A male sterility-associated cytotoxic protein ORF288 in Brassica juncea causes aborted pollen development.
A male sterility-associated cytotoxic protein ORF288 in Brassica juncea causes aborted pollen development.
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DOI：
10.1093/jxb/err355
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发表时间：
2012-02
影响因子：
6.9
通讯作者：
Shen J
中科院分区：
文献类型：
--
作者：
Jing B;Heng S;Tong D;Wan Z;Fu T;Tu J;Ma C;Yi B;Wen J;Shen J
细胞质雄性不育（CMS）是高等植物中普遍存在的现象，一些研究已经确定这种母系遗传的缺陷通常与线粒体突变体有关。大约有10个嵌合基因已被确定为与相应的CMS系统中的家庭油菜，但很少有直接的证据表明，这些基因导致雄性不育。本研究发现一个新的嵌合基因（orf288）位于atp6基因的下游，并与该基因在hau CMS不育系中共转录。Western blotting分析表明，该预测的开放阅读框（ORF）在雄性不育植株的线粒体中得到翻译。ORF288蛋白对大肠杆菌的生长有明显的抑制作用，表明ORF288蛋白对大肠杆菌具有毒性。coli宿主细胞。为了进一步证实orf288在雄性不育中的功能，将该基因融合到拟南芥APETALA3启动子控制下的植物靶向前序列并引入拟南芥中。近80%的orf288转基因植株不能发育花药。研究还发现，即使没有转运前序列，orf288的独立表达也会导致转基因植物的雄性不育。此外，orf 288和绿色荧光蛋白（GFP）融合蛋白在A. thaliana原生质体显示ORF288能够锚到线粒体，即使没有外部的线粒体靶向肽。这些结果为orf 288与芥菜型油菜hau CMS的雄性不育性有关提供了重要证据。
Cytoplasmic male sterility (CMS) is a widespread phenomenon in higher plants, and several studies have established that this maternally inherited defect is often associated with a mitochondrial mutant. Approximately 10 chimeric genes have been identified as being associated with corresponding CMS systems in the family Brassicaceae, but there is little direct evidence that these genes cause male sterility. In this study, a novel chimeric gene (named orf288) was found to be located downstream of the atp6 gene and co-transcribed with this gene in the hau CMS sterile line. Western blotting analysis showed that this predicted open reading frame (ORF) was translated in the mitochondria of male-sterile plants. Furthermore, the growth of Escherichia coli was significantly repressed in the presence of ORF288, which indicated that this protein is toxic to the E. coli host cells. To confirm further the function of orf288 in male sterility, the gene was fused to a mitochondrial-targeting pre-sequence under the control of the Arabidopsis APETALA3 promoter and introduced into Arabidopsis thaliana. Almost 80% of transgenic plants with orf288 failed to develop anthers. It was also found that the independent expression of orf288 caused male sterility in transgenic plants, even without the transit pre-sequence. Furthermore, transient expression of orf288 and green fluorescent protein (GFP) as a fused protein in A. thaliana protoplasts showed that ORF288 was able to anchor to mitochondria even without the external mitochondrial-targeting peptide. These observations provide important evidence that orf288 is responsible for the male sterility of hau CMS in Brassica juncea.