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Organization and expression of the mitochondrial genome in CMS (Moricandia) Brassica juncea: nuclear-mitochondrial incompatibility results in differential expression of the mitochondrial atpα gene

Gaikwad, K., Baldev, A., Kirti, P.B., Mohapatra, T., Bhat, S.R., Chopra, V., Prakash, S.
Plant breeding 2006 v.125 no.6 pp. 623-628
Brassica juncea, Moricandia, buds, gene expression regulation, genes, restriction mapping
The mitochondrial genome of CMS (Moricandia) Brassica juncea has been characterized. Southern analysis using nine different mt-specific gene probes revealed differences between B. juncea and M. arvensis and the CMS line. A northern profile of flower bud and leaf mt RNA blots was found conserved for six genes tested. However, tissue-specific expression was observed for atpα. A longer transcript was present in the bud tissue of the CMS line, which reverted to normal in the presence of the fertility restorer gene, while its expression was normal in the leaf tissues. The atpα gene was cloned from B. juncea, M. arvensis and the CMS line. Restriction mapping shows a high degree of restriction site conservation between the CMS and B. juncea lines with minor alterations at the 5' and the 3' ends, indicating the presence of an almost intact M. arvensisatpα gene in the CMS line harbouring a B. juncea nucleus. The results are discussed with respect to the potential role of atpα in generating male sterility in CMS (Mori) B. juncea.