Environmental stress is one of the major restrictions on plant development and foodstuff production. The adaptive response in plants largely occurs through an intricate signaling system, which is crucial for regulating the stress-responsive genes. Myelocytomatosis (MYC) transcription factors are the fundamental regulators of the jasmonate (JA) signaling branch that participates in plant development and multiple stresses. By binding to the cis-acting elements of a large number of stress-responsive genes, JA-responsive transcription factors activate the stress-resistant defense genes. The mechanism of stress responses concerns myriad regulatory processes at the physiological and molecular levels. Discovering stress-related regulatory factors is of great value in disclosing the response mechanisms of plants to biotic or abiotic stress, which could guide the genetic improvement of plant resistance. This review summarizes recent researches in various aspects of MYC2-mediated JA signaling and emphasizes MYC2 involvement in plant growth and stress response.

The endophytic microbiome in medicinal plants is rich and diverse, but few studies have followed the endophytic microbiome of medicinal plants in different tissues with their growth. In this study, we examined the endophytic bacterial and fungal community structures associated with both the stem and root compartments of Dendrobium huoshanense at different growth years via high-throughput sequencing of 16S rRNA genes and nrDNA fragments of internal transcribed spacer regions. Results indicated that more diverse prokaryotic and fungal operational taxonomic units were detected in roots than in stems, and the alpha diversity of endophytic prokaryotic significantly differed among the 1-, 2-, and 3-year-old roots. The dominant bacterial phyla Proteobacteria Firmicutes, Actinobacteria, Bacteroidetes, and Acidobacteria, and fungal phyla Ascomycota, Basidiomycota, and Ascomycota were detected in the stems and roots with 3 growth years. Moreover, linear discriminant effect size analysis revealed 138 differentially abundant taxonomic clades in the bacterial level, and 197 in the fungal level in six groups. Our results provide evidence for endophytic microbiota communities depending on the tissues and growth years of D. huoshanense. The results from this study should be useful to better understand medicinal plant-microbe interactions.

Dendrobium huoshanense is used to treat various diseases in traditional Chinese medicine. Recent studies have identified active components. However, the lack of genomic data limits research on the biosynthesis and application of these therapeutic ingredients. To address this issue, we generated the first chromosome-level genome assembly and annotation of D. huoshanense. We integrated PacBio sequencing data, Illumina paired-end sequencing data, and Hi-C sequencing data to assemble a 1.285 Gb genome, with contig and scaffold N50 lengths of 598 kb and 71.79Mb, respectively. We annotated 21,070 protein-coding genes and 0.96 Gb transposable elements, constituting 74.92% of the whole assembly. In addition, we identified 252 genes responsible for polysaccharide biosynthesis by Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation. Our data provide a basis for further functional studies, particularly those focused on genes related to glycan biosynthesis and metabolism, and have implications for both conservation and medicine.

Nitrogen-containing compounds especially alkaloids are important medicinal ingredients in caulis dendrobii plants. Using solid-phase extraction coupled with liquid chromatography tandem mass spectrometry and multivariate data analysis methods, metabolic profiling of the nitrogen-containing compounds was established to distinguish Dendrobium huoshanense and Dendrobium officinale. Hundreds of nitrogen-containing compounds from the two caulis dendrobii were purified by the MCX cartridges. Some compounds were identified by high-resolution tandem mass spectrometry technology. Together with multivariate data analysis methods, comparative analysis of the metabolic profiling from two caulis dendrobii was conducted. A total of 133 nitrogen-containing compounds were identified, including amino acids, pyrrolidines, tropanes, pyrimidines, purines, indoles, piperidines, guanidines, quinolines, isoquinolines and terpenoids. Metabolic profiling analysis showed that the composition and contents of these chemical components were significantly different between D. huoshanense and D. officinale.Moreover, some components were species-specific, distributed in the two caulis dendrobii, such as pilosine, ternatusine, etc. Because alkaloids are mainly derived from amino acids via multistep biochemical reactions, the correlation analysis suggested that amino acids were partially associated with several types of components and significantly correlated with certain alkaloids. Arginine was extremely correlated with guanidines. Pyrimidines, purines and niacin-nicotinamide metabolic intermediates were associated with three independent networks. The results further enriched the chemical components currently identified from caulis dendrobii and provided a technical reference for detecting nitrogen-containing compounds in other medicinal plants.

Unhealthy diet, in particular high-fat diet (HFD) intake, can cause the development of several metabolic disorders, including obesity, hyperlipidemia, type 2 diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), and metabolic syndrome (MetS). These popular metabolic diseases reduce the quality of life, and induce premature death worldwide. Evidence is accumulating that the gut microbiota is inextricably associated with HFD-induced metabolic disorders, and dietary intervention of gut microbiota is an effective therapeutic strategy for these metabolic dysfunctions. Polysaccharides are polymeric carbohydrate macromolecules and sources of fermentable dietary fiber that exhibit biological activities in the prevention and treatment of HFD-induced metabolic diseases. Of note, natural polysaccharides are among the most potent modulators of the gut microbiota composition. However, the prebiotics-like effects of polysaccharides in treating HFD-induced metabolic diseases remain elusive. In this review, we introduce the critical role of gut microbiota human health and HFD-induced metabolic disorders. Importantly, we review current knowledge about the role of natural polysaccharides in improving HFD-induced metabolic diseases by regulating gut microbiota.

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The acid hydrolysis of lignocellulosic material (LM) is one of the most widely studied and important subprocess in the LM biorefinery. After acid hydrolysis, LM can be converted to various biofuels, biochemicals, and biomaterials through chemical or biochemical methods. However, conventional LM acid hydrolysis is not regarded as a cost-effective and environmentally-friendly process because it has drawbacks such as difficulties in acid recovery, equipment corrosion, and chemical wastes from the neutralization of acid and the removal of LM degradation products. Use of ionic liquids and solid acids during LM hydrolysis has provided potential technical tools to overcome these problems and has given new life to the LM acid hydrolysis process in the biorefinery. This editorial will discuss the role of the LM acid hydrolysis process in the LM biorefinery, provide an analysis of the conventional LM acid hydrolysis process, and briefly discuss new developments in the LM acid process.

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