Systems Biology Applied to the Study of Papaya Fruit Ripening: The Influence of Ethylene on Pulp Softening

An integrated quality, physiological and transcriptomic analysis reveals mechanisms of kiwifruit response to postharvest transport vibrational stress

The 'Xuxiang' kiwifruit, a leading cultivar in China known for its high quality and yield, experiences quality degradation due to vibration stress during postharvest transportation. This study simulated the postharvest transportation vibrations of 'Xuxiang' kiwifruits to investigate the effects on the fruit quality and physiology. Different vibration intensities (0.26, 0.79, and 1.5 m s-2) and durations (0, 24, 48, 72, and 96 h) were applied to analyze the quality, physiological and transcriptomic changes of fruits after vibration stress, as well as the association between quality deterioration, gene networks, and key genes. Results indicated that vibration stress significantly accelerated the deterioration of fruit quality and induced physiological changes. As vibration intensity and duration increased, there was a rapid decrease in fruit firmness and an increase in weight loss, soluble solid content, relative conductivity, ethylene production, respiratory rate, and malondialdehyde levels. The most severe deterioration in fruit quality occurred at a vibration intensity of 1.5 m s-2. Transcriptome sequencing analysis was conducted on samples from different durations of exposure to the 1.5 m s-2 vibration intensity. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses identified key genes associated with ethylene metabolism and softening. Weighted Gene Co-Expression Network Analysis (WGCNA) and correlation analysis further determined that 24 of these genes were regulated by vibrational stress, impacting ethylene metabolism and cell wall degradation. Vibration stress induced changes in genes related to ethylene metabolism and cell wall degradation, promoting lipid peroxidation and respiratory changes, which compromise cell membrane integrity and lead to quality deterioration. Compared with untreated fruits, vibration stress caused the quality deterioration, physiological changes and transcriptional regulation of kiwifruits, indicating that kiwifruits respond to vibration stress through multiple aspects. It proposes a fresh outlook on the understanding of the mechanism of transport vibration stress and further illustrates the importance of monitoring vibration intensity and duration as well as reducing vibration.

Postharvest quality and ripening behaviour of un-explored genotypes of Himalayan plain mango diversity

India is renowned for its mango diversity, with more than 1000 genotypes reported. However, the Himalayan plains bear some elite genotypes which supposed to bear high postharvest value, the systemic postharvest study of which is yet to be attempted. The aim of present study is to evaluate the postharvest quality and ripening behviour of these important genotypes. Thus, 15 un-explored mango genotypes of this region were selected and evaluated for ripening behaviour and detailed postharvest profiling via internal (total phenolic and total flavonoid content), nutritional attributes (Brix: acid ratio, total carotenoid concentration, ascorbic acid content and antioxidant activity), sensory evaluation, fruit softening enzymes (polygalactouronase, pectin methylesterase and lipoxygenase), shelf life attributes (respiration rate, physiological loss in weight and storage life in days) external attributes (fruit weight, fruit firmness, peel thickness, fruit shape and dry seed weight) and mineral contents (Calcium, potassium and phosphorous) under ambient storage (25 ± 4 °C and 65 ± 5 % RH). The results revealed that the highest total flavonoid content (682.40 μg g-1), ascorbic acid (46.88 mg 100 g-1) and antioxidant activity (4.84 μmol TE g-1) exhibited by 'Sukul'. The total phenolic content was recorded as the highest in 'Safed Malda' (510.42 μg GAE g-1 FW), and total carotenoid concentration was recorded as the highest in 'Sipiya' (7.30 mg 100 g-1) 'Zardalu' (7.04 mg 100 g-1) and 'Mithua' (6.98 mg 100 g-1). Interestingly, genotypes such as 'Sukul', Sipiya' and 'Krishna Bhog 'exhibited a 4-5 days higher storage life than other selected genotypes. Screened genotypes exhibited a high diversity of nutritional and biochemical contents. The results of this study bear practical utility for research (quality improvement programme) and the processing industry.

Unveiling Plant-Based Pectins: Exploring the Interplay of Direct Effects, Fermentation, and Technological Applications in Clinical Research with a Focus on the Chemical Structure

Pectin, a plant-derived polysaccharide, possesses immense technological and biological application value. Several variables influence pectin's physicochemical aspects, resulting in different fermentations, interactions with receptors, and other functional properties. Some of those variables are molecular weight, degree of methylation and blockiness, and monosaccharide composition. Cancer cell cytotoxicity, important fermentation-related byproducts, immunomodulation, and technological application were found in cell culture, animal models, and preclinical and clinical assessments. One of the greater extents of recent pectin technological usage involves nanoencapsulation methods for many different compounds, ranging from chemotherapy and immunotherapy to natural extracts from fruits and other sources. Structural modification (modified pectin) is also utilized to enhance the use of dietary fiber. Although pectin is already recognized as a component of significant importance, there is still a need for a comprehensive review that delves into its intricate relationships with biological effects, which depend on the source and structure of pectin. This review covers all levels of clinical research, including cell culture, animal studies, and clinical trials, to understand how the plant source and pectin structures influence the biological effects in humans and some technological applications of pectin regarding human health.

Molecular and Genetic Events Determining the Softening of Fleshy Fruits: A Comprehensive Review

Fruit softening that occurs during fruit ripening and postharvest storage determines the fruit quality, shelf life and commercial value and makes fruits more attractive for seed dispersal. In addition, over-softening results in fruit eventual decay, render fruit susceptible to invasion by opportunistic pathogens. Many studies have been conducted to reveal how fruit softens and how to control softening. However, softening is a complex and delicate life process, including physiological, biochemical and metabolic changes, which are closely related to each other and are affected by environmental conditions such as temperature, humidity and light. In this review, the current knowledge regarding fruit softening mechanisms is summarized from cell wall metabolism (cell wall structure changes and cell-wall-degrading enzymes), plant hormones (ETH, ABA, IAA and BR et al.), transcription factors (MADS-Box, AP2/ERF, NAC, MYB and BZR) and epigenetics (DNA methylation, histone demethylation and histone acetylation) and a diagram of the regulatory relationship between these factors is provided. It will provide reference for the cultivation of anti-softening fruits.

Plasmodesmata and their role in the regulation of phloem unloading during fruit development

Fruit consumption is fundamental to a balanced diet. The contemporary challenge of maintaining a steady food supply to meet the demands of a growing population is driving the development of strategies to improve the production and nutritional quality of fruit. Plasmodesmata, the structures that mediate symplasmic transport between plant cells, play an important role in phloem unloading and distribution of sugars and signalling molecules into developing organs. Targeted modifications to the structures and functioning of plasmodesmata have the potential to improve fruit development; however, knowledge on the mechanisms underpinning plasmodesmata regulation in this context is scarce. In this review, we have compiled current knowledge on plasmodesmata and their structural characterisation during the development of fruit organs. We discuss key questions on phloem unloading, including the pathway shift from symplasmic to apoplastic that takes place during the onset of ripening as potential targets for improving fruit quality.