Self-digestive solution of Lysobacter enzymogenes LE16 as a biofungicide to control plant powdery mildew

ABSTRACT

The self-digestive solution (SDS) of the biocontrol bacterium Lysobacter enzymogenes LE16 shows strong antagonistic activities against multiple soil-borne phytopathogens but the positive evidence of this bacterium against plant foliar disease is still scanty. Thus, laboratory, greenhouse, and field experiments were carried out to estimate the efficacies of SDS, S-SDS (stored at room temperature for 12 months), and H-SDS (heated at 100°C for 30 min) against plant powdery mildew. This bacterium produced hydrolases (phosphatase, protease, lysozyme, chitinase, and β-1,3-glucanase) that degrade pathogen cell components and siderophores that compete for iron with phytopathogens. The top five antimicrobial metabolites identified in SDS were pyroglutamic acid, deoxycytidine, pyrrole-2-carboxylic acid, 13-oxo-9,11-tridecadienoic acid, and 3’-amino-3’-deoxythimidine. Among them, pyroglutamic acid may play a vital role in powdery mildew control. As a result, SDS, S-SDS, and H-SDS strongly inhibited the conidial germination of Erysiphe cichoracearum and Sphaerotheca fuliginea. The application of SDS significantly increased the activity of antioxidant enzymes in crop leaves and effectively controlled tobacco and cucumber powdery mildew in the greenhouse and the field. Therefore, L. enzymogenes LE16 can effectively control powdery mildew. The underlying mechanisms may be attributed to the induction of plant systemic resistance and the production of antifungal substances.

KEYWORDS:

• Lysobacter enzymogenes
• self-digestive solution
• biofungicide
• powdery mildew

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03650340.2023.2180799

Additional information

Funding

This work was supported by the The Cultivation Project of Guizhou University [(2020)04]; Zunyi Tobacco Company [2018-01]; The Basic Research Program in Guizhou Province [(2022)036]; The Gui Da Te Gang He Zi Program [(2021)06].