Table 2.
Summary of major genetic tools available in methanogens with associated references.
| Methanosarcina acetivorans/barkeri | Methanosarcina mazei | Methanococcus maripaludis (S2 and JJ) | Methanocaldococcus jannaschii | Methanothermobacter thermautotrophicus ΔH | |
|---|---|---|---|---|---|
| Transformation methods | Liposome mediated (Metcalf et al., 1997; Buan et al., 2011) | Liposome mediated (Metcalf et al., 1997; Ehlers et al., 2005) | Polyethylene glycol mediated (Tumbula et al., 1994; Sarmiento et al., 2011; Natural competence; Fonseca et al., 2020) | Heat shock (Susanti et al., 2019) | Interdomain conjugation (Fink et al., 2021) |
| Shuttle vectors | Metcalf et al., 1997; Buan et al., 2011 | Metcalf et al., 1997 | Whitman et al., 1997; Sarmiento et al., 2011 | – | Fink et al., 2021 |
| Positive selection marker | Puromycin (Metcalf et al., 1997; Buan et al., 2011) | Puromycin (Metcalf et al., 1997; Ehlers et al., 2005) Neomycin (Mondorf et al., 2012) |
Puromycin and neomycin (Whitman et al., 1997; Sarmiento et al., 2011) | Mevinolin and Simvastatin (Susanti et al., 2019) | Neomycin (Fink et al., 2021) |
| Counterselection marker | hpt (8-azahypoxanthine) (Pritchett et al., 2004; Buan et al., 2011) | hpt (8-azahypoxanthine) (Ehlers et al., 2011) | hpt (8-azahypoxanthine), upt (6-azauracil) (Moore and Leigh, 2005; Sarmiento et al., 2011) | – | – |
| Markerless genetic exchange | Pritchett et al., 2004; Buan et al., 2011 | Ehlers et al., 2011 | (Moore and Leigh, 2005; Sarmiento et al., 2011 | – | – |
| Inducible promoters | Tetracycline-inducible promoter (Guss et al., 2008) Acetate regulated promoter (Macauley et al., 2009) | Trimethylamine regulated promoter (Mondorf et al., 2012) | Nif promoter (Lie and Leigh, 2002; Chaban et al., 2007) Phosphate sensing promoter (Akinyemi et al., 2021) | – | – |
| CRISPR/Cas System | CRISPR/Cas9 (Nayak and Metcalf, 2017) | – | CRISPR/Cas12 (Bao and Scheller, 2021) | – | – |