Pepper is a globally cultivated vegetable known for its distinct pungent flavor, which is derived from the presence of capsaicinoids, a class of unique secondary metabolites that accumulate specifically in pepper fruits. Since the accumulation of capsaicinoids is influenced by various factors, it is imperative to comprehend the metabolic regulatory mechanisms governing capsaicinoids production. This review offers a thorough examination of the factors that govern the metabolism of capsaicinoids in pepper fruit, with a specific focus on three primary facets: (1) the impact of genotype and developmental stage on capsaicinoids metabolism, (2) the influence of environmental factors on capsaicinoids metabolism, and (3) exogenous substances like methyl jasmonate, chlorophenoxyacetic acid, gibberellic acid, and salicylic acid regulate capsaicinoid metabolism. The findings of this study are expected to enhance comprehension of capsaicinoids metabolism and aid in the improvement of breeding and cultivation practices for high-quality pepper in the future.

Volatile organic compounds (VOCs) play a significant role in influencing the flavor quality of cherry tomatoes (Solanum lycopersicum var. cerasiforme). The scarcity of systematic analysis of VOCs in cherry tomatoes can be attributed to the constraints imposed by detection technology and other contributing factors. In this study, the cherry tomato cultivar var. ‘Zheyingfen1’ was chosen due to its abundant fruit flavor. Two detection technology platforms, namely the commonly employed headspace solid-phase microextraction—gas chromatography–mass spectrometry (HS-SPME-GC-MS) and the most advanced headspace solid-phase microextraction—full two-dimensional gas chromatography–time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS), were employed in the analysis. The VOCs of cherry tomato cultivar var. ‘Zheyingfen1’ fruits at red ripening stage were detected. A combined total of 1544 VOCs were detected using the two aforementioned techniques. Specifically, 663 VOCs were identified by through the HS-SPME-GC-MS method, 1026 VOCs were identified by through the HS-SPME-GC×GC-TOFMS, and 145 VOCs were identified by both techniques. The identification of β-ionone and (E)-2-nonenal as the principal VOCs was substantiated through the application of the relative odor activity value (rOAV) calculation and subsequent analysis. Based on the varying contribution rates of rOAV, the analysis of sensory flavor characteristics revealed that cherry tomato cultivar var. ‘Zheyingfen1’ predominantly exhibited green and fatty attributes, accompanied by elements of fresh and floral flavor characteristics. In conclusion, our study conducted a comprehensive comparison of the disparities between these two methodologies in detecting VOCs in cherry tomato fruits. Additionally, we systematically analyzed the VOC composition and sensory flavor attributes of the cherry tomato cultivar var. ‘Zheyingfen1’. This research serves as a significant point of reference for investigating the regulatory mechanisms underlying the development of volatile flavor quality in cherry tomatoes.

Acid invertases (Ac-Invs) are crucial enzymes in plant physiology, regulating sucrose metabolism and hydrolyzing sucrose into glucose and fructose. These sugars serve not only as energy sources and structural components but also as signaling molecules, influencing diverse developmental processes, including seed and fruit growth, flowering, and stress responses. Ac-Invs are classified into cell wall invertases (CWINs) and vacuolar invertases (VINs) based on their subcellular localization, with both playing distinct roles in sucrose unloading, osmotic regulation, and sugar accumulation. Recent studies have also highlighted their involvement in abiotic stress adaptation and hormonal regulation, emphasizing their central role in plant resilience and productivity. However, gaps remain in understanding their regulatory mechanisms, particularly their interactions with plant hormones, defective invertases, and responses to environmental stresses. This review summarizes the biochemical characteristics, functions, and regulatory mechanisms of Ac-Invs, providing insights into their evolutionary significance and potential applications in crop improvement. Future research directions are proposed to elucidate unresolved questions and leverage Ac-Invs for enhancing agricultural sustainability.

