Astragalus-cultivated soil was a suitable bed soil for nurturing Angelica sinensis seedlings from the rhizosphere microbiome perspective.

Angelica sinensis (Oliv.) Diels is an important Chinese medicinal plant. A. sinensis seedlings are grown on an undisturbed alpine meadow soil to ensure the high-quality seedlings, but these soils are disappearing year after year. Thus, selecting a suitable bed soil for A. sinensis seedlings could ensure their long-term sustainability. Using HiSeq sequencing of 16S and 18S marker genes, we investigated the rhizosphere bacterial and fungal microbiotas of the seedlings grown in wheat, astragalus, potato, and angelica-cultivated soils at a geo-authentic habitat. Co-occurrence network analysis, canonical correspondence analysis, Mantel test, and Envfit test were used to examine the relationship between the microbiotas and the surrounding factors. Astragalus-cultivated soils exhibited the following properties: the highest plant weight, the highest neighborhood connectivity in the bacterial network, the highest ratio of positive/negative relationship in both bacterial and fungal networks, the highest relative abundance of the arbuscular mycorrhizal fungi and the ectomycorrhizal fungi, the lowest relative abundance of Rhizoctonia solani, the suitable soil pH, and the close relationship between the rhizosphere microbiotas and the ecological factors. Moreover, each growth stage has its own major drivers in all crop-cultivated soils. Climate temperature and soil pH at 56 days after planting, precipitation at 98 days, and plant weight as well as microbial biomass C and N at 129 days were the major drivers of the bacterial and fungal microbiotas. Overall, the astragalus-cultivated soil was a suitable bed soil for nurturing A. sinensis seedlings to replace the undisturbed alpine meadow soils.

Arbuscular mycorrhizal fungal communities in soils where astragalus had grown for 2 years were similar to those in the abandoned farmland.

Purpose: Astragalus-cultivated soils are enriched in arbuscular mycorrhizal fungi (AMF); however, the community changes of AMF between years in stragalus-cultivated soils are still unclear. Methods: To illustrate this, using high-throughput amplicon sequencing and quantitative real-time PCR, we analyzed the AMF communities of the abandoned farmlands and interannual astragalus-cultivated soils for 1-, 2-, 3-, and 4-years, including community composition, dominant, core, specific and significantly fluctuating AMF, co-occurrence network, alpha diversity, and beta diversity. Results: A total of 74 OTUs were classified into one phylum, Glomeromycota; one class, Glomeromycetes; four orders; four families; and six genera. The 2-year soil had the highest number of reads among the interannual soils. Only one OTU was shared among all interannual soils. The treatments significantly affected the Ace, Shannoneven, and Shannon estimators of the communities. The 2-year soil had the highest richness, evenness, and diversity among all interannual soils and was the closest to the abandoned farmland in terms of alpha diversity. Glomus of the family Glomeraceae was the dominant genus present in all treatments, and the composition of the dominant genus in interannual soils was different. Both Glomus and Diversispora were the core AMF in interannual soils, and specific AMF existed in different interannual soils. Glomus is a genus that exhibits significant interannual variation. The interannual time significantly affected the network connectivity. The results of the principal coordinate analysis showed that the community composition of the interannual soils was close to each other and separated from the abandoned farmland, and that the interannual time significantly affected the community composition. Conclusion: Among the interannual soils, the 2-year soil may be more suitable for A. sinensis seedling rotation.

Rhizosphere bacterial and fungal communities during the growth of Angelica sinensis seedlings cultivated in an Alpine uncultivated meadow soil.

BACKGROUND: Angelica sinensis seedlings are grown in alpine uncultivated meadow soil with rainfed agroecosystems to ensure the quality of A. sinensis after seedling transplantation. The aim was to investigate the rhizosphere bacterial and fungal communities during the growth stages of A. sinensis seedlings. METHODS: The bacterial and fungal communities were investigated by HiSeq sequencing of 16S and 18S rDNA, respectively. RESULTS: Proteobacteria and Bacteroidetes were bacterial dominant phyla throughout growth stages. Fungal dominant phyla varied with growth stages, dominant phyla Ascomycota and Chytridiomycota in AM5, dominant phyla Basidiomycota, Ascomycota and Zygomycota in BM5, and dominant phyla Basidiomycota and Ascomycota in CM5. There was no significant variation in the alpha-diversity of the bacterial and fungal communities, but significant variation was in the beta-diversity. We found that the variation of microbial community composition was accompanied by the changes in community function. The relative abundance of fungal pathogens increased with plant growth. We also identified the core microbes, significant-changing microbes, stage-specific microbes, and host-specific microbes. Plant weight, root length, root diameter, soil pH, rainfall, and climate temperature were the key divers to microbial community composition. CONCLUSIONS: Our findings reported the variation and environmental drivers of rhizosphere bacterial and fungal communities during the growth of A. sinensis seedlings, which enhance the understanding of the rhizosphere microbial community in this habitat.

