Prunus mume is the only fragrant flowering species of Prunus. According to the previous studies, benzyl acetate and eugenol dominate its floral scent. However, the diversity of its floral scents remains to be elucidated. In this work, the floral volatiles emitted from eight intraspecific cultivars of P. mume with white, pink and red flowers, were collected and analyzed using headspace solid-phase microextraction combined with gas chromatograms-mass spectrometry (HS-SPME-GC-MS). In total, 31 volatile compounds were identified, in which phenylpropanoids/benzenoids accounted for over 95% of the total emission amounts. Surprisingly, except for benzyl acetate and eugenol, several novel components, such as benzyl alcohol, cinnamyl acohol, cinnamy acetate, and benzyl benzoate were found in some cultivars. The composition of floral volatiles in cultivars with white flowers was similar, in which benzyl acetate was dominant, while within pink flowers, there were differences of floral volatile compositions. Principal component analysis (PCA) showed that the emissions of benzyl alcohol, cinnamyl alcohol, benzyl acetate, eugenol, cinnamyl acetate, and benzyl benzoate could make these intraspecific cultivars distinguishable from each other. Further, hierarchical cluster analysis indicated that cultivars with similar a category and amount of floral compounds were grouped together. Our findings lay a theoretical basis for fragrant plant breeding in P. mume.

Low temperature is a primary factor limiting the distribution of Prunus mume. In order to produce a variety that has both cold tolerance and the characteristic fragrance of true mume, previous researchers crossbred a strong-tolerance variety apricot mei, P. mume ‘DF’ (‘Dan Fenghou’) and the weak-tolerance variety of true mume, P. mume ‘BY’ (‘Beijing Yudie’). They gained an offspring variety named P. mume ‘XR’ (‘Xiang Ruibai’), but its cold tolerance is unknown at this point. Here, three varieties (XR, BY, and DF) were selected as the materials, and different low-temperature treatments were used, with temperature as the only variable. Conventional biological methods, such as ion leakage rate, different tissues, and plant viability statistics, were used, as well as an innovative use of infrared engineering and moisture monitoring for dynamic observation of the water-to-ice process in tissues. The results were as follows: DF cold tolerance was the highest, followed by XR and then BY. The LT₅₀ of XR was increased by 6 °C after five days of cold priming at 4 °C, which indicated a stronger cold acclimation ability than the parent varieties. The XR variety enhanced the antioxidant capacity by increasing SOD and POD enzyme activities during low temperature treatment, thus enhancing the cold tolerance. The antioxidant enzyme genes PmSOD3, PmPOD2, PmPOD19, and PmPOD22 had important regulatory roles in XR’s cold acclimation process.

Cestrum nocturnum is a plant that blooms and emits fragrance at night but the mechanism behind its fragrance release remains poorly understood. Here, the floral substances and differential regulatory genes in the petals of C. nocturnum at night were explored by HS-SPME-GC/MS and transcriptome sequencing. Benzaldehyde, phenyl acetaldehyde and benzyl acetate were identified as the main floral scent substances involved in the phenylpropanoid biosynthesis pathway of C. nocturnum. The DEGs in this pathway, PALs, PAAS, PARs, 4CLs, CFATs, BEAT, EGSs and BAMT, showed high expression levels during flowering. Additionally, these genes may play an important role in the formation of a regulatory network for floral scent substance synthesis. DEGs in day/night alternates and plant hormone signalling pathways also had important functions in flowering and fragrance release. These included CO, FT and genes related to the promotion of phytohormone (GA, ABA, IAA, BR) biosynthetic and signal transduction, which showed high expression levels during flowering. These results provide a theoretical reference for the expression levels of differentially expressed functional genes in the flowering and fragrance release of C. nocturnum and lay a foundation for further research on night-blooming aromatic flowers.

Introduction: Flower color is a key ornamental and ecological trait that influences both aesthetic appeal and pollinator interactions. Although the biosynthetic and regulatory mechanisms of floral pigmentation are well characterized in several model species, they remain poorly understood in Meconopsis , an alpine genus renowned for its striking color diversity. Elucidating the molecular basis of petal coloration is crucial for the genetic improvement and conservation of this unique ornamental resource. Methods: Here, we combined metabolomic and transcriptomic analyses to investigate the molecular mechanisms underlying flower coloration in three Meconopsis species— M. balangensis (blue), M. punicea (red), and M. integrifolia (yellow)—using M. argemonantha (white) as a control. Results: Metabolite profiling revealed strong correlations between color parameters and pigment composition, particularly flavonoids and anthocyanins. Blue and red pigmentation were primarily attributed to cyanidin- and delphinidin-based anthocyanins, while yellow coloration resulted from quercetin derivatives. Transcriptome analysis identified key structural genes ( F3’H , DFR , ANS , UFGT , CHS , F3H , and FLS ) and regulatory transcription factors (MYB and bHLH) that collectively modulate flavonoid biosynthesis across species. Discussion: Our findings demonstrate that divergence in the regulation of the flavonoid biosynthetic pathway drives color differentiation among Meconopsis species. This study provides new insight into the metabolic and transcriptional control of alpine flower coloration and establish a theoretical foundation for the molecular breeding of novel Meconopsis cultivars.

Drought stress severely limits the growth and productivity of Morus alba, yet the molecular mechanisms underlying its adaptation remain poorly understood. Trehalose, an important osmoprotectant and signaling molecule, plays a key role in plant responses to abiotic stress, and its biosynthesis is primarily regulated by trehalose-6-phosphate synthase (TPS). However, the characteristics and potential functions of TPS genes in M. alba have not been systematically investigated. In this study, we identified 11 TPS genes (MaTPSs) in the M. alba genome and performed comprehensive analyses, including phylogenetic relationships, gene structures, conserved motifs, cis-regulatory elements, and expression profiles. Phylogenetic analysis classified MaTPSs into TPS I and TPS II subfamilies, with closer evolutionary relationships to Populus trichocarpa than to Arabidopsis thaliana. Promoter analysis revealed the presence of multiple stress- and hormone-responsive elements, suggesting their potential involvement in abiotic stress regulation. Physiological measurements showed that drought stress significantly increased trehalose accumulation, with a 1.6-fold increase in leaves and a 2.2-fold increase in roots. Expression profiling further demonstrated that six MaTPS genes were upregulated under drought stress, among which MaTPS4, MaTPS9, MaTPS10, and MaTPS11 exhibited significant induction (approximately 5-, 5-, 8-, and 10-fold, respectively). Correlation analysis further indicated that trehalose accumulation was positively associated with all upregulated MaTPS genes (p < 0.05). Taken together, these results suggest that MaTPS genes may be involved in drought-responsive regulation of trehalose metabolism in M. alba. This study provides a valuable foundation for future functional validation and the genetic improvement of drought tolerance in mulberry.