新疆两种药用阿魏植物内生细菌多样性及抗病促生菌株筛选

Abstract

Xinjiang, a region of high salinity and drought, is a host to many arid and semi-arid plants. Endophytes live within a plant for at least part of its life cycle without causing apparent disease. Many of these plants including Ferula spp. have indigenous pharmaceutical histories. As many of the medicinal properties of plants are in tandem with the associated microorganisms residing within the plant tissues, it is advisable to explore the endophytic potential of such plants. The present study involved the isolation of endophytes from different tissues of F. sinkiangensis K. M. Shen and F. songorica Pall. ex Spreng and analyzed the distribution pattern among the plant tissues. In addition, the plant growth promoting traits and their biocontrol potential ontaining proction of protease and cellulose, posphate solubilization, ntrogen fixation, sderophore production, indole acetic acid (IAA) synthesis and atagonism assay were studied. During the study, a total of 170 endophytic bacteria belonging to 3 phyla, 15 orders, 20 families, 27 genera and 58 species were isolated from F. songorica. 125 endophytic bacteria belonging to 3 phyla, 13 orders, 23 families and 29 genera were isolated from F. sinkiangensis. The genera Bacillus and Streptomyces constituted a major portion of the endophytic microbes associated with F. songorica and also F. sinkiangensis. The index values according to Shannon and Margalef were 4.02 and 16.55 respectively. Comparing the endophytes from different habitats, it was found that endophytes from Tacheng exhibited more abundant, but those from Shihezi showed more diverse. The 170 endophytes strains in F. songorica were distributed in 27 genera, but 125 endophytes strains in F. sinkiangensis were distributed 29 genera. During this study, root tissues were found to be a more suitable host for endophytic bacteria as compared to stem.Growth promotion assays indicate that most of the endophytes were able to promote plant growth. In this study, 88.0% of the total isolates from F. songorica were capable of grow in nitrogen-free medium, 79.4% and 75.8% of the isolates from F. sinkiangensis were able to produce IAA and fix nitrogen respectively, and 57.1 % of the strains were positive in siderophore production. Salt tolerant experiment of endophytes showed that 5 strains of endophytes grew normally under the condition of 7 % NaCl. Further research about growth promotion ability was carried out by seed germination of wheat.It demonstrated that endophytes bacteria could improve the germination rate of wheat seeds, increase the length and biomass accumulation under salt stress.During This study, there are some potential novel specises belonging to the genera Nocardioides, Paracoccus, Amycolatopsis and Porphyrobacter discovered. This research showed that the protcection of Ferula resource and endophytes in plant tissue were urgently required. This study revealed the great significant ecological adaptability of Ferula, and also the function of endophyes in improving plant disease resistance and stress toleration