Saposhnikovia divaricata, 2n = 2x = 16, as a perennial species, is widely distributed in China, Mongolia, Russia, etc. It is a traditional Chinese herb used to treat tetanus, rubella pruritus, rheumatic arthralgia and other diseases. Here, we assembled a 2.07 Gb and N50 scaffold length of 227.67 Mb high-quality chromosome-level genome of S. divaricata based on the PacBio Sequel II sequencing platform. The total number of genes identified was 42948, and 42456 of them were functionally annotated. A total of 85.07% of the genome was composed of repeat sequences, comprised mainly of long terminal repeats (LTRs) which represented 73.7% of the genome sequence. The genome size may have been affected by a recent whole-genome duplication event. Transcriptional and metabolic analyses revealed bolting and non-bolting S. divaricata differed in flavonoids, plant hormones, and some pharmacologically active components. The analysis of its genome, transcriptome, and metabolome helped to provide insights into the evolution of bolting and non-bolting phenotypes in wild and cultivated S. divaricata and lays the basis for genetic improvement of the species.

Chromatin modification governs plant abiotic stress responses, yet the regulatory interplay between H3K36 methylation-mediated transcriptome reprogramming

Ginsenoside accumulation is tissue- and germplasm-specific, yet its transcriptional regulation remains unclear. We combined HPLC, PacBio full-length transcriptome, and Illumina RNA-seq to compare 4-year cultivated ginseng with 26-year wild-simulated ginseng. After clustering and error correction, we obtained 265,373 (CG) and 210,343 (WSG) non-redundant full-length transcript isoforms. Total saponins ranked leaves > roots > stems. In leaves, PPT type (Re and Rg1) predominated and was significantly higher in CG than WSG; in roots, PPD type dominated, and all monomer saponins in WSG were significantly higher. Transcriptome analysis revealed widespread alternative splicing (mainly retained introns), with key genes like CYP716A47 showing differential expression and splicing. WGCNA identified a yellow module positively correlated with PPD-type ginsenosides, enriched in terpenoid and CYP/UGT pathways and containing CYP716A47 and multiple UGT candidates. qRT-PCR validated 12 selected genes (6 known, 6 novel). Our findings reveal multilevel transcriptional and post-transcriptional regulation associated with the distinct production backgrounds of cultivated and wild-simulated ginseng and provide candidate targets for future functional studies and metabolic engineering.

Northern corn leaf blight (NCLB), caused by the fungal pathogen Setosphaeria turcica, is a devastating foliar disease that significantly threatens maize production in China. Previous studies have demonstrated that SET domain gene 102 (SDG 102), a gene encoding an H3K36 methyltransferase, plays a crucial role in regulating maize growth, development, and stress responses. This study used the wild-type (WT), SDG102 overexpression line (OE), and silencing line (SL) of the corn inbred line B73 as materials. After artificial inoculation with S. turcica, the phenotypic characteristics, disease index, yield, and other related traits of different strains were compared, and RNA-Seq was used to analyze the changes in the gene expression profile. The results showed that overexpression of SDG102 significantly inhibited pathogen spore germination and hyphal growth and enhanced the activity of antioxidant enzymes and the ability to scavenge reactive oxygen species in plants prior to S. turcica infection, the opposite trend was observed in SDG102 silencing lines. Compared with the wild-type, 1546 and 1837 differentially expressed genes (DEGs) responsive to S. turcica were identified in OE and SL, respectively. These differentially expressed genes primarily function in pathways such as plant–pathogen interactions, plant hormone signaling, and secondary metabolite biosynthesis. In the OE lines, genes related to plant–pathogen interactions, reactive oxygen species (ROS) production, and key phenylpropanoid biosynthesis genes exhibited higher expression levels. Furthermore, SDG102 regulates the synthesis of auxin (JA) and abscisic acid (SA) as well as the transcription of their signaling pathway genes, thereby influencing maize resistance to large leaf spot disease. Under corn leaf blight conditions, SDG102 overexpression increased yield by 9.29% compared to WT, while SL reduced yield by 10.10%. In conclusion, SDG102 enhances maize resistance to NCLB by positively regulating the expression of disease resistance genes, antioxidant enzyme activity, and hormone-mediated defense pathways.