Two-Spotted Spider Mite-Induced ROS-Dependent Direct Defenses

Plants empoly diverse strategies to resist arthropod herbivores that were divided into direct defenses and indirect defenses, and some direct defense were ROS-dependent direct deferance with characterized ROS-dependent direct deferance induced by pathogen, like bacterial, fungal and virus. With the frijole (Phaseolus vulgaris.L) invaded by the two spotted spider mites (Tetranychus urticae Koch), in T.urticae-frijole interaction, performances, egg laying amounts, juvenils of T.urticae and damages to frijole leaves inflicted by adult female spider mites, the effect of spider mite to frijole on the release of endogenous ROS and the system of antioxidases, the effct of T.urticae and mechamical wiunding on ROS-dependent direct deferance were studied in this paper. The experiments show.1. The basic data were abtained though researching performances, egg laying amounts, juvenils of T.urticae and damages to frijole leaves inflicted by adult female spider mites in T.urticae-frijole interaction. These data were useful to selecting treatment conditions of infectation by spider mite, and the dentisy of spider mite was quantitative. Results:Daily egg laying amounts procreated by one adult female spide mite(2/4-d-old at day 0 of experiment) were increased during 1-3d and decreaced during 4-6d, and eggs began to hatch out on the third day. Therefore the densities of T.urticae were nearly invariable over a period of 5d.The sippled-bleached effect on frijole leaves over period of 5d infilicted by 1,5,10,15 adult female spide mites increaced along the increasing densisy of adult females and over time.2. Differentical ti ming of spider mite inducing the release of endogenous ROS and the regulation of antioxidant enzymes were studied. As them tured out. (1) Frijole leaves produced ROS induced by T.urticae, and the changes of H2O2 content and the generating rate of O2-showed regularity that growth of peaks delayed with the increacing densities of T.urticae; (2) The system of antioxide activied by T.urticae. SOD activity and the generating rate of O2-peaked at same time. The excessive was controled to some degree with actions of CAT and APX. POD activity raised and it was higher than other three antioxidases. (3) Lignin was produced and the changes of lignin liked changes of H2O2 content and the generating rate of O2-, that is, growth of peaks delayed with the increacing densities of T.urticae; It went to show that the production of lignin influenced by ROS. The experiments show that T.urticae induced ROS-dependent direct deferance with characterized ROS-dependent direct deferance induced by pathogen, like bacterial, fungal and virus. And The effects of differential ti ming and density of spider mite-induced ROS-dependent direct deferance in frijole plants were different, insdead that were absolutely positive correlaion.3.To know whether the difference of the dependent direct deferance in between leaves which were invaded by the two spotted spider mites and leaves on which was pinpricked, the release of endogenous ROS and SA content were studied. The experiments showed that T.urticae induced ROS-dependent direct deferance, and produced ROS and SA at the same time. Whereas H2O2 content, the generating rate of O2-, lignin and SA content of spider mite-induced or wound-induced is different, the former may be dependent on many defenes like ROS-dependent direct deferens, and yet the latter may be only dependent would-induced deferance.