| Locoweed is a kind of perennial herb poisonous plant, mainly including Astragalus, Oxytropis and Sphaerophysa, which can cause the animal appearing typical neurological symptoms and pathological changes, because of containing swainsonine. Locoweed is the major poisoning grass in natural grassland of our country, and the resistance is too strong to eradicate, leading considerable economic losses to animal husbandry. Some studies find that fungal endophyte is closely related to the synthesis of swainsonine, resistance of plant, and biological activity of metabolites. Fungal endophyte of Astragalus variabilis colleted in Tengeli and Malian Lake in Inner Mongolia and Astragalus strictus collected in Gongbujiangda, Linzhou, and Duilongdeqing in Tibet were isolated and identified in our studies. Specie and population diversity were analyzed by using biodiversity software. Genetic diversity was detected with RAPD and ISSR primers to amplify of the DNA of fungal endophyte in Astragalus variabilis and Astragalus strictus. This study will provide a significant theoretical and technical basisi for synthesis mechanism of swainsonine, interaction between fungal endophyte and host plant, and stress resistance of host plant. The following results have been obtained in this study.1. Isolation, identification and diversity analysis of endophytic fungi in Astragalus variabilis776 strains of endophytic fungi were isolated from 1486 tissues of Astragalus variabilis in Tenger and MaLian Lake in Inner Mongolia, which were combined to 25 genera and 39 species. The number of Undifilum oxytropis was the most. There were 27 species isolated in TGL, 21 species isolated in MLH. There were 11 species were isolated in all of the 2 sampling sites. There were 18 species only isolated in TGL, 10 species only isolated in MLH. There were 25 species isolated in stems, 21 species isolated in leaves, 13 species isolated in flowers, 11 species isolated in peels, 1 species isolated in seed. αdiversity index showed that the species diversity of fungi in Astragalus variabilis was rich. The species diversity index of peel was higher, and species diversity index of the sampling sites were MHL>TGL.2. Isolation, identification and diversity analysis of endophytic fungi in Astragalus strictus832 strains of endophytic fungi were isolated from 1410 tissues of Astragalus strictus in Gongbujiangda, Linzhou, and Duilongdeqing in Tibet, which were combined to 31 genera and 47 species. The number of Undifilum oxytropis was the most. There were 17 species isolated in GBJD, 17 species isolated in LZH, 30 species isolated in DLDQ. There were 3 species were isolated in all of the 3 sampling sites. There were 10 species only isolated in GBJD, 6 species only isolated in LZH, 17 species only isolated in DLDQ. There were 26 species isolated in stems, 37 species isolated in leaves, 28 species isolated in flowers. αdiversity index showed that the species diversity of fungi in Astragalus strictus was rich. The species diversity of all tissues were leaf> flower> stem, and the species diversity index of the sampling sites were DLDQ>GBJD>LZH. For βdiversity, Motisita-Horn index and Jaccard index showed that the similarity of LZH and DLDQ was highest.3. Genetic diversity of endophytic fungi in two AstragalusRAPD and ISSR primers were used to amplify the DNA of 39 species endophyte fungi in Astragalus variablilis and 47 species endophyte fungi in Astragalus strictus for genetic diversity analysis. RAPD and ISSR results of Astragalus variablilis show that genetic diversity of endophyte fungi in Astragalus variablilis was rich, and the genetic diversity of species and population was similiar. RAPD and ISSR results of Astragalus strictus show that genetic diversity of endophyte fungi in Astragalus strictus was rich, but the genetic diversity of species was higher than population. Phylogenetic analysis showed that the genetic distance was maximum between GBJD and DLDQ was maximum, and the DLDQ and LZH was minimum. |
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