626 / 2019-04-25 17:20:50

Silver nanoparticles inhibit Arabidopsis root growth and induce root waving in an ethylene and brassinosteroid-dependent manner

nanoparticle,root growth,Plant hormone

Growth and Development > Growth and Development

Silver nanoparticles (AgNPs) are used in a wide range of consumer products due to their antimicrobial, optical and conductive properties, and their leakage could potentially pose a risk to the environment. However, it remains unclear how AgNPs interact with plant growth and development. Our study showed that treatment of AgNPs (size 10-20 nm at 3-10 mg/L) inhibited Arabidopsis root growth and induced root waving phenotypes, and the effect was more pronounced than that of silver ion (Ag+) at equivalent concentrations. Microscopic analyses of the root tips revealed that AgNP treatments reduced root apical meristem size. Using hormone signaling and biosynthesis mutants, we found that the ethylene signaling mutant ctr1-1 showed no response to AgNP treatment, suggesting that ethylene signaling downstream of CTR1 is necessary for the response. Similarly, root growth of the brassinosteroid (BR) biosynthesis mutants dwf4 and det2-1 and the BR-insensitive mutants bri1-116 and bin2-1 did not respond to AgNP treatments. This suggests that BR is involved in AgNP-mediated root responses, and the response is dependent on the BRI1-dependent brassinosteroid signaling pathway. Our results highlighted the effects of AgNPs on root growth and development, which act through the ethylene and brassinosterod signaling pathways.