Picea mongolica is a rare tree species in China, which is of great significance in combating desertification and improving the harsh ecological environment. Due to the low rate of natural regeneration, high mortality, and susceptibility to pests and cold springs, Picea mongolica has gradually become extinct. At present, somatic embryogenesis (SE) is the most effective method of micro-proliferation in conifers, but the induction rate of embryogenic callus (EC) is low, and EC is difficult to differentiate from non-embryonic callus (NEC). Therefore, the EC and NEC of Picea mongolica were compared from the morphology, histological, physiological, and transcriptional levels, respectively. Morphological observation showed that the EC was white and transparent filamentous, while the NEC was compact and brownish-brown lumpy. Histological analyses showed that the NEC cells were large and loosely arranged; the nuclei attached to the edge of the cells were small; the cytoplasm was low; and the cell gap was large and irregular. In the EC, small cells, closely arranged cells, and a large nucleus and nucleolus were observed. Physiological studies showed significant differences in ROS-scavenging enzymes between the EC and NEC. Transcriptome profiling revealed that 13,267 differentially expressed genes (DEGs) were identified, 3682 were up-regulated, and 9585 were down-regulated. In total, 63 GO terms had significant enrichment, 32 DEGs in plant hormone signal transduction pathway were identified, and 502 different transcription factors (TFs) were characterized into 38 TF families. Meanwhile, we identified significant gene expression trends associated with somatic embryo development in plant hormones (AUX/IAA, YUCCA, LEA, etc.), stress (GST, HSP, GLP, etc.), phenylpropanoid metabolism (4CL, HCT, PAL, etc.), and transcription factors (AP2/ERF, MYB, WOX, etc.). In addition, nine genes were chosen for RT-qPCR, and the results were consistent with RNA-Seq data. This study revealed the changes in morphology, histology, physiology, and gene expression in the differentiation of NEC into EC and laid the foundation for finding the key genes to promote EC formation.

Prunasin and amygdalin are important factors that influence the kernel taste of apricots, however, the regulatory mechanisms underlying this are unclear. In this study, we analyzed the phenotype and transcriptome of kernels during development in Prunus sibirica (bitter kernels) and Prunus armeniaca × Prunus sibirica (kernel consumption apricot, sweet kernels). Prunasin and amygdalin content was significantly higher in bitter kernels compared with that in sweet kernels. Prunasin content exhibited a decreasing trend in both bitter and sweet kernels. The fastest decline was observed in bitter and sweet kernels during S3–S4 (82.21%) and S2–S3 (59.65%), respectively. The amygdalin content in the bitter kernels exhibited the fastest increase between 45–60 d after flowering, and reached a peak at 6.22% on 60 d after flowering. In contrast, the peak in sweet kernels occurred at 60 d after flowering, with a much lower content of 0.18%. Transcriptome analysis revealed 6,942 differentially expressed genes (DEGs), with a subset of 38 DEGs specifically enriched in the cyanoamino acid metabolic pathway. Among these, the ten candidate genes, including CYP79, CYP71, UGT1, AH, and PH, were identified as crucial in regulating prunasin and amygdalin metabolism. Furthermore, a weighted gene co-expression network analysis (WGCNA) unveiled two modules that exhibited significant correlation with prunasin and amygdalin content. Five DEGs were located at the center of the co-expression network, and were identified as hub genes, with four positively regulating prunasin content and one negatively regulating amygdalin content. Our results provide novel insights into the molecular-level regulation of the apricot kernel taste.

Studying the evolutionary history of plants in the Qinghai-Tibetan Plateau region provides a theoretical basis for the conservation and use of plant genetic resources. In this study, we analyzed five chloroplast gene fragments to examine the genetic diversity and phylogeography of Prunus mira in 577 individuals from 32 populations. The results indicated that P. mira populations exhibit high genetic diversity and significant phylogeographic structure (NST > GST). High genetic differentiation (FST = 0.979) and limited gene flow were detected among populations, likely due to geographic isolation. Neutrality tests and mismatch analysis indicated that the P. mira population has not experienced significant expansion during the historical period and remains relatively stable. Additionally, based on haplotype distribution and genetic diversity levels, we propose that P. mira had three refugia during the glacial period. Considering the genetic diversity of P. mira populations, we propose dividing all populations into two conservation units and prioritizing in situ conservation of populations with high genetic diversity within each unit. Furthermore, ex situ conservation of specific populations could prevent the loss of unique genes, such as those in populations with low genetic diversity but distinct haplotypes.

The production and quality of apricots in China is currently limited by the availability of germplasm resource characterizations, including identification at the species and cultivar level. To help address this issue, the complete chloroplast genomes of Prunus armeniaca L., P. sibirica L. and kernel consumption apricot were sequenced, characterized, and phylogenetically analyzed. The three chloroplast (cp) genomes ranged from 157,951 to 158,224 bp, and 131 genes were identified, including 86 protein-coding genes, 37 rRNAs, and 8 tRNAs. The GC content ranged from 36.70% to 36.75%. Of the 170 repetitive sequences detected, 42 were shared by all three species, and 53–57 simple sequence repeats were detected with AT base preferences. Comparative genomic analysis revealed high similarity in overall structure and gene content as well as seven variation hotspot regions, including psbA-trnK-UUU, rpoC1-rpoB, rpl32-trnL-UAG, trnK-rps16, ndhG-ndhI, ccsA-ndhD, and ndhF-trnL. Phylogenetic analysis showed that the three apricot species clustered into one group, and the genetic relationship between P. armeniaca and kernel consumption apricot was the closest. The results of this study provide a theoretical basis for further research on the genetic diversity of apricots and the development and utilization of molecular markers for the genetic engineering and breeding of apricots.

GmSRC7 is a broad-spectrum antiviral R gene from soybean, but its downstream and functionally related genes remain unclear. Virus-induced gene silencing (VIGS) assays in Nicotiana benthamiana (Nb) showed that suppression of several gene families—WRKY transcription factors, chaperones, ethylene pathway components, MAPK cascade elements, salicylic acid (SA) signaling genes, calcium-dependent protein kinases, nuclear migration proteins, RNA replication-related genes, and immune regulators—consistently weakened GmSRC7-mediated resistance to Soybean Mosaic Virus (SMV) and Tobacco Mosaic Virus (TMV). Targeted silencing of four regulatory genes—NbEDS1, NbARF1, NbSGT1, and NbCOI1—markedly enhanced GmSRC7-mediated resistance to SMV and TMV in our experiments. Silencing the serine/threonine kinase gene NbPBS1 increased GmSRC7-conferred resistance to SMV but did not significantly alter its resistance to TMV. Transient expression assays showed that NbARF1, NbSGT1, and NbCOI1 antagonize GmSRC7-mediated defense against SMV and TMV, whereas NbPBS1 specifically suppresses anti-SMV activity without affecting TMV resistance. Transient overexpression of SA-degrading enzymes (AtS3H, AtS5H, and NahG) significantly reduced GmSRC7-conferred resistance to SMV, indicating that SA is essential for this R protein-mediated defense. Genes were also grouped by immune pathways and function: co-expression of chaperone family genes inhibited GmSRC7 activity against SMV and TMV, while co-expression of WRKY family genes enhanced anti-SMV activity of GmSRC7. Finally, transient silencing of soybean genes GmEDS1, GmSGT1-1, GmSGT1-2, GmJAR1, and GmSGS3 compromised GmSRC7-mediated resistance to SMV.