The phenomenon of male sterility (MS) is described as inability of a plant to produce fertile pollen. For hybrid breeding this is a very usefull instrument, because the plant is prevented from selfing by pollen sterility. In this way it is possible to produce pure hybrid seeds under usage of the heterosis effect. In most cases The reason for cytoplasmic male sterility lies in mitochondrial genome rearrangements.

 
Location of the orf H522, conferring cytoplasmic male sterility in H. annuus within the mitochondrial genome (total length ca. 300 kbp).

atpA: a subunit of F1 ATPase
cob : Apocytochrome b
ndh1 : NADH/H+ Dehydrogenase 1
rps13 : ribosomal protein S13
18S : 18S ribosomal RNA
26S : 26S ribosomal RNA
atp6:  subunit  6 of F0 ATPase
atp9 : subunit  9 of F0 ATPase
coxI-III : Cytochrom b Oxidases I-III

 

• KÖHLER, R.H., LÖSSL, A. and ZETSCHE, K., (1990): Nucleotide sequence of the F1-ATPase alpha subunit gene of sunflower mitochondria; Nucl. Acids Res. 18: 4588
• KÖHLER, R., HORN, R., LÖSSL, A. and ZETSCHE, K., (1991): Cytoplasmic male sterility in sunflower is correlated with the co-transcription of a new open reading frame with the atpA gene. Mol. Gen. Genet. 227: 369-376
• SICULELLA L. und J. PALMER 1988 Physical and gene organization of mitochondrial DNA in fertile and male sterile sunflower. CMS associated in structure and transcription of the atpA gene, NAR Vol 16: 3787-3799
• HORN, R., KÖHLER, R. and ZETSCHE, K., (1991): A 16 kDa protein is associated with cytoplasmic male-sterility in sunflower. Plant Mol. Biol. 17: 29-36
• HORN, R., HUSTEDT, J., HORSTMEYER, A., HAHNEN, J., ZETSCHE, K. and FRIEDT, W., (1996): The cms-associated 16 kDa protein encoded by orfH522 in the PET1 cytoplasm is also present in other male-sterile cytoplasms of sunflower. Plant Mol. Biol. 30: 523-538
• More on Cytoplasmic male Sterility (CMS)

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Andreas LÖSSL, 02.09.1999