Abstract: 【Aim】 This study aims to investigate how infestation of Tetranychus cinnabarinus induces the generation of six defense signal molecules, including jasmonic acid (JA), salicylic acid (SA), ethylene (ET), nitricoxide (NO), abscisic acid (ABA) and hydrogen peroxide (H₂O₂) in leaves of Zea mays seedlings. 【Methods】 We measured the contents of the signal molecules in leaves of corn seedlings at 0, 24, 48, 72 and 96 h after inoculation of T. cinnabarinus (10, 20 and 30 individuals per leaf) by using spectrophotometry (SP), high-performance liquid chromatography (HPLC) or enzyme-linked immunosorbent assay (ELISA). 【Results】 Our data demonstrated that the contents of JA, ABA and H₂O₂ in leaves of corn seedlings infected by T. cinnabarinus increased rapidly within 24 h after infestation, and peaked at 24 h after inoculation of 30 individuals per leaf, which were 4.13, 3.84 and 3.20-fold as high as those of the un-inoculated control, respectively. Subsequently, the contents of JA, ABA and H₂O₂ in the infected group descended sharply from 24 to 48 h after infestation. The contents of ABA and H₂O₂ in the infected group stayed at a low level from 48 to 96 h after infestation, whereas the JAcontent in the infected group reached another peak at 96 h after infestation. The NO content in the infected group rose up from 24 to 48 h after infestation, peaked at 48 h after inoculation of 30 individuals per leaf, which was 5.09-fold as high as that of the control. The contents of SA and ET in the infected group had been increasing during the whole time of infestation, and peaked at 96 h after inoculation of 30 individuals per leaf, which were 5.17 and 2.99-fold as high as those of the control, respectively. The contents of the six signal molecules in leaves of corn seedlings infested by 30 individuals per leaf were significantly higher than those in the un-inoculated control. 【Conclusion】 The results suggest that the infestation of T. cinnabarinus induces the accumulation of JA, SA, ET, NO, ABA and H₂O₂ in leaves of corn seedlings, which are activated sequentially during infestation process.

Key words: Tetranychus cinnabarinus, Zea mays, defense signal molecules, jasmonic acid, salicylic acid, ethylene, nitricoxide, abscisic acid, hydrogen peroxide