The Molecular Mechanism Of Defense And Tissue Regeneration After Cutting In Zoysia Japonica

In order to explore the molecular mechanisms of the defense mechanisms after pruning and the tissue regeneration process of Zoysia japonica,we studied some influence that those phytohonnones such as Jasmonate(JA),abscisic acid(ABA),auxin(IAA)and cytokinin(CTK)had caused.In this research,hydrogen peroxide level and cell membrane penneability of wounded leaves of Zoysia japonica cultivar 'Zenith' were detected at 0 h,2 h,6 h,and 24 h after cutting and we analyzed recovery of the wounded leaves.Photographs and microscopic observations were performed simultaneously during the regeneration process to analyze those changes in the morphology and meristem microstructure in apical meristems.The transcriptome data were screened to analyze the distribution of differentially expressed genes(DEGs)in metabolic process.In the meantime,ELISA and qRT-PCR techniques were used to investigate the response patterns of JA,ABA,IAA,CTK,and related genes.Through this research,results are as follows:1.In Zoysia japonica,there may be a biosynthetic process of ABA induced by the ROS outbreak,resulting in a ABA level of 2 h after pruning,which is higher than that of 6 h after cutting.Moreover,the synthesized ABA may be involved in wound healing and ROS elimination after cutting.2.After cutting,JA in Zoysia japonica may be involved in the overall trauma defense response of the plant,while the JA signal transduction pathway may be synergistic with the ethylene signal pathway to resist the damage caused by the pathogenic bacteria caused by the wound.3.In the pruned Zoysia japonica,ZjPINl regulated IAA polar transport in response to pruning may participate in the formation of organ primordia in the 2 h and 24 h stem apex meristem of Zoysia japonica,while IAA signal transduction pathway is more active after pruning 6 h,which may be related to the rapid growth of subsequent plants.4.ZjWUS may participate in the proliferation of cells in stem apex meristem after cutting 2 h and 24 of Zoysia japonica,while CTK signal begins to be active at 6 h after cutting,which in turn inhibits the expression of ZjWUS,and maintains the stable number of stem cells in the stem apex meristem and the production of tillers.These results showed that JA,ABA,IAA and CTK,those four plant hormones played important role in downstream response to signal transduction pathways to the defense mechanisms and tissue regeneration of Zoysia japonica.This study provided a theoretical basis for the molecular mechanisms of defense mechanisms and tissue regeneration after mechanical damage in plant.