Differential expression of alternative oxidase genes in maize mitochondrial mutants.
Plant Cell
; 14(12): 3271-84, 2002 Dec.
Article
em En
| MEDLINE
| ID: mdl-12468742
ABSTRACT
We have examined the expression of three alternative oxidase (aox) genes in two types of maize mitochondrial mutants. Nonchromosomal stripe (NCS) mutants carry mitochondrial DNA deletions that affect subunits of respiratory complexes and show constitutively defective growth. Cytoplasmic male-sterile (CMS) mutants have mitochondrial DNA rearrangements, but they are impaired for mitochondrial function only during anther development. In contrast to normal plants, which have very low levels of AOX, NCS mutants exhibit high expression of aox genes in all nonphotosynthetic tissues tested. The expression pattern is specific for each type of mitochondrial lesion the NADH dehydrogenase-defective NCS2 mutant has high expression of aox2, whereas the cytochrome oxidase-defective NCS6 mutant predominantly expresses aox3. Similarly, aox2 and aox3 can be induced differentially in normal maize seedlings by specific inhibitors of these two respiratory complexes. Translation-defective NCS4 plants show induction of both aox2 and aox3. AOX2 and AOX3 proteins differ in their ability to be regulated by reversible dimerization. CMS mutants show relatively high levels of aox2 mRNAs in young tassels but none in ear shoots. Significant expression of aox1 is detected only in NCS and CMS tassels. The induction pattern of maize aox genes could serve as a selective marker for diverse mitochondrial defects.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Oxirredutases
/
DNA Mitocondrial
/
Zea mays
Idioma:
En
Revista:
Plant Cell
Assunto da revista:
BOTANICA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos