Community structure characteristics of arbuscular mycorrhizal fungi from root of three Polygonatum species in Yunnan

【Objective】 The fungi infection，fungi diversity and community structure differences of arbuscular mycorrhizal fungi（AMF）from roots of Polygonatum species in Yunnan were determined，and the relationship between AMF diversity of Polygonatum root and physicochemical properties of rhizosphere soil was discussed. It laid the foundation for the research and development and application of AMF fertilizer which was specialized for Polygonatum species.【Method】 In this study，the roots and rhizosphere soil of three main cultivated species of Polygonatum in Yunnan，Polygonatum sibiricum Delar. ex Redoute，Polygonatum cyrtonema Hua and Polygonatum kingianum Coll. et Hemsl，were used as experimental materials. Micromorphological observations were used to determine the parameter of AMF infection in the roots of different Polygonatum species and spore density in the rhizosphere soil. The diversity and community structure difference of AMF in the roots of different Polygonatum species were analyzed using Illumina high-throughput sequencing technology. Pearson correlation coefficient method was used to analyze the correlation between AMF diversity and soil physicochemical factors.【Result】The results showed that the AMF infection intensity and infection rate in roots of the three Polygonatum species ranged from 15.11% to 39.21% and 44.34% to 92.22% respectively，and the spore density of rhizosphere soil ranged from 105.33 to 285.33 spore/25 g. P. sibiricum had significantly higher infection intensity than the other two Polygonatum species（P＜0.05，the same below）. P. kingianum had the highest spore density in rhizosphere soil. A total of 38 OTUs were obtained from the roots of the three Polygonatum species by high-throughput sequencing，belonging to four orders，five families，five genera，and fourteen species after excluding uncategorized species，with Glomus accounting for the highest proportion（80.61%）. The results of diversity analysis showed that the AMF diversity index was significantly different among the roots of different Polygonatum species. Comparing with other species，the roots of P. kingianum had the highest number of AMF-OTUs，the highest Shannon index and the lowest Simpson index，indicated that it had a higher AMF species abundance in root. PLS-DA results showed that the AMF community structure was greatly different in the roots of the three Polygonatum species. Paraglomus was the dominant genus in the root of P. kingianum （59.86%），while Glomus was the dominant genus in the roots of P. sibiricum（95.55%）and P. cyrtonema（99.47%）. The results of correlation analysis indicated that the contents of alkali-hydrolyzed nitrogen and organic matter in rhizosphere soil had extremely significantly negative correlation with the Shannon index of AMF in the roots of Polygonatum（P＜0.01）. 【Conclusion】The diversity and community structure of AMF in the roots closely correlates with Polygonatum species. Glomus and Paraglomus may play important roles in the development of functional AMF inoculants of Polygonatum.