Exogenous application of glycine betaine increases the chilling tolerance of pomegranate fruits cv. Malase Saveh during cold storage

Enhancing Postharvest Quality and Shelf Life of Strawberries through Advanced Coating Technologies: A Comprehensive Investigation of Chitosan and Glycine Betaine Nanoparticle Treatments

The application of natural polymer-based coatings presents a viable approach to prolong the longevity of fruits and tissue damage. This study investigates the impact of treatments involving glycine betaine (GB), chitosan (CTS), and chitosan-coated glycine betaine nanoparticles (CTS-GB NPs) on preserving the quality and reducing decay in strawberry fruits. The fruits were subjected to treatments with GB (1 mM), CTS (0.1%), CTS-GB NPs (0.1%), or distilled water at 20 °C for 5 min, followed by storage at 4 °C for 12 days. The results indicate that CTS and CTS-GB NPs treatments resulted in the highest tissue firmness, total anthocyanin content, and ascorbate peroxidase activity, while exhibiting the lowest decay percentage and weight loss, as well as reduced malondialdehyde levels at the end of storage. GB, CTS, and CTS-GB NPs treatments demonstrated elevated catalase activity and antioxidant capacity, coupled with lower electrolyte leakage and hydrogen peroxide levels. These treatments did not significantly differ from each other but were markedly different from the control. The results substantiate that CTS and CTS-GB NPs treatments effectively preserve strawberry quality and extend storage life by bolstering antioxidant capacity and mitigating free radical damage.

Glycine betaine inhibits postharvest softening and quality decline of winter jujube fruit by regulating energy and antioxidant metabolism

Winter jujube fruit easily softens after harvest. To investigate the effects of glycine betaine (N,N,N-trimethylglycine; GB) treatment on the quality of postharvest jujubes, fresh winter jujubes (Zizyphus jujuba Mill. cv. Dongzao) were immersed in 20 mmol·L^-1 GB for 20 min. The results showed that GB application can effectively maintain cell wall component content by restraining gene expression and enzyme activities, including PG, CX, PME and β-Glu. Meanwhile, the activities of antioxidant enzymes (APX, CAT, SOD, POD) and the contents of nonenzymatic antioxidants (MDA, H₂O₂, ASA, GSH) were enhanced in treated jujubes, thereby reducing the content of ROS. In addition, energy metabolism enzyme activities (H⁺-ATPase, Ca²⁺-ATPase, SDH and CCO) and gene expression were also significantly increased, thus maintaining higher energy levels (ATP, ADP, AMP and EC). In summary, GB enhances ATP biosynthesis by increasing energy metabolism. It offers essential energy for the antioxidant metabolism, thus retarding the softening of postharvest jujubes.

Effects of exogenous glycine betaine and cycloleucine on photosynthetic capacity, amino acid composition, and hormone metabolism in Solanum melongena L

Although exogenous glycine betaine (GB) and cycloleucine (Cyc) have been reported to affect animal cell metabolism, their effects on plant growth and development have not been studied extensively. Different concentrations of exogenous glycine betaine (20, 40, and 60 mmol L^-1) and cycloleucine (10, 20, and 40 mmol L^-1), with 0 mmol L^-1 as control, were used to investigate the effects of foliar spraying of betaine and cycloleucine on growth, photosynthesis, chlorophyll fluorescence, Calvin cycle pathway, abaxial leaf burr morphology, endogenous hormones, and amino acid content in eggplant. We found that 40 mmol L^-1 glycine betaine had the best effect on plant growth and development; it increased the fresh and dry weight of plants, increased the density of abaxial leaf hairs, increased the net photosynthetic rate and Calvin cycle key enzyme activity of leaves, had an elevating effect on chlorophyll fluorescence parameters, increased endogenous indoleacetic acid (IAA) content and decreased abscisic acid (ABA) content, and increased glutamate, serine, aspartate, and phenylalanine contents. However, cycloleucine significantly inhibited plant growth; plant apical dominance disappeared, plant height and dry and fresh weights decreased significantly, the development of abaxial leaf hairs was hindered, the net photosynthetic rate and Calvin cycle key enzyme activities were inhibited, the endogenous hormones IAA and ABA content decreased, and the conversion and utilization of glutamate, arginine, threonine, and glycine were affected. Combined with the experimental results and plant growth phenotypes, 20 mmol L^-1 cycloleucine significantly inhibited plant growth. In conclusion, 40 mmol L^-1 glycine betaine and 20 mmol L^-1 cycloleucine had different regulatory effects on plant growth and development.

