Analysis of the mitochondrial genome of a cybrid between two solanaceae

SANCHEZ PUERTA, MV; PALMER, JD

Rosario

Congreso; 8th International Conference for Plant Mitochondrial Biology ICPMB; 2013

Universidad Nacional de Rosario

Cybrid (cytoplasmic hybrid) plants represent a valuable model to study mitochondrial genome recombination, cytoplasmic male sterility (CMS), and horizontal transfer between plant mitochondria. A green cybrid Nt+Hn was produced by protoplast fusion of two solanaceae: Nicotiana tabacum (albino) and Hyoscyamus niger (green). The cybrid plant (Nt+Hn) had abnormal flowers that were deficient in fertile pollen grains showing a CMS phenotype. We extracted total DNA from the cybrid and from H. niger, and they were deeply sequenced using the Illumina Hiseq platform. The chloroplast genomes of the cybrid and H. niger were fully assembled and were ca. 155 kb in length. The cybrid contained chloroplasts, which belonged to H. niger. The mitochondrial genomes of H. niger (~465 kb) and the cybrid (~580 kb) assembled into 13 and 18 contigs, respectively. In addition to the 36 protein-coding genes identified in tobacco and H. niger, the cybrid mtDNA had two copies (one from each parent) of three mitochondrial genes. Parental and cybrid mtDNAs had 17 cis-splicing and 6 trans-splicing group II introns. Furthermore, the cybrid and H. niger also had a group I intron in the cox1 gene. Only 1% of the cybrid mtDNA was homologous to chloroplast sequences. Using the program Mauve, homologous regions of the parental and cybrid mtDNA were aligned. The cybrid mtDNA was a highly re-arranged combination of both parental mtDNAs.