Integrated analysis of transcriptome and proteome changes related to the Ogura cytoplasmic male sterility in cabbage

PLoS One. 2018 Mar 12;13(3):e0193462. doi: 10.1371/journal.pone.0193462. eCollection 2018.

Abstract

Cabbage (Brassica oleracea L. var. capitata), an important vegetable crop in the Brassicaceae family, is economically important worldwide. In the process of hybrid seed production, Ogura cytoplasmic male sterility (OguCMS), controlled by the mitochondrial gene orf138, has been extensively used for cabbage hybrid production with complete and stable male sterility. To identify the critical genes and pathways involved in the sterility and to better understand the underlying molecular mechanisms, the anther of OguCMS line R2P2CMS and the fertile line R2P2 were used for RNA-seq and iTRAQ (Isobaric Tags for Relative and Absolute Quantitation) proteome analysis. RNA-seq analysis generated 13,037,109 to 13,066,594 SE50-clean reads, from the sterile and fertile lines, which were assembled into 36,890 unigenes. Among them, 1,323 differentially expressed genes (DEGs) were identified, consisting of 307 up- and 1016 down-regulated genes. For ITRAQ analysis, a total of 7,147 unique proteins were identified, and 833 were differentially expressed including 538 up- and 295 down-regulated proteins. These were mainly annotated to the ribosome, spliceosome and mRNA surveillance pathways. Combined transcriptomic and proteomic analyses identified 22 and 70 genes with the same and opposite expression profiles, respectively. Using KEGG analysis of DEGs, gibberellin mediated signaling pathways regulating tapetum programmed cell death and four different pathways involved in sporopollenin synthesis were identified. Secretion and translocation of the sporopollenin precursors were identified, and the key genes participating in these pathways were all significantly down-regulated in R2P2CMS. Light and transmission electron (TE) microscopy revealed fat abnormal tapetum rather than vacuolization and degradation at the tetrad and microspore stages of the OguCMS line. This resulted in the failed deposition of sporopollenin on the pollen resulting in sterility. This study provides a comprehensive understanding of the mechanism underlying OguCMS in cabbage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brassica / genetics
  • Brassica / metabolism
  • Brassica / physiology*
  • Gene Expression Profiling / methods*
  • Gene Expression Regulation, Plant
  • Gene Ontology
  • Genes, Plant
  • Metabolic Networks and Pathways
  • Organ Size
  • Plant Infertility*
  • Proteomics / methods*
  • Sequence Analysis, RNA / methods

Grants and funding

This work was supported by Grants from the Natural Science Foundation of China (31372065), the National Key Research and Development Program (2016YFD0101702, 2016YFD0101804) and the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-Year Plan Period (2014BAD01B08) to JK. The work reported here was carried out in the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing 100097, China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.