Biodiversity Of Endophytic Bacteria Associated With Pinellia Ternate And Their Effect On The Accumulation Of Secondary Metabolites Of P.ternata

This study aims to investigate the diversity of endophytic bacteria from the medicinal plant Pinellia ternata and potential plant growth promoting activities,and evaluate the effect of plant growth promoting bacteria(PGPB)on the growth and the accumulation of secondary metabolite of P.ternata,which were collected from Xuzhou of Jiangsu Province.We combinated of pure culture and free culture to analyze the community structure of endophytic bacteria in P.ternata.According to the morphological characteristics,we choosed the representative cultivated endogenous strains to do phylogenetic analysis.PGPB were selected based on the results of PGP indicators and wheat growth experiment.We also explored the influence of the strain KLBMPPT001,KLBMPPT024 and Co-culture on the accumulation of secondary metabolites of P.ternata.We isolated 53 endophytic bacteria from root,stem and leaf of P.ternata.16 S rRNA gene sequencing showed that 35 culturable endophytic bacteria belonged to two phyla(Firmicutes and Proteobacteria)and seven different genera,the genera Bacillus was the most predominant isolates.High throughput sequencing data analysis showed that endophytic bacteria from P.ternate included six phyla(Actinobacteria、Proteobacteria、Tenericutes、Firmicutes、Bacteroidetes、Cyanobacteria)and many different genera,and many endophytic bacteria can’t be detected in pure culture.The result showed that the most predominant isolates included twenty nine different genus such as Flavobacterium and so on.We found that many endophytic bacteria from P.ternate have the potential growth promoting activities based on the experiment of plant growth promoting.The result of plant growth promoting of bacteria showed that 78% strains are equipped with potential ability of nitrogen fixation,48% strains have the ability of phosphate solubilization,30% strains have the ability of organic phosphorus solubilization,96% strains could product siderophores,57% strains have the potential ability of ACC deaminase,65% strains could product indole-3-acetic acid,87% strains could product cellulase,74% strains could product xylanase,70% strains could product protease,22% strains could product amylase.The results of wheat growth experiment showed that some strains could promote the wheat growth and some strains could inhibit the growth of wheat in plates.The effect of strains(KLBMPPT001,KLBMPPT011,KLBMPPT012,KLBMPPT024)on wheat growth promoting is most obvious.The results of wheat experiment in pot showed that four strains could promote the wheat growth in different level.KLBMPPT001 increased shoot length up to 14%,and root length up to 48%.The wheat has the largest long shoots(25.34 cm)when inoculated KLBMPPT024.KLBMPPT001 and KLBMPPT024 were re-isolated from inoculated wheats.The results of inoculating P.ternata aseptic seedlings indicated that strains KLBMPPT001 and KLBMPPT024 significantly promoted the growth of host plant P.ternate and affected the accumulation of P.ternata secondary metabolites.Compared with control group,these strains increased the shoot length up to 55%-194%,root length up to 90%-307%,leaf area up to 121%-232%,fresh weight up to 6%-231%,dry weight up to 17%-165%,and the accumulation of total alkaloids increased up to 50%-140%,guanosine increased up to 17%-219%.This study showed the rich diversity of endophytic bacteria in P.ternata and potential plant growth-promoting activity and the effect of PGPB on the accumulation of secondary metabolite in P.ternate.The results provide a solid foundation for solving medicinal plant P.ternate resources shortage and accumulation of active ingredients.