As a woody plant, peony (Paeonia suffruticosa) has a long growth cycle and inefficient traditional breeding techniques. There is an urgent need in peony molecular breeding to establish an efficient and stable in vitro regeneration and genetic transformation system, in order to overcome the recalcitrant characteristics of peony regeneration and shorten the breeding cycle. The development of plant somatic embryos is an important way to establish an efficient and stable in vitro regeneration and genetic transformation system. Plant-specific WUSCHEL-related homeobox (WOX) family transcription factors play important roles in plant development, from embryogenesis to lateral organ development. Therefore, in this research, four PoWOX genes of “Fengdan” (Paeonia ostii) were cloned from the peony genome and transcriptome data of preliminary peony somatic embryos. The sequence characteristics and evolutionary relationships of the PoWOX genes were analyzed. It was demonstrated that the four PoWOX genes, named PoWOX1, PoWOX4, PoWOX11, and PoWOX13, belonged to three branches of the WOX gene family. Their expression patterns were analyzed at different stages of development and in different tissues of peony seedlings. The expression localization of the PoWOX genes was determined to be the nucleus via subcellular localization assay. Finally, the interaction protein of the PoWOX genes was identified via yeast two-hybrid assay combined with bimolecular fluorescence complementation assay. It was shown that PoWOX1 and PoWOX13 proteins could form homodimers by themselves, and PoWOX11 interacted with PoWOX1 and PoWOX13 to form heterodimers. Peony stem cell activity may be regulated from PoWOX1 and PoWOX13 by forming dimers and moving to peony stem cells through plasmodesmata. Additionally, PoWOX11–PoWOX1 and PoWOX11–PoWOX13 may play important regulatory functions in promoting the proliferation of stem cells and maintaining the homeostasis of stem cells in the SAM of peony stems. Exploring the critical genes and regulatory factors in the development of the peony somatic embryo is beneficial not only to understand the molecular and regulatory mechanisms of peony somatic embryo development but also to achieve directed breeding and improvements in efficiency through genetic engineering breeding technology to accelerate the fundamental process of molecular breeding in peony.

BABY BOOM (BBM) is one of the members of the plant-specific APETALA2/ethylene-responsive factor (AP2/ERF) transcription factor superfamily. It acts as a key regulator of plant cell pluripotency, playing a significant role in promoting somatic embryogenesis. In this study, a BBM gene named PoBBM was screened, cloned, and identified from the third-generation full-length transcriptome data of Paeonia ostii. Its open reading frame was 2136 bp, encoding 711 amino acids. Sequence feature analysis revealed that it possessed two AP2 conserved domains and eight motifs, including bbm-1. The phylogenetic tree indicated that PoBBM clusters with AtBBM in the euANT group of the Arabidopsis AP2 family, which is most closely related to grape VvBBM and may have the same ancestry as grape. Subcellular localization demonstrated that the PoBBM protein was localized in the nucleus. Semi-quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess the PoBBM transcript levels during ten developmental stages of somatic embryos and in five tissue types of peonies. The results indicate that PoBBM was highly expressed in the early stages of peony somatic embryo development. The expression on 0–15 d was the highest and decreased gradually with somatic embryogenesis. The gene is almost not expressed after 40 d since somatic embryo formation. PoBBM was expressed in roots, stems, leaves, seeds, and calli, with the highest levels in seeds, followed by leaves and calli. The PoBBM protein displayed transcriptional self-activation activity, which may facilitate further research on its relationships with other proteins. The above results provide a key gene PoBBM for somatic embryogenesis in peonies, which is significant for advancing the establishment of a stable and efficient regeneration and genetic transformation system for peonies.

Moso bamboo (Phyllostachys edulis (Carriere) J. Houzeau), native to China, is one of the most economically and ecologically important bamboo species. Since the economic interests and the strong clonality, it has been widely cultivated in southern China, which inevitably reduces the natural stands and leads to gene loss in this species. In this study, three natural populations of Moso bamboo distributed in Anhui, Guangxi, and Zhejiang province, were used to analyze the correlation between phenotypic traits, cell structure, and material properties from the perspective of phenotypic, genetic, and environmental. Among those traits and properties, fiber width was correlated with wall thickness at breast height and average nodes length under branch positively. Leaf length was correlated positively with fiber lumen diameter and parenchyma lumen diameter. Furthermore, it showed a very close correlation between moisture content, bending strength, modulus of elasticity, and diameter at breast height, clear height, and leaf length. The lumen diameter of fiber cell wall thickness is positively correlated with bending strength and modulus of elasticity. Density is positively correlated with parenchyma cell wall thickness. The experimental design is relatively detailed and representative, and the workload is huge. This study reflects the research objectives with scientific and rational experiments and data. This study will analyze the differences of various indicators from the perspective of genetic to build a bridge between micro-structure and macro-structure for rational utilization of the whole area of Moso bamboo resources in China.

