HSP_(70)基因表达对高粱育性的影响(英文)

高粱细胞质雄性不育系３１９７Ａ（３Ａ）在常温条件下是不育的（Ｆｉｇｓ．１１＆２），经热激（４５℃）诱导不同程度地恢复了育性（Ｆｉｇｓ．１３＆４），为研究其不育机理提供了线索。热激２ｈ后，３Ａ中即可产生一类线粒体热激蛋白（ＨＳＰｓ）。其中，分子量为７０ｋＤ的ＨＳＰ７０含量最高，也最为稳定。不过，３Ａ中ＨＳＰｓ的稳定性弱于保持系３１９７Ｂ（３Ｂ）（Ｆｉｇ．２，Ｐａｎｅｌｓ１～４）。放线菌素Ｄ抑制ＨＳＰｓ的合成，而氯霉素无此作用（Ｆｉｇ．２，Ｐａｎｅｌｓ５＆６），表明：ＨＳＰｓ是由核基因编码、在细胞质中合成、再跨膜转运到线粒体中的。３Ａ幼穗经热激后，线粒体的总蛋白量猛增了２．７倍（Ｆｉｇ．３），达到３Ｂ的水平，育性亦变为可育的。Ｆｉｇ．４表明：ＨＳＰ７０反义链ｃＤＮＡ（Ｒ１）能进入到３Ｂ花药细胞中，并与靶ＲＮＡ（ＨＳＣ７０ｍＲＮＡ）结合，而对照、正义链ｃＤＮＡ（Ｄ）链无此反应。由此、再增加一个通用保守序列的反义链ｃＤＮＡ（Ｒ２）、共两个探针（Ｒ１、Ｒ２），可以检测到：３Ａ在常温下没有能力合成ＨＳＣ７０ｍＲＮＡ（Ｆｉｇ．５），而在热激条件下，转变为有能力（Ｆｉｇ．６）。启示：３Ａ在热激条件下由不育转变为可育

Effect of the Expression of HSP 70 Gene on the Fertility of Sorghum 1

It was found that the Cytoplasmic Male Sterility (CMS) line of sorghum 3197A (3A) can be induced to become fertile by heat shock treatment, whereas the maintainer line 3197B (3B) is fertile, whether it is heat shocked or not. During the pollen mother cell (PMC) stage, with heat shock treatment, the 3A line changed into fertile from sterile, and five protein bands: 70kD (HSP 70 ), 31kD, 24kD, 18kD and 16kD were found. And identical bands were also appeared in 3B line with similar treatment. By comparing the amount of protein in mitochondria during ear stage of 3A sorghum, the amount of protein increased by 2.7 times, and was almost as much as that in 3B. A comparison of the heat shock proteins (HSPs) of mitochondria in 3A and 3B lines revealed that HSPs were encoded by the nuclear DNA and transported to the mitochondria. Moreover, HSPs were more heat stable in 3B than in 3A line, and this may be related to the stability of fertility in 3B line. To demonstrate the correlation between fertility and HSPs, DNA complementary to HSP 70 was injected into ears of 3A and 3B line. It is found that under normal conditions, there was no HSP 70 mRNA in 3A line, whereas after heat shock this mRNA appeared, and the antisense cDNA could combine with the target RNA of 3B either dealt with normal temperature or heat shocked. These results are discussed within the frame of fertility versus sterility in sorghum.