Multiple omics revealed the growth-promoting mechanism of Bacillus velezensis strains on ramie.

Beneficial bacteria that promote plant growth can shield plants from negative effects. Yet, the specific biological processes that drive the relationships between soil microbes and plant metabolism are still not fully understood. To investigate this further, we utilized a combination of microbiology and non-targeted metabolomics techniques to analyze the impact of plant growth-promoting bacteria on both the soil microbial communities and the metabolic functions within ramie (Boehmeria nivea) tissues. The findings indicated that the yield and traits of ramie plants are enhanced after treatment with Bacillus velezensis (B. velezensis). These B. velezensis strains exhibit a range of plant growth-promoting properties, including phosphate solubilization and ammonia production. Furthermore, strain YS1 also demonstrates characteristics of IAA production. The presence of B. velezensis resulted in a decrease in soil bacteria diversity, resulting in significant changes in the overall structure and composition of soil bacteria communities. Metabolomics showed that B. velezensis significantly altered the ramie metabolite spectrum, and the differential metabolites were notably enriched (P < 0.05) in five main metabolic pathways: lipid metabolism, nucleotide metabolism, amino acid metabolism, plant secondary metabolites biosynthesis, and plant hormones biosynthesis. Seven common differential metabolites were identified. Correlation analysis showed that the microorganisms were closely related to metabolite accumulation and yield index. In the B. velezensis YS1 and B. velezensis Y4-6-1 treatment groups, the relative abundances of BIrii41 and Bauldia were significantly positively correlated with sphingosine, 9,10,13-TriHOME, fresh weight, and root weight, indicating that these microorganisms regulate the formation of various metabolites, promoting the growth and development of ramie. Conclusively, B. velezensis (particularly YS1) played an important role in regulating soil microbial structure and promoting plant metabolism, growth, and development. The application of the four types of bacteria in promoting ramie growth provides a good basis for future application of biological fertilizers and bio-accelerators.

Integrated microRNA and whole-transcriptome sequencing reveals the involvement of small and long non-coding RNAs in the fiber growth of ramie plant.

BACKGROUND: MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the two main types of non-coding RNAs that play crucial roles in plant growth and development. However, their specific roles in the fiber growth of ramie plant (Boehmeria nivea L. Gaud) remain largely unknown. METHODS: In this study, we performed miRNA and whole-transcriptome sequencing of two stem bark sections exhibiting different fiber growth stages to determine the expression profiles of miRNAs, lncRNAs, and protein-encoding genes. RESULTS: Among the identified 378 miRNAs and 6,839 lncRNAs, 88 miRNAs and 1,288 lncRNAs exhibited differential expression. Bioinformatics analysis revealed that 29 and 228 differentially expressed protein-encoding genes were targeted by differentially expressed miRNAs and lncRNAs, respectively, constituting eight putative competing endogenous RNA networks. lncR00022274 exhibited downregulated expression in barks with growing fibers. It also had an antisense overlap with the MYB gene, BntWG10016451, whose overexpression drastically increased the xylem fiber number and secondary wall thickness of fibers in the stems of transgenic Arabidopsis, suggesting the potential association of lncR00022274-BntWG10016451 expression with fiber growth. CONCLUSIONS: These findings provide insights into the roles of ncRNAs in the regulation of fiber growth in ramie, which can be used for the biotechnological improvement of its fiber yield and quality in the future.

Untargeted metabolomics reveal rhizosphere metabolites mechanisms on continuous ramie cropping.

Ramie is an important fiber feed dual-purpose crop in China and plays an important role in the national economy. However, ramie yield and quality can be reduced after many years of continuous cultivation. Currently, relatively little research has been conducted on rhizosphere metabolites and their pathways in continuous ramie cropping. Therefore, a healthy group (CK) and obstacle groups (XZQG, JZ, DJY, and GXD) with 8 years of continuous cultivation were selected for the study. LC-MS and GC-MS untargeted metabolomics were used to explore and analyze ramie rhizosphere metabolites and pathways. The results revealed that significant differences in the agronomic traits of ramie occurred after 8 years of continuous cultivation, with dwarfed plants and decreased yields in the obstacle groups. Metabolomic analysis identified 49 and 19 rhizosphere metabolites, including lipids, organic acids, phenols, and amino acids. In addition, four differential metabolic pathways (phenylpropanoid biosynthesis, fatty acid metabolism, amino acid metabolism, and ascorbate and aldarate metabolism) were elucidated. It was also clarified that sinapic acid, jasmonic acid, glutamine, and inositol might be the main metabolites affecting ramie continuous-cropping obstacle groups, and they were significantly correlated with ramie agronomic traits and physiological indicators. This provided important insights into the mechanisms affecting continuous ramie cropping. Accordingly, it is expected that the increase or decrease of sinapic acid, jasmonic acid, glutamine, and inositol in the soil will alleviate obstacles to continuous ramie cropping and promote the healthy development of the ramie industry in the future.

