J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (1): 150-166.DOI: 10.1111/jipb.13363

• Molecular Physiology • Previous Articles     Next Articles

Methionine oxidation and reduction of the ethylene signaling component MaEIL9 are involved in banana fruit ripening

Lisha Zhu1, Lin Chen2, Chaojie Wu1, Wei Shan1, Danling Cai1, Zengxiang Lin1, Wei Wei1, Jianye Chen1, Wangjin Lu1, Jianfei Kuang1*   

  1. 1. State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticulture South China Agricultural University Guangzhou 510642 China;
    2. Key Laboratory of Biology and Genetic Improvement of Horticultural CropsSouth China), Ministry of Agriculture and Rural Affairs, College of Horticulture South China Agricultural University Guangzhou 510642 China
    *Correspondence: Jianfei Kuang (jfkuang@scau.edu.cn)
  • Received:2022-07-27 Accepted:2022-09-02 Online:2022-09-14 Published:2023-01-01

Abstract: The ethylene insensitive 3/ethylene insensitive 3-like (EIN3/EIL) plays an indispensable role in fruit ripening. However, the regulatory mechanism that links post-translational modification of EIN3/EIL to fruit ripening is largely unknown. Here, we studied the expression of 13 MaEIL genes during banana fruit ripening, among which MaEIL9 displayed higher enhancement particularly in the ripening stage. Consistent with its transcript pattern, abundance of MaEIL9 protein gradually increased during the ripening process, with maximal enhancement in the ripening. DNA affinity purification (DAP)-seq analysis revealed that MaEIL9 directly targets a subset of genes related to fruit ripening, such as the starch hydrolytic genes MaAMY3D and MaBAM1. Stably overexpressing MaEIL9 in tomato fruit hastened fruit ripening, whereas transiently silencing this gene in banana fruit retarded the ripening process, supporting a positive role of MaEIL9 in fruit ripening. Moreover, oxidation of methionines (Met-129, Met-130, and Met-282) in MaEIL9 resulted in the loss of its DNA-binding capacity and transcriptional activation activity. Importantly, we identified MaEIL9 as a potential substrate protein of methionine sulfoxide reductase A MaMsrA4, and oxidation of Met-129, Met-130, and Met-282 in MaEIL9 could be restored by MaMsrA4. Collectively, our findings reveal a novel regulatory network controlling banana fruit ripening, which involves MaMsrA4-mediated redox regulation of the ethylene signaling component MaEIL9.

Key words: banana, EIN3/EIL, redox regulation, ROS, starch degradation

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