Table_4_Comparative Genome and Transcriptome Study of the Gene Expression Difference Between Pathogenic and Environmental Strains of Prototheca zopfii.xls

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.

佐氏原壁菌（Prototheca zopfii）广泛存在于自然环境中，可引发人类侵袭性感染（原壁菌病，protothecosis）。近年来原壁菌病的发病率呈快速上升趋势，尤其在免疫功能受损患者的全身性感染中更为突出。由于此前多数研究主要聚焦于病原菌株的分类与鉴定，学界对该疾病的发病机制认知有限，因此免疫低下患者感染后的预后不良。本研究通过下一代测序（Next Generation Sequencing）技术，构建了两株病原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，佐氏原壁菌病原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，这或可增强菌体对抗巨噬细胞吞噬溶酶体内严酷环境的能力，以及在厌氧环境下的生存能力。本研究还发现了若干与黏附、穿透宿主皮肤相关的显著上调基因，推测此类基因可提升病原菌株的毒力水平。最后，本研究所报道的佐氏原壁菌基因组与转录组数据，可为后续针对该病原体发病机制的相关研究提供重要基础。