Hedysari Radix, a significant Chinese herbal medicine from Northwest China’s arid region, is renowned for its unique tonic effects in traditional Chinese medicine practices. This plant, a member of the Leguminosae family, forms a symbiotic relationship with nitrogen-fixing rhizobia. However, the Hedysarum polybotrys-rhizobium symbiotic system remains underexplored. The root nodule structure of H. polybotrys was examined using an optical microscope (OM). This examination revealed that its root nodules consist of meristematic zone, infection zone, nitrogen fixation zone, and senescence zone, arranged from top to bottom. This structure suggests that the root nodules of H. polybotrys belong to the indeterminate nodule category. In the fields of transmission electron microscopy (TEM) and fields emission scanning electron microscopy (FESEM), significant differences were observed between infected and un-infected cells. Rhizobium, identified via 16S rRNA technology and classified as the genus Mesorhizobium through phylogenetic analysis. Reinoculation of rhizobium into H. polybotrys seedlings resulted in nodule formation on the roots. Notably, inoculated plants exhibited a considerable increase in nodule number, leaf count, leaf length, aboveground height, aboveground fresh weight, root length, and root diameter compared to uninoculated controls, demonstrating that rhizobium inoculation enhances plant growth.

Catechins includ galloylated catechins and non-galloylated catechins, among which galloylated catechins exhibit stronger antioxidant, anti-inflammatory and anti-cancer activities. Section Chrysantha Chang, the only group of yellow Camellia with rich catechins in their flowers, is a common health drink in southern China. To date, few studies have examined galloylated catechins biosynthesis in flowers of this group. To enrich the genetic information of the galloylated catechins biosynthesis, the ONT sequencing platform was used to perform full-length transcriptome sequencing of C. perpetua flowers and 7,972,574 transcripts was identified, including 42,883 simple sequence repeats (SSRs), 41,961 coding sequences (CDSs) and 2,602 long non-coding RNAs (lncRNAs). 36,516 transcripts were successfully annotated, and 147 critical enzyme-encoding genes were identified as involved in the galloylated catechins biosynthesis pathway, including 17 CpSCPL1A genes. Bioinformatics analysis revealed that each CpSCPL1A protein consisted of 427–506 amino acids, and all CpSCPL1A proteins were divided into 5 groups with conserved motifs 1, 4, 5, 6 and 8. Based on the correlation analysis between the gene expression of 17 CpSCPL1A genes and the content of galloylated catechins, 11 candidate CpSCPL1A genes were identified to be involved in the biosynthesis of 4 types of galloylated catechins in C. perpetua flowers. The results enrich the transcriptome data for C. perpetua and provide valuable insights into the importance of the CpSCPL1A gene family members in the galloylated catechins biosynthesis.

Suspension-cultured cells of a temperate bamboo species (Phyllostachys nigra) accumulate substantial amounts of hydroxycinnamic acid derivatives and lignin under culture conditions that promote xylogenesis. In our previous study, we found a metabolite specifically produced in bamboo cells cultured under lignification-inducing conditions in a medium containing N6-benzyladenine (BA), but the chemical structure was not elucidated. In this study, we purified and identified this compound as BA N9-β-D-glucopyranoside (BA-9G). Despite the presence of three nitrogen positions (N-3, N-7, and N-9) that may be glucosylated in the adenine moiety of BA, bamboo cells specifically produced BA-9G (i.e., without other glucoside types) when cells were cultured in the presence of BA. This finding suggests that bamboo cells possess a regio-specific N-glucosyltransferase for catalyzing cytokinin glucoside formation. The biological activity of BA-9G as a cytokinin was compared with that of BA on the basis of adventitious shoot formation on internodal segments of ipecac (Carapichea ipecacuanha) plants grown under in vitro conditions. The activity of BA-9G was more moderate than that of BA, but BA-9G was less cytotoxic than BA at a high concentration, suggesting that BA-9G may be useful as a plant growth regulator. The development of a viable system for the regio-specific bioproduction of BA-9G in bamboo cells may increase the availability of this highly expensive and rare cytokinin derivative.

The unfolded protein response (UPR) is a central regulatory pathway that ensures the proper function of the endoplasmic reticulum (ER) through efficient protein folding and quality control. In Arabidopsis, bZIP60 mRNA is activated by an IRE1-mediated unconventional splicing that excises a 23-nucleotide intron, resulting in the spliced form (bZIP60s mRNA) that encodes the active bZIP60 transcription factor lacking a transmembrane domain. In this study, we investigated the functional role of the spliced form-specific C-terminal extension, hereafter referred to as ORF2. Transient expression assays in Arabidopsis mesophyll protoplasts demonstrated that full-length bZIP60s potently activates the BiP3 promoter compared to a truncated variant lacking ORF2. Fusion of ORF2 to transcription factors unrelated to the UPR did not enhance their transcriptional potency, underscoring its specialized role in the context of bZIP60s. Furthermore, mutation in a conserved nuclear localization signal within ORF2 decreased promoter activation by bZIP60s. Fusion of ORF2 to GFP enhanced the nuclear localization of GFP. Our results suggest that ORF2 is critical for the full transcriptional activity of bZIP60s to ensure an efficient UPR.