Sequence Variation of the Chloroplast Gene ndh D Region in Cytoplasmic Male Sterile Sorghum

A fragment SAAU-02 700 was amplified specifically from total DNA of seven sorghum varieties with male fertile cytoplasm (N cytoplasm). PCR assays indicated that it was amplified from chloroplast (cp) DNA. Sequence analysis revealed this newly cloned fragment contained a portion of chloroplast gene psa C (88bp) and part of ndh D gene (192bp). Total DNA,mitochondrial (mt) DNA,and cpDNA were digested with Eco R Ⅰ+ Hin dⅢ and probed with fragment SAAU-02 700 . The Southern hybridization patterns displayed a 0.74kb band both in total DNA and cpDNA,but an additional faint band 0.45kb in size was found only in the latter. No polymorphic hybridization signal between the N-cytoplasm and male sterile cytoplasm (S cytoplasm) was observed. Southern hybridization of total DNA of CMS line A 1Tx623 and fertile line Tx623 digested with Hae Ⅲ gave a band 4.9kb in size in the former and a 4.45kb band in the latter. This revealed that the sequence of ndh D from CMS line was likely altered. Further studies designed to determine whether or not the variation has some effect on the metabolism of mitochondria and chloroplast,even on the occurrence of male sterility in sorghum are underway.