| Lilium is an important cut,potted and garden flower in the world today.The wilt caused by pathogenic fungus Fusarium oxysporum is one of the most serious diseases in the lily industry.At present,the wilt disease control mainly relies on resistant varieties.In this study,the resistance of four lily species to Fusarium oxysporum was determined,and two lily species with different resistance to Fusarium oxysporum were selected to explore their early response to pathogen infection from the transcriptome level.Resistance genes have been mined from different disease resistance pathways.Two WRKY genes were cloned from Lilium henryi and their physicochemical properties were analyzed.Screening of resistance lily resources and mining of resistance genes can provide guidance for hybrid breeding of disease-resistant lily varieties,and the discovery of disease resistance genes and metabolic pathways will provide molecular basis for fusarium wilt control.The main research results are as follows:1.The disease resistance of Lilium davidii var.willmottiae(E.H.Wilson)Raffill,Lilium lancifolium,Lilium henryi Baker and Lilium regale Wilson was identified by inoculation of Fusarium oxysporum by in vitro scale-prick method.The identification results showed that the disease resistance of Lilium davidii var.willmottiae(E.H.Wilson)Raffill was the weakest,the resistance of Lilium lancifolium was in the middle,and the disease resistance of Lilium henryi Baker and Lilium regale Wilson was strong.2.The tissue culture seedlings of Lilium henryi Baker and Lilium davidii var.willmottiae(E.H.Wilson)Raffill were selected,and the roots were infected with Fusarium oxysporum.Transcriptome sequencing was performed on root tissues of seedlings at 4h,12 h and 24 h after infection,respectively,and the uninoculated root tissues were taken as controls(CK).Compared with the control,the amount of upregulated differential expressed genes were significantly more than the down-regulated genes in the three periods after inoculation of Fusarium oxysporum in Lilium henryi Baker and Lilium davidii var.willmottiae(E.H.Wilson)Raffill.3.KEGG enrichment analysis showed that the biosynthesis of α-linolenic acid,amino acid biosynthesis,and phenylpropanin biosynthesis pathway were enriched significantly after Lilium henryi Baker treatment by pathogens,while in Lilium davidii var.willmottiae(E.H.Wilson)Raffill,amino acid biosynthesis and PPAR signaling pathway were significantly enriched after treatment.4.The differential expression level of metabolic pathways and transcription factors associated with plant-pathogen interaction were analyzed.According to the difference of gene expression level and the role of genes in the metabolic pathway of disease resistance,it was speculated that the differential expression of JMT、C4H、COMT、FLS、WRKY22、WRKY33、WRKY40、MYC2、LIWRKY32、MYB30-like、CAT genes might be related to the resistance of lily to Fusarium oxysporum.5.Two genes,WRKY22 and WRKY40,encoding 281 and 267 amino acids respectively,were cloned from Lilium henryi Baker,both of which contained WRKY conserved domains,and subcellular localization were predicted to be located in the nucleus.6.The knockout vector of WRKY22 gene was constructed,and Lilium henryi Baker was transformed by pollen conversion method. |
