Reference gene screening for Real-time quantitative PCR in Polygonum multiflorum / 中国中药杂志

To select suitable references gene of Polygonum multiflorum for gene expression analysis in different tissues, five candidate reference genes like Actin,GAPDH,SAND,PP2A,TIP41 were selected from the transcriptome data of P. multiflorum, then the specific primers were designed. The expression stability of the five reference genes in different tissues of P. multiflorum was analyzed by Real-time quantitative PCR through avilable analysis methods such as geNorm, NormFinder, BestKeeper, Delta CT and RefFinder, to ensure the reliability of the analysis results. The results showed that there were significant differences in the expression levels and stability of candidate genes in different tissues of P. multiflorum. Ct distribution analysis of the expression levels of candidate genes showed that the expression levels of Actin and GAPDH genes were relatively high in different tissues, while the expression levels of SAND, PP2A and TIP41 were lower. The stability of each candidate gene was analyzed by different methods. The results of geNorm analysis showed that the expression of PP2A and GAPDH was the most stable, the expression stability of SAND was the worst, the stability of PP2A was the highest in both NormFinder and Delta CT, the stability of SAND was the lowest, and the stability of Actin was the most stable in BestKeeper analysis. Through the comprehensive evaluation and analysis of the stability of candidate genes by RefFinder, it is concluded that the stability of PP2A gene is the highest, followed by GAPDH, Actin, TIP41, SAND, and SAND gene is the worst. Therefore, the PP2A gene is an ideal reference gene for the analysis of gene expression in different tissues of P. multiflorum.

Screening of plant growth-promoting rhizobacteria and its effect on seed germination of Polygonum multiflorum / 中国中药杂志

In this study, the rhizobacteria and actinomycetes of Polygonum multiflorum were screened for the strains with indole acetic acid(IAA)-producing capacity by Salkowski method, the siderophore-producing strains by Chrome Azurol S(CAS) assay, and the strains with inorganic phosphorus-solubilizing capacity by PKO inorganic phosphorus medium. The strains were identified by morphological identification, physiological and biochemical characteristics, and 16 S rDNA sequences. Furthermore, the effect of growth-promoting strains on the seed germination and development of P. multiflorum was tested. The results showed that among 196 strains, two strains F17 and F42 were found to be capable of producing IAA and siderophore and solubilizing inorganic phosphorus simulta-neously. For F17 and F42, the results are listed below: 38.65 and 33.64 mg·L~(-1) for IAA production, 0.85 and 0.49 for siderophore-producing capacities(A_s/A_r), and 1.35 and 1.70 for inorganic phosphorus-solubilizing capacities(D/d), respectively. Comprehensive analysis revealed that strains F17 and F42 were identified as Pseudochrobactrum asacharolyticum and Bacillus aryabhattai, respectively, and both could significantly promote the seed germination of P. multiflorum.

Effect of Polygonum multiflorum-Andrographis paniculata intercropping system on rhizosphere soil actinomycetes community structure and diversity of P. multiflorum / 中国中药杂志

To investigate the effect of Polygonum multiflorum-Andrographis paniculata intercropping system on rhizosphere soil actinomycetes of P. multiflorum, the community structure and diversity of soil actinomycetes were studied by using the original soil as the control group and the rhizosphere soil actinomycetes communities of P. multiflorum under monoculture and intercropping systems as the experimental group. In this study 655 221 effective sequences were obtained with an average length of 408 bp. OTU coverage and rarefaction curve showed that the sequencing could represent the real situation of soil actinomycetes. According to the results of alpha diversity analysis, the diversity soil actinomycetes varied as follows: original soil>intercropping soil>monoculture soil. The soil actinomycetes community structure and the relative abundance of dominant genera were significantly changed by both monoculture and intercropping, especially monoculture. OTU clustering and PCA analysis of soil samples showed that all the soil samples were divided into three distinct groups and the original soil was more similar to intercropping soil. In addition, intercropping increased the relative abundance of some beneficial actinomyces, such as Kitasatospora and Mycobacterium, which was beneficial to maintain soil health and reduce the occurrence of soil-borne diseases. The results show that, P. multiflorum-A. paniculata intercropping reduced the change of community structure and the decrease of diversity of soil actinomycetes caused by P. multiflorum monoculture, and made the actinomycete community in rhizosphere soil of P. multiflorum close to the original soil.