Table 1.
Examples of different types of phenolics and diverse functions that they perform for plants and bacteria.
| Examples | Functions | |
|---|---|---|
| Phenolics | Coniferyl alcohol, sinapinic acid, cinnamic acid | vir gene inducers, determinants of scent and attractants of pollinators and symbiotic microbes in plants, etc. |
| Hydroxybenzoate, hydroxycinnamates, 5‐hydroxyanthraquinones | Allelochemicals for plant competition | |
| Umbelliferone, p‐hydroxybenzoic acid, vanillyl alcohol, isoflavones | Chemoattractants in Rhizobium | |
| Sinapinic acid, syringic acid, ethylsyringamide, propylsyringamide, carbethoxyethylensyringamide, parahydroxybenzoate, ferulic acid | vir gene inducers in Agrobacterium | |
| Vanillyl alcohol, bromo acetosyringone | Inhibitors of vir gene induction in Agrobacterium | |
| Acetosyringone, α‐hydroxyacetosyringone, p‐hydroxybenzoate | Chemoattractants in Agrobacterium and Rhizobium, and vir gene inducers in Agrobacterium | |
| Salicylic acid | Quorum quencher in Agrobacterium | |
| Hydroquinones | Allelochemical for plant competition | |
| Coumarins, xanthones, anthocyanidins | Determinants of colour and attractants of pollinators in plants | |
| Caffeic acid | vir gene inducer in Agrobacterium | |
| 3,4‐Dihydroxybenzoic acid | Chemoattractant in Agrobacterium and Rhizobium | |
| Protocatechuic acid, β‐resorcylic acid, protocatechuate, p‐resorcylate, catechol | vir gene inducer in Agrobacterium | |
| Chlorogenic acid | Precursor for lignin and suberin synthesis in plants | |
| Lignin, tannins and suberins | Structural components of plant cells | |
| Catechins | Plant defence | |
| Flavonoids, flavonols, flavones, genistein, daidzein, O‐acetyldaidzein, 6‐O‐malonylgenistin, 6‐O‐malonyl daidzin, glycitin, 6‐O‐malonylglycitin | nod gene inducers in Rhizobium | |
| Apigenin, naringenin, luteolin | Chemoattractants in Agrobacterium and Rhizobium, and nod gene inducers in Rhizobium | |
| Gallate, gallic acid, pyrogallic acid, syringic acid, kaempferol | vir gene inducers in Agrobacterium | |
| Flavanones, quercetin | nod gene inducers in Rhizobium | |
| Isoflavonoids | Chemoattractants and nod gene inducers in Rhizobium | |
| Cajanin, medicarpin, glyceoline, rotenone, coumestrol, phaseolin, phaseolinin, limonoids, tannins, flavonoids | Phytoalexins, phytoanticipins and nematicides in plant defence |