Characterizing host-pathogen interactions between Zostera marina and Labyrinthula zosterae

Code, output files, figures, and supplementary information associated with the manuscript, "Characterizing host-pathogen interactions between <em>Zostera marina</em> and <em>Labyrinthula zosterae</em>." <br> Seagrass meadows serve as an integral component of coastal ecosystems but are declining rapidly due to numerous anthropogenic stressors including climate change. Eelgrass wasting disease, caused by opportunistic <em>Labyrinthula </em>spp., is an increasing concern with rising seawater temperature. To better understand the host-pathogen interaction, we paired whole organism physiological assays with dual transcriptomic analysis of the infected host and parasite. Eelgrass (<em>Zostera marina</em>) shoots were placed in one of two temperature treatments, 11° C or 18° C, acclimated for 10 days, and exposed to a waterborne inoculation containing infectious <em>Labyrinthula zosterae</em> (<em>Lz</em>) or sterile seawater. At two- and five-days post-exposure, pathogen load, visible disease signs, whole leaf phenolic content, and both host- and pathogen- transcriptomes were characterized. Two days after exposure, more than 90% of plants had visible lesions and <em>Lz</em> DNA was detectable in 100% percent of sampled plants in the <em>Lz </em>exposed treatment. Concentrations of total phenolic compounds were lower after 5 days of combined exposure to warmer temperatures and <em>Lz</em>, but were unaffected in other treatments. Concentrations of condensed tannins were not affected by <em>Lz</em> or temperature, and did not change over time. Analysis of the eelgrass transcriptome revealed 540 differentially expressed genes in response to <em>Lz </em>exposure, but not temperature. <em>Lz</em>-exposed plants had gene expression patterns consistent with increased defense responses through altered regulation of phytohormone biosynthesis, stress response, and immune function pathways. Analysis of the pathogen transcriptome revealed up-regulation of genes potentially involved in breakdown of host defense, chemotaxis, phagocytosis, and metabolism. The lack of a significant temperature signal was unexpected, but suggests a more pronounced physiological response to <em>Lz</em> infection as compared to temperature. Pre-acclimation of eelgrass plants to the temperature treatments may have contributed to the limited physiological responses to temperature. Collectively, these data characterize a widespread physiological response to pathogen attack and demonstrate the value of paired transcriptomics to understand infections in a host-pathogen system.

本数据集包含与研究论文《大叶藻（*Zostera marina*）与大叶藻枯萎病菌（*Labyrinthula zosterae*）的宿主-病原体互作特征解析》相关的代码、输出文件、图表及补充信息。
海草床是海岸生态系统的重要组成部分，但受气候变化等多重人为胁迫影响，正快速衰退。由机会性寄生藻*Labyrinthula*属物种引发的大叶藻枯萎病，随海水温度升高正日益受到关注。为深入解析宿主-病原体互作机制，本研究将全生物体生理学实验与感染宿主及病原体的双转录组分析相结合。
实验将大叶藻（*Zostera marina*）芽体置于11℃或18℃两个温度梯度下驯化10天，随后分别用含感染性大叶藻枯萎病菌（*Labyrinthula zosterae*，简称Lz）的水体接种液或无菌海水进行处理。于暴露后第2天和第5天，分别对病原体载量、可见病害症状、叶片总酚含量以及宿主和病原体的转录组进行表征分析。
暴露后2天，Lz处理组中超过90%的植株出现可见病斑，且100%的采样植株均可检测到Lz DNA。在高温与Lz联合暴露5天后，植株总酚类化合物浓度显著降低，但其他处理组的总酚浓度未受明显影响。缩合单宁浓度则不受Lz感染或温度变化的影响，且随时间未发生显著变化。
对大叶藻转录组的分析显示，共有540个差异表达基因响应Lz感染，但不受温度调控。经Lz处理的植株，其基因表达模式符合通过调控植物激素生物合成、应激响应及免疫功能通路增强防御反应的特征。对病原体转录组的分析发现，参与宿主防御降解、趋化性、吞噬作用及代谢过程的基因出现上调表达。
未检测到显著的温度相关转录信号，这一结果出乎预期，但表明相较于温度变化，植株对Lz感染的生理响应更为显著。大叶藻植株预先进行温度驯化，可能是导致其对温度的生理响应有限的原因之一。综上，本研究数据表征了宿主对病原体侵染的普遍生理响应，并证实了双转录组分析在解析宿主-病原体互作系统中感染机制的应用价值。