| Cynomorium songaricum Rupr.,a traditional medicinal plant,grows in the arid desert area.As a parasitic plant,most C.songaricum parasite on the root of Nitraria.L and has pharmacological activities,such as anti-aging,replenishing blood and laxative.In this study,the plant materials of parasitic plant C.songaricum,the root of its host Nitraria tangutorum Bobr.and the root of control N.tangutorum in 5 different developmental stages were collected from two different areas in Alashan Left Banner.Endophytic fungi were isolated and identified from the plant materials,and the community structure,species distribution characteristics,biodiversities and ecological succession of endophytic fungi were studied.The analysis results of endophytic fungi isolated with plant tissue culture method showed that 299 endophytic fungi were separated from 15 types of plant tissues,of which 111 kinds were seperated from C.songaricum,48 kinds were seperated from the root of N.tangutorum and 40 kinds were seperated from control,the root of N.tangutorum natural growing independently.The isolation rate of all endophytic fungi were 24.92%.In general,the numbers of endophytic fungi from C.songaricum were less than that from the root of N.tangutorum.Total DNA of endophytic fungi was extracted,and 5.8S-ITS-28 S region was amplified with PCR,sequenced.Then the ITS sequences from 299 isolates were obtained,respectively.All the sequences were analysed and conbined into operational taxonomic units(OTU)based on 97% similarity threshold.A representative strain sequence was selected in each OTU and compared with the data in the Genbank database.Finally,the taxonomic status of the strains were determined.Results showed that 299 sequences were afiliated to 52 OTUs and included 31 genera and 1 unknown species.They contained 16,21 and 14 genera in C.songaricum,the root of host N.tangutorum and the root of control N.tangutorum,respectively.The species distribution of endophytic fungi were statistically analyzed and the dominant strains were evaluated by the isolation frequency.Results showed that Fusarium,Penicillium,Ilyonectria and Aspergillus were the dominant genera in C.songaricum while Fusarium,Penicillium,Ilyonectria and Alternaria were the primary genera in root of host N.tangutorum.Fusarium and Aspergillus were the dominant genera in the control team,N.tangutorum.Fusarium was the shared dominant genera among three plant materials.There were some differences in the distribution of endophytic fungi in different development stages,different regions and different plant tissues while some strains also have specificity to their hosts.The evolutionary changes of C.songaricum and the root of host N.tangutorum of the 5 dominant genera above were not consistent at different developmental stages.Margalef index,Shannon-Wiener index,Pielou evenness index,Simpson index,McIntosh index and Brillouin index were used to analyze the diversities of endophytic fungi.Results showed that Margalef index,Shannon-Wiener index and Brillouin index were the highest in the root of host N.tangutorum in decline period(SNT5),up to 4.445,2.55 and 1.99 respectively.Pielou evenness index,Simpson index and McIntosh index were the highest in C.songaricum in germination period(CSR2)at 0.98,0.978 and 0.956,respectively.In general,the diversity of endophytic fungi in different plant samples was abundant,but the indexes were different among different plant samples.The similarity coefficient was highest between the flower of C.songaricum(TCSF)and the stem of C.songaricum(TCSS)both in TongGu-naoer town at 0.73.There are not the same strain between TCSF and C.songaricum in growing period in Xilin-gaole town(CSR3)as well as TCSF and the root of host N.tangutorum in growing period in Xilin-gaole town(SNT3).The endophytic fungi from C.songaricum-N.tangutorum parasitism in growing period and vigorous period were most similar.This study enriched the resource of endophytic fungi from medicinal plant and provided a scientific basis for recognizing and exploiting C.songaricum. |
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