Grapevine development and ripening are complex processes that involve several biochemical pathways, including fatty acid and lipid metabolism. Fatty acids are essential components of lipids, which play crucial roles in fruit maturation and flavor development. However, the dynamics of fatty acid metabolism in grape flowers and berries are poorly understood. In this study, we present those dynamics and investigate the mechanisms of fatty acid homeostasis on ‘Thompson Seedless’ berries using metabolomic and proteomic analyses. Low-polar metabolite profiling indicated a higher abundance of fatty acids at the pre-flowering and pre-veraison stages. Proteomic analyses revealed that grape flowers and berries display unique profiles of proteins involved in fatty acid biosynthesis, triacylglycerol assembly, fatty acid β-oxidation, and lipid signaling. These findings show, for the first time, that fatty acid metabolism also plays an important role in the development of non-oil-rich tissues, opening new perspectives about lipid function and its relation to berry quality.

As it was previously reported, black spot development in the skin of Hass avocado has been related to a decreased antioxidant defense system. The aim of this study was to investigate the effect of different postharvest storage conditions on controlling black spot development targeting their effect on the antioxidant system (non-enzymatic and enzymatic) of the skin. Four postharvest treatments (T1: regular air storage (RA) at 5 °C for 40 d; T2: controlled atmosphere storage (CA) of 4 kPa O₂ and 6 kPa CO₂ at 5 °C for 40 d; T3: 10 d RA + 30 d CA and T4: 5 µM methyl jasmonate (MeJA) for 30 s + 10 RA + 30 d CA) were tested on controlling black spot incidence in fruit from six orchards from different agroclimatic zones and harvests. Then, on two selected orchards and harvests, the evolution of total phenolics (TPC), antioxidant capacity (AC) and antioxidant enzymes (catalase (CAT), polyphenol oxidase (PPO), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia lyase (PAL)) was monitored. Results revealed that incidence of black spot disorder was not associated to an agroclimatic zone and harvest stage. Immediate application of CA (T2) controlled black spot development during prolonged storage (40 d) and under these conditions TPC content remained higher compared to the other treatments. No clear role of CAT, PPO, SOD, POD and PAL on controlling black spot was observed. The results obtained are of value for the Hass avocado supply chain since a clear performance of CA was evidenced that will result in reduction of postharvest losses associated to this problem.

Sweet cherry may develop surface pitting during prolonged cold storage, and susceptibility among varieties is related to metabolites in response to cold and mechanical damage. This study aimed to evaluate the metabolic changes in sweet cherry fruits subjected to melatonin treatment and induced surface pitting. Melatonin (400 µM) was applied to sweet cherries before pitting induction and then stored at 1 °C for 20 d. Melatonin treatment attenuated the severity of pitting damage during cold storage, with an average severity value of 3.1 for cherries with melatonin and 2.6 without melatonin. In addition, melatonin application appeared to modulate metabolic responses due to the regulation of metabolic pathways related to abiotic stress. Upregulation of different secondary metabolites was observed after 16 h of melatonin treatment and cold storage. Moreover, some metabolites of the sphingolipid and sulfur metabolism were upregulated after 10 d. This research is the first to show that melatonin may influence the response of sweet cherries to cold and mechanical damage.