Genome-Wide Association Study of Six Forage Traits in Ramie (Boehmeria nivea L. Gaud).

Genome-wide association study (GWAS) of six forage traits using whole-genome sequencing data generated from 301 ramie accessions found that traits were continuously distributed; the maximum variant coefficient was fresh weight per clump (FWPC) (2019) and individual plant height (IPH) (2019) minimum. Correlation analysis demonstrated that 2019 and 2020 results were similar; all traits were correlated. GWAS analysis demonstrated that six traits exhibited consistent and precise association signals. Of the latter, 104 were significant and detected in 43 genomic regions. By screening forage trait-associated single nucleotide polymorphisms and combining Manhattan map with genome annotation, signals were categorized according to functional annotations. One loci associated with fresh weight per plant (FWP) (chromosome 5; Bnt05G007759), two associated with FWPC (chromosome 13; Bnt13G018582, and Bnt13G018583), and two associated with leaf dry weight per plant (LDWP) and dry weight per plant (DWP) (chromosome 4; Bnt04G005779 and Bnt04G005780), were identified. We describe forage trait candidate genes that are highly correlated with FWP and FWPC; Bnt05G007759 may be involved in nitrogen metabolism, while Bnt13G018582 and Bnt13G018583 may encode TEOSINTE branch 1/CYCLOIDEA/proliferating cytokine 1 (TCP) domains. Bnt04G005779 and Bnt04G005780, which may regulate growth and development, are highly related to LDWP and DWP. These genomic resources will provide a basis for breeding varieties.

Magnetic molecularly imprinting polymers, reduced graphene oxide, and zeolitic imidazolate frameworks modified electrochemical sensor for the selective and sensitive detection of catechin.

A glassy carbon electrode (GCE) was modified with magnetic molecularly imprinted polymers (mMIPs) using catechin as a template, reduced graphene oxide (rGO), and zeolitic imidazolate frameworks-8 (ZIF-8) for the sensitive detection of catechin (mMIPs/rGO-ZIF-8/GCE). The prepared rGO, ZIF-8, and mMIPs exhibited typical structures and properties determined by various characterizations. The mMIPs showed good selectivity for catechin among several structural analogs. The mMIPs/rGO-ZIF-8/GCE showed a higher maximum peak current for catechin than that of a single component modified GCE. After the optimization of the material ratio, coating amounts, pH, and scan rate, the mMIPs/rGO-ZIF-8/GCE exhibited good selectivity, good linearity, and a low detection limit (LOD) for catechin. The linear range was 0.01 nmol/L-10 µmol/L and the LOD was 0.003 nmol/L (S/N = 3). The relative standard deviations for reproducibility and stability tests (n = 6) were 5.2% and 6.1%, respectively. A recovery between 99.1 and 101.3% was obtained in the detection of catechin in spiked samples. Based on these findings, the proposed mMIPs/rGO-ZIF-8/GCE could be developed further, and future research could be conducted on alternate fabrication strategies and methods to create more portable and practical electrochemical sensors. Graphical Abstract.

Ultrasensitive Electrochemical Sensor for Luteolin Based on Zirconium Metal-Organic Framework UiO-66/Reduced Graphene Oxide Composite Modified Glass Carbon Electrode.

Luteolin is a kind of natural flavonoid with many bioactivities purified from a variety of natural herbs, fruits and vegetables. Electrochemical sensing has become an outstanding technology for the detection of luteolin in low concentration due to its fast response, easy operation and low cost. In this study, electroreduced graphene oxide (ErGO) and UiO-66 were successively modified onto a glassy carbon electrode (UiO-66/ErGO/GCE) and applied to the detection of luteolin. A combination of UiO-66 and ErGO showed the highest promotion in the oxidation peak current for luteolin compared with those of a single component. The factors affecting the electrochemical behavior of UiO-66/ErGO/GCE were evaluated and optimized including pH, accumulation potential, accumulation time and scan rate. Under optimum conditions, UiO-66/ErGO/GCE showed satisfactory linearity (from 0.001 µM to 20 µM), reproducibility and storage stability. The detection limit of UiO-66/ErGO/GCE reached 0.75 nM of luteolin and was suitable for testing real samples. Stable detection could be provided at least eight times by one modified electrode, which guaranteed the practicability of the proposed sensor. The fabricated UiO-66/ErGO/GCE showed a rapid electrochemical response and low consumption of materials in the detection of luteolin. It also showed satisfactory accuracy for real samples with good recovery. In conclusion, the modification using MOFs and graphene materials made the electrode advanced property in electrochemical sensing of natural active compounds.