Table 3.

Defense mechanism of bacterial endophytes against pathogens.

Bacterial Endophyte	Mode of Defense Actions against Pathogens	References
Bacillus subtilis XZ18-3	Endophyte shows antagonistic antifungal activity by accumulating reactive oxygen species (ROS) in Rhizoctonia cerealis, which causes rot and blight in wheat.	[44]
Bacillus thuringiensis SY33.3	Endophyte shows an antagonistic effect by producing an extracellular chitinase enzyme against causative agents such as Fusarium oxysporum f. sp. niveum, Verticillium dahlia, and Aspergillus niger, which causes wilt and black mold in grapes, apricots, onions, and peanuts.	[8]
Streptomyces roseoverticillatus 63 (Sr-63)	Endophyte shows an antagonistic effect by producing carbazomycin B metabolite against the pathogen Xanthomonas oryzae pv. oryzae, which causes bacterial leaf blight in rice. It inhibits the pathogen metabolic activity by decreasing the malate dehydrogenase activity and suppressing the pathogen protein expression.	[45]
Bacillus velezensis Bs006	Endophyte shows antagonistic activity by producing antimicrobial cyclic lipopeptides such as turins, surfactants, and fengycins and suppresses Fusarium oxysporum f. sp. Physalis, which causes Fusarium wilt in goldenberry.	[46]
Bacillus circulans GN03	Endophyte isolated from Brassica Chinensis has unrivalled efficacy in plant growth promotion and disease resistance by a significant hoard of defense and growth-related hormones (SA, JA, gibberellic acid, brassinosteroid, and indole-3-acetic acid (IAA)). The in vivo model shows that endophytes protect cotton seedlings against the Verticillium dahliae strain V991, whichcauses Verticillium wilt.	[47]
Chromobacterium vaccinii; C. vaccinii MWU328, MWU300, and MWU205	Endophytic strains have a broad spectrum of antifungal VOC activity that mitigates the growth of the Phoma sp. and Coleophoma sp., which cause fruit rot in cranberry.	[48]
Bacillus sp. strains G4L1	Endophyte actively resists Ralstonia solanacearum, which causes bacterial wilt in tomato, via upregulation of the lipoxygenase gene in the stem, expression of the PR-1 gene and Glutelin genes in roots, and protection of the plant by induction of JA, SA, and the ethylene-dependent defense signaling pathway.	[49]
Bacillus velezensis strain J.K.	Endophyte isolated from the rice hybrid variety Oryza sativa L., Shenliangyou 5814 produces secondary metabolites that show a significant antagonistic effect against the pathogen Magnaporthe oryzae, which causes rice blast in rice.	[50]
Pantoea dispersa (RO-18, RO-20, RO-21, and SO-13)	Endophytes strongly inhibit mycelium growth and spore germination and modify the morphology of Ceratocytis Fimbriata hyphae via antifungal effects and curb black rot in sweet potato.	[51]
Streptomycetes sp. strain FJAT-31547	Endophyte shows an antagonistic effect by producing the antifungal component n-hexadecanoic acid against the growth of Fusarium oxysporum and Ralstonia solanacearum, which causes Fusarium wilt and bacterial wilt in tomato, respectively.	[36]
Aspergillus capensis CanS-34A	Endophyte isolated from Brassica napus produces antifungal the metabolite rosellichalasin (3), which inhibits phytopathogens such as Botrytis cinerea, Monilinia fructicola, Sclerotinia sclerotiorum, and S. trifoliorum, which cause grey mold, rot and canker, and rot in fruits and vegetables, respectively.	[52]
Streptomyces angustmyceticus NR8-2	Endophyte produces β-1, 3-glucanase antifungal metabolites and volatile compounds to suppress Curvularia lunata and Colletotrichum sp., which cause leaf spots in Brassica rapa subsp. Pekinensis.	[53]
Streptomyces AMA49	Endophyte produces antifungal metabolites oligomycin A and its derivatives, which show an antagonism effect by inhibiting the germination of conidia and formation of appressorium of the pathogen Pyricularia – oryzae, which causes rice blast in rice.	[54]
Pseudomonas aeruginosa, Burkholderia gladioli, Burkholderia rinojensis, and Burkholderia arboris	In vitro and in vivo studies revealed that these endophytes have a significate antifungal antagonistic effect against the seed colonization pathogen Colletotrichum truncatum, which causes anthracnose in pepper.	[55]