RESUMEN
Cytoplasmic male sterility (CMS), encoded by the interacting mitochondrial and nuclear genes, causes pollen abortion or non-viability. CMS is widely used in agriculture and extensively studied in crops. Much less is known about CMS in wild species. We performed a comparative transcriptomic analysis of male sterile and fertile individuals of Silene vulgaris, a model plant for the study of gynodioecy, to reveal the genes responsible for pollen abortion in this species. We used RNA-seq datasets previously employed for the analysis of mitochondrial and plastid transcriptomes of female and hermaphrodite flower buds, making it possible to compare the transcriptomes derived from three genomes in the same RNA specimen. We assembled de novo transcriptomes for two haplotypes of S. vulgaris and identified differentially expressed genes between the females and hermaphrodites, associated with stress response or pollen development. The gene for alternative oxidase was downregulated in females. The genetic pathways controlling CMS in S. vulgaris are similar to those in crops. The high number of the differentially expressed nuclear genes contrasts with the uniformity of organellar transcriptomes across genders, which suggests these pathways are evolutionarily conserved and that selective mechanisms may shield organellar transcription against changes in the cytoplasmic transcriptome.
Asunto(s)
Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Estrés Oxidativo/genética , Infertilidad Vegetal/genética , Polen/genética , Silene/genética , Silene/fisiología , Núcleo Celular/genética , Regulación hacia Abajo/genética , Ontología de Genes , Haplotipos/genética , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Anotación de Secuencia Molecular , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcriptoma/genéticaRESUMEN
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.
Asunto(s)
Magnoliopsida/fisiología , Infertilidad Vegetal/genética , Polen/genética , ARN no Traducido/genética , Autoincompatibilidad en las Plantas con Flores/genética , Genes Mitocondriales , Genes de Plantas , Polen/fisiología , ARN no Traducido/metabolismoRESUMEN
An extraordinary variation in mitochondrial DNA sequence exists in angiosperm Silene vulgaris. The atp1 gene is flanked by very variable regions, as deduced from four completely sequenced mitochondrial genomes of this species. This diversity contributed to a highly variable transcript profile of this gene observed across S. vulgaris populations. We examined the atp1 transcript in the KOV mitochondrial genome and found three 5' ends, created most likely by the combination of transcription initiation and RNA processing. Most atp1 transcripts terminated about 70 bp upstream of the translation stop codon, which was present in only 10 % of them. Controlled crosses between a KOV mother and a geographically distant pollen donor (Krasnoyarsk, Russia) showed that nuclear background also affected atp1 transcription. The distant pollen donor introduced the factor(s) preventing the formation of a long 2,100 nt-transcript, because this long atp1 transcript reappeared in the progeny from self-crosses. The highly rearranged mitochondrial genomes with a variation in gene flanking regions make S. vulgaris an excellent model for the study of mitochondrial gene expression in plants.