Prevention of Chilling Injury in Pomegranates Revisited: Pre- and Post-Harvest Factors, Mode of Actions, and Technologies Involved

The storage life of pomegranate fruit (Punica granatum L.) is limited by decay, chilling injury, weight loss, and husk scald. In particular, chilling injury (CI) limits pomegranate long-term storage at chilling temperatures. CI manifests as skin browning that expands randomly with surface spots, albedo brown discoloration, and changes in aril colors from red to brown discoloration during handling or storage (6-8 weeks) at <5-7 °C. Since CI symptoms affect external and internal appearance, it significantly reduces pomegranate fruit marketability. Several postharvest treatments have been proposed to prevent CI, including atmospheric modifications (MA), heat treatments (HT), coatings, use of polyamines (PAs), salicylic acid (SA), jasmonates (JA), melatonin and glycine betaine (GB), among others. There is no complete understanding of the etiology and biochemistry of CI, however, a hypothetical model proposed herein indicates that oxidative stress plays a key role, which alters cell membrane functionality and integrity and alters protein/enzyme biosynthesis associated with chilling injury symptoms. This review discusses the hypothesized mechanism of CI based on recent research, its association to postharvest treatments, and their possible targets. It also indicates that the proposed mode of action model can be used to combine treatments in a hurdle synergistic or additive approach or as the basis for novel technological developments.

Exogenous Application of Glycine Betaine Maintains Bioactive Compounds, Antioxidant Activity, and Physicochemical Attributes of Blood Orange Fruit During Prolonged Cold Storage

Exogenous application of glycine betaine (GB) was evaluated on bioactive compounds, antioxidant activity, and physicochemical attributes of blood orange fruit cv. Moro at 3°C for 90 days. Vacuum infiltration (30 kPa) of GB was applied at 15 and 30 mM for 8 min. Parameters were measured after 1, 30, 60, and 90 days of storage plus 2 days at 20°C to simulate the shelf-life period. GB treatments significantly reduced weight and firmness losses in “Moro” blood orange fruit during cold storage. GB treatment maintained a higher concentration of organic acids (citric, malic, succinic, and oxalic acids) and sugars (sucrose, glucose, and fructose), especially for the higher GB doses (30 mM). During storage, GB treatments enhanced total anthocyanin concentration, total phenolic content, and total antioxidant activity. With respect to enzyme activities, the application of exogenous GB showed increases in catalase (CAT), ascorbate peroxidase, superoxide dismutase, phenylalanine ammonia-lyase, while suppressing the polyphenol oxidase activity. Overall, the most effective treatment was 30 mM GB leading to maintaining bioactive compounds, antioxidant activity, and quality in “Moro” blood orange fruit during long-term storage. The positive results would permit the use of GB as a postharvest tool to maintain the quality attributes of blood orange fruit.

Application of Glycine betaine coated chitosan nanoparticles alleviate chilling injury and maintain quality of plum (Prunus domestica L.) fruit