Enhanced Heavy Metal Tolerance and Accumulation by Transgenic Sugar Beets Expressing Streptococcus thermophilus StGCS-GS in the Presence of Cd, Zn and Cu Alone or in Combination.

Phytoremediation is a promising means of ameliorating heavy metal pollution through the use of transgenic plants as artificial hyperaccumulators. A novel Streptococcus thermophilus γ-glutamylcysteine synthetase-glutathione synthetase (StGCS-GS) that synthesizes glutathione (GSH) with limited feedback inhibition was overexpressed in sugar beet (Beta vulgaris L.), yielding three transgenic lines (s2, s4 and s5) with enhanced tolerance to different concentrations of cadmium, zinc and copper, as indicated by their increased biomass, root length and relative growth compared with wild-type plants. Transgenic sugar beets accumulated more Cd, Zn and Cu ions in shoots than wild-type, as well as higher GSH and phytochelatin (PC) levels under different heavy metal stresses. This enhanced heavy metal tolerance and increased accumulation were likely due to the increased expression of StGCS-GS and consequent overproduction of both GSH and PC. Furthermore, when multiple heavy metal ions were present at the same time, transgenic sugar beets overexpressing StGCS-GS resisted two or three of the metal combinations (50 µM Cd-Zn, Cd-Cu, Zn-Cu and Cd-Zn-Cu), with greater absorption in shoots. Additionally, there was no obvious competition between metals. Overall, the results demonstrate the explicit role of StGCS-GS in enhancing Cd, Zn and Cu tolerance and accumulation in transgenic sugar beet, which may represent a highly promising new tool for phytoremediation.

Characteristics of miniature Cheddar-type cheese made by microbial rennet from Bacillus amyloliquefaciens: a comparison with commercial calf rennet.

Miniature Cheddar-type cheeses were produced using microbial rennet from Bacillus amyloliquefaciens (milk-clotting enzyme [MCE]) or calf rennet (CAR). With the exception of pH, there were no significant differences in gross composition between MCE-cheese (MCE-C) and CAR-cheese (CAR-C). The pH value of CAR-C was significantly higher than that of MCE-C at 40 and 60 d of ripening. The total nitrogen content of the pH 4.6-soluble fraction obtained from MCE-C was higher than that obtained from CAR-C. However, nitrogen content of the 12% TCA-soluble fraction was similar between CAR-C and MCE-C. The extent of α(s1)-casein and ß-casein hydrolysis, measured by urea-PAGE, was similar in both cheese samples. The hydrolysis of ß-casein was lower than that of α(s1)-casein. Different reverse phase-high-performance liquid chromatography peptide profiles of ethanol-soluble and ethanol-insoluble fractions were obtained from CAR-C and MCE-C. The peptide content in the 2 cheese samples increased throughout ripening; the ratio of hydrophobic to hydrophilic peptides was lower in MCE-C than in CAR-C. Compared with CAR-C, MCE-C was softer as a result of higher protein hydrolysis. Microbial rennet from B. amyloliquefaciens contributed to higher proteolytic rates, which reduced ripening time.

Enhanced ß-galactosidase production of Aspergillus oryzae mutated by UV and LiCl.

In order to breed a high-yield ß-galactosidase-producing strain, Aspergillus oryzae was used as the parent strain and mutagenized with ultraviolet (UV) and UV plus lithium chloride (LiCl), respectively. After being mutagenized by UV, the ß-galactosidase activity of mutant UV-15-20 reached 114.08 U/mL, which revealed a 49.22% increase compared with the original strain. A mutant UV-LiCl-38 with high ß-galactosidase activity (121.42 U/mL) was obtained after compound mutagenesis of UV and LiCl; the ß-galactosidase activity of this mutant was 58.82% higher than that of the parent strain. Subculture testing indicated that UV-15-20 and UV-LiCl-38 had good hereditary stability and may be ideal strains for the production of ß-galactosidase. Additionally, it was demonstrated that compound mutagenesis with UV and LiCl is an effective mutation method for breeding industrially interesting strains.

