Ethylene-mediated MdERF105l-MdPSY2/MdBCH1/MdATG8i module positively regulates carotenoid accumulation during apple fruit ripening

Ethylene can affect fruit quality by promoting ripening and coloring. Carotenoids are important indicators of apple quality and nutritional value. However, the mechanism by which ethylene regulates carotenoids in apples remains unclear. In this study, exogenous ethephon treatment markedly accelerated carotenoid accumulation, upregulated the transcription of key carotenoid pathway genes, and enhanced cellular autophagy during apple fruit ripening; conversely, the opposite effects were observed under 1-methylcyclopropene treatment. Moreover, MdERF105l responded significantly to ethylene. Results from apple fruits, apple callus, and tomato transgenic materials showed that MdERF105l was a positive factor in carotenoid synthesis and could significantly enhance autophagy. Further research confirmed that MdERF105l promoted carotenoid accumulation and autophagy by interacting with the promoters of MdPSY2 , MdBCH1 , and MdATG8i . Therefore, this study revealed the molecular mechanism underlying carotenoid accumulation in apple via the MdERF105l- MdPSY2 / MdBCH1 / MdATG8i module. The findings will provide new insights for the study of carotenoids in plants.