Population Distribution Characteristics And Genetic Diversity Of Endophytic Fungi From Oxytropis Kansuensis

Locoweeds (Astragalus, Oxytropis and Sphaerophysa) are perennial herb flowering poisonous plantsthat induce chronic neurological disease due to the toxic alkaloid swainsonine.“Locoweeds” had been theprimary poisonous weeds in the western natural grassland owing to the kinds of factors, such as natural,human, shortages of fund and lagging management, and it caused the direct economic losses of more thanbillion RMB every year. The latest study has demonstrated that endophytic fungi play the leading role inthe synthetic process of locoweed toxin swainsonine, they are primary source of swainsonine in locoweedplants. After studies nearly20years showed that endophytic fungi not only participated in swainsoninebiosynthesis, but also promoted the host plants growth and improve plants resistance. The study isolatedand identified the endophytic fungi from the Oxytropis kansuensis sampled from Qinghai province andGansu province, and analyzed the endophytic fungi diversity using the biodiversity index. The study usedPAPD and ISSR primer to research genetic diversity of Undifilum oxytropis. The study would provide animportant theoretical and technical basis for the future research of locoweed endophytic fungi andrelationship between them, locoweed comprehensive prevention and control technology. This research hasachieved following results:1. Isolation and identification of endophytic fungi from Oxytropis kansuensisThe species accumulation curve was nearly a gradual curve, showed that simple was full. The bestisolation conditions of different tissues were determined using general tissue mass separation process.Endophytic fungi were isolated from different tissues of Oxytropis kansuensis sampled from threeecological communities under the best isolation conditions.985strains of endophytic fungi were isolatedfrom2489tissues.985strains of endophytic fungi were identified for41species and belonged to30families (the endophytic fungi had no mycelium defined as a species, uncluture fungi defined as a speciesdespite their slight morphological differences.). QLQ isolated21species of endophytic fungi, TZG isolated27species, MYQ isolated19species. Isolated rate was different in sites and tissues. QLQ had highestisolation rate, TZG had lowest. 2. Diversity of Oxytropis kansuensis endophytic fungiThe study chose Fisher-α index, Shannon index and Simpson’ diversity index for research ofα-diversity, chose Motisita-Horn index and Jaccard index for research of β-diversity. The studyremoved the only once-isolated endophyte fungi species (rare species) in Estimate S. Forα-diversity, Fisher-α index was from5.72to8.67, Shannon index was from1.79to1.95,Simpson’ diversity index was from3.65to3.85. These results showed that endophytic fungi diversity wasrich. For β-diversity, the results of Motisita-Horn index and Jaccard index showed that QLQand MYQ had the highest similarity.3. Effect of different conditions on diversity of Oxytropis kansuensis endophytic fungiThe study used different cultured condition (PDA and BDA) and growth condition (dark and light) toascertain the effect of different conditions on diversity of endophytic fungi from Oxytropis kansuensis. Theeffect of different conditions on diversity was mainly in isolated species of endophytic fungi. Totally (notincluding species of unknow and uncultured), PDA had cultured25species, BDA had34species, darkcondition had32species and light condition had21species.13species of endophytic fungi was culturedfrom these four conditions. For cultured condition,5species were only cultured on PDA,14species wereonly cultured on BDA. For growth condition,17species were only cultured on dark condition,7specieswere only cultured on light condition. The effect of different conditions on diversity was also in diversityindex, specifically in the site of QL.4. Genetic diversity of Undifilum sp.Our study used ISSR and PAPD primer to random amplified genomic DNA of58strains Undifilum sp.from three sites for statistical differences in their genetic diversity. The results of RAPD showed that PPBwas63.49%, Na was1.6349, Ne was1.2706, H was0.1725, I was0.2714. Genetic diversity at the specieslevel was significantly higher than the population level. Phylogenetic analysis showed that, in Undifilum sp.,genetic variation was occurred within populations, but there was some gene flow within the species. Theresults of Nei’S unbiased measures of genetic identity and genetic distance showed that Nei’S unbiasedmeasures of genetic identity was0.8601to0.9298. Pop1and Pop5had the smallest genetic distance, Pop2and Pop4had the biggest genetic distance. The results of ISSR showed that PPB was66.67%, Na was1.6667, Ne was1.2897, H was0.1791, I was0.2822.