Metabolomic and transcriptomic analyses highlight metabolic regulatory networks of Salvia miltiorrhiza in response to replant disease.

BACKGROUND: Salvia miltiorrhiza, a well-known traditional Chinese medicine, frequently suffers from replant diseases that adversely affect its quality and yield. To elucidate S. miltiorrhiza's metabolic adaptations to replant disease, we analyzed its metabolome and transcriptome, comparing normal and replant diseased plants for the first time. RESULTS: We identified 1,269 metabolites, 257 of which were differentially accumulated metabolites, and identified 217 differentially expressed genes. Integrated transcriptomic and metabolomic analyses revealed a significant up-regulation and co-expression of metabolites and genes associated with plant hormone signal transduction and flavonoid biosynthesis pathways in replant diseases. Within plant hormone signal transduction pathway, plants afflicted with replant disease markedly accumulated indole-3-acetic acid and abscisic acid, correlating with high expression of their biosynthesis-related genes (SmAmidase, SmALDH, SmNCED, and SmAAOX3). Simultaneously, changes in hormone concentrations activated plant hormone signal transduction pathways. Moreover, under replant disease, metabolites in the local flavonoid metabolite biosynthetic pathway were significantly accumulated, consistent with the up-regulated gene (SmHTC1 and SmHTC2). The qRT-PCR analysis largely aligned with the transcriptomic results, confirming the trends in gene expression. Moreover, we identified 10 transcription factors co-expressed with differentially accumulated metabolites. CONCLUSIONS: Overall, we revealed the key genes and metabolites of S. miltiorrhiza under replant disease, establishing a robust foundation for future inquiries into the molecular responses to combat replant stress.

Genome-wide identification of glycoside hydrolase family 1 members reveals GeBGL1 and GeBGL9 for degrading gastrodin in Gastrodia elata.

KEY MESSAGE: We revealed the intrinsic transformation molecular mechanism of gastrodin by two ß-d-glucosidases (GeBGL1 and GeBGL9) during the processing of Gastrodia elata. Gastrodia elata is a plant resource with medicinal and edible functions, and its active ingredient is gastrodin. However, the intrinsic transformation molecular mechanism of gastrodin in G. elata has not been verified. We speculated that ß-d-glucosidase (BGL) may be the key enzymes hydrolyzing gastrodin. Here, we identified 11 GeBGL genes in the G. elata genome. These genes were unevenly distributed on seven chromosomes. These GeBGL proteins possessed motifs necessary for catalysis, namely, TF(I/M/L)N(T)E(Q)P and I(V/L)T(H/S)ENG(S). These GeBGLs were divided into five subgroups together with homologous genes from Arabidopsis thaliana, rice, and maize. Quantitative real-time PCR analysis showed GeBGL genes expression was tissue-specific. Gene cloning results showed two mutation sites in the GeBGL1 gene compared with the reference genome. And, the GeBGL4 gene has two indel fragments, which resulted in premature termination of translation and seemed to turn into a pseudogene. Furthermore, protein expression and enzyme activity results proved that GeBGL1 and GeBGL9 have the activity of hydrolyzing gastrodin into 4-hydroxybenzyl alcohol. This study revealed the function of ß-d-glucosidase in degrading active compounds during the G. elata processing for medicinal purposes. These results offer a theoretical foundation for elevating the standard and enhancing the quality of G. elata production.