Total Arabidopsis RNA was isolated according to the manufacturer's protocol using an Isolate RNA Minikit (Bioline, NJ). cDNA was synthesized using a high‐capacity DNA reverse transcription kit (Applied Biosystems, CA). RT‐qPCR reactions were done using a 7500 Fast Real‐Time PCR system (Applied Biosystems, CA) as described earlier (Mooney et al., 2019 (link)). Arabidopsis Actin2 (At3g18780) was used as the internal control gene, and all experiments were repeated at least three times as biological replicates, if not otherwise stated. For in planta detection of U‐PEST and U‐SBC expression specific primer pairs were designed that covered eK and PEST or SBC regions, respectively. All primers used are listed in Table S1. The 2(‐Delta Delta C(T)) method was used to calculate relative gene expression (Livak & Schmittgen, 2001 (link)).