Somatic embryogenesis (SE) is a process of somatic cells that dedifferentiate to totipotent embryonic stem cells and generate embryos in vitro. Despite recent scientific headway in deciphering the difficulties of somatic embryogenesis, the overall picture of key genes, pathways, and co-expression networks regulating SE is still fragmented. Therefore, deciphering the molecular basis of somatic embryogenesis of hybrid sweetgum remains pertinent. In the present study, we analyzed the transcriptome profiles and gene expression regulation changes via RNA sequencing from three distinct developmental stages of hybrid sweetgum: non-embryogenic callus (NEC), embryogenic callus (EC), and redifferentiation. Comparative transcriptome analysis showed that 19,957 genes were differentially expressed in ten pairwise comparisons of SE. Among these, plant hormone signaling-related genes, especially the auxin and cytokinin signaling components, were significantly enriched in NEC and EC early. The K-means method was used to identify multiple transcription factors, including HB-WOX, B3-ARF, AP2/ERF, and GRFs (growth regulating factors). These transcription factors showed distinct stage- or tissue-specific expression patterns mirroring each of the 12 superclusters to which they belonged. For example, the WOX transcription factor family was expressed only at NEC and EC stages, ARF transcription factor was expressed in EC early, and GRFs was expressed in late SE. It was noteworthy that the AP2/ERF transcription factor family was expressed during the whole SE process, but almost not in roots, stems and leaves. A weighted gene co-expression network analysis (WGCNA) was used in conjunction with the gene expression profiles to recognize the genes and modules that may associate with specific tissues and stages. We constructed co-expression networks and revealed 22 gene modules. Four of these modules with properties relating to embryonic potential, early somatic embryogenesis, and somatic embryo development, as well as some hub genes, were identified for further functional studied. Through a combination analysis of WGCNA and K-means, SE-related genes including AUX22, ABI3, ARF3, ARF5, AIL1, AIL5, AGL15, WOX11, WOX9, IAA29, BBM1, MYB36, LEA6, SMR4 and others were obtained, indicating that these genes play an important role in the processes underlying the progression from EC to somatic embryos (SEs) morphogenesis. The transcriptome information provided here will form the foundation for future research on genetic transformation and epigenetic control of plant embryogenesis at a molecular level. In follow-up studies, these data could be used to construct a regulatory network for SE; Key genes obtained from coexpression network analysis at each critical stage of somatic embryo can be considered as potential candidate genes to verify these networks.

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Objective. Combined spinal epidural anesthesia (CSEA) is applied to lower limb orthopaedic surgery in the elderly. This study is aimed at exploring the effect of CSEA in orthopaedic surgery of elderly patients. Methods. A total of 40 elderly patients with femoral fracture needing hip replacement or femoral head replacement in our hospital from June 2021 to June 2022 were selected as the research objects. The subjects were divided into observation group ( n = 20 ) and control group ( n = 20 ) by random number table method. The control group was given epidural anesthesia, while the observation group was given CSEA. Hemodynamic indexes (heart rate (HR) and mean arterial pressure (MAP)), visual analogue scale (VAS) pain score changes, anesthetic effects, and postoperative complications were compared between the two groups. Results. After operation, the observation group had lower HR and MAP values than the control group ( P < 0.05 ). The dosage of local anesthetics in the observation group was significantly less than that in the control group ( P < 0.05 ). The onset time and improvement time of sensory block in the observation group were significantly faster than those in the control group ( P < 0.05 ). The observation group had a lower VAS score than the control group ( P < 0.05 ). There was no significant difference in Bromage score or incidence of complications between the two groups ( P > 0.05 ). Conclusion. The use of CSEA has good anesthetic effect. It has the disadvantage of no headache after traditional spinal anesthesia, is not limited by time, and can be used for postoperative analgesia, which is more suitable for the anesthesia of lower limb orthopaedic surgery in the elderly.

Robinia pseudoacacia is an important afforestation tree introduced to China in 1878. In the present study, we examined the genetic diversity among 687 strains representing four improved varieties and two secondary provenances, comprising 641 clones and 46 seedlings. Ninety-one simple sequence repeats (SSRs) were selected through segregation analysis and polymorphism characterization, and all sampled individuals were genotyped using well-characterized SSR markers. After excluding loci with non-neutral equilibrium, missing locus data and null alleles, we used 36 primer pairs to assess the genetic diversity of these germplasm resources, revealing vast genetic differentiation among the samples, with an average of 8.352 alleles per locus and a mean Shannon′s index of 1.302. At the population level, the partitioning of variability was assessed using analysis of molecular variance, which revealed 93% and 7% variation within and among collection sites, respectively. Four clusters were detected using structure analysis, indicating a degree of genetic differentiation among the six populations. Insights into the genetic diversity and structure of R. pseudoacacia provide a theoretical basis for the conservation, breeding and sustainable development in China.

Vegetative propagation is an important method of reproduction and rejuvenation in horticulture and forestry plants with a long lifespan. Although substantial juvenile clones have been obtained through the vegetative propagation of ornamental plants, the molecular factors that regulate rejuvenation during vegetative propagation are largely unknown. Here, root sprouting and root cutting of Robinia pseudoacacia were used as two vegetative propagation methods. From two consecutive years of transcriptome data from rejuvenated seedlings and mature trees, one gene module and one miRNA module were found to be specifically associated with rejuvenation during vegetative propagation through weighted gene co-expression network analysis (WGCNA). In the gene module, a transcription factor-encoding gene showed high expression during vegetative propagation, and it was subsequently named RpTOE1 through homology analysis. Heterologous overexpression of RpTOE1 in wild-type Arabidopsis and toe1 toe2 double mutants prolonged the juvenile phase. The qRT-PCR results predicted RpFT to be a downstream gene that was regulated by RpTOE1. Further investigation of the protein-DNA interactions using yeast one-hybrid, electrophoretic mobility shift, and dual luciferase reporter assays confirmed that RpTOE1 negatively regulated RpFT by binding directly to the TOE binding site (TBS)-like motif on its promoter. On the basis of these results, we showed that the high expression of RpTOE1 during vegetative propagation and its inhibition of RpFT played a key role in the phase reversal of R. pseudoacacia.