ISSN:
1617-4623
Keywords:
Chloroplast
;
RNA polymerase
;
Deletion
;
Cytoplasmic male sterility
;
Sorghum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Fertile lines of sorghum (Sorghum bicolor) were shown to differ from cytoplasmic male sterile (CMS) lines by the presence of a 3.8 kb HindIII chloroplast DNA fragment in the former and a smaller (3.7 kb) fragment in the latter. DNA/DNA hybridization studies showed that these two fragments are homologous. Fertile plants from S. versicolor, S. almum, S. halepense, and Sorghastrum nutans (Yellow Indiangrass) also have the 3.8 kb fragment, and CMS lines studied containing A1, A2 and A3 cytoplasms have the 3.7 kb fragment. The size difference between the two fragments was localized to a 1.0 kb SacI-HindIII fragment by restriction mapping. A r65 by deletion, which is flanked by a 51 by tandem repeat, was identified in the CMS lines by sequencing the clones. Comparison of the two sequences with those from maize, rice, tobacco, spinach, pea, and liverwort revealed that the deleted sequence is located in the middle of the RNA polymerase β″ subunit encoded by the gene rpoC2. The amino acid sequence deleted in the CMS lines is in a monocot-specific region which contains two protein motifs that are characteristic of several transcriptional activation factors, namely, a leucine zipper motif and an acidic domain capable of forming an amphipathic α-helix. Further studies designed to determine whether or not the deletion is involved in CMS of sorghum are underway.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00277120
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