Fig. 2

The old12 mutant displays a low-temperature-induced lesion mimic phenotype. A Panel I, 28 DAS old12 and wild-type (WT) plants grown in long-day photoperiod (16 h) at 28 °C. Panel II, Phenotype of old12 and WT plants grown for 28 days + 14 days at 28 °C. Panel III, Transfer of old12 plants grown for 28 days at 28 °C to 16 °C for 14 days results in stunted growth and an early onset of senescence as compared to WT. Scale bar = 1 cm. B Chlorophyll (Chl) content in the fifth and sixth leaf of old12 and WT at the different growth conditions shown in (A). Box plots show median and interquartile ranges (IQR), outliers (> 1.5 times IQR) are shown as circles. C Expression of SA pathway and defense-related genes in old12 and WT leaves grown for 28 days at 28 °C (I), or 28 days at 28 °C plus 2 days at 28 °C (II), or 28 days at 28 °C plus 2 days at 16 °C (III). The relative expression level is shown as mean ± SD of three biological replicates. Expression level for each time point was normalized against ACTIN2 (ACT2). Asterisks indicate significant difference under the conditions tested between old12 and wild type for the genes indicated (Student’s t-test; p ≤ 0.05)