Table 1. Genes Involved in AM Symbiosis and Phenotypes Associated with Their Knockout or Knockdown.
| Gene Name | Gene Product | Phenotype | References |
|---|---|---|---|
| Mt-DXS2 | 1-Deoxy-d-xylulose 5-phosphate synthase | RNAi: Increased number of degenerating arbuscules | (Floss et al., 2008a) |
| Mt-CCD1 | Carotenoid cleavage dioxygenase | RNAi: Increased number of degenerating arbuscules | (Floss et al., 2008b) |
| Ps-CCD7 | Carotenoid cleavage dioxygenase | Reduced colonization | (Gomez-Roldan et al., 2008) |
| Ps-CCD8 | Carotenoid cleavage dioxygenase | Reduced colonization | (Gomez-Roldan et al., 2008) |
| Ph-PDR1 | ABC transporter | Reduced colonization | (Kretzschmar et al., 2012) |
| *Mt-DMI2 (Mt-NORK) | Receptor-like kinase | No epidermal penetration | (Endre et al., 2002; Stracke et al., 2002) |
| Lj-SYMRK | |||
| Ps-SYM19 | |||
| * Pa-NFP | LysM receptor kinase | RNAi: Abortion of arbuscule formation in P. andersonii | (Op den Camp et al., 2011; Maillet et al., 2011; Buendia et al., 2016; Madsen et al., 2003) |
| Mt-NFP | Wild-type AMS phenotype in Mt-nfp and Lj-nfr5 but fewer lateral roots in Mt-nfp | ||
| Lj-NRF5 | VIGS: No epidermal penetration in S. lycopersicum | ||
| Sl-LYK10 | |||
| Lj-NFR1 | LysM receptor kinase | Reduced colonization | (Miyata et al., 2014; Zhang et al., 2015a) |
| Mt-LYK3 | |||
| Os-CERK1 | |||
| Os-D14 | Alpha/beta-fold hydrolase | Increased colonization | (Yoshida et al., 2012) |
| Os-D14L | Alpha/beta-fold hydrolase | No colonization | (Gutjahr et al., 2015) |
| Os-D3 | F-box protein | Reduced colonization and arbuscule formation | (Yoshida et al., 2012) |
| Zm-NOPE1 | GlcNAc transporter | No colonization | (Nadal et al., 2017) |
| Os-NOPE1 | |||
| * Lj-Castor | Cation channel | No epidermal penetration | (Imaizumi-Anraku et al., 2005; Gutjahr et al., 2008) |
| Os-Castor | |||
| Mt-DMI1 | Cation channel | No epidermal penetration | (Ané et al., 2004; Imaizumi-Anraku et al., 2005; Banba et al., 2008) |
| Lj-POLLUX | |||
| Ps-SYM8 | |||
| Os-POLLUX | |||
| Lj-NUP133 | Nucleoporin | Delayed colonization | (Kistner et al., 2005; Kanamori et al., 2006) |
| Lj-NUP85 | Nucleoporin | Delayed colonization | (Kistner et al., 2005; Saito et al., 2007) |
| Lj-NENA | Nucleoporin | No epidermal penetration | (Groth et al., 2010) |
| Mt-MCA8 | SERCA-type calcium ATPase | Reduced epidermal penetration | (Capoen et al., 2011) |
| Mt-CNCG15 | Nuclear-localized cyclic nucleotide-gated channel | Reduced colonization | (Charpentier et al., 2016) |
| Mt-DMI3 | Calcium/calmodulin-dependent protein kinase | No epidermal penetration | (Lévy et al., 2004; Tirichine et al., 2006; Chen et al., 2007; Banba et al., 2008) |
| Lj-CCaMK | |||
| Ps-SYM9 | |||
| Os-DMI3 (Os-CCaMK) | |||
| * Lj-CYCLOPS | Coiled-coil domain containing protein | No formation of arbuscules in L. japonicus and O. sativa | (Kistner et al., 2005; Messinese et al., 2007; Yano et al., 2008; Horváth et al., 2011; Ovchinnikova et al., 2011; Larkan et al., 2013) |
