Background: Being a promising tropical woody oilseed crop, the evergreen and recurrent plants of Sacha Inchi (Plukenetia volubilis L.) has complex phenology and source–sink interactions. Carbon source–sink manipulations with control and two treatments (reduce source, ca. 10% mature leaf pruning; reduce sink, 10% fruitlet thinning) were conducted on 2.5-year-old field-grown P. volubilis plantation during the early-wet season in a seasonal tropical area. Results: Leaf photosynthetic rate and specific leaf area largely remained unchanged in response to defoliation or defloration. Compared with control, higher N contents on average were observed in both remaining leaves and branches of the defoliated plants, suggesting that N-mobilization was mainly due to the enhanced N uptake from soil. Carbon, but not N, is a source-driven growth process of P. volubilis plants, as defoliation reduced the contents of non-structural carbohydrates (especially sugar) in branches, although temporally, whereas defloration increased available C reserve. The seasonal dynamic pattern of fruit ripening was altered by source–sink regulations. Total seed yield throughout the growing season, which depends on fruit set and retention (i.e., number of matured fruit) rather than individual fruit development (size), was slightly increased by defloration but was significantly decreased by defoliation. Compared with control, defloration did not enrich the KEGG pathway, but defoliation downregulated the TCA cycle and carbohydrate and lipid metabolisms in fruitlets after 24 days of the applications of source–sink manipulation. Conclusion: Carbohydrate reserves serve to buffer sink–source imbalances that may result from temporary adjustment in demand for assimilates (e.g., defloration) or shortfalls in carbon assimilation (e.g., defoliation). Defoliation is disadvantageous for the yield and also for carbohydrate and lipid accumulation in fruits of P. volubilis plants. Although more studies are needed, these results provide new insights to the further improvement in seed yield of the strong source-limited P. volubilis plants by source/sink manipulations.

Somatic embryogenesis (SE) is a more rapid and controllable method for plant propagation than traditional breeding methods. However, it often suffers from limited efficiency. SERK1 promotes SE in several plants, including pineapple (Ananas comosus L.). We investigate the embryonic cell-specific transcriptional regulation of AcSERK1 by methylation analysis of CpG islands in AcSERK1 regulatory sequences. This revealed differences in the methylation status of CpG islands between embryonic callus and non-embryonic callus; the methylation inhibitor 5-azaC increased AcSERK1 expression and also accelerated SE. These findings indicate that the expression of AcSERK1 is regulated epigenetically. This study lays the foundation for further analysis of epigenetic regulatory mechanisms that may enhance the efficiency of SE in pineapple and other plants.

Plant tissue culture methods, such as somatic embryogenesis, are attractive alternatives to traditional breeding methods for plant propagation. However, they often suffer from limited efficiency. Somatic embryogenesis receptor kinase (SERK)1 is a marker gene of early somatic embryogenesis in several plants, including pineapple. It can be selectively induced and promotes a key step in somatic embryogenesis. We investigated the embryonic cell-specific transcriptional regulation of AcSERK1 by constructing a series of vectors carrying the GUS (Beta-glucuronidase) reporter gene under the control of different candidate cis-regulatory sequences. These vectors were transfected into both embryonic and non-embryonic callus, and three immature embryo stages and the embryonic-specific activity of the promoter fragments was analyzed. We found that the activity of the regulatory sequence of AcSERK1 lacking −983 nt ~−880 nt, which included the transcription initiation site, was significantly reduced in the embryonic callus of pineapple, accompanied by the loss of embryonic cell-specific promoter activity. Thus, this fragment is an essential functional segment with highly specific promoter activity for embryonic cells, and it is active only from the early stages of somatic embryo development to the globular embryo stage. This study lays the foundation for identifying mechanisms that enhance the efficiency of somatic embryogenesis in pineapple and other plants.

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.

Shredded pineapple, a type of rare high-quality fresh pineapple, is convenient to eat and has high economic value worldwide. In this study, the crown buds and sucker buds of shredded pineapple were used to study the effects of different explants and the ratios of different hormones (i.e., 6-benzylaminopurine, 6-BA; naphthaleneacetic acid, NAA; and indolebutyric acid, IBA) on the induction, proliferation, differentiation, and rooting of pineapple, and the effects of seedling refining on the survival rate of transplants, to establish a regeneration system for shredded pineapple. The results showed that the most suitable explant was crown buds, the optimal medium for adventitious bud induction was MS+3.0 mg/L 6-BA+3.0 mg/L NAA, the optimal proliferation medium was MS+3.0 mg/L 6-BA+1.0 mg/L NAA, the optimal adventitious bud growth was the MS medium, and the optimal rooting medium was MS+2.0 mg/L IBA. The peak survival rate of regenerated plants was observed after seven days of seedling refining. This study successfully established and optimized a tissue culture and rapid propagation regeneration system for shredded pineapple, which provides technical support for the low-cost rapid production and genetic transformation of pineapples.

Enhancing the horticultural and commercial value of Ananas comosus through polyploidy has great potential, as does meeting market demands. This study used different colchicine treatments, durations, and concentrations to induce polyploidy in pineapple somatic embryo callus. Consequently, a maximum polyploid induction rate of 40.00% was achieved in somatic embryogenic callus exposed to 0.1% colchicine for 20 days. Flow cytometry revealed 202 tetraploids among the regenerated plants analyzed. Polyploid plants, in contrast to diploid ones, are morphologically characterized by having thicker, heavier, wider, and shorter leaves, a larger leaf area, a darker color, a shorter overall height, thicker stems, and fewer, shorter leaf spines that are more irregularly distributed and differently shaped. In polyploids, the stomata were both larger and less numerous than in diploid plants, and the stomatal guard cells and leaf epidermal cells were larger too. The study revealed that polyploid plants exhibited much higher levels of chlorophyll and PEPC enzyme activity than the diploid control plants. Compared to diploid control plants, polyploid plants displayed enhanced resistance to salt and heat following treatment. Overall, this research outlined an efficient strategy for inducing polyploidy in pineapples, paving the way for future advancements in pineapple germplasm resources.