Background: Phospholipase A (PLA) enzymes catalyze the hydrolysis of glycerophospholipids, releasing free fatty acids and lysophospholipids that play vital roles in plant growth, development, and stress responses. Methods: This study identified and analyzed SlPLA genes through bioinformatics and further explored the function of PLA genes under cold stress through virus-induced gene silencing (VIGS) experiments. Results: This study systematically characterized the SlPLA gene family in tomato, identifying 80 genes distributed across 12 chromosomes. Phylogenetic analysis categorized these genes into three groups: pPLA, PLA1, and PLA2. Conserved motifs and gene structure analysis revealed distinct patterns, with some genes lacking untranslated regions (UTRs), which suggests functional diversification. Promoter analysis indicated that SlPLA genes are regulated by light, hormones, and stress-related elements, particularly cold stress. RNA-seq data and qRT-PCR results indicated the differential expression of SlPLA genes across various tissues in tomato cultivars (Heinz and Micro-Tom). Under cold stress, certain SlPLA genes, especially SlPLA1-2, were up-regulated, suggesting their involvement in cold tolerance. Silencing SlPLA1-2 resulted in increased membrane damage, elevated malondialdehyde (MDA) levels, higher electrolyte leakage, and a lower expression of cold-responsive genes within the ICE1-CBF-COR pathway and jasmonic acid (JA) biosynthesis. Conclusions: This study discovered 80 SlPLA genes in tomato across 12 chromosomes, categorizing them into pPLA, PLA1, and PLA2 via phylogenetic analysis. The qRT-PCR analysis identified that SlPLA1-2 was strongly induced by cold stress, and further experiments regarding genetics and physiology revealed that SlPLA1-2 boosts the cold tolerance of tomato by affecting the CBF signaling pathway and JA biosynthesis, offering insights for future stress-resilience breeding.

The comprehensive analysis of NBS-LRR resistance genes in the pepper (Capsicum annuum L.) genome reveals their structural diversity, evolutionary history, and functional importance in plant immunity. A total of 252 NBS-LRR genes were identified, distributed unevenly across all chromosomes, with 54% forming 47 gene clusters. These clusters, driven by tandem duplications and genomic rearrangements, underscore the dynamic evolution of resistance genes. Phylogenetic analysis demonstrated the dominance of the nTNL subfamily over the TNL subfamily, reflecting lineage-specific adaptations and evolutionary pressures. Structural analyses identified six conserved motifs (P-loop, RNBS-A, kinase-2, RNBS-B, RNBS-C, and GLPL) essential for ATP/GTP binding and resistance signaling. Subfamily-specific differences in motif composition and sequence similarity highlight their functional divergence and specialization. Comparative analyses across species further revealed a greater prevalence of nTNL genes in angiosperms, with significant losses of TNL genes in monocots. This study enhances our understanding of the evolution and diversification of plant-resistance genes and provides a foundation for developing disease-resistant crops through targeted breeding strategies.

Cherry tomato is a notable dietary source of metabolites associated with antioxidant functions. However, how ripening reshapes primary, specialized, and volatile metabolites remains incompletely resolved. Green-ripe and red-ripe fruits were comparatively analyzed using targeted HPLC assays for quality indices and vitamins, UPLC–MS/MS for non-volatile metabolites, and HS-SPME–GC–MS for volatiles. Ripening was accompanied by a pronounced accumulation of lycopene and an increase in soluble solids, reflecting a shift of sugars toward glucose and fructose while sucrose remained low. Organic acids declined overall, with citric acid remaining predominant. The free-amino-acid pool expanded, with redistribution from GABA toward glutamate and aspartate. Vitamins exhibited stage-dependent patterns; antioxidant-related vitamins (A, E, and C) were higher at the red-ripe stage, indicating a compositional enhancement relevant to nutritional quality. Non-volatile metabolomics revealed 618 differentially accumulated metabolites, with phenolic acids, flavonoids, alkaloids, amino acids, and lipids as major classes. Phenolic acids and flavonols, dominated by hydroxycinnamoyl-quinic acids and quercetin/kaempferol glycosides, accumulated at the red-ripe stage, whereas steroidal glycoalkaloids decreased, suggesting conversion away from bitter or anti-nutritional constituents. GC–MS profiling identified 788 volatiles, with esters, terpenoids, and ketones contributing more than half of the volatilome. Ripening favored fruity–floral odorants such as β-ionone and (5Z)-octa-1,5-dien-3-one, while reducing green-leaf aldehydes. These stage-specific shifts in metabolite composition jointly define the sensory and nutritional maturation of cherry tomato. The identified metabolite markers provide a foundation for evaluating fruit maturity and guiding breeding toward improved quality attributes.