细胞质雄性不育高粱叶绿体 ndh D 基因的序列变异

片段SAAU－02 700特异地扩增自7种具可育细胞质的高粱材料的总DNA，含有叶绿体psa C(88bp)和ndh D(192bp)基因的部分序列。该片段与Eco Ri HindⅢ酶切的总DNA，线粒体DNA和叶绿体DNA杂交，在总DNA中获得了0.74kb的杂交带，而在叶绿体中获得0.74kb和0．45kb两条杂交带。与线粒体DNA无杂交；与经Hae Ⅲ酶切的总DNA杂交，在不育系中获得4．9kb的杂交带，而保持系的杂交带为4．45kb。参考GenBank中高粱的近缘物种玉米叶绿体基因组的序列，构建了ndh D基因区的酶切位点图谱，借此分析得出高粱不育系的叶绿体ndh D基因序列已发生改变。这种变异与高粱细胞质雄性不育反生的关系正在探讨中。

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

A fragment SAAU-02700 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 EcoR Ⅰ+HindⅢ and probed with fragment SAAU-02700. 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 A1Tx623 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.