J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (9): 2036-2055.DOI: 10.1111/jipb.13506

• Abiotic Stress Responses • Previous Articles     Next Articles

MaBEL1 regulates banana fruit ripening by activating cell wall and starch degradation-related genes

Zunyang Song1,2, Xiaoyang Zhu1*, Xiuhua Lai1, Hangcong Chen1, Lihua Wang1, Yulin Yao1, Weixin Chen1 and Xueping Li1*   

  1. 1. Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center for Postharvest Technology of Horticultural Crops in South China, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou 510642, China;
    2. Key Laboratory of Food Processing Technology and Quality Control in Shandong Province, College of Food Science and Engineering, Shandong Agricultural University, Tai'an 271018, China
    *Correspondences: Xueping Li (lxp88@scau.edu.cn, Dr. Li is fully responsible for the distributions of all materials associated with this article); Xiaoyang Zhu (xiaoyang_zhu@scau.edu.cn)
  • Received:2023-02-10 Accepted:2023-05-12 Online:2023-05-13 Published:2023-09-01

Abstract: Banana is a typical subtropical fruit, sensitive to chilling injuries and prone to softening disorder. However, the underlying regulatory mechanisms of the softening disorder caused by cold stress remain obscure. Herein, we found that BEL1-LIKE HOMEODOMAIN transcription factor 1 (MaBEL1) and its associated proteins regulate the fruit softening and ripening process. The transcript and protein levels of MaBEL1 were up-regulated with fruit ripening but severely repressed by the chilling stress. Moreover, the MaBEL1 protein interacted directly with the promoters of the cell wall and starch degradation-related genes, such as MaAMY3, MaXYL32, and MaEXP-A8. The transient overexpression of MaBEL1 alleviated fruit chilling injury and ripening disorder caused by cold stress and promoted fruit softening and ripening of “Fenjiao” banana by inducing ethylene production and starch and cell wall degradation. The accelerated ripening was also validated by the ectopic overexpression in tomatoes. Conversely, MaBEL1-silencing aggravated the chilling injury and ripening disorder and repressed fruit softening and ripening by inhibiting ethylene production and starch and cell wall degradation. MaABI5-like and MaEBF1, the two positive regulators of the fruit softening process, interacted with MaBEL1 to enhance the promoter activity of the starch and cell wall degradation-related genes. Moreover, the F-box protein MaEBF1 does not modulate the degradation of MaBEL1, which regulates the transcription of MaABI5-like protein. Overall, we report a novel MaBEL1-MaEBF1-MaABI5-like complex system that mediates the fruit softening and ripening disorder in “Fenjiao” bananas caused by cold stress.

Key words: cold stress, fruit ripening, interaction, MaBEL1, softening disorder, transcriptional regulation

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