Analysis of the green control effect and regulatory mechanism of ginger extract on root rot pathogens of <italic>Polygonatum</italic>

To explore the green prevention and control scheme of Polygonatum root rot and the resistance mechanism of natural plant substances to plant response to pathogen infection， different concentrations of ginger extract were used to treat three main pathogens of Polygonatum root rot， namely Fusarium oxysporum， Fusarium redolens and Aspergillus awamori. At the same time， the physical and chemical indexes and transcriptome data of Polygonatumkingianum under different treatment conditions were determined， and the differentially expressed genes （DEGs） were verified by qRT-PCR， and the inhibitory effect and regulatory mechanism of ginger extract on Polygonatum root rot were analyzed. The results showed that 2.5% and 5.0% old ginger extract exhibited good antifungal effects against both F. oxysporum and A. awamori， with the 5.0% extract achieving an inhibition rate of 42.3% against A. awamori. Pot experiment results showed that 7 days after inoculation， the survival rate of P. kingianum in the old ginger extract treatment group increased by 50%. Compared with the control group， the SOD activity in the rhizomes of P. kingianum in this treatment group increased and peaked at 3 days. The MDA content was significantly lower than that in the control group and the single inoculation group， and the POD activity showed a reverse trend of decreasing first， then increasing and then decreasing. The total phenol yield of P. kingianum rhizomes showed an upward trend after treatment with old ginger extract， reaching the peak on the 4th day and being significantly higher than that in the control group and the single inoculation group. Transcriptome sequencing combined with weighted gene co-expression network analysis （weighted gene co-expression network analysis） indicated that DEGs were significantly enriched in the phenylpropane synthesis， flavonoid synthesis and TCA cycle pathways， and 6 key candidate genes were screened out from these pathways. The qRT-PCR analysis revealed that F5H， POD， PAL， CAD and ISD genes were highly expressed in the IA， while the gene expression pattern of DRA was opposite. In summary， ginger extracts at concentrations of 2.5% and 5.0% both have favorable antifungal activity against F. oxysporum and A. awamori， respectively. Ginger extract exerts a certain protective effect on P. kingianum in response to root rot pathogen infection. Treatment with this extract can induce the upregulated expression of genes CAD， PAL， POD， and ISD in P. kingianum， thereby significantly enhancing its disease resistance and stress tolerance.