Role of Nutritional Status on Arsenic Toxicity in Daphnia pulex: A Transcriptomic Perspective on Individual and Interactive Effects

Our results show that phosphorus limitation was the dominant stressor as a main effect and as a co-stressor. Interaction terms with phosphorus produced exponentially more differentially expressed genes than main effects alone.

Our results also indicate that the low phosphorus x arsenic interaction impacts Daphnia pulex gene expression greater than the low food x arsenic interaction. Importantly, all nutrient–arsenic interactions exhibited antagonistic gene expression patterns supporting a growing body evidence that arsenic behaves antagonistically as a co-stressor. This study provides novel mechanistic insight into how phosphorus content, rather than food quantity, modulates arsenic toxicity at the transcriptional level.