Sugars Will Eventually be Exported Transporter (SWEET) gene family plays indispensable roles in plant physiological activities, development processes, and responses to biotic and abiotic stresses, but no information is known for roses. In this study, a total of 25 RcSWEET genes were identified in Rosa chinensis ‘Old Blush’ by genome-wide analysis and clustered into four subgroups based on their phylogenetic relationships. The genomic features, including gene structures, conserved motifs, and gene duplication among the chromosomes of RcSWEET genes, were characterized. Seventeen types of cis-acting elements among the RcSWEET genes were predicted to exhibit their potential regulatory roles during biotic and abiotic stress and hormone responses. Tissue-specific and cold-response expression profiles based on transcriptome data showed that SWEETs play widely varying roles in development and stress tolerance in two rose species. Moreover, the different expression patterns of cold-response SWEET genes were verified by qRT-PCR between the moderately cold-resistant species R. chinensis ‘Old Blush’ and the extremely cold-resistant species R. beggeriana. Especially, SWEET2a and SWEET10c exhibited species differences after cold treatment and were sharply upregulated in the leaves of R. beggeriana but not R. chinensis ‘Old Blush’, indicating that these two genes may be the crucial candidates that participate in cold tolerance in R. beggeriana. Our results provide the foundation for function analysis of the SWEET gene family in roses, and will contribute to the breeding of cold-tolerant varieties of roses.

Roses are one of the most important flowers applied to landscape, cut flowers, fragrance and food industries widely. As an effective method for plant reproduction, the regeneration via somatic embryos is the most promising method for breed improvement and genetic transformation of woody plants. However, lower somatic embryogenesis (SE) induction rates and genotypic constraints impede progress in genetic transformation in rose. This study describes a plant regeneration system for the famous red cut flower cultivar Rosa hybrida ‘Carola’. The stems without petioles cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg·L⁻¹ 6-benzylaminopurine (6-BA), 0.05 mg·L⁻¹ a-naphthalene acetic acid (NAA) and 30 g·L⁻¹ sucrose showed the maximum proliferation coefficient of shoots with 3.41 for the micropropagation system. We evaluated the effects of different plant growth regulators (PGRs) on the induction, proliferation and conversion of somatic embryos. The induction rate of calli reached 100% on MS medium supplemented with 2.0 g·L⁻¹ NAA and 30 g·L⁻¹ glucose. The highest induction rate of somatic embryos achieved a frequency of 13.33% on MS medium supplemented with 2.0 mg·L⁻¹ zeatin (ZT), 0.1 mg·L⁻¹ NAA and 30 g·L⁻¹ glucose. The most suitable carbohydrate with 60 g·L⁻¹ glucose resulted in a proliferation rate of somatic embryos (4.02) on MS medium containing 1.5 mg·L⁻¹ ZT, 0.2 mg·L⁻¹ NAA and 0.1 mg·L⁻¹ gibberellic acid (GA₃). The highest somatic embryos germination rate (43.33%) was obtained from the MS medium supplemented with 1.0 mg·L⁻¹ 6-BA, 0.01 mg·L⁻¹ IBA and 30 g·L⁻¹ glucose. Finally, the germinated somatic embryos successfully rooted on 1/2 MS medium containing 1.0 mg·L⁻¹ NAA, 30 g·L⁻¹ sucrose, and the vigorous plantlets were obtained after hardening-off culture. This study provided a stable and efficient protocol for plant regeneration via somatic embryos in R. hybrida ‘Carola’, which will be beneficial to the further theoretical study and genetic improvement in roses.

Phalaenopsis orchids are one of the most important ornamental crops, prized for their beautiful flowers and long flowering phase. Hundreds of commercially available cultivars display a remarkable range of variation in key horticultural traits, including inflorescence type, floral size, and color patterning. While most current cultivars have been developed through cross-breeding or mutation breeding, genetic homogenization has become a growing concern. This is largely due to extensive hybridization among existing cultivars, which are predominantly derived from a limited number of parental species. Additionally, trait linkage in Phal. can hinder the integration of desirable characteristics in progeny. Therefore, there is an urgent need to decipher the genetic programs governing key horticultural traits to facilitate both conventional and molecular breeding. Despite significant research efforts, progress has been hampered by several resource limitations. These include a scarcity of high-quality genome assemblies, the lack of stable genetic transformation systems, and insufficient materials for molecular biology studies—a challenge exacerbated by the plant’s relatively long life cycle. Consequently, the molecular mechanisms underlying the formation and diversity of most important horticultural traits in Phal. orchids remain largely unexplored. This review summarizes recent research advances, with a primary focus on the key floral traits in Phal. orchids, including inflorescence type, flowering time, floral organ organization, color patterning, size, longevity, scent, organ shape, cuticle production, and wax biosynthesis. Furthermore, we offer perspectives on future research directions aimed at elucidating the genetic basis for the remarkable diversity of these traits and advancing molecular breeding in Phal. orchids.

