Coordinated and contrasting maturation of phenotypically distinct strains of Eimeria maxima

Intraspecific phenotypic variation markedly influences the damage that parasites inflict on their hosts. Such is the case for strains of Eimeria maxima, a costly enteric parasite of poultry, where strain APU-1 exhibits greater pathogenicity than APU-2. Here, we examined how these strains differ as oocysts mature to the fully-sporulated stage. We performed mi-croscopy and RNA-Sequencing on oocysts at regular intervals (6-12 hours) during sporulation. Although each strain underwent parallel development, APU-1 initially approached maturation more slowly. Each strain achieved full sporu-lation and similar transcription profiles by hour 36, after which strains appeared to diverge. These differences may in-fluence subsequent virulence. Candidate biomarkers of oocyst viability include 58 genes contributing at least 1,000 Transcripts Per Million throughout sporulation. Many genes resemble constitutively expressed genes also important to Eimeria acervulina. Mature and immature oocysts differentially express certain genes. Expression of some such bi-omarkers appears strain-specific. These data illuminate processes that may generally underlie sporulation in Eimeria and related genera, such as Cyclospora, and identify biological processes which differentiate among them. Drivers of devel-opment and senescence may provide tools to assess the viability of oocysts, which would greatly benefit the poultry industry and food safety applications. Overall design: To investigate transcriptional changes during oocyst development that may differentiate pathogenically distinct strains of E. maxima, oocysts from chickens (replicates) were collected every 6-12 hours over a 48 hour sporulation time course for RNA-Sequencing

物种内表型变异显著影响寄生虫对其宿主造成的损害。以家禽中成本高昂的肠道寄生虫 Eimeria maxima 的菌株为例，其中 APU-1 菌株的致病性高于 APU-2。在本研究中，我们考察了这些菌株在子孢子成熟至完全孢子化阶段时的差异。我们对孢子化过程中不同时间间隔（6-12小时）的子孢子进行了显微观察和 RNA 测序。尽管每个菌株经历了平行的发展，但 APU-1 在初始阶段成熟的速度较慢。每个菌株在 36 小时后达到完全孢子化和相似的转录谱，此后菌株似乎开始分化。这些差异可能影响后续的致病力。子孢子存活性的候选生物标志物包括在整个孢子化过程中至少产生每百万转录本数 1,000 的 58 个基因。许多基因与对 Eimeria acervulina 至关重要的组成型表达基因相似。成熟和未成熟子孢子差异表达某些基因。某些此类生物标志物的表达似乎具有菌株特异性。这些数据揭示了可能普遍存在于 Eimeria 及其相关属（如 Cyclospora）孢子化过程中的过程，并确定了区分它们的生物学过程。发育和衰老的驱动因素可能提供评估子孢子存活性的工具，这将极大地造福家禽业和食品安全应用。总体设计：为了研究可能区分 E. maxima 不同致病菌株的子孢子发育过程中的转录变化，我们每隔 6-12 小时收集了鸡的子孢子（重复样本），在 48 小时的孢子化时间进程中进行了 RNA 测序。