Revealing the Impact of the Environment on Cistanche salsa: From Global Ecological Regionalization to Soil Microbial Community Characteristics.

To understand the regulatory relationship between the environment and Cistanche salsa, here we integrated the macro- and microdimension methods. From a macroperspective, the MaxEnt model indicated that countries along the Belt and Road Initiative, such as China, Egypt, and Libya, were particularly suitable for growth of C. salsa from ancient times (Last Glacial Maximum and mid-Holocene) to the future (2050 and 2070). The Jackknife test revealed that precipitation is an important ecological factor that affects C. salsa's distribution. From a microperspective, 16S rRNA amplicon sequencing data showed that the soil microbial communities of three ecotypes (desert-steppe, grassland, and gravel-desert) were significantly different (p < 0.001). Core microbiome analysis demonstrated that the bacterial genera Arthrobacter, Sphingomonas, and Bacillus were enriched core taxa of C. salsa. LEfSe and random forest were used to excavate the Gillisia (desert-steppe), Flavisolibacter (grassland), and Variibacter (gravel-desert) as biomarkers that can distinguish among microbial communities from the three ecotypes. The prediction profile showed that the metabolic function of the microbial community was enriched in metabolic pathways and environmental information processing. Correlation analyses revealed that the altitude, precipitation of the warmest quarter (bio18), mean diurnal range (bio2), and mean temperature of the warmest quarter (bio10) were important ecological factors that affect the composition of soil microbial communities. This work provided new insights into the regulatory relationship among the suitable distribution of C. salsa, soil microbial communities, and ecological drivers. Moreover, it deepened the understanding of the interaction between desert plants and ecological factors in arid environments.

Regulatory relationship between quality variation and environment of Cistanche deserticola in three ecotypes based on soil microbiome analysis.

The environment affects the composition and function of soil microbiome, which indirectly influences the quality of plants. In this study, 16S amplicon sequencing was used to reveal the differences in soil microbial community composition of Cistanche deserticola in three ecotypes (saline-alkali land, grassland and sandy land). Through the correlation analysis of microbial community abundance, phenylethanoid glycoside contents and ecological factors, the regulatory relationship between microbial community and the quality variation of C. deserticola was expounded. The metabolic function profile of soil microbiome was predicted using Tax4Fun. Data showed that the soil microbial communities of the three ecotypes were significantly different (AMOVA, P < 0.001), and the alpha diversity of grassland soil microbial community was the highest. Core microbiome analysis demonstrated that the soil microbial communities of C. deserticola were mostly have drought, salt tolerance, alkali resistance and stress resistance, such as Micrococcales and Bacillales. The biomarkers, namely, Oceanospirillales (saline-alkali land), Sphingomonadales (grassland) and Propionibacteriales (sandy land), which can distinguish three ecotype microbial communities, were excavated through LEfSe and random forest. Correlation analysis results demonstrated that 2'-acetylacteoside is positively correlated with Oceanospirillales in saline-alkali land soil. The metabolic function profiles displayed highly enriched metabolism (carbohydrate and amino acid metabolisms) and environmental information processing (membrane transport and signal transduction) pathways. Overall, the composition and function of soil microbiomes were found to be important factors to the quality variation of C. deserticola in different ecotypes. This work provided new insight into the regulatory relationship amongst the environment, soil microbial community and plant quality variation.

Radiation-inducible radioprotective exopolysaccharides of Bacillus siamensis CV5 from irradiated roots of Cistanche violacea to decrease free radical damage produced by ionizing radiation.

Purpose: To assess exopolysaccharides (EPS) of Bacillus siamensis CV5, isolated from irradiated roots of Cistanche violacea, for their induction by ionizing radiation (IR) and their antioxidant and radioprotective power.Materials and methods: Isolated bacteria from the roots of C. violacea were screened for EPS production. The most EPS-producing bacterium was selected and the response surface methodology (RSM) was applied to elucidate the IR dose effects on EPS production. Gamma irradiation effects on the morphology and functional groups of EPS were studied using microscopy and Fourier transform infra-red (FT-IR). The radioprotective potential of EPS on the survival of B. siamensis CV5 following IR was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Free radicals scavenging potentialities (FRSP) of non-irradiated and irradiated EPS were evaluated through 2, 2--diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and ferric reducing ability of plasma (FRAP) assays.Results: Twenty strains, isolated from irradiated roots of C. violacea, were screened for their EPS production. IR-resistant B. siamensis CV5 was the most EPS-producing strain. Its purified EPS contained rhamnose, fructose, mannose and glucose. RSM indicated that EPS of CV5 (CV5-EPS) are radiation inducible. Micrographs of CV5-EPS suggested an increase in the total area and a decrease in the Feret's statistical diameter following exposure to IR. FT-IR spectra of these EPS revealed an increase of various functional groups. The MTT survival assay demonstrated a positive correlation between the added quantity of CV5-EPS and the viability of irradiated CV5 (p < .01). DPPH, ABTS and FRAP assays indicated that the antioxidant activities of CV5-EPS increased significantly with the irradiation dose (p < .01).Conclusions: CV5-EPS were demonstrated as radiation-inducible and radioprotective biomolecules. This radioprotective potential of CV5-EPS could be associated with their antioxidant activities. In the future, irradiated EPS could be tested as a gel in cancer radiotherapy for minimizing the damage caused by rays to surrounding healthy tissues.

[Diversity of endophytic fungi from Cistanche deserticola].

To study the diversity of endophytic fungi community from Cistanche deserticola, samples were collected from two planting bases in Inner Mongolia and Ningxia autonomous regions separately in spring and autumn. As a result, 618 strains of endophytic fungi had been isolated from samples. It was identified that 453 of the strains which accounted for 73.30% were spore strains, respectively belonging to 24 genera, and Fusarium (25.89%) and Acremonium (16.99%) were determined as dominant species. Number and species of endophytic fungi from C. deserticola showed a great diversity, and the differences of parts, localities and seasons were demonstrated.