Tr. Rocheford et Dr. Pring, INTERACTION OF NUCLEAR AND MITOCHONDRIAL GENOMES IN THE ALTERATION OFMAIZE MITOCHONDRIAL ORF221 TRANSCRIPTS, Theoretical and Applied Genetics, 89(7-8), 1994, pp. 951-958
The interaction of nuclear and mitochondrial genomes in the alteration
of maize (Zea mays L.) mitochondrial orf221 transcript patterns was e
xamined. Northern analyses involving specific maize nuclear genotypes
associated with N, C or S cytoplasms revealed considerable orf221 tran
script heterogeneity. F-1 progenies were de veloped from maize inbred-
cytoplasm combinations that differed for orf221 transcript patterns. N
orthern analyses revealed that the presence or level of abundance of c
ertain orf221 transcripts was dependent on nuclear genotype. The maize
inbred B37(C) exhibits orf221 transcripts of 3 500, 3 200, 2 800, and
1 300 nt whereas the F-1 of B37(C)xKy21(N) does not exhibit a 2 800-n
t transcript but does give transcripts of 2 100 and 1 250 nt in additi
on to 3 500-, 3 200- and 1 300-nt transcripts, Northern analyses also
suggested that the size or the presence of certain orf221 transcripts
was related to the mitochondrial genome configuration. Maize inbred A6
19 exhibits a 2 300-nt orf221 transcript when associated with N cytopl
asm and a 2 100-nt orf221 transcript when associated with C and S cyto
plasms. As a result of deletion of the gene T-urf13, the A188(T7) mito
chondrial mutant exhibits only a 3100-nt orf221 transcript and not the
very complex T-urf13/orf221 transcript pattern associated with A188(T
). The genetic stock A188(T7)xW64A(N)(2) gives a highly abundant 2 100
-nt orf221 transcript not detected in A188(T7). Deletion of T-urf13 ha
s enabled the nuclear genotype of W64A(N) to alter orf221 transcript p
atterns in a manner not detected in T cytoplasm. This observation sugg
ests that alteration of the mitochondrial genomic configuration adjace
nt to orf221 results in a different response to nuclear gene products
from that observed when orf221 is present in the T mitochondrial genom
e configuration.