Plant growth-promoting activities of bacterial endophytes isolated from the medicinal plant Pairs polyphylla var. yunnanensis.

Pairs polyphylla var. yunnanensis (Paris L.) is a valuable medicinal plant used in traditional Chinese medicine. The market demand for P. polyphylla has increased over time, but it has slow growth and a low natural propagation rate. Endophytic bacteria are bioactive microorganisms that form a mutualistic relationship with host plants in long-term coordinated evolution, and they can promote the growth and accumulation of effective components in host plants. The aims of this study were to identify endophytic bacteria of P. polyphylla and to characterize their properties in promoting plant growth. A total of 10 endophytic bacteria were isolated from rhizomes of P. polyphylla. The isolated endophytes exhibited a variable capacity for indole acetic acid production, phosphate solubilization and nitrogen fixation. To investigate the effects of the endophytes on plant growth, four endophyte strains, G5, J2, G20, and Y2, were selected to compare their ability to promote plant growth. The results indicated that microbial endophytes isolated from P. polyphylla rhizomes play a vital role in improving P. polyphylla plant growth and could be used as inoculants to establish a sustainable crop production system.

Comparative transcriptomic analysis reveals genes regulating the germination of morphophysiologically dormant Paris polyphylla seeds during a warm stratification.

We previously analyzed the expression of genes associated with Paris polyphylla var. yunnanensis seed maturation and dormancy release; however, we were unable to clarify the relationship between gene expression levels and these processes. To reveal the molecular mechanisms underlying P. polyphylla var. yunnanensis seed dormancy release during a warm stratification, the transcriptomes of dormant and germinating P. polyphylla var. yunnanensis seeds were separately analyzed by RNA sequencing and were also compared with the transcriptomes of stem-leaf and root tissues harvested during the seed maturation stage. The RNA sequencing of five tissues generated 234,331 unigenes, of which 10,137 (4.33%) were differentially expressed among the analyzed tissues. The 6,619 unigenes whose expression varied among mature dormant, sprouted, and germinated seeds included 95 metabolic and 62 signaling genes related to abscisic acid, gibberellin, auxin, brassinosteroid, cytokinin, ethylene, jasmonic acid and salicylic acid. Additionally, 243 differentially expressed genes were annotated as known seed dormancy/germination-related genes. Among these genes, 109 were regulated by hormones or involved in hormone signal transduction. Finally, 310 transcription factor unigenes, including 71 homologs of known seed dormancy/ germination-related genes, were observed to be differentially expressed during a warm stratification. These results confirm that multiple hormones and transcription factors influence P. polyphylla var. yunnanensis seed dormancy release and germination during a warm stratification. This study identified candidate genes (e.g., ABI5) that should be cloned and functionally characterized regarding their effects on the release of P. polyphylla var. yunnanensis seed morphophysiological dormancy.

[Diversity of agronomic traits of Paris polyphylla var. chinensis and their correlation with rhizome yield and active compositions].

The supply deficiency of crude medicinal plant of Paris polyphylla var. chinensis has become a bottleneck for related medicinal industry. An important approach to increase herbal production is to breed high-yield cultivated variety, which characterized ideal plant morphology. In the present study, we collected 99 wild germplasm resources of P. polyphylla and then measured their 12 main agronomic traits and contents of polyphyllin Ⅶ,Ⅵ,Ⅱ,Ⅰ. Followed analyses were used to characterize those traits and explore the potential connection with herbal yield or quality. The results showed that: ①There was ample morphological diversity in wild P. polyphylla, whose variation of agronomic traits reduced according to followed order: content of polyphyllin, weight of dry rhizome, petiole length, stem length, petal length, pedicel length, sepal length, leaf width, leaf length, sepal width, leaf number, stamen number, petal number. ② Most of those traits were significantly correlated to each other and generally represented the characterization of photosynthetic organs or reproductive organ. ③The total content of polyphyllin Ⅶ,Ⅵ,Ⅱ,Ⅰvaried between 0.02% and 0.87% and averagedat 0.13%, which showed no significant correlation with any agronomic trait. ④Plant breeders should play more attention on those germplasm resources with large leaves, large sepals and high stem.

[Research on suitable distribution of Paris yunnanensis based on remote sensing and GIS].

Paris yunnanensis is a kind of rare medicinal herb, having a very high medicinal value. Studying its suitable ecological condition can provide a basis for its rational exploitation, artificial cultivation, and sustainable utilization. A practicable method in this paper has been proposed to research the suitable regional distribution of P. yunnanensis in Sichuan province. By the case study of P. yunnanensis in Sichuan province, and according to related literatures, the suitable ecological condition of P. yunnanensis such as altitude, mean annual temperature (MAT), annual precipitation, regional slope, slope ranges, vegetative cover, and soil types was analyzed following remote sensing (RS) and GIS.The appropriate distribution regionof P. yunnanensis and its area were extracted based on RS and GIS technology,combing with the information of the field validation data. The results showed that the concentrated distribution regions in counties of Sichuan province were, Liangshan prefecture, Aba prefecture, Sertar county of Ganzi prefecture, Panzhihua city, Ya'an city, Chengdu city, Meishan city, Leshan city, Yibin city, Neijiang city, Luzhou city, Bazhong city, Nanchong city, Guangyuan city and other cities and counties area.The suitable distribution area in Sichuan is about 7 338 km², accounting for 3.02% of the total study regional area. The analysis result has high consistency with the filed validation data, and the research method for P. yunnanensis distribution region based onspatial overlay analysis and the extracted the information of land usage and ecological factors following the RS and GIS is reliable.