Table 1.
Elicitors (including signaling compounds, priming agents and PDAs) that have been shown to induce plant defense after root treatment on different plant species.
| Elicitors used | Species | Effects on roots | Application method | Reference |
|---|---|---|---|---|
| PLANT DEFENSE ACTIVATORS | ||||
| Acibenzolar-s-methyl(ASM) |
Citrus paradisi x Poncirus trifoliata | - Reduced disease severity of citrus canker - PR-proteins production |
Soil drench | Francis et al., 2009 |
| Solanum lycopersicum | - Reduction of nematode infestation | Root-dip or soil drench | Molinari and Baser, 2010 | |
| Benzothiadiazole (BTH) | Gossypium hirsutum | - ROS and PR-proteins production | Seedling immersion | Zambounis et al., 2012 |
| Fragaria ananassa Duchense | - Comparable Podosphaera aphanis disease control to foliar treatment | Soil drenching | Pertot et al., 2009 | |
| Carica papaya | - Expression of defense-related enzymes - Reduction of Phytophthora palmivora symptoms - Increase of genes expression |
Root drench | Zhu et al., 2003 | |
| Chitin oligosaccharide (CO) | Arabidopsis thaliana | - ROS production - Defense-related gene expression |
Not indicated | Nars et al., 2013 |
| Chitosan |
Lycopersicon esculentum | - Cell wall reinforcement | Immersion of root fragment | Mandal and Mitra, 2007 |
| Solanum melongena L. | - Cell wall reinforcement - Increase of phenolic content |
Immersion of root fragment | Mandal, 2010 | |
| Medicago truncalata | - ROS production - Induction of defense-associated genes |
Not indicated | Nars et al., 2013 | |
| Arabidopsis thaliana | - ROS production - Defense-related gene expression |
Not indicated | Nars et al., 2013 | |
| Solanum lycopersicum | - Phenolic content increase - Reduced symptoms and disease incidence with R. solanacearum - Enzymes activity increase |
Hydroponic culture | Mandal et al., 2013 | |
| Phoenix dactylifera L. | - Increase of phenolic content - Changes in Fusarium oxysporum morphology - Increase of enzyme activity |
Root injection | El Hassni et al., 2004 | |
| Saccharin | Glycine max | - Reduction of P. pachyrhizi disease severity | Root drench | Srivastava et al., 2011 |
| SIGNALING COMPOUNDS | ||||
| Hexanoic acid | Solanum lycopersicum | - Protection against Botrytis cinerea - callose deposition in leaves |
Hydroponic culture | Vicedo et al., 2009 |
| Isonicotinic acid (INA) | Citrus paradisi x Poncirus trifoliata | - Reduced disease severity of citrus canker - PR-proteins production |
Soil drench | Francis et al., 2009 |
| Jasmonic acid (JA) | Solanum lycopersicum | - Phenolic content increase - Enzymes activity increase |
Hydroponic culture | Mandal et al., 2013 |
| Phoenix dactylifera L. | - Enhanced Fusarium oxysporum resistance - Enzymes activity increase - ROS production |
Root injection | Jaiti et al., 2009 | |
| Beta vulgaris L. | - Synthesis of PR proteins, regulatory proteins, secondary metabolite biosynthetic enzymes, plant cell wall modifying proteins -Reduction of Botrytis cinerea, Penicillium claviforme and Phoma betae disease symptoms |
Submerssion of roots | Fugate et al., 2012, 2017 | |
| Methyl salicylate (MeSA) | Solanum melongena L. | - Cell wall reinforcement - Increase of phenolic content |
Immersion of root fragment | Mandal, 2010 |
| Solanum lycopersicum | - Reduction of nematode infestation | Root-dip or soil drench | Molinari and Baser, 2010 | |
| Methyl-Jasmonate (MeJA) |
Helianthus annuus L. | - Increase in the activity of ROS implicated enzymes - ROS production (H2O2) |
Seedling immersion | Parra-Lobato et al., 2009 |
| Arabidopsis thaliana | - Increase of phytochemical exudation - Gene expression modification |
Seedling immersion | Badri et al., 2008 | |
| Solanum melongena L. | - Cell wall reinforcement - Increase of phenolic content |
Root fragment immersion | Mandal, 2010 | |
| Gossypium hirsutum | - ROS production - PR-proteins production |
Seedling immersion | Zambounis et al., 2012 | |
| Kalanchoe blossfeldiana | - Anthocyanin accumulation | Roots were soaked in MeJA solution | Góraj-Koniarska et al., 2015 | |
| Nitric oxide (NO) | Arabidopsis thaliana | - Increase of phytochemical exudation - Gene expression modification |
Seedling immersion | Badri et al., 2008 |
| Salicylic acid (SA) |
Arabidopsis thaliana | - Increase of phytochemical exudation - Gene expression modification |
Seedling immersion | Badri et al., 2008 |
| Solanum lycopersicum | - Increase of the defense enzyme activity - Enhanced resistance against Fusarium oxysporum infection |
Root feeding | Mandal et al., 2009 | |
| Solanum melongena L. | - Cell wall reinforcement - Increase of phenolic content |
Immersion of root fragment | Mandal, 2010 | |
| Solanum lycopersicum | - Increase of SA content - Increase of enzymes activity - Reduce of disease symptoms |
Hydroponic culture | Mandal et al., 2009 | |
| Solanum lycopersicum | - Phenolic content increase - Reduced symptoms and disease incidence with R. solanacearum - Enzymes activity increase |
Hydroponic culture | Mandal et al., 2013 | |
| Solanum lycopersicum | - Protection against Botrytis cinerea - Callose deposition in leaves |
Hydroponic culture | Vicedo et al., 2009 | |
| Solanum lycopersicum | - Reduction of nematode infestation | Root-dip or soil drench | Molinari and Baser, 2010 | |
| Lycopersicon esculentum | - Synthesis of PR-proteins - Induce PR-1 gene expression - Resistance against A. solani |
Hydroponic vessels | Spletzer and Enyedi, 1999 | |
| PRIMING AGENT | ||||
| BABA | Solanum lycopersicum | - Protection against Botrytis cinerea - Callose deposition in leaves |
Hydroponic culture | Vicedo et al., 2009 |
| Arabidopsis thaliana | - Enhanced resistance to A. brassicicola and P. cucumerina - Enhanced levels of resistance against A. brassicicola and P. cucumerina - Enhanced resistance to P. cucumerina and A. brassicicola - Callose deposition in leaves |
Soil drench | Ton and Mauch-Mani, 2004 | |