| Os-CYCLOPS | Reduced numbers of arbuscules in M. truncatula, P. sativum, and S. lycopersicum | ||
| Mt-IPD3 | |||
| Ps-SYM33 | |||
| Sl-CYCLOPS | |||
| Mt-DELLA1 | GRAS transcription factors | Intraradical colonization but very limited formation of arbuscules | (Floss et al., 2013; Foo et al., 2013; Yu et al., 2014) |
| Mt-DELLA2 | |||
| Ps-LA | |||
| Ps-CRY | |||
| Os-SLR1 | |||
| Ps-NA | Kaurenoic acid oxidase | Increased colonization | (Foo et al., 2013) |
| * Mt-RAM1 | GRAS transcription factor | Cortical cell penetration and trunk formation but almost no hyphal branching | (Gobbato et al., 2012, 2013; Rich et al., 2015; Park et al., 2015) |
| Lj-RAM1 | |||
| Ph-ATA | |||
| * Lj-RAD1 | GRAS transcription factor | Stunted arbuscules in Lj-rad1 | (Xue et al., 2015; Park et al., 2015) |
| Mt-RAD1 | Reduced colonization in Mt-rad1; reduced number of arbuscules and increased arbuscule degeneration | ||
| * Os-DIP1 | GRAS transcription factor | RNAi: Reduced colonization | (Yu et al., 2014) |
| Mt-NSP1 | GRAS transcription factor | Reduced colonization | (Delaux et al., 2013b) |
| Mt-NSP2 | GRAS transcription factor | Reduced colonization | (Maillet et al., 2011) |
| Os-AM18 | GRAS transcription factor | Reduced colonization | (Fiorilli et al., 2015) |
| * Mt-MIG1 | GRAS transcription factor | RNAi: Small and malformed arbuscules | (Heck et al., 2016) |
| Mt-LOM1 | GRAS transcription factor | RNAi: Reduced colonization | (Couzigou et al., 2017) |
| Gm-NF-YA1a/b | CCAAT-binding transcription factor | RNAi: Reduced colonization | (Schaarschmidt et al., 2013) |
| * Mt-ERF1 | AP2 transcription factor | amiR: Collapsed arbuscules | (Devers et al., 2013) |
| * Mt-MYB1 | MYB transcription factor | Suppression of premature arbuscule degeneration in Mt-pt4/myb1 | (Floss et al., 2017) |
| * Mt-VAPYRIN | MSP and ANK repeat-containing protein | No arbuscule formation and reduced epidermal penetration | (Pumplin et al., 2010; Feddermann et al., 2010) |
| Ph-PAM1 | Small protrusions into cortical cells in P. hybrida | ||
| * Mt-VAMP721d/e | R-SNAREs/vesicle-associated membrane proteins | RNAi: Stunted arbuscules | (Ivanov et al., 2012) |
| * Mt-EXO70I | Exocyst complex protein | Stunted arbuscules | (Zhang et al., 2015b) |
| * Mt-SYP132A | Qa-SNARE/syntaxin | RNAi: Collapsed arbuscules | (Pan et al., 2016) |
| Lj-VTI12 | Qb-SNARE | amiR: Increased number of collapsed arbuscules | (Lota et al., 2013) |
| Mt-MSBP1 | Membrane-bound steroid-binding protein | RNAi: Aberrant arbuscule development | (Kuhn et al., 2010) |
| * Mt-STR | Half-ABC transporter | Stunted arbuscules | (Zhang et al., 2010; Gutjahr et al., 2012; Kojima et al., 2014) |
| Os-STR | |||
| Lj-STR | |||
| * Mt-STR2 | Half-ABC transporter | Stunted arbuscules | (Zhang et al., 2010; Gutjahr et al., 2012) |
| Os-STR2 | |||
| * Mt-RAM2 | Glycerol-3-phosphate acyl transferase | Collapsed arbuscules | (Wang et al., 2012; Keymer et al., 2017) |
| Lj-RAM2 | |||
| * Mt-FatM | Acyl-(ACP) thioesterase | Collapsed arbuscules | (Bravo et al., 2016) |
| * Lj-DIS | Ketoacyl-ACP synthase | Collapsed arbuscules | (Keymer et al., 2017) |
