Effects of urban traffic noise on the early growth and transcription of Arabidopsis thaliana

Man-made noise in cities has been recognized as one of the major contributors to a range of adverse health outcomes, including heart disease. Besides the detrimental effects on human health, noise can act as a potential threat to other organisms in the ecosystem. Despite the growing concern, the biological effects of noise pollution on plants, in particular, remain largely obscure. Therefore, this study aimed to investigate the impacts of urban traffic noise on the growth of Arabidopsis thaliana (A. thaliana). We hypothesized that traffic noise could stimulate plant growth (seed germination and seedling growth) since noise treatment has been reported to improve immunity and drought tolerance in A. thaliana (1, 2). Seeds in the experimental group were exposed to 48 hours of traffic noise recorded in a highly congested area of Seoul, while the control group was exposed to background white noise. Compared with background white noise, traffic noise exposure had no effects on seed germination but significantly increased the growth of seedlings by 39%. We further investigated the traffic noise-induced molecular changes in the A. thaliana seedlings by employing RNA sequencing. We detected aberrant expression of 690 genes in traffic noise-exposed seedlings. The differentially expressed genes were enriched for various biological pathways, such as stress response and auxin signaling. The observed molecular changes suggest profound impacts of traffic noise on the physiology of A. thaliana. The results of our research can help shed light on the fundamental principles underlying the noise-plant interaction as well as provide a further basis for conserving our ecosystem.