Enzyme inhibitor studies reveal complex control of methyl-D-erythritol 4-phosphate (MEP) pathway enzyme expression in Catharanthus roseus.

In Catharanthus roseus, the monoterpene moiety exerts a strong flux control for monoterpene indole alkaloid (MIA) formation. Monoterpene synthesis depends on the methyl-D-erythritol 4-phosphate (MEP) pathway. Here, we have explored the regulation of this pathway in response to developmental and environmental cues and in response to specific enzyme inhibitors. For the MEP pathway entry enzyme 1-deoxy-D-xylulose 5-phosphate synthase (DXS), a new (type I) DXS isoform, CrDXS1, has been cloned, which, in contrast to previous reports on type II CrDXS, was not transcriptionally activated by the transcription factor ORCA3. Regulation of the MEP pathway in response to metabolic perturbations has been explored using the enzyme inhibitors clomazone (precursor of 5-ketochlomazone, inhibitor of DXS) and fosmidomycin (inhibitor of deoxyxylulose 5-phosphate reductoisomerase (DXR)), respectively. Young leaves of non-flowering plants were exposed to both inhibitors, adopting a non-invasive in vivo technique. Transcripts and proteins of DXS (3 isoforms), DXR, and hydroxymethylbutenyl diphosphate synthase (HDS) were monitored, and protein stability was followed in isolated chloroplasts. Transcripts for DXS1 were repressed by both inhibitors, whereas transcripts for DXS2A&B, DXR and HDS increased after clomazone treatment but were barely affected by fosmidomycin treatment. DXS protein accumulated in response to both inhibitors, whereas DXR and HDS proteins were less affected. Fosmidomycin-induced accumulation of DXS protein indicated substantial posttranscriptional regulation. Furthermore, fosmidomycin effectively protected DXR against degradation in planta and in isolated chloroplasts. Thus our results suggest that DXR protein stability may be affected by substrate binding. In summary, the present results provide novel insight into the regulation of DXS expression in C. roseus in response to MEP-pathway perturbation.

BjMT2, a metallothionein type-2 from Brassica juncea, may effectively remove excess lead from erythrocytes and kidneys of rats.

The remedial effects of a plant metallothionein type-2 were observed from lead (Pb) injured rats. BjMT2 from Brassica juncea was expressed in Escherichia coli and purified by affinity chromatography, a purified BjMT2 protein was obtained which strongly reacted with the thiol reagent MBB (monobromobimane). The profiles of erythrocytes, renal tubules and glomerulus of kidney of rats suffered pathological changes from excess Pb were evidently improved by supplying the BjMT2. Quantitative analysis showed that the content of Pb and the amount of leukocytes in blood were significantly declined after supplying BjMT2 to rats. The results indicated that the BjMT2 may have the potential function to decrease Pb toxicification in rate organs and tissues.

Research advances on transgenic plant vaccines.

In recent years, with the development of genetics molecular biology and plant biotechnology, the vaccination (e.g. genetic engineering subunit vaccine, living vector vaccine, nucleic acid vaccine) programs are taking on a prosperous evolvement. In particular, the technology of the use of transgenic plants to produce human or animal therapeutic vaccines receives increasing attention. Expressing vaccine candidates in vegetables and fruits open up a new avenue for producing oral/edible vaccines. Transgenic plant vaccine disquisitions exhibit a tempting latent exploiting foreground. There are a lot of advantages for transgenic plant vaccines, such as low cost, easiness of storage, and convenient immune-inoculation. Some productions converged in edible tissues, so they can be consumed directly without isolation and purification. Up to now, many transgenic plant vaccine productions have been investigated and developed. In this review, recent advances on plant-derived recombinant protein expression systems, infectious targets, and delivery systems are presented. Some issues of high concern such as biosafety and public health are also discussed. Special attention is given to the prospects and limitations on transgenic plant vaccines.