Endophytic bacteria isolated from plant tissues have significant potential as biocontrol agents, enhancing the resistance of host plants to diseases. However, reports describing these endophytic bacteria from the perennial Atractylodes macrocephala Koidz. (a medicinal plant) are limited. Our study aimed to screen and identify antagonistic bacteria, investigate their plant growth-promoting properties, and analyse the volatile organic compounds (VOCs) produced by these bacteria. In the present study, 8 strains of endophytic bacteria were screened for their ability to inhibit the root rot pathogen Fusarium incarnatum. Among these strains, Pseudomonas sp. AMK8 showed broad-spectrum antifungal activity against F. solani, F. oxysporum, Phytophthora parasitica and Selerotium rolfsii. It is also able to produce siderophores, dissolve inorganic phosphorus and produce IAA. In the plate dual-culture method, AMK8 caused a significant increase in biomass production, including fresh and dry weights, and cotyledon length compared with those of the mock group (P < 0.05). Moreover, a gas chromatography‒mass spectrometry (GC‒MS) system was used to characterize the VOCs emitted by strain AMK8. In the samples inoculated with this bacterium, 10 different compounds were detected, including six alkanes, an ether, an amine, an ester, and a sulfide. This study clearly demonstrated that Pseudomonas sp. AMK8 has potential biocontrol activity against plant pathogens and promotes plant growth via the release of VOCs.
Shi et al. (Sun,) studied this question.