Screening of Leuconostoc suionicum Strain HJ-L and Its Antifungal Mechanism against Leaf Mold of Zanthoxylum
Tian Fengming
Chen Qiang
Li Donglan
Song Fan
Wang Guobin
Ye Wenbin
Shi Zhiguo
Abstract：To screen for lactic acid bacteria with antagonistic activity against Alternaria alternata,the causal agent of leaf mold in Zanthoxylum,and to investigate the antifungal mechanism,lactic acid bacteria were isolated from the milky white exudate naturally secreted by healthy Zanthoxylum trees in the Longnan City of Gansu Province.With A.alternata as the indicator pathogen,antagonistic strains were screened.The effective strain was identified by morphological observation and molecular phylogenetic analysis,and its antifungal activity,metabolites,and biological characteristics were systematically evaluated.The results showed that the antagonistic strain HJ-L exhibited an inhibition rate of 83.2%against A.alternata.Strain HJ-L was identified as Leuconostoc suionicum.The ethyl acetate extract of its fermentation broth showed a minimum inhibitory concentration(MIC)of 10.00 mg/mL and a minimum fungicidal concentration(MFC)of 10.00 mg/mL against the pathogen,and induced abnormal mycelial morphology.Strain HJ-L also exhibited broad-spectrum antifungal activity against five other plant pathogenic fungi,namely Fusarium solani,F.oxysporum,F.proliferatum,F.circinatum,and Colletotrichum fioriniae,with inhibition rates ranging from 62.5%to 88.7%.Metabolomic analysis revealed seven potential antifungal compounds derived from the fermentation extract of strain HJ-L,including nicotinic acid,3-indolepropionic acid,citric acid,linoleic acid,methylparaben,benzoic acid,and palmitoleic acid,covering organic acids,phenolic acids,and unsaturated fatty acids.Metabolic pathway analysis indicated that these compounds were primarily involved in the tricarboxylic acid(TCA)cycle,fatty acid biosynthesis,biosynthesis of unsaturated fatty acids,phenylalanine metabolism,nicotinate and nicotinamide metabolism,and tryptophan metabolism,providing a potential molecular basis for the antifungal activity of strain HJ-L.Therefore,the antagonistic strain HJ-L has the potential to be developed as a biological control agent against Zanthoxylum leaf mold and serves as a promising microbial resource for the biocontrol of this disease.
Keywords：Zanthoxylum leaf moldAlternaria alternataLactic acid bacteriaLeuconostoc suionicumAntifungal activityBiological control
Publication Date：2026-07-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：12( 95-106 )