||||||
| pRL100053 | Transmembrane protein | ++ | + | ++ | ND | ND | ND |
| pRL80032 | LysR family transcriptional regulator | ++ | + | — | ND | ND | ND |
| Nodule-general | |||||||
| pRL100199 (fixB) | Electron-transfer protein FixB | ND | ND | +++ | — | ND | ND |
| pRL120205 (eryB) | Erythritol phosphate dehydrogenase | ND | ND | ++ | ++ | — | ND |
| pRL90058 (rmrR) | TetR family transcriptional regulator of RND family efflux transporter | ND | ND | ++ | ++ | + | ND |
| RL0688 (cheA1) | Chemotaxis protein CheA | ND | ND | ++ | ++ | + | ND |
| RL0149 | XRE family transcriptional regulator | ND | ND | ++ | ++ | + | ND |
| RL1545 | Short-chain dehydrogenase/reductase | ND | ND | ++ | ++ | ++ | ND |
| RL2606 (purC1) | Saicar synthetase | ND | ND | ++ | ++ | + | ND |
| RL3549 (glnII) | Glutamine synthetase II | ND | ND | ++ | ++ | + | ND |
| RL3654 (pssD) | Polysaccharide biosynthesis protein | ND | ND | — | — | — | ND |
| Nodule bacteria | |||||||
| pRL120198 | l-xylulose kinase | ND | ND | ++ | ++ | ND | + |
| RL1496 (iolR) | SIS (sugar isomerase)-RpiR family transcriptional regulator | ND | ND | ++ | ++ | ND | + |
| RL3986 (ruvC) | Holliday junction endoDNase RuvC | ND | ND | ++ | ++ | ND | + |
| Bacteroid | |||||||
| pRL100195 (nifB) | FeMo cofactor biosynthesis protein NifB | ND | ND | +++ | — | ND | ND |
*
Rhizosphere colonization by a single strain.
†
Root colonization by a single strain.
‡
Nodule formation by a single strain.
§
C2H2 (acetylene) reduction when peas inoculated with a single strain.
¶
Nodule occupancy when in competition with wild type bacteria.
#
Regrowth of bacteria from crushed nodules. ++, wild-type levels; +, reduced levels; +++, increased levels; —, no measurable activity; ND, not determined.