Oridonin, the main active constituent of Rabdosia rubescens, is known to exert antitumor activity via the induction of apoptosis in numerous types of human cancer cells. However, the underlying regulatory mechanisms of mitochondrial ROS in oridonin‑induced HepG2 apoptosis remain largely unknown, due to limitations of subcellular imaging resolution. Previously, it has been suggested that mitochondria serve a potential role in sensing and signaling cellular redox changes in vital biological processes such as cell death and the abiotic stress response, based on studies involving the mitochondrial‑targeted redox‑sensitive green fluorescent protein (GFP). To address this, a mitochondrial‑targeted Grx1‑roGFP2 (mtGrx1‑roGFP2) biosensor was implemented to monitor real‑time mitochondrial redox changes of HepG2 cells in response to either H2O2/DTT or oridonin/SS31 treatment. It was determined that oridonin caused a perturbation in mitochondrial redox status, which in turn contributed to oridonin‑induced apoptosis. Furthermore, a novel mechanism underlying the regulation of mitochondrial redox changes in oridonin‑induced HepG2 apoptosis, presumably dependent on PARP cleavage, was proposed. In conclusion, the present study provides evidence in support of mitochondrial redox changes as a potential mediator in the apoptotic activities of oridonin in HepG2 cells, which provides insight into the molecular mechanisms by which mitochondrial redox signaling regulates oridonin‑induced apoptosis in cancer therapy, and the development of mitochondria‑specific oridonin as a promising novel anticancer therapeutic strategy.

The efficacy of microbial inoculants in enhancing plant drought tolerance is context-dependent, varying with drought severity and the dynamic interactions within the plant–soil microbe system. We conducted a two-factor pot experiment using Achnatherum splendens under three moisture regimes (well-watered (control), moderate drought, and severe drought) and four inoculation treatments (sterile inoculum (control), Bacillus subtilis (BS), arbuscular mycorrhizal fungi (AMF), and their co-inoculation (MIX)). The resulting 12 treatment combinations were each replicated four times. Drought stress significantly reduced both shoot and root biomass, disrupted redox homeostasis by altering antioxidant enzyme activities and osmolyte accumulation, and induced pronounced shifts in rhizosphere microbial community composition and structure. Microbial inoculation modified osmolyte accumulation and antioxidant enzyme activity, with effects varying in magnitude and direction across moisture regimes and physiological indicators, and was generally associated with elevated soil nutrient availability and extracellular enzyme activities, though the magnitude of these effects was modulated by moisture regime. The MIX treatment showed the strongest positive responses for a subset of plant physiological and soil biochemical indicators. Bacterial and fungal co-occurrence networks exhibited divergent structural responses to inoculation and drought, with network complexity (e.g., connectivity and modularity) differentially shaped by both factors. Mantel tests and partial least squares path modeling revealed that under well-watered and moderate drought conditions, soil physicochemical properties were the primary drivers of microbial alpha and beta diversity; in contrast, under severe drought, osmotic adjustment emerged as the dominant physiological determinant of biomass maintenance. Collectively, these results reveal that the functional outcomes of microbial inoculation are contingent upon abiotic context, particularly drought intensity. This study provides a mechanistic basis and preliminary empirical evidence for subsequent field validation and further development of moisture-matched microbial intervention strategies for the ecological restoration of drought-vulnerable A. splendens ecosystems.

Background: There is an abundance of the neuroactive β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in grass pea (Lathyrus sativus), pea (Pisum sativum), and several Chinese traditional herbs such as Panax notoginseng. It is well known for its dose- and context-dependent effects on its toxicological characteristics (inducing neurodegenerative neurolathyrism upon excessive consumption) or for its pharmacological effects (including neuroprotection and wound healing). Therefore, reducing β-ODAP levels improves the safety profile of β-ODAP-containing species for utilization, whereas increasing them facilitates their isolation and purification. LsBAHD3 acyltransferase, named after the first letter of BEAT benzylalcohol O-acetyltransferase (BEAT), anthocyanin O-hydroxycinnamoyltransferase (AHCT), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and deacetylvindoline 4-Oacetyltransferase (DAT), was proven to be β-ODAP synthetase. Methods: In this report, the interaction of miR172f with LsBAHD3 was investigated through bioinformatic analysis and transient co-expression assays in Nicotiana benthamiana. Functions of miR172f in β-ODAP biosynthesis were also investigated through knockdown in the hairy roots of L. sativus and via transcriptomic analysis. Results: The results suggest that the knockdown of miR172f in hairy roots of L. sativus increased β-ODAP content via targets to LsBAHD3. In this process, protein ubiquitination, cysteine and methionine metabolism, enzyme regulator activity, and so on were associated with β-ODAP biosynthesis. Conclusions: These results identify miR172f as a novel regulator of β-ODAP biosynthesis through targeting of LsBAHD3, offering new insight into the gene expression of β-ODAP synthetase and the genetic network governing β-ODAP biosynthesis in L. sativus.