Characterization of radish mitochondrial atpA: influence of nuclear background on transcription of atpA-associated sequences and relationship with male sterility

Abstract

We have previously shown that the mitochondrial gene atpA, encoding the alpha subunit of F1 ATP synthase, is associated with DNA rearrangements and nuclear-specific transcript patterns in the male-sterile cytoplasm of Ogura radish. Here we present a detailed characterization of this gene from both the normal (fertile) and Ogura (male-sterile) cytoplasms of radish to determine if it is involved in Ogura cytoplasmic male sterility. The normal and Ogura radish atpA loci are virtually identical for 3.8 kb, including a 507 codon open reading frame whose product is approximately 92% identical to other plant ATPA polypeptides. Rearrangement breakpoints have been identified 613 bp 5' and 1663 bp 3' to the atpA coding region. The 5' rearrangement breakpoint is located within a repeated sequence that has been associated with other rearrangement events in radish mitochondria. The previously identified transcript difference results from transcription originating upstream of this rearrangement site. Although the presence of this transcript is affected by nuclear background, analyses in several different sterile and fertile nuclear backgrounds indicate that the presence of this transcript is not strictly correlated with male sterility. In addition, normal levels of ATPA polypeptide are present in sterile plants containing the Ogura cytoplasm.

Overexpression of mitochondrial genes in alloplasmic common wheat with a cytoplasm of wheatgrass (Agropyron trichophorum) showing depressed vigor and male sterility

“…Molecular roles of Rf genes have been thought to alter mitochondrial genome structure [15,26,35], transcription and/or post-transcriptional processing of mitochondrial genes [12,13,20,22,27,38,41] that often causes modification of translation products [ 13,36]. To understand the role ofAgropyron telosomes on the restoration of normal vigor and male fertility of the alloplasmic hybrids, we compared mitochondrial genome organization and gene expression using seedlings of one representative line showing depressed vigor and the corresponding restored and control lines.…”

Molecular and biological studies on male sterile cytoplasm in Cruciferae. II. The origin of Ogura male sterile cytoplasm inferred from the segregation pattern of male sterility in the F1 progeny of wild and cultivated radishes (Raphanus sativus L.)

“…The mitochondrial atp6 gene as a molecular marker of male sterile cytoplasm Ogura mitochondrial DNA possesses many rearrangements, including atpA, atp6 and coxI genes (Makaroff et al, 1989(Makaroff et al, , 1990(Makaroff et al, , 1991. However, the genetic roles of these rearrangements on the expression of male sterility were unclear, except atpA and coxl, which seemed to be irrelevant (Makaroff et al, 1990(Makaroff et al, , 1991.…”

“…However, the genetic roles of these rearrangements on the expression of male sterility were unclear, except atpA and coxl, which seemed to be irrelevant (Makaroff et al, 1990(Makaroff et al, , 1991. To distinguish Ogura from normal-type mtDNA, we developed a PCR assay system using atp6 as a molecular marker, and found that wild radishes with Ogura-type mtD-NA were widely distributed in Japan (Yamagishi & Terachi, 1994).…”

“…Mitochondrial (mt) transcription in Polima cytoplasm has been studied (Witt et al, 1991) and the mtDNA sequence of atp6 gene has been characterized (Handa & Nakajima, 1992). In Ogura cytoplasm, mtD-NA rearrangements including atp6, atpA, coxl genes have been thoroughly investigated (Makaroff et al, 1989(Makaroff et al, , 1990(Makaroff et al, , 1991. These two male sterile cytoplasms have also been studied for practical uses (Bonnet, 1977;Fu et al, 1990).…”

Suppression of cytoplasmic male sterility by nuclear genes alters expression of a novel mitochondrial gene region.

“…Transcripts by Either of Two Distinct Rf Genes Fang and McVetty (1989) nuclear influences on ogu atpA transcripts are unrelated to fertility restoration (Makaroff et al, 1990). To investigate whether the alterations in atp6 region transcripts observed in the restored plants were specifically due to the correspo^iding pol Rf genes, we analyzed the transcripts of the near isogenic lines Westar (pol) and Westar-Rf (pol) and compared these with the corresponding Westar (nap) line.…”