Table 2.
Locations and summary of mutant and expression studies for putative virulence genes of Clavibacter michiganensis ssp. michiganensis.
| Time of expression (hpi) | ||||||
|---|---|---|---|---|---|---|
| Gene | Location | Expression in minimal medium† | Systemic infection | Foliar infection | Results from genetic studies | Suspected role |
| Chp family proteases | ||||||
| chpA* | PAI | Yes | ||||
| chpB* | PAI | |||||
| chpC | PAI | Yes | 72‡ | 8‡ | Mutant has reduced incidence of plants with foliar blisters, reduced incidence of wilting (Chalupowicz et al., 2017), reduction of in planta titre and weak disease symptoms (Stork et al., 2008) | Colonization, virulence |
| chpD* | PAI | |||||
| chpE | PAI | 192§ | ||||
| chpF | PAI | Yes | 192§ | |||
| chpG | PAI | Yes | 192§ | No effect on systemic colonization or virulence, abolished HR in non‐host plants (Lu et al., 2015; Stork et al., 2008) | ||
| pat‐1 | pCM2 | 24, 48‡, 12, 24, 72, 96, 168¶, 192§ | Induces virulence when cloned into Cmm100 (Meletzus et al., 1993). | Virulence | ||
| phpA | pCM2 | Yes | Does not induce virulence when cloned into Cmm100 (Burger et al., 2005) | |||
| phpB | pCM2 | No | Does not induce virulence when cloned into Cmm100 (Burger et al., 2005) | |||
| Chymotrypsin‐related serine proteases | ||||||
| ppaA | PAI | Yes | ||||
| ppaB1 | PAI | Yes | 192[Link], [Link] | |||
| ppaB2 | PAI | Yes | 192[Link], [Link] | |||
| ppaC | PAI | Yes | 192§ | |||
| ppaD | PAI | Yes | 192§ | |||
| ppaE | PAI | No | ||||
| ppaF | Other | No | ||||
| ppaG | Other | No | 192§ | |||
| ppaH | Other | Yes | 192§ | |||
| ppaI | Other | No | 192§ | |||
| ppaJ | pCM1 | Yes | ||||
| Subtilase proteases | ||||||
| sbtA | PAI | No | 16‡ | Mutant has reduced incidence of foliar blisters, less wilting (Chalupowicz et al., 2017) | Virulence | |
| sbtB | Other | No | Early†† | |||
| sbtC | Other | No | 192§ | |||
| Cellulases | ||||||
| celA | pCM1 | Yes | 8, 16, 24, 28[Link], [Link], 12, 24, 72, 96, 168¶, 192§ | Not detected at ≥ four‐fold | Mutant does not induce wilting in Cmm101; gene induces wilting when cloned into Cmm100 (Jahr et al., 2000) | Virulence |
| celB* | Other | No | ||||
| Xylanases | ||||||
| xysA | Other | Yes | ||||
| xysB | Other | No | Early†† | |||
| Pectinases | ||||||
| pgaA | Other | Yes | 192§ | 8, 16‡ | Mutant has reduced incidence of foliar blisters (Chalupowicz et al., 2017) | Virulence (foliar) |
| pelA1 | PAI | 192§ | ||||
| pelA2 | PAI | |||||
| Endoglucanases | ||||||
| endX/Y | Other | 8, 16‡ | Mutant has reduced incidence of foliar blisters (Chalupowicz et al., 2017) | Virulence (foliar) | ||
| Transcriptional regulators | ||||||
| vatr1 | Other | Reduced wilting symptoms during systemic infection (Chalupowicz et al., 2017; Savidor et al., 2014) | Virulence | |||
| vatr2 | Other | 24, 48, 72‡ | 8, 16‡ | Reduced incidence of foliar blisters, less wilting (Chalupowicz et al., 2017) | Virulence | |
| wcoP | 240‡‡ | |||||
| Other | ||||||
| gmdA | Other | No | ||||
| manB | No | |||||
| perF | 8, 16, 24, 48‡ | Reduced incidence of foliar blisters (Chalupowicz et al., 2017) | Virulence (foliar) | |||
| srtA | Reduced incidence of foliar blisters (Chalupowicz et al., 2017) | Virulence (foliar) | ||||
| tomA | PAI | |||||
*Presumed pseudogene.
†Transcript levels significantly greater than in medium supplemented with plant tissue homogenate for at least one time point (Flügel et al., 2012).
‡Transcript levels ≥ four‐fold relative to that at time zero (Chalupowicz et al., 2017).
§Protein detected in planta at 8 days post‐infection, and significantly up‐regulated in medium supplemented with xylem sap vs. rich defined medium (Savidor et al., 2012).
¶Transcript levels significantly greater than in minimal medium (Chalupowicz et al., 2010).
**Proteomic analysis could not differentiate between ppaB1 and ppaB2, which only differ by one amino acid (Savidor et al., 2012).
††Transcript levels significantly greater in xylem mimicking medium vs. minimal medium (Hiery et al., 2013).
‡‡Transcript levels significantly greater at 10 days post‐infection vs. in minimal medium (Flügel et al., 2012).