Table 1.
Summary of seed priming approaches for crop disease resistance improvement.
| Priming approach category | Priming stimuli | Crop species | Priming impact and pathways affected | Type of immune memory | Crop disease resistance retest treatment | References |
|---|---|---|---|---|---|---|
| Biological priming | Trichoderma harzianum TriH_JSB27 | Solanum lycopersicum | T. harzianum TriH_JSB27 -primed tomato plants exhibited induction of defense-related SlPAL genes. | Somatic immune memory | Primed tomato plants exhibited enhanced disease resistance against Ralstonia solanacearum. | Jogaiah et al., 2013 |
| Pseudomonas fluorescens | Pennisetum glaucum | P. fluorescens -primed pearl millet plants exhibited significant changes in protein abundance. | Somatic immune memory | Primed pearl millet plants displayed increased disease resistance against downy mildew. | Anup et al., 2015 | |
| T. longibrachiatum | Allium cepa | T. longibrachiatum-primed onion plants exhibited accumulation of stress-responsive metabolites. | Somatic immune memory | Primed onion plants exhibited enhanced disease resistance against Fusarium oxysporum f. sp. cepa (FOC) infection. | Abdelrahman et al., 2016 | |
| Bacillus amyloliquefaciens, P. fluorescens | Withania somnifera | Priming of Ashwagandha with two bacteria combinations induced plant physiological and transcriptional changes. | Somatic immune memory | Primed Ashwagandha plants exhibited increased disease resistance against Alternaria alternata. | Mishra et al., 2018 | |
| T. harzianum, T. asperellum, Paenibacillus dendritiformis | Capsicum annuum | Priming of chilli with T. harzianum, T. asperellum, and P. dendritiformis induced plant physiological, transcriptional, and metabolic changes. | Somatic immune memory | Primed chilli plants exhibited increased disease resistance against anthracnose disease. | Yadav et al., 2021 | |
| T. atroviride | Beta vulgaris | T. atroviride-primed sugar beet plants exhibited upregulation of BvPR3 gene. | Somatic immune memory | Priming of sugar beet plants with T. atroviride decreases the severity of CLS disease. | Kappel et al., 2022 | |
| Heat-stable metabolites of B. gaemokensis strain PB69 | Cucumis sativus, C. annuum | Priming of cucumber and pepper with heat-stable bacterial metabolites induced expression of defense-related genes. | Somatic immune memory | Primed cucumber and pepper plants exhibited increased resistance against Pseudomonas syringae pv. lachrymans. | Song et al., 2017 | |
| Total crude protein (TCP) extract of Trichoderma spp. | P. glaucum | Priming of pearl millet with TCP from Trichoderma spp. enhanced levels of peroxidase and lipoxygenase | Somatic immune memory | Primed pearl millet plants displayed enhanced disease resistance against downy mildew. | Nandini et al., 2017 | |
| Lipopolysaccharide (LPS) elicitors isolated from P. fluorescens | P. glaucum | Priming of pearl millet with LPS induced ROS burst, callose deposition, and induction of PR genes. | Somatic immune memory | Primed pearl millet plants exhibited increased disease resistance against downy mildew disease. | Lavanya et al., 2018 | |
| Salicylic acid |
Solanum melongena, S. lycopersicum |
Priming of eggplant plants with SA induced expression of MPK1, GPX, and PRs, whereas SA seed-primed tomato plants exhibited induction of APx, CAT and GR. | Somatic immune memory | Primed eggplant and tomato plants exhibited increased disease resistance against Verticillium wilt, and bacterial spot disease, respectively. | Mahesh et al., 2017; Srinivasa et al., 2022 | |
| Jasmonic acid | S. lycopersicum | JA-primed tomato plants exhibited enhanced expression of the JA-dependent defense gene PinII. | Somatic immune memory | Primed tomato plants exhibited resistance to herbivory by spider mites, caterpillars aphids, and infection of B. cinerea. | Worrall et al., 2012 | |
| Methyl jasmonate | S. lycopersicum | MeJA seed-primed tomato plants exhibited an increase in the levels SA, kaempferol, and quercetin, upregulation of PAL5, BSMT, CHS, FLS, and downregulation of ICS gene. | Somatic immune memory | Primed tomato plants exhibited enhanced disease resistance to the hemi-biotroph Fusarium oxysporum. | Król et al., 2015 | |
| β-aminobutyric acid (BABA) | S. lycopersicum, P. glaucum | BABA-primed pearl millet plants showed significant changes in protein abundance including the over-representation of proteins related to glucose metabolism | Somatic immune memory | Primed tomato and pearl millet plants exhibited increased disease resistance against powdery mildew and downy mildew, respectively. | Worrall et al., 2012; Anup et al., 2015 | |
| Chemical priming | Chitosan | P. glaucum, C. sativus, B. vulgaris | Priming of pearl millet seeds with chitosan increased levels of chitosanase, whereas chitosan-primed cucumber plants showed enhanced deposition of lignin, callose, and H2O2. Chitosan seed-primed sugar beet plants exhibited upregulation of PR3, PAL, and GST genes. | Somatic immune memory | Primed pearl millet plants exhibited increased disease resistance downy mildew, whereas primed cucumber and sugar beet plants exhibited enhanced disease resistance against powdery mildew and CLS disease, respectively. | Manjunatha et al., 2008; Jogaiah et al., 2020; Kappel et al., 2022 |
| 2,6-dichloroisonicotinic acid (INA) | Phaseolus vulgaris | INA-primed common bean plants and its stress-free offsprings exhibited enrichment of H3K4me3 and H3K36me3, as well as low nucleosome occupancy at PvPR1 gene. | Transgenerational immune memory | Primed common bean plants and its stress-free offsprings exhibited reduced susceptibility to P. syringae pv. phaseolicola pathogen. | Martínez-Aguilar et al., 2021 | |
| Cholic acid-glycine conjugates (CAGCs) | Oryza sativa | Seed priming of rice plants with CAGCs induced expression of defense-related genes. | Somatic immune memory | Primed rice plants exhibited enhanced resistance against leaf blight disease. | Pal et al., 2021 | |
| Nanomaterial priming | Mycogenic selenium nanoparticles (SeNPs) | S. lycopersicum | SeNPs-primed tomato plants exhibited accumulations of lignin, callose, and elevated levels of LOX, PAL, GLU, and SOD. | Somatic immune memory | Primed tomato plants displayed enhanced resistance against the late blight. | Joshi et al., 2021 |
| Nanoemulsions formulated from membrane lipids of Trichoderma brevicompactum (UP-91) | P. glaucum | Priming of pearl millet with nanoemulsions induced deposition of lignin, enhanced expression of LOX, AOC, and α-DOX genes, and potentiated production of JA and MeJA. | Somatic immune memory | Primed pearl millet plants displayed enhanced resistance against the downy mildew disease. | Nandini et al., 2019 |