High-generation near-isogenic lines combined with multi-omics to study the mechanism of polima cytoplasmic male sterility

Benqi Wang,Cheng Dai,Jinxiong Shen,Jie Liu,Jinxing Tu,Jin Wen,Jian Guo,Lei Chu,Chaozhi Ma,Tingdong Fu,Zunaira Farooq,Bin Yi,Huadong Wang

doi:10.1186/s12870-021-02852-7

Abstract

BackgroundCytoplasmic male sterility (CMS), which naturally exists in higher plants, is a useful mechanism for analyzing nuclear and mitochondrial genome functions and identifying the role of mitochondrial genes in the plant growth and development. Polima (pol) CMS is the most universally valued male sterility type in oil-seed rape. Previous studies have described the pol CMS restorer gene Rfp and the sterility-inducing gene orf224 in oil-seed rape, located in mitochondria. However, the mechanism of fertility restoration and infertility remains unknown. Moreover, it is still unknown how the fecundity restorer gene interferes with the sterility gene, provokes the sterility gene to lose its function, and leads to fertility restoration.ResultIn this study, we used multi-omics joint analysis to discover candidate genes that interact with the sterility gene orf224 and the restorer gene Rfp of pol CMS to provide theoretical support for the occurrence and restoration mechanisms of sterility. Via multi-omics analysis, we screened 24 differential genes encoding proteins related to RNA editing, respiratory electron transport chain, anther development, energy transport, tapetum development, and oxidative phosphorylation. Using a yeast two-hybrid assay, we obtained a total of seven Rfp interaction proteins, with orf224 protein covering five interaction proteins.ConclusionsWe propose that Rfp and its interacting protein cleave the transcript of atp6/orf224, causing the infertility gene to lose its function and restore fertility. When Rfp is not cleaved, orf224 poisons the tapetum cells and anther development-related proteins, resulting in pol CMS mitochondrial dysfunction and male infertility. The data from the joint analysis of multiple omics provided information on pol CMS’s potential molecular mechanism and will help breed B. napus hybrids.

Highlights

Cytoplasmic male sterility (CMS), which naturally exists in higher plants, is a useful mechanism for analyzing nuclear and mitochondrial genome functions and identifying the role of mitochondrial genes in the plant growth and development
The results showed that the restorer gene and the protein involved in RNA editing might work together in the pol CMS atp6/orf224 transcript
In a previous study of pol CMS, the materials of sterile, maintainer, and restorer lines were compared with northern blotting, and the results showed that the original atp6/orf224 was transcribed into 1.1 kb, 2.2 kb, and 1.9 kb transcripts relative to the sterile and restorer lines, respectively

Summary

Introduction

Cytoplasmic male sterility (CMS), which naturally exists in higher plants, is a useful mechanism for analyzing nuclear and mitochondrial genome functions and identifying the role of mitochondrial genes in the plant growth and development. Previous studies have described the pol CMS restorer gene Rfp and the sterility-inducing gene orf224 in oil-seed rape, located in mitochondria. Elevated expression of CMS genes might cause mitochondrial function defects, resulting in insufficient energy supply for male organ development, triggering abortion [12]. Many proteins encoded by CMS genes, including URF13, ORF138, ORF79, and ORPH79, are transmembrane proteins These proteins may bind to the mitochondrial inner membrane, affecting the hydrogen ion concentration gradient, affecting ATP synthesis [14,15,16]

Methods

Results

Discussion

Conclusion