Table_7_Comparative Genome and Transcriptome Study of the Gene Expression Difference Between Pathogenic and Environmental Strains of Prototheca zopfii.xlsx

Prototheca zopfii commonly exists in the environment, and causes invasive infections (protothecosis) in humans. The morbidity of protothecosis has increased rapidly in recent years, especially in systemic infections of patients with an impaired immune system. The infection in immunocompromised patients has a poor prognosis due to limited understanding of the pathogenesis of the disease, as most previous studies mainly focused on classification and recognition of pathogenic strains. In this study, we constructed the genome and transcriptome of two pathogenic strains and one environmental strain, by next generation sequencing methods. Based on our preliminary gene expression findings, genes in P. zopfii pathogenic strains are significantly up-regulated in metabolism in peroxisome, such as glyoxylate cycle, which may improve the organism’s resistance to the harsh environment in phagolysosome of macrophage and its ability to survive in an anaerobic environment. We also found some significant up-regulated genes, which are related to adherence and penetration in dermatophytes, and we speculate that this may enhance the virulence capacity of pathogenic strains. Finally, the genomes and transcriptomes of P. zopfii described here provide some base for further studies on the pathogenesis of this organism.祖氏无绿藻（Prototheca zopfii）广泛分布于自然环境中，可引发人类侵袭性感染（无绿藻病，protothecosis）。近年来无绿藻病的发病率呈快速攀升态势，尤以免疫系统受损患者的全身性感染病例居多。由于既往多数研究主要聚焦于致病性菌株的分类与识别，学界对该病的发病机制认知不足，因此免疫功能低下患者感染后的预后效果普遍较差。本研究通过下一代测序（next generation sequencing）技术，成功构建了两株致病性菌株与一株环境菌株的基因组与转录组。基于初步的基因表达分析结果，祖氏无绿藻致病性菌株的部分基因在过氧化物酶体代谢通路（如乙醛酸循环）中显著上调，该现象或可增强菌体对巨噬细胞吞噬溶酶体内严酷环境的耐受能力，以及在厌氧环境下的生存能力。本研究还发现了一批与皮肤癣菌黏附、穿透功能相关的显著上调基因，据此推测该类基因可提升致病性菌株的毒力水平。本研究所报道的祖氏无绿藻基因组与转录组数据，可为后续深入解析该病原菌的发病机制提供重要研究基础。