中文摘要：

通过对3个拟南芥（Arabidopsis thaliana）雄性不育突变体（ms1521,st350,st454）的分析,研究了MS1521基因在花药发育过程中的功能。ms1521是通过EMS诱变野生型拟南芥得到的一株突变体,遗传分析表明ms1521是隐性单核基因控制的。利用图位克隆的方法对不育基因MS1521进行了定位,结果将MS1521定位于拟南芥第一条染色体上26kb的区间内,该定位区间内有一个影响花器官形态建成的基因UFO。测序结果表明在ms1521突变体中UFO基因编码区的958bp处发生了单碱基突变,导致MS1521该位点的氨基酸由天冬酰胺变成了天冬氨酸。另外两个表型与ms1521相似的突变体st350和st454来自T-DNA插入突变体群体。测序结果表明突变体st350和st454分别在UFO基因编码区发生了提前终止突变。等位分析表明它们与MS1521基因是等位的。3个突变体营养生长期发育正常,但生殖生长发育出现异常：有的雄蕊只有花丝没有花药;或者有花药但花丝变短;或者雄蕊有正常的花丝和花药,花药中有可育的花粉,但药室不能开裂;最终导致突变体不育的表型。进一步细胞学观察发现药室不能开裂是由于药室内壁细胞纤维化和木质化增厚不明显造成的。以上这些结果表明MS1521基因在花药发育过程中起重要作用。

英文摘要：

This paper described the functional analyses of the MS1521 gene in anther development by using three Arabidopsis male sterile mutants （ms1521,st350 and st454）. Mutant ms1521 was generated by ethyl-methane sulfonate （EMS） mutagenesis treatment. Genetic analysis showed that ms1521 mutant was controlled by a single recessive nuclear gene. A map-based cloning approach was used,and MS1521 was mapped to a region of 26 kb on chromosome 1 which contained a floral-organ identity gene UFO. Sequence analysis revealed that ms1521 had an AAC-GAC base-pair change in the UFO coding region,which resulted in the replacement of an Asn by an Asp residue in the C-terminal region. The other two mutants,st350 and st454 with same phenotypes of ms1521,were identified from a T-DNA insertion mutant population. Direct sequence analyses showed that both mutants had a pre-mature stop codon in the UFO coding region. Allelism tests indicated that ST350,ST454 and MS1521 belonged to the same locus. These three mutants grew normally during the vegetative growth stage,but showed developmental defects at the reproductive growth stage：some stamens failed to develop anther,while others had normal anthers but their filaments were shorter than that of the wild type and others with normal stamens but failed in anther dehiscence. All the defects described above leaded to the sterile phenotype. Further cytological observations showed that the mutant anthers lacked of cell wall fiberization and secondary thickening in the endothecium which was required for anther dehiscence. These results indicated that MS1521 gene played an important role in Arabidopsis anther development.