MITOCHONDRIAL ATP SYNTHASE GENES MAY BE IMPLICATED IN CYTOPLASMIC MALE-STERILITY IN SORGHUM-BICOLOR

Incompatible nuclear-cytoplasmic interactions are responsible for the phenomenon of cytoplasmic male sterility in plants. We have analysed m ale sterile (2077A, 296A), maintainer fertile (2077B, 296B) and fertil ity restored (2077R, 296R) lines of sorghum for the restriction fragme nt locations of various mitochondrial genes and their transcripts. We report here a polymorphism in genes related to the ATP synthase comple x between two different cytoplasms from the A and B set of lines of 20 77 and 296. There is also a difference in the transcript size of the a tpA gene between the A and B cytoplasms. We propose that incompatibili ty in nuclear cytoplasmic interactions may be explained in terms of in compatible subunits being synthesized by the mitochondria and nucleus for a multisubunit complex of the mitochondrial membrane such as ATPas e.