Isolation And Growth-promoting Effect Of Endophytic Bacteria From Tripterygium Wilfordii

Tripterygium wilfordii(Tripterygium wilfordii Hook.F.),a kind of precious medicinal plants,is mainly distributed in China's Fujian,Zhejiang,Anhui,Jiangxi,Taiwan and other provinces and belongs to the celastraceae plants of the genus Tripterygium wilfordii.Endophytic bacteria widely exists in various kinds of healthy plant tissues and organs.They coexist harmoniously and influence mutually with their host plant.The symbionts of endophytic bacteria and their host plants is also regarded as a kind of common phenomenon in nature.In the plant ecosystem,the endophytic bacteria live very long in plant body and have an important impact on the physiological and biochemical activity of the host plants.Some endophytic bacteria have been shown to play a beneficial role in biology,not only can they promote the growth by dissolving phosphorus,fixing nitrogen,producing iron carrier,secreting auxin and many other ways,but also play an important role in fields of plant adversity resistance,resistance to animal feeding and resistance of pathogenic bacteria.In recent years,domestic and foreign scholars have screened endophytic bacteria which have important influence on the process of plant secondary metabolism from different medicinal host plants one after another.Not only can they produce their own special active substances,but also participate in synthesis of plant active ingredients or promote the transformation of plant secondary metabolites.This article separated endophytic bacteria from healthy tripterygium wilfordii,screened and identified those bacteria with probiotic effects.We evaluated the actual impact on the growth-promoting and triptolide synthesis through the vaccine technology and suspended elicitor adding technology.The main results are as follows:1.A total of twenty-three endophytic bacteria were isolated from Tripterygium wilfordii,among which four strains were selected for further studying based on their capabilities of growth-promoting and wheat germination.All four isolated strains could produce phytohormone,and LG3 and LJ10 strains were capable of dissolving phosphorus.Additionally,LG3 and LY4 strains were both proved to have nitrogen-fixing function and 1-aminocyclopropane-1-carboxylate deaminase activity.2.Bacterial 16S rDNA sequence identification and homology analysis suggested that LG3 and LY4 strains belonged to the Enterobacter and LJ10 belonged to the Pantoea and LY3 belonged to the All their similarity was 99%.3.The results of reinoculation experiment demonstrated that four endophytic bacteria could not only promote the growth of Tripterygium wilfordii,but also improve the triptolide contents of different organs significantly.In physiological and biochemical aspects,these four endophytic bacteria can improve host's chlorophyll content and the activity of peroxidase(POD)and superoxide dismutase(SOD)and reduce the production rate on superoxide anion and the content of malondialdehyde in plant.4.The experiment inoculated 4 target strains into hydroponic tripterygium wilfordii,and the result showed that these four target strains could promote the growth of tripterygium wilfordii plant.LY4 and LG3 strains grew the most obvious effect.At the same time,the four target strains could promote nutrient elements's(including C,N,P,K)absorption in different degrees and triptolide's synthesis.While polyphenol oxidase(PPO)activity of each treatment changed little,phenylalanine ammonia solution enzyme(PAL)activity is in contrast to the growth conditions of tripterygium wilfordii,namely the better TWHF grew,the lower the PAL activity was.5.Inducer was devided into 3 kinds:endophytic bacteria bacterium liquid(P),crude extractings from endophytic bacteria(J)and untreated living bacterium(H).We added these three kinds of inducer into tripterygium wilfordii suspension cells,and the results showed that the three kinds of inducer can increase the soluble sugar's consumption rate in suspension cell cultures and the content of soluble protein in the cell.P group processing had obvious influence on the growth of tripterygium wilfordii suspension cells,among them,the P-LJ10 and P-LG3 processing grew the best effect.