Metatranscriptomes of Stephanodiscus binderanus and its chytrid Zygophlyctis sp.

Stephanodiscus binderanus is a frequent component of winter diatom blooms in the Laurentian Great Lakes and can persist into the spring months. Recent studies have examined the impact of climate change on these blooms, particularly in relation to changes in ice cover, turbidity, light penetration, and water temperature. Alongside these environmental factors, fungal parasites, notably those in the Chytridiomycota group, play a role in suppressing phytoplankton growth and altering bloom succession. To address the effects of both biotic and abiotic factors on S. binderanus, a range of temperatures (9.5 - 22.1 C) and a range of light intensities (15, 30, 50, 100 umol m-2 s-1) were tested for both Zygophlyctis sp. (chytrid) infected or uninfected S. binderanus cultures. Growth was monitored for a period of 13 days before samples were harvested for metatranscriptomes. Upon completion, the remaining volume between replicates was pooled to reach a reasonable volume for transcriptomic analysis. Three temperature treatments were created: Low (9.4 - 13.1 C), Mid (15 - 18.8 C), and High (19.5 - 24 C). Pooled temperature samples were then filtered onto a 0.22 um PES Sterivex cartridge filter in duplicate for a total of 12 filters per light treatment (duplicates of each temperature from infected and uninfected samples). Whole RNA was extracted from Sterivex cartridge filters using the PowerWater RNeasy kit. Due to low sample concentration as estimated by the Bioanalyzer, eight samples were dropped from the analysis (all samples from the 15 umol light treatment, the low temperature infected from the 30 umol light treatment, and the high temperature infected from the 50 umol light treatment). CD genomics performed additional RNA QC, which identified other samples that were not suitable for sequencing (Removed treatments included the low temperature infected sample from the 100 umol PPFD, the mid temperature uninfected from the 50 umol PPFD, and both the low and mid temperature uninfected from the 30 umol PPFD). The remaining 12 samples that were sequenced were run twice as technical replicates to generate 1.6 to 5.5GB data per sample. Sequencing was done on a NovaSeq PE150 with a target of 50M total reads per sample.