Leaves of Persea americana Mill. are a potential source of bioactive compounds; however, current knowledge is limited by the lack of studies that simultaneously evaluate multiple cultivars and leaf developmental stages under comparable field conditions, as well as by inconsistent sampling criteria across studies. This study aimed to assess how leaf developmental stage and cultivar influence phenolic composition and antioxidant activity in avocado leaves grown under field conditions. Total polyphenols, total flavonoids, quercetin-3-O-galactoside, and chlorogenic acid were selected as representative compounds due to their relevance in plant defense and antioxidant capacity. These compounds, together with antioxidant activity, were quantified in young expanding (E1) and fully expanded (E6) leaves of seven avocado cultivars using spectrophotometric methods and HPLC-DAD, and analyzed through two-way ANOVA. Results showed that leaf developmental stage significantly influenced flavonoid content, chlorogenic acid, and antioxidant activity, which were consistently higher in E1 leaves. In contrast, total polyphenol content exhibited cultivar-dependent responses, increasing toward E6 only in specific genotypes, while quercetin-3-O-galactoside remained stable across developmental stages but varied among cultivars. Overall, the results indicate that phenolic metabolism in avocado leaves is regulated by both developmental stage and genotype in a compound-specific manner, with no consistent pattern associated with racial background. From a practical perspective, these findings provide a basis for selecting leaf material according to the intended application: young leaves for higher antioxidant capacity and flavonoid content, and specific cultivars at advanced stages for higher total polyphenol accumulation, supporting the functional valorization of avocado leaves as a source of bioactive compounds.

Background/Objectives: The physiological disorder known as “orange spot” in Juglans regia L. cv. Chandler is an emerging kernel quality issue of increasing concern for the Chilean walnut industry. Characterized by a localized orange discoloration of the embryo, its etiology remains unknown. This study aimed to determine whether orange spot is associated with bacterial infection and to elucidate the metabolic alterations underlying its development, testing the hypothesis that it results from oxidative imbalance and lipid disorganization. Methods: Untargeted metabolomic profiling and fatty acid methyl ester (FAME) analysis were applied to compare affected (orange) and unaffected (white) walnut kernels collected from a commercial orchard in Melipilla, Chile, during the 2018 and 2022 seasons. Bacterial DNA was screened by PCR amplification of the 16S rRNA gene (799F/1193R). Results: Orange spot incidence reached 31–34% across seasons. No bacterial-sized amplicons were detected in either kernel type, indicating the absence of detectable bacterial DNA under the analyzed conditions. Metabolomic analyses revealed significant alterations in glyoxylate and dicarboxylate metabolism, glutamate-related pathways, and glycerophospholipid metabolism. Affected kernels exhibited reduced levels of L-glutamic acid and antioxidant-associated metabolites, alongside increased gluconic, citric and quinic acid, consistent with the redox imbalance and membrane oxidative degradation. FAME analysis showed higher total fatty acid content in affected kernels, suggesting intensified lipid turnover associated under oxidative stress. Conclusions: Orange spot is a physiological, non-infectious disorder linked to premature oxidative stress and lipid disorganization, negatively affecting walnut kernel quality.

Surface pitting is a physiological disorder characterized by depressions on the fruit surface, caused by subepidermal cell collapse and exacerbated during cold storage. This study evaluated antioxidant responses and cell wall disassembly in sweet cherry cultivars exhibiting contrasting susceptibility to surface pitting. Four cultivars were evaluated over two growing seasons under controlled cold storage and shelf-life conditions, with pitting experimentally induced. Surface pitting severity was strongly genotype-dependent. After 15 d at 1 °C in the first season, pitting severity was higher in ‘Sweetheart’ and ‘Lapins’ (2.4 and 1.9, respectively) than in ‘Regina’ (0.6), while in the second season, ‘Sweetheart’ reached the highest damage at shelf life (3.5) and ‘Santina’ remained low (0.8), confirming lower susceptibility in ‘Regina’ and ‘Santina’ than in ‘Sweetheart’ and ‘Lapins’. Cell wall-related traits and pectinolytic enzyme activities exhibited strong seasonal variability and were not consistently associated with pitting incidence. In contrast, resistant cultivars exhibited higher non-enzymatic antioxidant levels. Total phenolic content reached 4.1 ± 0.4 mg g⁻¹ in ‘Regina’ at the end of storage, while antioxidant capacity reached 51.5 ± 3.3% DPPH inhibition, up to 2-fold higher than susceptible cultivars. Enzymatic antioxidant activities were influenced by cultivar and season and showed limited association with pitting development. These results indicate that phenolic-based non-enzymatic antioxidant capacity plays a central role in conferring tolerance to surface pitting in sweet cherry during cold storage.