Floral scent is an important ornamental trait in garden plants.  Monoterpenes, a major class of terpenoids, constitute the primary volatile components of lily floral scents.  1-Deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) catalyzes the second enzymatic step in the MEP pathway, which supplies precursors for monoterpene biosynthesis.  However, the functional role of the DXR gene in floral monoterpene production in Lilium Oriental Hybrid ‘Sorbonne’ remains unclear.  In this study, ‘Sorbonne’ was used as the experimental material, and a differentially expressed LiDXR gene was identified from early transcriptomic data, showing high temporal correlation with the synthesis and emission dynamics of floral volatiles during flowering.  The LiDXR gene was cloned and subjected to bioinformatics analysis, revealing that it encodes a protein of 472 amino acids.  LiDXR expression peaked at the half-open floral stage and was significantly higher in petals than in other floral organs.  Subcellular localization analysis indicated that the LiDXR protein is targeted to chloroplasts in leaf epidermal cells.  VIGS of LiDXR reduced monoterpene levels by downregulating the expression of downstream TPS genes in the MEP pathway.  Consistently, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) revealed a significant decrease in total volatile terpene content in silenced lilies.  Transgenic Arabidopsis thaliana and petunia plants overexpressing LiDXR exhibited enhanced growth vigor and accelerated flowering.  GC-Murashige and Skoog’s (MS) analysis of transgenic petunias showed a 78% increase in total volatile terpenes compared to wild-type plants.  Overexpression of LiDXR also modulated the expression of other MEP pathway genes, thereby influencing the biosynthesis of downstream terpenoids, including monoterpenes.  This study elucidates the functional role of LiDXR in terpenoid metabolism and provides a theoretical foundation for floral scent breeding in lily and other ornamental plants.

Integrated agronomic optimization (IAO) adopts suitable crop varieties, sowing dates, planting density, and advanced nutrient management to redesign the entire production system according to the local environment, and it can achieve synergistic improvements in crop yields and resource utilization.  However, the intensity and magnitude of the impacts of IAO on soil quality under long-term intensive production and high nitrogen use efficiency (NUE) require further clarification.  Based on a 13-year field experiment conducted in Dawenkou, Tai’an, Shadong Province, China, we investigated the effects of four cultivation modes on the grain yield, NUE, and soil aggregate structure, as well as the fraction of organic matter (SOM) and soil quality, reflected by the integrated fertility index (IFI), during the winter wheat maturation periods in 2020–2022.  The four cultivation modes were traditional local farming (T1), farmer-based improvement (T2), increased yield regardless of production cost (T3), and integrated soil–crop system management (T4).  As the IAO modes, T2 and T4 were characterized by denser planting, reduced nitrogen (N) fertilizer application rates, and delayed sowing compared to T1 and T3, respectively.  In this long-term experiment, IAO was found to maintain aggregate stability, increase SOM content (by increasing organic carbon and total nitrogen of the light fraction (LF) and the particulate organic matter fraction (POM)), and improve SOM quality (by increasing the proportions of LF and POM and the ratio of organic carbon to total nitrogen in SOM).  Compared to T1, the IFI values of T2, T3, and T4 increased by 10.91, 23.38, and 25.55%, and by 17.78, 6.41, and 28.94% in the 0–20 and 20–40 cm soil layers, respectively.  The grain yield of T4 was 22.52% higher than that of T1, and reached 95.98% of that in T3.  Furthermore, the NUE of T4 was 35.61% higher than those of T1 and T3.  In conclusion, our results suggest that the IAO mode T4 synergistically increases grain yield and NUE in winter wheat, while maximizing soil quality.

Xenocoumacins (Xcns), the major antimicrobial natural products produced by Xenorhabdus nematophila, have gained widespread attention for their potential application in crop protection.  However, the regulatory mechanisms involved in the biosynthesis of Xcns remain poorly understood.  In this study, we identified 21 potential two-component systems (TCSs) in X. nematophila CB6 by bioinformatic analysis.  Among them, the response regulators (RRs), GlrR and ArcA, were proven to positively regulate the production of Xcns based on gene deletion and complementation experiments.  In addition, our results showed that GlrR played an important role in cell growth, while ArcA was involved in both cell morphology and growth.  Using a variety of molecular biological and biochemical techniques, we found that GlrR controlled the Xcns biosynthesis by indirectly regulating the expression levels of the biosynthetic gene cluster (BGC).  ArcA directly binded to the promoter regions of xcnA and xcnB to regulate the transcription of the Xcns BGC, and the binding sites were also identified.  This study provides valuable insights into the regulatory network of Xcns biosynthesis, which will contribute to the construction of a high-yielding strain.

Foot-and-mouth disease virus (FMDV) is a highly contagious picornavirus that causes severe economic losses in livestock worldwide. The nonstructural protein 3A of FMDV is essential for viral replication and virulence, and mutations in 3A are associated with altered host tropism, highlighting its role in mediating host-virus interactions. However, the molecular mechanisms underlying the interplay between 3A and host cellular factors remain poorly understood. Here, through systematic screening and functional analyses, we identify the E3 ubiquitin ligase NSMCE1 as a novel host-encoded negative regulator of FMDV replication. NSMCE1 interacts directly with the FMDV 3A protein and mediates its K33-linked ubiquitination at lysine 16 (K16). This modification promotes the proteasomal degradation of 3A, thereby suppressing FMDV replication. Consistent with this mechanism, recombinant virus with a mutation at lysine 16 of 3A enhances the replication capacity of FMDV both in vitro and in vivo, confirming the critical role of this regulatory event. Our findings reveal a previously unrecognized role for NSMCE1 in limiting FMDV infection through targeted regulation of viral protein 3A and uncover a regulatory role of the ubiquitin-proteasome system in picornavirus replication. These insights advance our understanding of host antiviral defense mechanisms and provide a potential foundation for the development of novel antiviral therapies targeting the ubiquitin pathway.