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.

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.

Resequencing of 301 ramie accessions identifies genetic loci and breeding selection for fibre yield traits.

Ramie is an important fibre-producing crop in China; however, the genetic basis of its agronomic traits remains poorly understood. We produced a comprehensive map of genomic variation in ramie based on resequencing of 301 landraces and cultivars. Genetic analysis produced 129 signals significantly associated with six fibre yield-related traits, and several genes were identified as candidate genes for respective traits. Furthermore, we found that natural variations in the promoter region of Bnt14G019616 were associated with extremely low fibre abundance, providing the first evidence for the role of pectin methylesterase in fibre growth of plants. Additionally, nucleotide diversity analysis revealed that breeding selection has been markedly focussed on chromosome 9 in which ~ 39.6% sequence underwent selection, where one gibberellin-signalling-repressed DELLA gene showed distinct selection signatures in the cultivars. This study provides insights into the genetic architecture and breeding history of fibre yield traits in ramie. Moreover, the identification of fibre yield-related genetic loci and large-scale genomic variation represent valuable resources for genomics-assisted breeding of this crop.

Identification of the rhizospheric microbe and metabolites that led by the continuous cropping of ramie (Boehmeria nivea L. Gaud).

Continuous cropping lowers the production and quality of ramie (Boehmeria nivea L. Gaud). This study aimed to reveal the metagenomic and metabolomic changes between the healthy- and obstacle-plant after a long period of continuous cropping. After 10 years of continuous cropping, ramie planted in some portions of the land exhibited weak growth and low yield (Obstacle-group), whereas, ramie planted in the other portion of the land grew healthy (Health-group). We collected rhizosphere soil and root samples from which measurements of soil chemical and plant physiochemical properties were taken. All samples were subjected to non-targeted gas chromatograph-mass spectrometer (GS/MS) metabolome analysis. Further, metagenomics was performed to analyze the functional genes in rhizospheric soil organisms. Based on the findings, ramie in Obstacle-group were characterized by shorter plant height, smaller stem diameter, and lower fiber production than that in Health-group. Besides, the Obstacle-group showed a lower relative abundance of Rhizobiaceae, Lysobacter antibioticus, and Bradyrhizobium japonicum, but a higher relative abundance of Azospirillum lipoferum and A. brasilense compared to the Health-group. Metabolomic analysis results implicated cysteinylglycine (Cys-Gly), uracil, malonate, and glycerol as the key differential metabolites between the Health- and Obstacle-group. Notably, this work revealed that bacteria such as Rhizobia potentially synthesize IAA and are likely to reduce the biotic stress of ramie. L. antibioticus also exerts a positive effect on plants in the fight against biotic stress and is mediated by metabolites including orthophosphate, uracil, and Cys-Gly, which may serve as markers for disease risk. These bacterial effects can play a key role in plant resistance to biotic stress via metabolic and methionine metabolism pathways.

Systemic delivery of small interfering RNA targeting the interleukin-2/15 receptor ß chain prevents disease progression in experimental arthritis.

The role of interleukin (IL)-15 in the pathogenesis of rheumatoid arthritis (RA) is well established; however, systemic knockdown of IL-15 receptor (IL-15R) for reduction in inflammation at local sites has not been demonstrated. In this study, the therapeutic effect of intravenously administered siRNA targeting the ß chain of IL-15R which is shared by the receptor for IL-2 was examined in rats with adjuvant-induced arthritis (AA). Polyethylenimine (PEI)-complexed siRNA nanoparticles could easily accumulate in arthritic paws of AA rats. In the paws, the nanoparticles were avidly taken up by macrophages and to a lesser extent by T cells. Weekly administered IL-2/15Rß siRNA polyplexes were capable of decreasing disease progression in AA rats, with striking inhibition of clinical, radiologic, and histologic features of RA. The observed therapeutic effect was associated with reduced expression of proinflammatory mediators in the inflamed joints. Thus, this study provides evidence that IL-2/15Rß could be targeted for the treatment of RA.