The PtdIns3P phosphatase MtMP promotes symbiotic nitrogen fixation via mitophagy in Medicago truncatula.

Abstract

Symbiotic nitrogen fixation is a complex process in which legumes interact with rhizobia under nitrogen starvation. In this study, we found that myotubularin phosphatase (MtMP) is mainly expressed in roots and nodules in Medicago truncatula. MtMP promotes autophagy by dephosphorylating PtdIns3P on autophagosomes. The mp mutants inoculated with rhizobia showed a significant reduction in nitrogenase activity and significantly higher number of mitochondria than those of wild-type plants under nitrogen starvation, indicating that MtMP is involved in mitophagy of the infection zone. Mitophagy may provide carbon skeletons and nitrogen for the development of bacteroids and the reprogramming of infected cells. In conclusion, we found, for the first time, that myotubularin phosphatase is involved in autophagy in plants. MtMP-involved autophagy plays an active role in symbiotic nitrogen fixation. These results deepen our understanding of symbiotic nitrogen fixation.

• Authors: Qixia Xue, Chen Shen, Qianwen Liu, Peng Liu, Da Guo, Lihua Zheng, Jinling Liu, Chang Liu, Qinyi Ye, Tao Wang, Jiangli Dong
• Journal: iScience (iScience) Vol. 26 Issue 10 Pg. 107752 (Oct 20 2023) ISSN: 2589-0042 [Electronic] United States
• PMID: 37954141 (Publication Type: Journal Article)
• Copyright: © 2023 The Authors.