A comparative analysis of the tomato MAPK cascade at the transcriptional and translational levels under low-temperature conditions.

Mitogen-activated protein kinases (MPKs) are involved in the cold response of plants; however, in tomatoes, their regulation has been studied only at the mRNA level. In this study, a comparative analysis of the transcriptional and translational regulation of the MAPK cascade in tomato (Solanum lycopersicum) under cold stress and hardening was conducted using polysomic profiling with parallel sequencing of total and polysomic RNA fractions. For representatives of all four groups (A-D), as well as the upstream kinases SlMAPKKK, we calculated mRNA differential expression and translational efficiency. Most cascade components were regulated predominantly at the translational level and mRNA levels remained stable. Groups C and D were profiled for the first time under cold conditions, and candidate translational cold regulators were identified.