*Article* **Mutation of YL Results in a Yellow Leaf with Chloroplast RNA Editing Defect in Soybean**

**Xiaowei Zhu 1,2, Yi Pan 1, Zhi Liu 1, Yucheng Liu 1, Deyi Zhong 1,3, Zongbiao Duan 1, Zhixi Tian 1,4, Baoge Zhu 1,\* and Guoan Zhou 1,\***


Received: 15 May 2020; Accepted: 11 June 2020; Published: 16 June 2020

**Abstract:** RNA editing plays a key role in organelle gene expression. Little is known about how RNA editing factors influence soybean plant development. Here, we report the isolation and characterization of a soybean *yl* (*yellow leaf*) mutant. The *yl* plants showed decreased chlorophyll accumulation, lower PS II activity, an impaired net photosynthesis rate, and an altered chloroplast ultrastructure. Fine mapping of *YL* uncovered a point mutation in *Glyma.20G187000*, which encodes a chloroplast-localized protein homologous to *Arabidopsis thaliana* (*Arabidopsis*) ORRM1. *YL* is mainly expressed in trifoliate leaves, and its deficiency affects the editing of multiple chloroplast RNA sites, leading to inferior photosynthesis in soybean. Taken together, these results demonstrate the importance of the soybean YL protein in chloroplast RNA editing and photosynthesis.

**Keywords:** soybean; *yellow leaf* mutant; photosynthesis; chloroplast RNA editing
