The Role of Non-Coding RNAs in Cytoplasmic Male Sterility in Flowering Plants

Abstract

The interactions between mitochondria and nucleus substantially influence plant development, stress response and morphological features. The prominent example of a mitochondrial-nuclear interaction is cytoplasmic male sterility (CMS), when plants produce aborted anthers or inviable pollen. The genes responsible for CMS are located in mitochondrial genome, but their expression is controlled by nuclear genes, called fertility restorers. Recent explosion of high-throughput sequencing methods enabled to study transcriptomic alterations in the level of non-coding RNAs under CMS biogenesis. We summarize current knowledge of the role of nucleus encoded regulatory non-coding RNAs (long non-coding RNA, microRNA as well as small interfering RNA) in CMS. We also focus on the emerging data of non-coding RNAs encoded by mitochondrial genome and their possible involvement in mitochondrial-nuclear interactions and CMS development.

Keywords: cytoplasmic male sterility; gene expression; global transcriptome; non-coding RNA; pollen development.

Figure 1

Induction and biogenesis of miRNA during CMS. Mitochondrial biogenesis is altered by the action of cytoplasmic male sterility (CMS)-associated genes sending retrograde signals to the nucleus by means of the NAC transcription factor ANAC017 localized close to endoplasmatic reticulum and/or by other unknown factors. They trigger miRNA gene expression and the production of pri-miRNA, which is subsequently trimmed by the complex containing DICER LIKE1 (DCL1), HYPONASTIC LEAVES1 (HYL), SERRATE (SE) and other proteins in the nucleus. Afterwards, miRNA duplexes are transported to the cytoplasm, where they join ARGONAUTE1 (AGO1), find target mRNAs and initiate its cleavage or translation inhibition by RNA-induced silencing complex (RISC). The figure is based on well-supported model except for blue dashed arrows representing an unknown signal.