Oil palm (Elaeis guineensis Jacq.) is the most efficient oil-producing crop globally, yet progress in its research has been hampered by the lack of effective genetic transformation systems. The EPSPS gene, encoding 5-enolpyruvylshikimate-3-phosphate synthase, has been used as a transgenic selection marker in various crops, including rice and soybean. This study evaluated the EPSPS/glyphosate selection system for oil palm transformation. We constructed a binary expression vector, pCGlyDESCLI-C, containing the TIPS-EiEPSPS selection marker from goosegrass and the mScarlet-I red fluorescent reporter gene. This vector was introduced into oil palm embryonic callus (EC) via Agrobacterium-mediated transformation. After optimizing the transformation steps, positive calli were obtained, and integration of the foreign gene into the oil palm genome was confirmed through molecular analysis. Notably, the selection efficiency of the EPSPS/glyphosate selection system exceeded that of the traditional hpt/hygromycin selection system, demonstrating its advantages. Our findings support the effectiveness of the TIPS-EiEPSPS/glyphosate selection system for oil palm genetic transformation, marking its first application in this species and offering a valuable tool for advancing research on this economically significant crop.

The makapuno coconut endosperm is distinguished by its soft and irregular texture, in contrast to the solid endosperm of regular coconuts. To establish a scientific foundation for studying makapuno coconuts, callus was induced from makapuno endosperm using a combination of plant growth regulators. The induction was successful, and the resulting callus was subsequently subcultured for further study. Transcriptome sequencing of the makapuno callus identified 429 differentially expressed genes (DEGs), with 273 upregulated and 156 downregulated, compared to callus derived from regular coconut endosperm. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that these DEGs were involved in key metabolic pathways, including fructose and mannose metabolism, carbon fixation in photosynthetic organisms, galactose metabolism, and amino sugar and nucleotide sugar metabolism. Furthermore, lipid content analysis of the makapuno callus revealed a significantly higher total lipid level compared to regular callus, with notable differences in the levels of specific fatty acids, such as myristic acid, palmitic acid, and linoleic acid. This study establishes a novel platform for molecular biological research on makapuno coconuts and provides valuable insights into the molecular mechanisms underlying the formation of makapuno callus tissue. The findings also lay the groundwork for future research aimed at elucidating the unique properties of makapuno endosperm and exploring its potential applications.

Somatic embryogenesis (SE)—the reprogramming of somatic cells to follow an embryogenic pathway—remains inefficient in the tropical monocot areca palm (Areca catechu L.) due to poorly understood constraints on cell fate transition. Using single-factor and orthogonal experiments, we investigated how plant growth regulators (PGRs), nitrogen source, and carbon supply regulate the acquisition of embryogenic competence. The optimal condition (Y3 medium + 6-BA + TDZ + 30 g/L sucrose) yielded a somatic embryo induction rate of 48.62%, more than six-fold higher than that of the unoptimized control. Cytologically, embryogenic callus consisted of small, densely cytoplasmic cells with large, centrally positioned nuclei with decondensed chromatin (i.e., loosely packed, transcriptionally active chromatin) and minimal vacuolation—hallmarks of meristematic, embryogenic-competent cells—whereas non-embryogenic callus contained large, highly vacuolated irregular cells. Histological tracking revealed that areca somatic embryos faithfully recapitulate the zygotic developmental program, including bipolarity establishment and procambium differentiation. Mechanistically, we show that the 6-BA + TDZ combination likely acts by inducing endogenous auxin synthesis; moderate ammonium supply (Y3 medium, NO₃⁻/NH₄⁺ ratio 3.6:1) minimizes browning; and 30 g/L sucrose provides optimal energy supply and osmotic regulation. This optimized SE system establishes a tractable model for studying somatic cell reprogramming in a woody monocot.

Coconut (Cocos nucifera L.) is an important tropical horticultural crop valued for its edible endosperm with high oil content. However, the molecular mechanisms governing carbon partitioning and the regulation of glycolytic genes during endosperm development remain largely unclear. Fructose-1,6-bisphosphate aldolase (FBA), a key enzyme in glycolysis, plays a central role in carbohydrate metabolism, yet its transcriptional regulatory mechanisms in coconut have not been elucidated. In this study, the CoFBA promoter (proFBA) was isolated and used for yeast one-hybrid screening, leading to the identification of a GATA transcription factor, CoGATA2. Subcellular localization analysis confirmed that CoGATA2 is localized in the nucleus. Yeast one-hybrid assays, electrophoretic mobility shift assays (EMSA), and transient expression in coconut protoplasts demonstrated that CoGATA2 directly binds to a proFBA fragment containing the predicted GATA motif and represses CoFBA expression. Moreover, virus-induced gene silencing (VIGS) of CoGATA2 in coconut callus resulted in significant upregulation of CoFBA expression and increased fructose-1,6-bisphosphate (FBP) levels. Collectively, these findings demonstrate that CoGATA2 functions as a transcriptional repressor of CoFBA and that this regulation correlates with altered FBP levels in coconut callus. However, the precise mechanism by which FBP accumulation occurs and its relationship to glycolytic flux require further investigation. This study provides new insights into the transcriptional regulation of a key glycolytic gene in coconut and offers a foundation for future efforts to manipulate carbon partitioning in this important horticultural crop.

Oil palm (Elaeis guineensis Jacq.) is a tropical woody oil crop with high economic value, but its low genetic transformation efficiency hinders molecular breeding. Growth-regulating factors (GRFs) and GRF-interacting factors (GIFs) play key roles in plant regeneration, yet their functions in oil palm remain unexplored. Here, we identified 14 EgGRF and 4 EgGIF genes via genome-wide analysis. Transcriptome and RT-qPCR showed that EgGRF1, EgGRF7, and EgGIF3 were significantly upregulated in regenerable tissues, and dual-luciferase assays confirmed protein interactions between EgGRF1/EgGRF7 and EgGIF3. We then optimized Agrobacterium-mediated transformation parameters, achieving a screening efficiency of 3.58% under optimal conditions (OD₆₀₀ = 0.5, infection for 40 min, 200 μmol/L acetosyringone, 60 h co-cultivation). Functional evaluation revealed that EgGRF1-EgGIF3 co-expression significantly increased both screening efficiency (5.32% ± 0.34%) and differentiation rate (56.39%), outperforming single-gene transformations. EgGRF1 alone also markedly improved differentiation (49.46%). Collectively, these results demonstrate that EgGRF1 is a key positive regulator of oil palm callus differentiation, and its synergistic expression with EgGIF3 further enhances screening efficiency and differentiation capacity at the embryogenic stage, providing an optimized protocol and candidate genes for oil palm genetic improvement.

Palmitoleic acid (C16:1Δ9) has high nutritional and industrial value, but enriching it in rice is hindered by low endogenous levels and poorly underst