The coconut is an important tropical economical crop and exhibits high tolerance to various types of salinity stress. However, little is known about the molecular mechanism underlying its salt tolerance. In this study, RNA-Seq was applied to examine the different genes expressed in four coconut varieties when exposed to a salt environment, resulting in the generation of data for 48 transcriptomes. Comparative transcriptome analysis showed that some genes involved in cutin and wax biosynthesis were significantly upregulated in salt treatment compared to the control, including CYP86A4, HTH, CER1, CER2, CER3, DCR, GPAT4, LTP3, LTP4, and LTP5. In particular, the expression of CER2 was induced more than sixfold, with an RPKM value of up to 205 ten days after salt treatment in Hainan Tall coconut, demonstrating superior capacity in salt tolerance compared to dwarf coconut varieties. However, for yellow dwarf and red dwarf coconut varieties, the expression level of the CER2 gene was low at four different time points after exposure to salt treatment, suggesting that this gene may contribute to the divergence in salt tolerance between tall and dwarf coconut varieties. Cytological evidence showed a higher abundance of cuticle accumulation in tall coconut and severe damage to cuticular wax in dwarf coconut.

To characterize the nutrients and bioactive compounds in grape berries and to explore the real cause of the “French paradox” phenomenon, we performed metabolomic analysis of 66 grape varieties worldwide using liquid chromatography–tandem mass spectrometry (LC-MS). A nontargeted metabolomics approach detected a total of 4889 metabolite signals. From these, 964 bioactive and nutrient compounds were identified and quantified, including modified flavonoids, medicinal pentacyclic triterpenoids, vitamins, amino acids, lipids, etc. Interestingly, metabolic variations between varieties are not explained by geography or subspecies but can be significantly distinguished by grapes’ color, even after excluding flavonoids and anthocyanins. In our analysis, we found that purple grape varieties had the highest levels of key bioactive components such as flavonoids, pentacyclic triterpenes, and polyphenols, which are thought to have a variety of health benefits such as antioxidant, anti-inflammatory, and antitumor properties, when compared to grapes of other colors. In addition, we found higher levels of vitamins in red and pink grapes, possibly explaining their role in preventing anemia and scurvy and protecting the skin. These findings may be a major factor in the greater health benefits of wines made from purple grapes. Our study provides comprehensive metabolic profiling data of grape berries that may contribute to future research on the French paradox.

Coconut palms (Cocos nucifera L.) are globally significant palms with both economic and cultural value. Despite the increasing demand for coconut products, production is decreasing globally due to palm senility, pests, and diseases. It has been estimated that over half of the world’s coconut palms need to be replaced immediately. The coconut industry has acknowledged that conventional propagation methods are unlikely to yield sufficient high-quality planting material. Therefore, coconut tissue culture is considered a potential solution to this problem. By using coconut tissue culture, a large number of plantlets can be obtained in a short period of time. In this study, the quality of explants and the development stage (visible shoot/non-visible shoot) of coconut used for micropropagation were examined. To our knowledge, little research has been undertaken on this aspect of coconut micropropagation. Our results indicated that tender coconut fruit exhibited an advantage over mature fruits. In addition, coconut plumule explants subjected to an extended storage of 15 days demonstrated enhanced development compared to those without storage. Notably, smaller embryos utilized as explants displayed superior callus formation compared to their larger counterparts. Finally, embryos possessing shoots exhibited improved callus initiation, albeit accompanied by a more pronounced browning effect. Further investigations are required to obtain more knowledge about the most suitable conditions for plumule explants that lead to optimal callus initiation.

Squamosa Promoter-Binding Protein Like (SPL) is a critical transcription factor that plays a significant role in regulating plant growth and development. Mining the coconut SPL family offers valuable insights into the regulation of important agronomic traits, including the length of the juvenile phase. In this study, 25 CnSPLs were identified and were classified into eight subfamilies. Analysis of gene structure and conserved protein motifs indicated a high conservation of CnSPLs within the same subfamilies; however, variations in protein structure and gene length were observed across different subfamilies. Gene expansion analysis indicated that most gene members within subfamilies originated from duplications of the same genomic segment, and transposable element insertion contributed to the divergence of gene sequences within these subfamilies. Characterization of the miR156 target sequence in SPL transcripts revealed that subfamilies IV to VIII contained these sequences, while subfamilies I to III did not. In both coconut and 14 other plant species, some SPLs lost their miR156-binding loci due to gene structure variations. The gene expression profiles revealed significant divergence between miR156-targeted and non-targeted CnSPLs; the former exhibited low expression levels in the endosperm, while the latter showed comparable expression across all tissues. Notably, CnSPL15A demonstrated steadily increasing expression levels in leaves throughout successive leaf primordia and significantly promoted flowering when overexpressed in Arabidopsis. Transient expression assays and 5′ RACE confirmed that CnSPLs are targeted by miR156. This study establishes a foundation for investigating the evolutionary characteristics of CnSPLs and provides a theoretical framework for analyzing the functions of key CnSPLs involved in the coconut flowering control pathway.