Method for isolating mesophyll protoplasts from Arabidopsis as a system for monitoring RNA stability using transcriptional inhibitors (e.g. cordycepin) under stress treatments (e.g. high-light or hydrogen peroxide treatment).Adapted from Yoo S.-D., Cho Y.-H. & Sheen J. (2007) Arabidopsis mesophyll protoplasts: a versatile cell system for transient gene expression analysis. Nature Protocols 2, 1565–1572.