Citrus suavissima 'Wuzi Ougan' is a seedless bud variation of C. suavissima with male sterility and pollen abortion from the tetrad stage. RNA of C. suavissima and C. suavissima 'Wuzi Ougan' was extracted and the full-length cDNA was cloned and bioinformatics analysis of amino acid sequences was conducted. The results showed that the sequence length of CsRAD51 was 1210bp, containing an ORF of 1029bp. The deduced protein was hydrophobic one, encoded 388 amino acids. Its molecular weight was 45740.1D, with atom number of 6555 and isoelectric point of 10.20. Homologous alignment demonstrated the homology coefficient of C. suavissima'Wuzi Ougan' with C. sinensis,Jatropha curcas,Elaeis guineensis, Cucumis sativus and Populus nigra was 99%,98%,98%,98%,98% respectively. The Real-time PCR results showed that the relative expression of CsRAD51 in C. suavissima'Wuzi Ougan' was significantly higher than C. suavissimaat microsporocyte stage, tetrad stage and uninucleus microspore stage, indicating that overexpression of CsRAD51 inhibited double-strand break-induced homologous recombination and led to DNA damage and abnormal meiosis.%'无籽瓯柑'的雄性不育主要表现为花粉败育,起始于小孢子母细胞减数分裂时期.本研究克隆了'无籽瓯柑'减数分裂相关基因CsRAD51,并采用荧光定量PCR检测其在瓯柑及'无籽瓯柑'中的表达差异.结果显示,CsRAD51基因的cDNA全长1210 bp,含有一个1029 bp的ORF区;其编码的蛋白质属于疏水性蛋白,分子量45740.1D,氨基酸数388,原子总数6555,等电点10.20.同源性比对发现,'无籽瓯柑'CsRAD51的氨基酸序列与甜橙、麻疯树、油棕、黄瓜、黑杨等的RAD51蛋白高度同源,分别达99%,98%,98%,98%,98%.RT-PCR结果显示'无籽瓯柑'CsRAD51在小孢子母细胞、四分体以及单核花粉粒时期的相对表达量显著高于瓯柑.CsRAD51的过量表达可能影响了DSBs的同源重组修复,致使'无籽瓯柑'小孢子母细胞时期减数分裂异常.
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