An endophytic fungus Schizophyllum commune isolated from Panax ginseng enhances hairy roots growth and ginsenoside biosynthesis

Using endophytic fungal elicitors to increase the accumulation of valuable secondary metabolites in plant tissue culture is an effective biotechnology strategy. In this study, a collection of 56 strains of endophytic fungi were isolated from different organs of cultivated Panax ginseng, of which seven strains can be symbiotically co-cultured with the hairy roots of P. ginseng. Further experiments observed that strain 3R-2, identified as endophytic fungus Schizophyllum commune, can not only infect hairy roots but also promote the accumulation of specific ginsenosides. This was further verified because S. commune colonization significantly affected the overall metabolic profile of ginseng hairy roots. By comparing the effects of S. commune mycelia and its mycelia extract (EM) on ginsenoside production in P. ginseng hairy roots, the EM was confirmed to be a relatively better stimulus elicitor. Additionally, the introduction of EM elicitor can significantly enhance the expressions of key enzyme genes of pgHMGR, pgSS, pgSE, and pgSD involved in the biosynthetic pathway of ginsenosides, which was deemed the most relevant factor for promoting ginsenosides production during the elicitation period. In conclusion, this study is the first to show that the EM of endophytic fungus S. commune can be considered as an effective endophytic fungal elicitor for increasing the biosynthesis of ginsenosides in hairy root cultures of P. ginseng.

Mechanisms of Epichloë bromicola to Promote Plant Growth and Its Potential Application for Coix lacryma-jobi L. Cultivation

Endophytic fungi play important roles in regulating plant growth and development and usually used as a promising strategy to enhance the biosynthesis of host valuable secondary metabolite, but the underlying growth-promoting mechanisms are only partly understood. In this study, the wild-type Arabidopsis thaliana seedlings co-cultured with fungal endophyte Epichloë bromicola showed auxin (IAA)-stimulated phenotypes, and the growth-promoting effects caused by E. bromicola were further verified by the experiments of spatially separated co-culture and fungal extract treatment. IAA was detected and identified in the extract of E. bromicola culture by LC-HRMS/MS, whereas 2,3-butanediol was confirmed to be the predominant volatile active compound in the diethyl ether and ethyl acetate extracts by GC-MS. Further study observed that IAA-related genes including synthesis key enzyme genes (CYP79B2, CYP79B3, NIT1, TAA1 and YUCCA1) and controlling polar transport genes (AUX1, BIG, EIR1, AXR3 and ARF1), were highly expressed at different periods after E. bromicola inoculation. More importantly, the introduction of fungal endophyte E. bromicola could effectively promote the growth and accumulation of coixol in Coix under soil conditions. Our study showed that endophytic fungus E. bromicola might be considered as a potential inoculant for improving medicinal plant growth.

Transcriptome sequencing and signal transduction for the enhanced tanshinone production in Salvia miltiorrhiza hairy roots induced by Trichoderma atroviride D16 polysaccharide fraction

Salvia miltiorrhiza Bunge. is commonly used to treat vascular diseases because of its activity ingredients, phenolic acids, and tanshinones. Polysaccharide fraction (PSF) extracted from Trichoderma atroviride D16 could promote tanshinone accumulation in S. miltiorrhiza hairy roots. Transcriptome sequencing was conducted to describe the global gene expression of PSF-treatment hairy roots, and data analyses showed enzymes of tanshinone biosynthetic pathways were up-regulated, and genes associated to signal molecules and transcription factors were responsive. Endogenous H2O2, abscisic acid, and nitric oxide contents were measured after PSF treatment, while tanshinone accumulations were measured with treatment of exogenous H2O2 or H2O2 inhibitor on PSF-treatment S. miltiorrhiza hairy roots. The results showed H2O2 was important in tanshinone biosynthesis caused by PSF and nitric oxide might be the downstream molecules of H2O2. Taken together, the study indicates that D16 PSF enhances the accumulation of tanshinones through enzymes of tanshinone biosynthetic pathways, signal molecules, and transcription factors.

[Epidemic situation of human echinococcosis in Inner Mongolia Autonomous Region: a sampling survey from 2012 to 2017]

OBJECTIVE

To investigate the epidemiological characteristics of human echinococcosis in Inner Mongolia Autonomous Region, so as to provide evidence for the development of the precision control strategy of human echinococcosis in the region.

METHODS

A sampling survey of human echinococcosis was conducted in 28 banners (counties, districts) of Inner Mongolia Autonomous Region from 2012 to 2017, and the epidemiological characteristics were descriptively analyzed.

RESULTS

A total of 90 058 residents were examined for echinococcosis in 28 banners (counties, districts) of Inner Mongolia Autonomous Region from 2012 to 2017, and 71 patients were detected with echinococcosis, with a detection rate of 0.08%. No echinococcosis cases were identified in 8 banners (counties), and there were 6 banners (counties) with echinococcosis prevalence of 0.1% to 1%, and 14 with prevalence of 0 to 0.1%. The echinococcosis prevalence was significantly greater in women (0.11%) than in men (0.05%) (χ² = 10.09, P = 0.001), and the highest prevalence was detected in patients at ages of over 50 years (38 cases, 53.52%). In addition, the highest echinococcosis prevalence was detected in herdsmen (0.14%), or in primary school children (0.13%).

CONCLUSIONS

Human echinococcosis is widely, but lowly prevalent in Inner Mongolia Region, with a diverse density of infections. Echinococcosis has remarkable characteristics of regional and population clusters in Inner Mongolia Region, and the management of echinococcosis requires to be reinforced in key regions and populations.

[Spatial distribution characteristics of reported echinococcosis patients in Inner Mongolia Autonomous Region from 2013 to 2018]

OBJECTIVE

To investigate the spatial distribution patterns and changing tendency of reported echinococcosis patients in Inner Mongolia Autonomous Region from 2013 to 2018, so as to provide the evidence for the management of echinococcosis in high-risk areas.

METHODS

All data pertaining to echinococcosis patients in Inner Mongolia Autonomous Region were captured from the National Notifiable Communicable Disease Reporting System from 2013 to 2018 and analyzed using a spatial epidemiological method.

RESULTS

The incidence of reported echinococcosis was 0.22 to 0.41 per 100 000 in Inner Mongolia Autonomous Region from 2013 to 2018, and the number of banner reporting echinococcosis patients increased from 24 in 2013 to 39 in 2018. The highly prevalent areas of echinococcosis were mainly concentrated in West Ujimqin Banner (the highest incidence, 19.23 per 100 000), East Ujimqin Banner (the highest incidence, 12.93 per 100 000) and New Barag Right Banner (the highest incidence, 11.66 per 100 000). Three-dimensional trend analysis showed that the areas with high incidence of reported echinococcosis were mainly located in central by eastern parts of Inner Mongolia Autonomous Region. There was a positive spatial autocorrelation in the number of echinococcosis patients, and the cases appeared a clustering distribution (Moran's I > 0, P < 0.05), with "high-high" and "low-high" regions.

CONCLUSIONS

The reported echinococcosis patients show a spatial aggregation in Inner Mongolia Autonomous Region, and the hotspot areas are mainly concentrated in Xilingol League and Chifeng City, in which targeted control interventions for Inner Mongolia Autonomous Region are recommended to be intensified.