利用大蜡螟模型研究白念珠菌SUMO编码基因SMT3在致病性调控中的作用

Using Galleria mellonella model to investigate the role of SMT3 gene in regulating pathogenicity of Candida albicans

目的探讨白念珠菌SMT3基因在致病性调控中的作用。方法利用瞬时CRISPR/Cas9系统构建SMT3纯合子缺失菌株,并检测其侵入生长和生物被膜形成能力;利用大蜡螟感染模型检测SMT3缺失株致病能力,通过糖原染色观察组织内白念珠菌菌体形态,并进一步检测SMT3缺失株对大蜡螟幼虫血细胞的破坏作用。结果SMT3缺失促进了侵入生长和生物被膜形成,其感染的大蜡螟幼虫平均存活期为3.5 d,致病性较野生型菌株(平均存活期为8.5 d)显著增强;SMT3缺失株感染的大蜡螟幼虫血细胞数为1.4×10^(7)/mL,较野生型组(2.9×10^(7)/mL)显著降低,仅为野生型组的48%。结论白念珠菌SMT3基因在致病性调控中发挥重要作用。

Objective To investigate the role of SMT3 gene in regulating pathogenicity of Candida albicans.Methods To delete the SMT3 gene,a transient CRISPR/Cas9 system was used.The genotype of the SMT3 deletion strain was checked by colony PCR.Invasive growth and biofilm formation of the SMT3 deletion strain were studied.To check the pathogenicity of C.albicans cells,wild-type and the SMT3 deletion strain were injected into the larvae of Galleria mellonella.The survival rate of infected larvae was checked daily and analyzed.As well,the morphology of C.albicans in the larvae was checked using a PAS staining.Moreover,the damaging effect of the SMT3 deletion strain on the hemolymph of G.mellonella was investigated.Results The SMT3 homozygous deletion strain was successfully constructed.Deletion of SMT3 gene significantly increased the invasive growth on solid media,and also elevated the ability of biofilm formation.Deleting SMT3 decreased the survival of infected G.mellonella,An average survival of 3.5 days in this group is significantly lower than the wild type group(8.5 days).In addition,deleting SMT3 caused a significant decrease in total hemolymph of infected larvae,(1.4×10^(7) cells per mL).Conclusion SMT3 gene plays important roles in regulating pathogenicity of C.albicans in G.mellonella model.