Characterisation and expression of the mitochondrial genome of a new type of cytoplasmic male-sterile sunflower.
A new cytoplasmic male sterile sunflower, CMS3 [44], was characterised in relation to the Petiolaris (PET1) cytoplasmic male-sterile sunflower, CMS89 [25]. Southern blot analysis showed that the mitochondrial genome of CMS3 contains unique rearrangements in at least five loci (atp6, atp9, atpA, nad1 + 5 and coxIII) compared to the PET1 sterile and the fertile cytoplasms. Transcripts of two (coxIII and atp6) of the five rearranged loci differed in CMS3 when compared to the corresponding loci in the PET1 and fertile cytoplasms. In organello protein synthesis experiments showed that the ca. 15 kDa mitochondrial polypeptide, characteristic of PET1, is not present in the CMS3 line. These data suggest that the molecular basis of male sterility in the CMS3 line differs from that of the PET1 cytoplasm. The nucleotide sequences of the coding and the immediate flanking regions of the coxIII and atp6 genes of CMS3 were compared to the corresponding regions from the fertile sunflower. In CMS3 the ORFB-coxIII locus is located immediately 3' to the atpA gene whereas in the fertile cytoplasm these two loci are ca. 60 kb apart. This DNA rearrangement probably involved a 265 bp repeat which may be implicated in the DNA recombination associated with PET1 CMS. The atp6 gene in CMS3 contains a 5'-terminal extention which results in an extended ORF. The potential involvement of the rearrangements associated with the coxIII and atp6 loci in relation to the CMS phenotype is discussed.
Department of Genetics, Vrije Universiteit, Amsterdam, The Netherlands.
M
M
Spassova
F
F
Moneger
C J
CJ
Leaver
P
P
Petrov
A
A
Atanassov
H J
HJ
Nijkamp
J
J
Hille
D000595:Amino Acid Sequence; D001483:Base Sequence; D002474:Cell-Free System; D003001:Cloning, Molecular; D003593:Cytoplasm; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D005111:Extrachromosomal Inheritance / Q000235:genetics*; D015321:Gene Rearrangement; D017343:Genes, Plant / Q000235:genetics*; D006368:Helianthus / Q000235:genetics*; D007246:Infertility / Q000235:genetics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis; D014176:Protein Biosynthesis; D006180:Proton-Translocating ATPases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial; D010940:Plant Proteins; D012333:RNA, Messenger; D003576:Electron Transport Complex IV; D006180:Proton-Translocating ATPases