The Studies On Rutin Primed Plant Resistant To Three Types Of Disease As A Plant Elicitor

Rutin, an important part of natural plant flavonoid compounds, has lots of functions such as improving plant stress resistance, antioxidation, scavenging free radicals, anti-bacterial and so on. In recent years, there is considerable interest in flavonoid compounds research. Rutin has been received with numerous applications in the field of the Food and Pharmaceutical, However compared to other flavonoid compounds, activity of rutin has not been studied on plant defense. In order to detect the antibacterial activity to several pathogens, extra rutin was added in cultural medium. It shows that, spraying rutin can not only enhance the resistance of plant to pathogen, but also increase the expression of plant defense related genes. As a conclusion, rutin has antibacterial activity of plant bacteria pathogens and could trigger the lant defense response as an elicitor. Finally, rutin was sprayed on several Arabidopsis marker mutants to analyze the signal transduction pathway of defense which is mediated by rutin.Different concentration of rutin was added to the cultural mediums so that to detect the antibacterial activity of several plant bacteria pathogens. The result showed that the minimum inhibitory concentration (MIC) of rutin against RS85is0.25mM with concentration in l×103cfu/ml; MIC of rutin against PXO61, PXO99and RH3is0.5mM, and it was2mM for against Ralslonia solanacearum pv. tobacco and Pseudomonas syringae pv. tomato DC3000. When the inoculation concentration of bacteria was OD6oo=0.5, the necessary concentration of rutin is0.5mM for PXO61, PXO71, JL691, PXO339c, PXO339b strains, and it is1mM forPXO86, PXO99and PXO339a, which completely suppressed the growth of rice bacterial blight pathogen.Rutin was sprayed on plant leaves in vitro in order to study the rutin-induced plant resistance againsted bacterial diseases. Nicotiana benthamianas was enhanced to resistant to Ralstonia solanacearum pv. tobacco after treated with rutin ahead, It showed that the number of R. solanacearum on treated leaves was drop down about6.19times compared to untreated leaves on3days after inoculation. In rice-bacterial blight compatible system, the susceptible rice variety MDJ8was increased to resistant to PXO99. The lession length was reduced, and the number of bacteria per leaf was dramatically decreased to about15.05times after6days inoculation. In Arabidoposis-Pseudomonas syringae pv. tomato DC3000compatible system, prctrcatcd of rutin promoted Arabidopsis thaliana Col-0more resistant to Pst. DC3000. The number of bacteria per leaf was decreased to about95.21times after3days inoculation. The above results suggested that rutin can activate the bacterial disease resistance in plants.The expression of plant defense-related (DR) genes were also analyzed after inoculated pathogen either pretreated rutin or not. The results show that the expression of NbPR1a, NhrhohB and NbNOAl in N. benthamianas, OsPR1a, OsPR1b, OsPR10, OsLOX, OsPAL and OsPOX in rice, and AtPR1, AtPR2, AtPR5, AtPAL in Arabidopsis, was strongly activated by their compatible bacteria pathogen inoculation with pretreated rutin. Except the detected OsCAT gene upregulated expression was not assoeaited with preteated rutin in rice leaves.Furthermore, the effect of pretreated rutin was studied on some Arabidopsis mutants and some transgenic Arabidopsis involved in plant defense signal pathways with Arabidoposis-Pst. DC3000compatible system. The reults show that the induced resistance was null on npr1mutant and transgenic plant carried NahG, decreased on pad4-1,jar1and ein2-5, and no effect on snc1-11. It suggested that the induced resistance by spraying rutin was mainly dependent on SA pathway, and it also involved in JA/ET pathway.In summary, rutin has antibacterial activity to plant pathogens in vitro, and aslo can induce the resistance to bacterial diseases. After spaying ahead, rutin will activate strongly to induce the expression of some DR genes after inoculation, and this induced resistance was mainly dependented on SA pathway. The results aslo provide the theory to develop bio-pesticide to prevent plant bacterial disease in the future.