J Integr Plant Biol ›› 2025, Vol. 67 ›› Issue (9): 2461-2479.DOI: 10.1111/jipb.13958

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  • 收稿日期:2025-03-07 接受日期:2025-05-29 出版日期:2025-09-01 发布日期:2025-09-02

Mitochondrial complex I assembles via a distal-pump module (PD)-early and PD-late pathway in maize

Baoyin Chen1,2, Manna Huang1,2, Junjun Wang1, Yuanye Gui1, Qingqing Wei1, Zhihui Xiu1, Feng Sun1, Yan‐Zhuo Yang1, Chunhui Xu1 and Bao‐Cai Tan1*   

  1. 1. Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
    2. National Key Laboratory of Wheat Improvement, College of Agronomy, Shandong Agricultural University, Tai'an 271018, China

    *Correspondence: Bao‐Cai Tan (bctan@sdu.edu.cn)
  • Received:2025-03-07 Accepted:2025-05-29 Online:2025-09-01 Published:2025-09-02
  • Supported by:
    This research was supported by the National Natural Science Foundation of China (Project Nos. 32230075 to B.C.T., 32001610 to B.C., and 32171922 to C.X.).

Abstract: The L-shape mitochondrial complex I (CI) consists of four modules: nicotinamide-adenine dinucleotide hydrogen-binding module (N) and ubiquinone-binding module (Q) in the matrix arm and proximal-pump module (PP) and distal-pump module (PD) in the membrane arm. As mitochondrial mutants are unavailable, the CI assembly pathway in plants is unclear. We investigated the CI assembly process using the maize RNA processing mutants deficient in individual CI components. Complexome profiling detected all major assembly intermediates of each module, confirming their independent assembly pathway. A block in the Q module assembly causes the accumulation of the membrane arm, whereas a block in the PD module assembly results in the accumulation of CI*, a subcomplex assembled by PP with the matrix arm. We further isolated and analyzed the mutants of two CI assembly factors, ZmGLDH and CRK1. The absence of either ZmGLDH or CRK1 eliminates the accumulation of CI* but allows a substantial amount of CI to be assembled. The membrane arm was also accumulated in zmgldh and crk1. Together, these results suggest two CI assembly pathways. The PD-early former starts with the assembly of PP with PD, forming the membrane arm, then joins with the matrix arm to produce CI. The PD-late pathway is initiated by assembling PP with the matrix arm to yield CI*, which is then combined with PD to form CI.

Key words: assembly, complex I, complexome profiling, maize, mitochondria

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