Characterization of mitochondrial atp6 gene in WA [wild abortive] cytoplasmic male sterile line of rice
2001
Maiti, M.K. | Sen, S. | Choudri, P.R. | Samanda, S. | Basu, A. | Sen, S.K. (IIT - BREF Biotek, Indian Inst. of Technology, Kharagpore 721032 (India))
The CMS (cytoplasmic male sterile) system with WA (wild abortive) cytoplasm derived from Oryza sativa L. spontanea has been used extensively in developing high yielding hybrid rice in the tropics, including China. However, the author's understanding on the relationship of the expression of mitochondrial gene(s) and the CMS trait in WA cytoplasm is yet to be developed. CMS has been observed in a variety of higher plants and is characterized by very low level or complete absence of pollen production. The phenomenon of CMS in plants is often associated with rearrangements of mt DNA resulting generation of chimeric genes creating new ORFs which are transcribed and translated into chimeric polypeptides. As CMS may have different causes it may be assumed that it is the consequence of mitochondrial dysfunction. It has been also known that differential degree of mitochondrial RNA editing plays important role in effecting altered mitochondrial functions. Studies revealed that the WA cytoplasm shows polymorphisms for the atp6 gene when compared to the maintainers and restorers. Although the size of the transcript did not show apparent variation, the organizational pattern of the atp6 gene shows significant changes. Analysis of the upstream and downstream regions of the atp6 coding region carry differences. It is also known that the kind of mitochondrial dysfunction by different ways can dramatically affect pollen production while other plant organs can overcome the consequences of mitochondrial dysfunction. Thus, the results warrant in-depth search for the causes of the mitochondrial dysfunction in WA cytoplasm, as encountered in atp6 gene of other CMS systems, including Chinsura Boro rice.
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