Comparative studies of mitochondrial proteomics reveal an intimate protein network of male sterility in wheat (Triticum aestivum L.).

Shuping Wang,Shoucai Ma,Na Niu,Gaisheng Zhang,Junwei Wang,Yingxin Zhang,Zheng Chen,Qilu Song,Junsheng Wang,Jialin Guo

doi:10.1093/jxb/erv322

Abstract

Plant male sterility has often been associated with mitochondrial dysfunction; however, the mechanism in wheat (Triticum aestivum L.) has not been elucidated. This study set out to probe the mechanism of physiological male sterility (PHYMS) induced by the chemical hybridizing agent (CHA)-SQ-1, and cytoplasmic male sterility (CMS) of wheat at the proteomic level. A total of 71 differentially expressed mitochondrial proteins were found to be involved in pollen abortion and further identified by MALDI-TOF/TOF MS (matrix-assisted laser desorption/ionization-time of fight/time of flight mass spectrometry). These proteins were implicated in different cellular responses and metabolic processes, with obvious functional tendencies toward the tricarboxylic acid cycle, the mitochondrial electron transport chain, protein synthesis and degradation, oxidation stress, the cell division cycle, and epigenetics. Interactions between identified proteins were demonstrated by bioinformatics analysis, enabling a more complete insight into biological pathways involved in anther abortion and pollen defects. Accordingly, a mitochondria-mediated male sterility protein network in wheat is proposed; this network was further confirmed by physiological data, RT-PCR (real-time PCR), and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) assay. The results provide intriguing insights into the metabolic pathway of anther abortion induced by CHA-SQ-1 and also give useful clues to identify the crucial proteins of PHYMS and CMS in wheat.

Highlights

Plant male sterility has been observed in numerous species (Schnable and Wise, 1998; Aalto et al, 2013; Bachtrog et al, 2014) since it was first recorded by Kölreuter in 1763
The results provide intriguing insights into the metabolic pathway of anther abortion induced by chemical hybridizing agent (CHA)-SQ-1 and give useful clues to identify the crucial proteins of physiological male sterility (PHYMS) and cytoplasmic male sterility (CMS) in wheat
Compared with MF-XN1376, PHYMS-XN1376 and CMS-XN1376 showed normal spike and floral development but failed to produce any viable pollen at different stages of pollen development (Fig. 1A, D, G, J, N, R); the pistils of PHYMS-XN1376 and CMS-XN1376 were normal and able to produce normal seeds when they were backcrossed with fertile pollen (Fig. 1B, E, H, K, O, S)

Summary

Introduction

Plant male sterility has been observed in numerous species (Schnable and Wise, 1998; Aalto et al, 2013; Bachtrog et al, 2014) since it was first recorded by Kölreuter in 1763. Some of these genes and/or open reading frames (ORFs) encode pollen abortion-related proteins, such as ORF256 (7 kDa) (Song and Hedgcoth, 1994), ORF13 (13 kDa) (Klein et al, 2005), ORF138 (19 kDa) (Yasumoto et al, 2009), ORF288 (32 kDa) (Jing et al, 2012), ORF79 (8.9 kDa) (Wang et al, 2006; Luan et al, 2013), PCF (25 kDa) (Bentolila et al, 2002), and WA352 protein (Luo et al, 2013; Tang et al, 2014) How these proteins mediate metabolic-induced male sterility still needs to be elucidated, and the protein–protein interaction network remains largely unexplored, especially in wheat

Methods

Results

Conclusion