Aberrant Meiotic Prophase I Leads to Genic Male Sterility in the Novel TE5A Mutant of Brassica napus.

Xiaohong Yan,Gang Wu,Rong Yuan,Keqi Li,Xinhua Zeng,Yunjing Li,Shasha Wang,Yuhua Wu,Fang Liu,Hongfei Gao,Li Zhu,Junling Luo

doi:10.1038/srep33955

Xiaohong Yan, Gang Wu + Show 10 more

Open Access

https://doi.org/10.1038/srep33955

Copy DOI

Journal: Scientific Reports	Publication Date: Sep 1, 2016
Citations: 12	License type: CC BY 4.0

Affiliation: Chinese Academy of Agricultural Sciences

Abstract

Genic male sterility (GMS) has already been extensively utilized for hybrid rapeseed production. TE5A is a novel thermo-sensitive dominant GMS line in Brassica napus, however, its mechanisms of GMS remain largely unclear. Histological and Transmission electron microscopy (TEM) analyses of anthers showed that the male gamete development of TE5A was arrested at meiosis prophase I. EdU uptake of S-phase meiocytes revealed that the TE5A mutant could accomplish DNA replication, however, chromosomal and fluorescence in situ hybridization (FISH) analyses of TE5A showed that homologous chromosomes could not pair, synapse, condense and form bivalents. We then analyzed the transcriptome differences between young floral buds of sterile plants and its near-isogenic fertile plants through RNA-Seq. A total of 3,841 differentially expressed genes (DEGs) were obtained, some of which were associated with homologous chromosome behavior and cell cycle control during meiosis. Dynamic expression changes of selected candidate DEGs were then analyzed at different anther developmental stages. The present study not only demonstrated that the TE5A mutant had defects in meiotic prophase I via detailed cytological analysis, but also provided a global insight into GMS-associated DEGs and elucidated the mechanisms of GMS in TE5A through RNA-Seq.

Highlights

Both cytoplasmic male sterility (CMS) and genic male sterility (GMS) are common pollination control systems for hybrid rapeseed production[1,2,3]
To elucidate the underlying molecular mechanism of the TE5A Genic male sterility (GMS) that is associated with abnormal meiosis prophase I phase, we used young floral buds (0.5–1.0 mm in diameter, at meiotic prophase I stage) of sterile plants and fertile plants of the BC3 population derived from the successive backcrossing of heterozygous TE5A sterile plants with the maintainer line GY12 to perform a genome-wide high-throughput transcriptome sequencing analysis (RNA-Seq) to identify differentially expressed genes (DEGs) participating in the control of fertility
Paraffin-cross sections of anthers showed that male gamete development was arrested at the first meiotic division stage, and Transmission electron microscopy (TEM) analysis of cross-sections of anthers showed that pollen mother cells (PMCs) were arrested at prophase I

Summary

Introduction

Both cytoplasmic male sterility (CMS) and genic male sterility (GMS) are common pollination control systems for hybrid rapeseed production[1,2,3]. In the Arabidopsis thaliana tam-1 mutant, only one replacement of an amino acid (Thr283Ile) disorders the cell cycle control associated with male meiosis, resulting in a failure to enter meiosis II, leading to the generation of dyad and diploid spores, thereby suggesting that CYCA1;2/TAM plays a crucial role in the transition from meiosis I to meiosis II25,26. To elucidate the underlying molecular mechanism of the TE5A GMS that is associated with abnormal meiosis prophase I phase, we used young floral buds (0.5–1.0 mm in diameter, at meiotic prophase I stage) of sterile plants and fertile plants of the BC3 population derived from the successive backcrossing of heterozygous TE5A sterile plants with the maintainer line GY12 to perform a genome-wide high-throughput transcriptome sequencing analysis (RNA-Seq) to identify differentially expressed genes (DEGs) participating in the control of fertility

Methods

Results

Discussion

Conclusion