The Investigation of Organelle Genomes of Extra Nuclear Sunflower Mutants with Variegated Phenotype

Abstract

The comparative analysis of complete chloroplast and mitochondrial DNA sequences of the original inbred line 3629 and three extra nuclear mutant lines variegated-1, variegated-15, variegated-17, obtained by the N-nitroso-N-methylurea induced mutagenesis, was done. The studied mutant lines were presented two different phenotypes with diverse chlorophyll content: Pale/green mutant line variegated-17 with 1.8% relative (to 3629 line) chlorophyll content in mutant leaf tissue and yellow/green lines variegated-1, variegated-15 with 6.3% and 4.3% relative chlorophyll content, respectively. Each line had unique variation sites in chloroplast DNA. Among chloroplast SNP there were determined 7 nonsynonymous substitutions, which were located in psaA (variegated-1), petD, rpl36, ccsA (variegated-15), rps4, rpoA, rpoC1 (variegated-17). The SNP of variegated-17 line has resulted in the frameshift (rpoC1) and premature stop codon formations (rpoA, rpoC1). The whole genome sequencing of mitochondrial DNA mutant lines revealed no differences as compared with original line 3629. Summarizing current data and our previous research of variegated mutants we assume that pale/green variegated phenotype is associated with significant disturbance of RNA polymerase subunits genes, and the lesions in photosynthetic genes lead to yellow/green mutant phenotype.