LAUSR

Low temperature is a major stress that severely affects plant development, growth, distribution, and productivity. Here, we examined the function of a 2-oxoglutarate-dependent dioxygenase-encoding gene, SlF3HL, in chilling stress responses in tomato (Solanum lycopersicum cv. Alisa Craig [AC]). Knockdown (KD) of SlF3HL (through RNA interference) in tomato led to increased sensitivity to chilling stress as indicated by elevated levels of electrolyte leakage, malondialdehyde (MDA) and reactive oxygen species (ROS). In addition, the KD plants had decreased levels of proline and decreased activities of peroxisome and superoxide dismutase. The expression of four cold-responsive genes was substantially reduced in the KD plants. Furthermore, seedling growth was significantly greater in AC or SlF3HL-overexpression plants than in the KD plants under either normal growth conditions with methyl jasmonate (MeJA) or chilling stress conditions. SlF3HL appears to positively regulate JA accumulation and the expression of JA biosynthetic and signaling genes under chilling stress. Together, these results suggest that SlF3HL is a positive regulator of chilling stress tolerance and functions in the chilling stress tolerance pathways, possibly by regulating JA biosynthesis, JA signaling, and ROS levels.Chill stress: Gene regulator identified in tomato plantsA gene involved in regulating responses to chill stress in tomato plants may prove valuable in reducing crop damage caused by low temperatures. A significant limiting factor in growing certain crops is cold stress – for example, tomato and cucumber plants suffer chill damage and reduced productivity at low temperatures (0 to 12 °C). Xianggiang Zhan at the Northwest A&F University in Shaanxi, China, and co-workers demonstrated that the gene SIF3HL is a key regulator of chilling stress tolerance in tomato plants. The team generated plants with no SIF3HL expressed and found that they responded poorly at low temperatures, with higher levels of reactive oxygen species and decreased levels of metabolic enzymes. Expression levels of four cold-responsive genes were also reduced. Plants overexpressing SIF3HL, on the other hand, coped well at low temperatures.