Isolation And Identification Of Endophytic Bacteria From Lavender And Its Growth Promoting Effect

Lavender has high economic value and can bring high economic benefits to local farmers in Ili.However,at present,lavender planting in China still depends on pesticides and chemical fertilizers.The extensive use of chemical fertilizers and pesticides has caused serious environmental pollution and even affected the quality of lavender.Studies have shown that plant endophytic bacteria producing1-aminocyclopropane-1-carboxylate(ACC)deaminase can promote the growth of can be used as one of the main resources for the development of biological bacterial fertilizer.However,at present,the research on the growth promoting effect of lavender endophytic bacteria has not been reported at home and abroad.Therefore,this study isolated and identified Lavender endophytic bacteria with ACC deaminase activity and endophytic fungi with antibacterial activity,and detected their biological activities.Objective: to isolate and screen endophytic fungi with antibacterial activity and endophytic bacteria with ACC deaminase from the root tissue of lavender in Huocheng County,Ili Kazakh Autonomous Prefecture,Xinjiang.Methods: lavender in Yili River valley was used as material,(1)endophytic fungi and endophytic bacteria were isolated from Lavender roots by tissue isolation method;(2)Strains with ACC deaminase activity were screened from Lavender endophytic bacteria;(3)The antibacterial activity of endophytic fungi was determined by disk diffusion method;(4)The strains were identified based on morphological characteristics,physiological and biochemical experiments and 16 S r RNA sequence analysis;(5)The seed germination experiment was used to detect the promoting effect of ACC deaminase active strains on lavender seed germination or lavender seedlings.Results: nine strains of endophytic fungi with different morphological characteristics were isolated from the roots of lavender.One strain ydz-8 with antibacterial activity was screened through antibacterial test,and identified as Trichoderma harzianum by molecular biological method.70 strains of endophytic bacteria with different colony and cell morphological characteristics were isolated from the root of lavender.Seven strains containing ACC deaminase were screened from 70 strains of endophytic bacteria with ACC as the only nitrogen source.The identification results showed that strains ydx-1,ydx-2,ydx-6 and ydx-7 were Klebsiella aerogenes,while strains ydx-8,ydx-12 and ydx-21 were Enterobacter ludwigii.All 7 strains had ACC deaminase activity in varying degrees,and the enzyme activity of strain ydx-8 was the highest.Compared with the sterile water treatment group,the ACC deaminase active strain treatment group had no significant effect on lavender seed germination.Strains dx-8,ydx-12 and ydx-21 showed different promoting effects on the growth of lavender seedlings,among which strain ydx-8 had the most obvious promoting effect.After 7days of growth of lavender seedlings treated with strain ydx-8,compared with the control group,the average root fresh weight increased by 10% and the average root length increased by 41%.Compared with the control group,the average root length and average fresh weight of lavender seedlings treated with strain ydx-6 decreased by 14%and 22% respectively.Conclusion: the ACC deaminase active strains and antibacterial fungi obtained in this study provide materials for the further study of the plant growth promoting mechanism of ACC deaminase active strains.