Genetic Diversity of Rhizobial Bacteria Nodulating Medicinal Plants of Astragalus Grown Wildly in West of Sichuan,China

作者 Jiang Huaming; Liu Songqing; Li Renquan; Peng Wanren; Zhang Xiaoping

期刊 Southwest China Journal of Agricultural Sciences , 2018,11:31

摘要 【Objective】The genetic diversity of the rhizobial bacteria nodulating medicinal plants of Astragalus grown wildly in the west of Sichuan was evaluated to provide a basis for strain screening. 【Method】The pure culture method was used for isolating the rhizobial strains from the nodules of 10 spieces plants of Astragalus grown wildly in the west of Sichuan, and BOXAIR-PCR,16S rDNA sequence analysis, 16S rDNA PCR-RFLP and Principal Component Analysis (PCA) were used for the determination of the genetic diversity and phylogenetic relationships. The growth performance under different salt concentrations in the range of pH and temperatures were tested. 【Result】A total of 35 rhizobial strains were isolated. Six clusters were formed based on the BOXAIR-PCR analysis; these strains were classified into 4 clusters in 16S rDNA PCR-RFLP,except SCAU549,SCAU568,and SCAU596 formed single cluster,respectively. The 16S rDNA Simpson genetic diversity index was D = 0.916.16S rDNA sequence analysis revealed that these strains tested were closely related to Rhizobium (20 / 35strains),Ochrobactrum(3 /35 strains) and Rhizobium-Agrobacterium(12 /35 strains),respectively. 27 /35 isolates performed good growth in the temperature range of 4 °C to 45 °C. All of 35 strains could grow at 28 °C after treatment in 60 °C for 10 minutes. Among the strains tested,28 strains could grow in the pH range of 4.0 to 10,and 5 strains could grow in pH 4 to pH 8. Strains SCAU533 and SCAU536 could only grow in pH6 to pH 8.18 strains could grow in YMA containing 4 % to 7 % NaCl,while SCAU542,SCAU543, SCAU544,SCAU545, and SCAU546 could tolerant 8 % NaCl. 【Conclusion】This study revealed the high genetic diversity of the rhizobia isolated from medicinal plants of Astragalus in the west of Sichuan. Most of the strains tested were adapted to high salt,different range of temperatures and pH.