Jasmonic acid (JA) carboxyl methyltransferase (JMT), a key enzyme in jasmonate-regulated plant responses, may be involved in plant defense and development by methylating JA to MeJA, thus influencing the concentrations of MeJA in plant. In this study, we isolated the JMT gene from Salvia miltiorrhiza, an important medicinal plant widely used to treat cardiovascular disease. We present a genetic manipulation strategy to enhance the production of phenolic acids by overexpresion SmJMT in S. miltiorrhiza. Global transcriptomic analysis using RNA sequencing showed that the expression levels of genes involved in the biosynthesis pathway of phenolic acids and MeJA were upregulated in the overexpression lines. In addition, the levels of endogenous MeJA, and the accumulation of rosmarinic acid (RA) and salvianolic acid (Sal B), as well as the concentrations of total phenolics and total flavonoids in transgenic lines, were significantly elevated compared with the untransformed control. Our results demonstrate that overexpression of SmJMT promotes the production of phenolic acids through simultaneously activating genes encoding key enzymes involved in the biosynthesis pathway of phenolic acids and enhancing the endogenous MeJA levels in S. miltiorrhiza.

Scutellaria baicalensis Georgi is an annual herb from the Scutellaria genus that has been extensively used as a traditional medicine for over 2000 years in China. Baicalin and other flavonoids have been identified as the principal bioactive ingredients. The biosynthetic pathway of baicalin in S. baicalensis has been elucidated; however, the specific functions of R2R3-MYB TF, which regulates baicalin synthesis, has not been well characterized in S. baicalensis to date. Here, a S20 R2R3-MYB TF (SbMYB12), which encodes 263 amino acids with a length of 792 bp, was expressed in all tested tissues (mainly in leaves) and responded to exogenous hormone methyl jasmonate (MeJA) treatment. The overexpression of SbMYB12 significantly promoted the accumulation of flavonoids such as baicalin and wogonoside in S. baicalensis hairy roots. Furthermore, biochemical experiments revealed that SbMYB12 is a nuclear-localized transcription activator that binds to the SbCCL7-4, SbCHI-2, and SbF6H-1 promoters to activate their expression. These results illustrate that SbMYB12 positively regulates the generation of baicalin and wogonoside. In summary, this work revealed a novel S20 R2R3-MYB regulator and enhances our understanding of the transcriptional and regulatory mechanisms of baicalin biosynthesis, as well as sheds new light on metabolic engineering in S. baicalensis.

R2R3-MYB transcription factors participate in multiple critical biological processes, particularly as relates to the regulation of secondary metabolites. The dried root of Scutellaria baicalensis Georgi is a traditional Chinese medicine and possesses various bioactive attributes including anti-inflammation, anti-HIV, and anti-COVID-19 properties due to its flavonoids. In the current study, a total of 95 R2R3-MYB genes were identified in S. baicalensis and classified into 34 subgroups, as supported by similar exon–intron structures and conserved motifs. Among them, 93 R2R3-SbMYBs were mapped onto nine chromosomes. Collinear analysis revealed that segmental duplications were primarily responsible for driving the evolution and expansion of the R2R3-SbMYB gene family. Synteny analyses showed that the ortholog numbers of the R2R3-MYB genes between S. baicalensis and other dicotyledons had a higher proportion compared to that which is found from the monocotyledons. RNA-seq data indicated that the expression patterns of R2R3-SbMYBs in different tissues were different. Quantitative reverse transcriptase-PCR (qRT-PCR) analysis showed that 36 R2R3-SbMYBs from different subgroups exhibited specific expression profiles under various conditions, including hormone stimuli treatments (methyl jasmonate and abscisic acid) and abiotic stresses (drought and cold shock treatments). Further investigation revealed that SbMYB18/32/46/60/70/74 localized in the nucleus, and SbMYB18/32/60/70 possessed transcriptional activation activity, implying their potential roles in the regulatory mechanisms of various biological processes. This study provides a comprehensive understanding of the R2R3-SbMYBs gene family and lays the foundation for further investigation of their biological function.

This study investigated Morchella importuna strain degeneration during repeated subculturing and employed metabolomics, transcriptomics, and other techniques to explore its molecular mechanisms. Significant metabolic and transcriptional differences were observed between normal mycelia (NM) and degenerated mycelia (DG). Metabolomic analysis revealed 699 differentially expressed metabolites (DEMs) that were predominantly enriched in secondary metabolite biosynthesis pathways, particularly flavonoids and indole alkaloids. Total flavonoid content was markedly higher in NM than in DG, with most flavonoid compounds showing reduced levels in degenerated strains. Transcriptomic profiling revealed 2691 differentially expressed genes (DEGs), primarily associated with metabolic pathways and genetic information processing. Integrated analysis showed that metabolic dynamics were regulated by DEGs, with pyruvate metabolism being significantly enriched. The FunBGCeX tool identified biosynthetic gene clusters (BGCs) in the M. importuna genome, highlighting the critical role of the non-reducing polyketide synthase (NR-PKS) gene in flavonoid biosynthesis. This gene exhibited significantly downregulated expression in DG strains. These findings indicate that M. importuna degeneration resulted from systemic dysregulation of gene expression networks and metabolic pathway reorganization. The results presented herein also provide theoretical insights into degeneration mechanisms and potential prevention strategies for this edible fungus.

Sporocarps of macrofungi support other diverse fungal species that are termed fungicolous fungi. However, the external environmental factors that affect the diversity and composition of fungicolous fungal communities remains largely unknown. In this study, the diversities, composition, and trophic modes of fungicolous fungal communities residing in host macrofungi from diverse habitats in the Qinling Mountains were analyzed. Additionally, the number of carbohydrate-active enzymes (CAZymes) encoded by saprophytic, pathogenic, and symbiotic fungi was also quantified and compared. The results revealed that the diversity and composition of fungicolous fungal communities varied with months of collection and the habitats of host fungi, and saprophytic fungi were more abundant on wood than on the ground. Meanwhile, it was also found that saprophytic fungi possessed higher abundances of cell-wall-degrading enzymes than pathogenic or symbiotic fungi. Based on the above findings, it was hypothesized that the greater abundance of saprophytic fungi on wood compared to the ground may be due to their possession of a more diverse array of enzymes capable of degrading wood cell walls, thereby allowing for more efficient nutrient acquisition from decaying wood.