所描述的近10,000种绿藻中的大多数是光自养生物;但是,一些物种失去了光合作用的能力,成为依赖寄生生存的专性异养生物。使用短读和长读基因组以及转录组数据获得了异养藻类无绿藻Pz20和Pz23的两个高质量基因组。基因组大小为31.2Mb和31.3Mb,分别,和重叠群N50值为1.99Mb和1.26Mb。尽管P.zopfii保留了其质体基因组,向异源性的转变导致质体和核基因组大小的减少,包括从核和质体基因组中丢失与光合作用相关的基因,以及消除编码类胡萝卜素加氧酶和山梨酯加氧酶的基因。基因的丢失,包括碱性亮氨酸拉链(bZIP)转录因子,黄素腺嘌呤二核苷酸连接氧化酶,和解旋酶,可能在自养向异养生物的传播以及非生物胁迫抗性和致病性过程中起作用。共有66个(1.37%)和73个(1.49%)基因被鉴定为两个P.zopfii基因组中潜在的水平基因转移事件,分别。苹果酸合酶和异柠檬酸裂解酶的基因,从细菌水平转移,可能在无藻和非光合生物的碳和氮代谢以及致病性中起关键作用。这两个高质量的P.zopfii基因组为它们作为专性异养生物和致病性的进化提供了新的见解。
目的:无绿藻属,其特征是异养性质和致病性,作为研究病理生物学的示例性模型。对原虫病传染病的了解有限归因于缺乏基因组资源。使用HiFi长读测序,两个菌株的核和质体基因组都产生了。研究结果表明,质体和核基因组大小同时减少,伴随着与光合作用相关的基因的丢失,类胡萝卜素加氧酶,碱性亮氨酸拉链(bZIP)转录因子,和其他人。水平基因转移分析显示存在1.37%和1.49%的细菌基因,包括苹果酸合酶和异柠檬酸裂解酶,它们在碳和氮代谢中起着至关重要的作用,以及致病性和专性异源性。两个高质量的P.zopfii基因组代表了研究其作为专性异养生物的适应和进化的宝贵资源,以及制定未来预防和治疗原虫病的策略。
The majority of the nearly 10,000 described species of green algae are photoautotrophs; however, some species have lost their ability to photosynthesize and become obligate heterotrophs that rely on parasitism for survival. Two high-quality genomes of the heterotrophic algae Prototheca zopfii Pz20 and Pz23 were obtained using short- and long-read genomic as well as transcriptomic data. The genome sizes were 31.2 Mb and 31.3 Mb, respectively, and contig N50 values of 1.99 Mb and 1.26 Mb. Although P. zopfii maintained its plastid genome, the transition to heterotrophy led to a reduction in both plastid and nuclear genome size, including the loss of photosynthesis-related genes from both the nuclear and plastid genomes and the elimination of genes encoding for carotenoid oxygenase and pheophorbide an oxygenase. The loss of genes, including basic leucine-zipper (bZIP) transcription factors, flavin adenine dinucleotide-linked oxidase, and helicase, could have played a role in the transmission of autotrophy to heterotrophs and in the processes of abiotic stress resistance and pathogenicity. A total of 66 (1.37%) and 73 (1.49%) genes were identified as potential horizontal gene transfer events in the two P. zopfii genomes, respectively. Genes for malate synthase and isocitrate lyase, which are horizontally transferred from bacteria, may play a pivotal role in carbon and nitrogen metabolism as well as the pathogenicity of Prototheca and non-photosynthetic organisms. The two high-quality P. zopfii genomes provide new insights into their evolution as obligate heterotrophs and pathogenicity.
OBJECTIVE: The genus Prototheca, characterized by its heterotrophic nature and pathogenicity, serves as an exemplary model for investigating pathobiology. The limited understanding of the protothecosis infectious disease is attributed to the lack of genomic resources. Using HiFi long-read sequencing, both nuclear and plastid genomes were generated for two strains of P. zopfii. The findings revealed a concurrent reduction in both plastid and nuclear genome size, accompanied by the loss of genes associated with photosynthesis, carotenoid oxygenase, basic leucine-zipper (bZIP) transcription factors, and others. The analysis of horizontal gene transfer revealed the presence of 1.37% and 1.49% bacterial genes, including malate synthase and isocitrate lyase, which play crucial roles in carbon and nitrogen metabolism, as well as pathogenicity and obligate heterotrophy. The two high-quality P. zopfii genomes represent valuable resources for investigating their adaptation and evolution as obligate heterotrophs, as well as for developing future prevention and treatment strategies against protothecosis.