| * Lj-CERBERUS | E3 ubiquitin ligase | Reduced intercellular hyphal elongation | (Takeda et al., 2013) |
| Mt-PUB1 | E3 ubiquitin ligase | Increased colonization | (Vernié et al., 2016) |
| Mt-Skl1 | NRAMP-like integral membrane protein | Increased number of infections | (Penmetsa et al., 2008) |
| Mt-SUNN | Leucine-rich repeat (LRR) receptor kinase | Increased arbuscule formation in P. sativum | (Morandi et al., 2000; Krusell et al., 2002; Nishimura et al., 2002; Searle et al., 2003; Schnabel et al., 2005) |
| Lj-HAR1 | |||
| Ps-SYM29 | |||
| Gm-NARK | |||
| Sl-SUT2 | Sucrose transporter | RNAi: increased mycorrhizal colonization | (Bitterlich et al., 2014) |
| Lj-SbtM1 | Subtilisin-like protease | RNAi: reduced colonization and decrease in arbuscule formation | (Takeda et al., 2009) |
| Lj-SbtM3 | Subtilisin-like protease | RNAi: reduced colonization and decrease in arbuscule formation | (Takeda et al., 2009) |
| Mt-SCP1 a | Serine carboxypeptidase | RNAi: malformed arbuscules | (Rech et al., 2013) |
| * Mt-PT4 | Phosphate transporter | Premature arbuscule degeneration | (Javot et al., 2007; Yang et al., 2012) |
| Os-PT11 | |||
| * Os-PT13 | Phosphate transporter | Small arbuscules | (Yang et al., 2012) |
| Mt-HA1 | ATPase | Degenerating arbuscules | (Krajinski et al., 2014; Wang et al., 2014) |
| * Mt-AMT2;3 | Ammonium transporter | Suppression of premature arbuscule degeneration in Mt-pt4/amt2;3 | (Breuillin-Sessoms et al., 2015) |
| * Mt-KIN2 | Protein kinase | Reduced colonization | (Bravo et al., 2016) |
| * Mt-KIN3 | Protein kinase | Reduced colonization | (Bravo et al., 2016) |
| * Mt-KIN5 | Serine-threonine protein kinase | Reduced colonization | (Bravo et al., 2016) |
| * Mt-RFCb | Replication factor C | Reduced colonization | (Bravo et al., 2016) |
| * Mt-CYT733A1 | P450 enzyme | Reduced colonization | (Bravo et al., 2016) |
| * Mt-PP2AB’1 | Protein phosphatase 2A | Reduced colonization | (Charpentier et al., 2014) |
The genes marked with an asterisk are present exclusively in plants that form AM symbiosis and are not present in non-hosts as described by Bravo et al. (2016). DIS, MIG1, MYB1, VAMP721d/e, PT13, AMT2;3, and CERBERUS are AM symbiosis-conserved genes but were not listed by Bravo et al. (2016) because the criteria used by these authors to define AM symbiosis conserved genes were exceptionally stringent and required broad conservation in monocot hosts including grass and non-grass monocot hosts. DIS, MIG1, MYB1, VAMP721d/e, PT13, and CERBERUS are present in either grass or non-grass monocot hosts but not in both of these groups. When a phenotype was reported from a knockdown of the gene, the method used is reported as RNAi, RNA interference; VIGS, virus-induced gene silencing; or amiR, artificial microRNA. Species names: Gm, Glycine max; Lj, Lotus japonicus; Mt, Medicago truncatula; Os, Oryza sativa; Ph, Petunia hybrida; Ps, Pisum sativum; Pa, Parasponia andersonii; Sl, Solanum lycopersicum; Zm, Zea mays.
a
Silencing of many homologs.