The use of edible coatings can lead to significant extension of the postharvest life of fresh horticultural products through the regulation of water and gaseous exchange during storage. In this regard, nano-engineered materials are of great interest to design novel and multifunctional edible coatings and are increasingly employed. Chitosan and glycine betaine have been reported to enhance fruit tolerance to chilling stress during cold storage. The current study applied new coating treatments to plum (Prunus domestica L. cv. 'Stanley') fruit at maturity stage in a completely randomized factorial design with three replicates. Plums were treated with distilled water (control), glycine betaine (GB) at 2.5 and 5 mM, chitosan (CTS) at 1% (w/v) or glycine betaine-coated chitosan nanoparticles (CTS-GB NPs) at 0.5 and 1% (w/v) and stored at 1 °C for up to 40 days. The application of CTS-GB NPs (0.5% w/v) was the most effective treatment and induced lower electrolyte leakage, MDA and H₂O₂ content, and significantly alleviated chilling injury. Furthermore, this treatment remarkably increased the activity of PAL enzyme, resulting in higher levels of phenolics, flavonoids and anthocyanins content, and enhanced DPPH scavenging capacity. In addition, CTS-GB NPs treatment increased endogenous GB (9.25 mg g^-1 DW) and proline (1929.29 μg g^-1 FW) accumulation leading to higher activity of CAT, POD, SOD and APX enzymes. Based on the obtained results, the commercial application of CTS-GB NPs could effectively reduce chilling injury, preserve nutritional quality, and prolong the storage potential and shelf life of plum fruit.

Exogenous Application of Proline and L-Cysteine Alleviates Internal Browning and Maintains Eating Quality of Cold Stored Flat ‘Maleki’ Peach Fruits

The postharvest life of flat peach fruit is limited by the appearance of chilling injury symptoms, especially internal browning. In this study, impacts of the exogenous application of proline (0, 5, 10, and 15 mM) and L-cysteine (0, 0.2, 0.4 and 0.6%) on attenuating chilling injury of flat peach fruit were evaluated all over the cold storage. The results demonstrated that the fruits treated with 15 mM proline and 0.4 % L-cysteine showed lower levels of internal browning and these treatments prevented the excess enhancement of total soluble solids (TSS), the decline of titratable acidity (TA) content and the loss of fruit firmness during storage time. A lower accumulation of hydrogen peroxide (H2O2), malondialdehyde (MDA), electrolyte leakage, and higher activity of antioxidant enzymes, along with higher ascorbic acid content and antioxidant capacity, were observed in treated fruits. Treated fruits also showed higher activity of phenylalanine ammonia lyase (PAL) and conversely lower activity of polyphenol oxidase (PPO), which led to a higher accumulation of total phenols and flavonoids. Moreover, a higher accumulation of endogenous proline was observed in 15 mM proline treated fruits. Eventually, according to our results, the exogenous administration of proline and L-cysteine as safe, natural and environmentally friendly treatments, preserved the nutritional quality of flat peach fruits during long-term cold storage.

The Distribution and Origins of Pyrus hopeiensis-"Wild Plant With Tiny Population" Using Whole Genome Resequencing

Pyrus hopeiensis is a valuable but endangered wild resource in the genus Pyrus. It has been listed as one of the 120 wild species with tiny population in China. The specie has been little studied. A preliminary study of propagation modes in P. hopeiensis was performed through seed propagation, hybridization, self-crossing trials, bud grafting, branch grafting, and investigations of natural growth. The results showed that the population size of P. hopeiensis was very small, the distribution range was limited, and the habitat was extremely degraded. In the wild population, natural hybridization and root tiller production were the major modes of propagation. Whole genome re-sequencing of the 23 wild and cultivated accessions from Pyrus species collected was performed using an Illumina HiSeq sequencing platform. The sequencing depth range was 26.56x-44.85x and the average sequencing depth was 32x. Phylogenetic tree and principal component analyses (PCA) based on SNPs showed that the wild Pyrus species, such as PWH06, PWH07, PWH09, PWH10, PWH13, and PWH17, were closely related to both P. hopeiensis HB-1 and P. hopeiensis HB-2. Using these results in combination with morphological characteristics, it speculated that P. hopeiensis populations may form a natural hybrid group with frequent gene exchanges between and within groups. A selective elimination analysis on the P. hopeiensis population were performed using Fst and π radio and a total of 381 overlapping genes including SAUR72, IAA20, HSFA2, and RKP genes were obtained. These genes were analyzed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) function enrichment. And four KEGG pathways, including lysine degradation, sphingolipid metabolism, other glycan degradation, and betaine biosynthesis were significantly enriched in the P. hopeiensis population. Our study provided information on genetic variation, evolutionary relationships, and gene enrichment in P. hopeiensis population. These data will help reveal the evolutionary history and origin of P. hopeiensis and provide guidelines for subsequent research on the locations of functional genes.