Chang-Qing Ruan

This study addresses postharvest preservation challenges of ethylene‐sensitive “Wushan” plum by developing a novel graphitic carbon nitride/titanium dioxide@polyvinyl alcohol (g‐C ₃ N ₄ /TiO ₂ @PVA) photocatalytic packaging film. The composite film, prepared by embedding g‐C ₃ N ₄ ‐modified TiO ₂ into a PVA matrix, exhibited ethylene photocatalytic‐degradation performance under LED light, excellent mechanical strength, and flexibility, making it highly suitable for practical application. These properties, combined with its enhanced oxygen and water vapor barrier capabilities, synergistically supported shelf‐life extension. Under LED irradiation, the film achieved 80% degradation of 50 ppm ethylene within 6 h while maintaining stable activity under high humidity (95% RH), low light intensity, and cyclic operations. Application to “Wushan” plums under LED irradiation reduced headspace ethylene compared to the pure PVA packaging, which in turn strongly associated with the suppression of the fruit’s endogenous ethylene biosynthesis pathway. This intervention delayed the respiratory peak by over 2 days and maintained fruit firmness 14.9% higher than controls, demonstrating a strong association between photocatalytic scavenging and physiological regulation. Our comprehensive investigation revealed synergistic effects between photocatalytic ethylene degradation and optimized micro‐environment regulation, achieving extended shelf life for climacteric fruit. This work proposes an innovative green preservation strategy integrating LED‐responsiveness photocatalysis and environmental adaptability for horticultural postharvest management.

The peptide PAF56 (GHRKKWFW) was reported to be an effective control for the main diseases of citrus fruit during postharvest storage. However, the mechanism of action of PAF56 is still unknown. In this paper, PAF56 might not induce defense resistance of citrus fruit. The SEM results visually indicated that the fungi mycelia became shrunken and distorted after being treated with PAF56. The destructive effects of PAF56 on the mycelial cell membrane of three kinds of pathogenic fungi (Penicillium digitatum, Penicillium italicum, and Geotrichum citri-aurantii) were verified by the K⁺ leakage and the release of nucleic acid. Furthermore, the interaction between peptide PAF56 and the pathogen spores was investigated, including the changes in cell membrane permeability and dynamic observation of the interaction of fluorescein labeled TMR-PAF56 and Geotrichum candidum spores. The results indicated that the antifungal activity of PAF56 on spores was time-dependent and directly related to the membrane damage. This research provided useful references for further research and practical application of peptides.

This study aimed to investigate the effect of Pichia galeiformis on disease resistance and elucidate the changes in phenylpropane biosynthesis treated by P. galeiformis in postharvest citrus. The results showed that P. galeiformis reduced the disease incidence and lesion diameters without direct contact with the pathogen Penicillium digitatum. Transcriptome analysis revealed that phenylpropanoid biosynthesis was triggered by P. galeiformis. Genes encoding phenylpropanoid biosynthesis were upregulated, including phenylalanine ammonia-lyase (PAL), 4-coumaroyl-CoA ligase (4CL), cinnamate-4-hydroxylase (C4H), peroxidase (POD), cinnamyl alcohol dehydrogenase (CAD), O-methyltransferase, and hydroxyl cinnamoyl transferase. Moreover, P. galeiformis increased the activity of PAL, 4CL, C4H, POD, polyphenol oxidase, and CAD in citrus pericarp. In addition, P. galeiformis treated citrus displayed higher levels of total phenolic compounds, flavonoid, and lignin and higher amounts of ferulic and sinapic acid. In conclusion, these results suggested that P. galeiformis could induce resistance through modulating the pathway of phenylpropanoid biosynthesis in postharvest citrus.