ABSTRACT: We used Bio-Rad laboratories, lnc. PCR assay panel to analyze expression levels of MAPK genes under various stress conditions and plant hormone treatments. Cucumber plants of the ‘Jinyan No.4’ cultivar were reared in growth chambers at 28 ± 1 °C with a photoperiod of 16 h light/8 h dark and light intensity of 400 μmol m−2 s−1. Three-week-old seedlings were used for all abiotic and biotic treatments. For heat or cold treatment, the seedlings were subjected to 35 ± 1 °C or 4 ± 1 °C conditions, respectively. The samples for RNA extraction were collected at 0, 1, 2, 4, and 8 h after treatment. For dehydration treatment, the leaves of plants were sampled at 0, 2, 4, and 6 d after watering stopped. For disease treatment, Pseudoperonospora cubensis (P.cubensis) was used to infect the seedlings, and leaves were collected at 0, 1, 2, and 3 d after infection. For hormone treatments, the seedling leaves were sprayed with 100 mM methyl jasmonate (meJA) or 100 mM abscisic acid (ABA) and then sampled at 0, 1, 2, 4, and 8 h intervals. The experiment was designed to examine the transcription patterns of 58 MAPK cascade genes in cucumber in response to three different abiotic stresses (cold, heat, and drought), one biotic stress (Pseudoperonospora cubensis) and two (MeJA and ABA) plant hormone treatments.