Premise of the Study: Microsatellite primers were developed for Paphiopedilum henryanum (Orchidaceae), a species threatened with extinction, to assess genetic diversity and population genetic structure.Methods and Results: Based on the transcriptome data of P. henryanum, 34 novel polymorphic microsatellite expressed sequence tag–simple sequence repeat markers were developed and characterized in 33 individuals from two P. henryanum populations. The results showed the number of alleles per locus ranged from two to four, and levels of observed and expected heterozygosity per locus ranged from 0.000 to 1.000 and from 0.000 to 0.7333, respectively. Of these markers, some primers showed good amplification results in seven other Paphiopedilum species.Conclusions: The developed microsatellite markers will be useful in exploring the genetic diversity and structure of P. henryanum. Furthermore, most loci were successfully cross‐amplified in seven other species of Paphiopedilum, indicating that they will be of great value for genetic study across this genus.

Paphiopedilum(Orchidaceae) is one of the world’s most popular orchids that is found in tropical and subtropical forests and has an enormous ornamental value.SEPALLATA-like (SEP-like) MADS-box genes are responsible for floral organ specification. In this study, threeSEP-like MADS-box genes,PhSEP1,PhSEP2, andPhSEP3, were identified inPaphiopedilum henryanum. These genes were 732–916 bp, with conserved SEPI and SEPII motifs. Phylogenetic analysis revealed thatPhSEPgenes were evolutionarily closer to the core eudicotSEP3lineage, whereas none of them belonged to core eudicotSEP1/2/4clades.PhSEPgenes displayed non-ubiquitous expression, which was detectable across all floral organs at all developmental stages of the flower buds. Furthermore, subcellular localization experiments revealed the localization of PhSEP proteins in the nucleus. Yeast two-hybrid assays revealed no self-activation of PhSEPs. The protein–protein interactions revealed that PhSEPs possibly interact with B-class DEFICIENS-like and E-class MADS-box proteins. Our study suggests that the threeSEP-like genes may play key roles in flower development inP. henryanum, which will improve our understanding of the roles of theSEP-like MADS-box gene family and provide crucial insights into the mechanisms underlying floral development in orchids.

Aerides rosea (Orchidaceae) boasts high ornamental value due to its pleasant aroma, foxtail spike, and elegant floral morphology. Inducing A. rosea to become tetraploid enhances horticultural traits and facilitates fertile intergeneric hybrids through crosses with other market-available tetraploid species. The experimental design involved the application of colchicine at varying concentrations—0.05%, 0.1%, and 0.2%—to a solid medium. Exposure durations were 5, 10, and 15 days, with treatments conducted under sterile conditions on 6-week-old protocorms post-germination. Results indicated that the protocorms were sensitive to colchicine concentrations exceeding 0.05%, with high concentrations leading to a mortality rate exceeding 50%. Flow cytometry (FCM) with 4′,6-diamidino-2-phenylindole (DAPI) staining confirmed a doubling of chromosome numbers in tetraploid plants (2n = 4x = 76) compared to diploid controls (2n = 2x = 38). Induction efficiency was significantly influenced by colchicine concentration and treatment duration. A 10-day treatment with 0.2% colchicine yielded a 70.00% tetraploid induction rate; however, considering protocorm survival, a 5-day treatment with 0.05% colchicine was preferable, achieving a 63.55% survival rate and a 56.67% tetraploid induction rate. Tetraploid plants exhibited distinct morphological traits, such as a more compact growth habit, thicker leaves, and increased stem and root thickness. Leaf morphology changes included larger stomata with reduced density, denser spongy mesophyll, and more pronounced venation. Tetraploids also demonstrated a 1.94-fold increase in genome size compared to diploids. The tetraploid genotypes developed in this study hold significant potential for future Aerides breeding programs.