As climate change intensifies soil drought and salinization, enhancing the drought and salt tolerance of moso bamboo (Phyllostachys edulis) is urgent. DHN genes are crucial for plant stress responses and have gained attention in plant resistance to drought and salinity. This study identified nine DHN family members (PeDHN1–PeDHN9) from moso bamboo, which were classified into K₂S-type, YK₂S-type, and Y₂K₂S-type dehydrins based on their characteristic motifs. We employed integrated bioinformatics approaches to analyze their gene structure, phylogeny, biological properties, and expression patterns under various stress conditions. Five genes (PeDHN2/4/5/6/8), which may have significant functional roles in moso bamboo, were selected for cloning. Subcellular localization experiments showed that YK₂S-type dehydrins (PeDHN2/5/6) localized to both the nucleus and the plasma membrane, while K₂S-type dehydrins (PeDHN4/8) were exclusively localized to the plasma membrane, indicating functional differentiation. qRT-PCR analysis revealed that the expression of PeDHN2/4/5/6/8 was significantly responsive to stress treatments with ABA, NaCl, and PEG. Additionally, overexpressing these genes in rice significantly enhanced seed germination rates and root development under salt and ABA stress, further confirming that PeDHN2/4/5/6/8 contribute to enhancing plant stress tolerance. Yeast one-hybrid assays demonstrated that two PeABF1 proteins could bind to the promoter of PeDHN4, suggesting that PeDHN4 may regulate stress responses through the ABA signaling pathway. Thus, these findings demonstrate that PeDHN2/4/5/6/8 are closely related to the response of moso bamboo to drought and saline-alkali environments. This research offers insights for moso bamboo cultivation and theoretical foundations for bamboo genetic improvement in stress environments.

The gene encoding 1-hydroxy-2-methyl-2-(E)-butenyl-4-pyrophosphate reductase, a key enzyme at the end of the methylerythritol 4-phosphate pathway (MEP), was cloned from the petals of Narcissus tazetta var. Chinensis ‘Jinzhanyintai’ and named NtHDR (accession number OQ739816). NtHDR exhibits a full-length coding sequence spanning 1380 base pairs, encoding a total of 460 amino acids. Through phylogenetic-tree analysis, it has been determined that NtHDR shared the closest evolutionary relationship with monocotyledons, specifically Asparagus officinalis and Zingiber officinale. Utilizing quantitative real-time PCR analysis, it was observed that NtHDR exhibited significant expression in both petals and corona, with expression levels varying throughout the flowering process of Narcissus. Specifically, in petals, NtHDR expression demonstrated a pattern of initial increase followed by subsequent decrease, while in corona, it consistently increased. Subsequent subcellular-localization experiments indicated that NtHDR was localized within the chloroplasts. To investigate the functional impact of NtHDR, a stable transformation was performed, where NtHDR was introduced into Nicotiana benthamiana. The resulting transgenic N. benthamiana flowers were analyzed using solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS) to characterize their volatile components. The analysis revealed the presence of the monoterpene compound linalool, as well as the phenylpropanoids benzyl alcohol and phenylethanol, within the floral fragrance components of the transgenic N. benthamiana plants. However, these compounds were absent in the floral fragrance components of wild-type tobacco plants, thus highlighting the impact of NtHDR transformation on the floral scent profile.

Narcissus tazetta var. chinensis M.Roem. (Chinese Narcissus) is a traditional and famous flower in China, and its corona shows a transition from green to yellow with the opening of flowers, which is of great ornamental value. To investigate the molecular mechanism of the corona color-forming in the Chinese Narcissus, in this study, a MYB gene was screened from the transcriptome of the corona by bioinformatics analysis methods, named NtMYB9. The expression level of the NtMYB9 gene was significantly higher in the corona than in the tepal, filament, ovary and leaf, and reached the highest level at the fourth period of complete coloration of the corona. The full-length sequence of the NtMYB9 coding region was cloned using the corona cDNA as a template. Sequence analysis revealed that NtMYB9 protein contained R2 and R3 domains, phylogenetic tree analysis showed that the NtMYB9 protein was most closely related to flavonol activators. Subcellular localization showed that NtMYB9 was localized in the nucleus. The overexpression of NtMYB9 gene into tobacco leaves and the expression level of seven enzyme genes related to the flavonoid biosynthesis pathway were significantly up-regulated. The transient transformation of Petunia × hybrida (Petunia) and Phalaenopsis aphrodite (Phalaenopsis) significantly revealed that the NtMYB9 gene could turn flowers yellow. These results suggest that the NtMYB9 gene is involved in the positive regulation of flavonoid biosynthesis in the Chinese Narcissus and may promote the synthesis of flavonols. In conclusion, these findings provide a valuable resource for further studies on the regulatory mechanism of the flavonoid biosynthesis pathway, and they are also beneficial to the molecular breeding of Chinese Narcissus.