White and blue LED irradiation effectively inhibit postharvest decay in citrus caused by Cladosporium cladosporioides

Light-emitting diode (LED) technology has emerged as an eco-friendly antimicrobial strategy for postharvest preservation. This study identified Cladosporium cladosporioides as a novel postharvest pathogen in Ehime Kashi No.28 citrus and systematically investigated the wavelength-dependent antifungal effects of LED irradiation. At 120 μmol m -2 s -1 intensity, white and blue spectra significantly suppressed C. cladosporioides mycelial growth by 35.5% compared to the dark control, outperforming red/green wavelengths. Further investigation revealed that C. cladosporioides exposed to white and blue LED irradiation (120 μmol m -2 s -1 ) underwent apoptosis, concomitant with suppressed mycelial proliferation and conidial germination. These effects correlated mechanistically with a triad of cellular disruptions, including loss of membrane integrity, ultrastructural disorganization of organelles, and substantial oxidative stress-induced damage. Crucially, in vivo trials demonstrated 53.6% (white LED irradiation) and 56.8% (blue LED irradiation) reductions in citrus lesion diameters while maintaining fruit quality. The dual functionality of wavelength-specific pathogen suppression and quality preservation positions LED irradiation as a sustainable, non-thermal method for citrus postharvest management. • Cladosporium cladosporioides was identified as novel citrus pathogen in Ehime Kashi No. 28. • White and blue LED light significantly inhibited the growth and pathogenicity of C. cladosporioides. • White and blue LED light caused cell ultrastructural alterations and oxidative damage in C. cladosporioides.