Changes in DNA base sequences in the mutant of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> induced by low-energy N<Superscript>+</Superscript> implantation

To reveal the mutation effect of low-energy ion implantation on Ambidopsis thaliana in vivo, T80II, a stable dwarf mutant, derived from the seeds irradiated by 30 keV N⁺ with the dose of 80 X 10¹⁵ ions/cm² was used for Random Amplified Polymorphic DNA (RAPD) and base sequence analysis. The results indicated that among total 397 RAPD bands observed, 52 bands in T80II were different from those of wild type showing a variation frequency 13.1%. In comparison with the sequences of A. thaliana in GenBank, the RAPD fragments in T80II were changed greatly in base sequences with an average rate of one base change per 16.8 bases. The types of base changes included base transition, transversion, deletion and insertion. Among the 275 base changes detected, single base substitutions (97.09%) occurred more frequently than base deletions and insertions (2.91%). And the frequency of base transitions (66.55%) was higher than that of base transversions (30.55%). Adenine, thymine, guanine or cytosine could be replaced by any of other three bases in cloned DNA fragments in T80II. It seems that thymine was more sensitive to the irradiation than other bases. The flanking sequences of the base changes in RAPD fragments in T80II were analyzed and the mutational “hotspot” induced by low-energy ion implantation was discussed.     

低能N+辐照拟南芥诱导基因组DNA碱基变异分析

用低能N+离子束注入拟南芥后获得的稳定突变体T80Ⅱ作为实验材料, 对突变体植株进行了RAPD标记, 并将T80Ⅱ和对照部分RAPD特异条带进行克隆测序和DNA序列分析. 结果显示, 在可分辨的总计397个RAPD条带中, T80Ⅱ株系中有52个条带表现出差异, 包括条带的缺失和增加, 条带变异率为13.1%; 克隆的T80Ⅱ序列中, 平均每16.8个碱基出现1个碱基变异位点, 表现出较高频率的碱基突变. 碱基突变类型包括碱基的颠换、转换、缺失、插入等. 在检测到的275个碱基突变中, 主要是单碱基置换(97.09%), 碱基缺失或者插入的比例较小(2.91%). 在碱基置换中, 转换的频率(66.55%)高于颠换的频率(30.55%). 此外, 构成DNA的4种碱基均可以被离子束辐照诱发变异, 而且每一种碱基都可以被其他3种碱基所替换, 但是胸腺嘧啶(T)的辐射敏感性要高于其他3种碱基. 通过分析突变碱基周边序列, 对低能N+离子注入拟南芥突变体引发的碱基突变热点进行了讨论.     

低能N+辐照拟南芥诱导基因组DNA碱基变异分析

用低能N~+离子束注入拟南芥后获得的稳定突变体T80Ⅱ作为实验材料,对突变体植株进行了RAPD标记,并将T80Ⅱ和对照部分RAPD特异条带进行克隆测序和DNA序列分析。结果显示,在可分辨的总计397个RAPD条带中,T80Ⅱ株系中有52个条带表现出差异,包括条带的缺失和增加,条带变异率为13.1％;克隆的T80Ⅱ序列中,平均每16.8个碱基出现1个碱基变异位点,表现出较高频率的碱基突变。碱基突变类型包括碱基的颠换、转换、缺失、插入等。在检测到的275个碱基突变中,主要是单碱基置换(97.09％),碱基缺失或者插入的比例较小(2.91％)。在碱基置换中,转换的频率(66.55％)高于颠换的频率(30.55％)。此外,构成DNA的4种碱基均可以被离子束辐照诱发变异,而且每一种碱基都可以被其他3种碱基所替换,但是胸腺嘧啶(T)的辐射敏感性要高于其他3种碱基。通过分析突变碱基周边序列,对低能N~+离子注入拟南芥突变体引发的碱基突变热点进行了讨论。     

Changes in DNA base sequences in the mutant of Arabidopsis thaliana induced by low-energy N+ implantation

Arabidopsis thaliana (L.) Heynh has many advantages for genome analysis, including a short generation time, small size, large number of offspring, and a relatively small nuclear genome in comparison to other angiosperms and contains a low proportion of repetitive DNA comparatively. Furthermore, the analysis of the completed genome sequence of A. thaliana has been reported[1]. Low-energy ion implantation has attracted more and more attention from researchers in China and Japan since recent s…     

N+注入引起向日葵蛋白质组变异研究初报

低能离子注入可以引起生物DNA分子结构的变异,但用蛋白质组学方法对低能离子注入后所引起的蛋白质诱变效应的研究尚缺乏文献报道。以向日葵种子为实验材料,对N 注入后种子的蛋白质组进行了初步分析,共获得369个蛋白质点,其中包括对照种子中的8个特异点和处理种子中的4个特异点。这些特异点的分子量在15～34ku之间。通过基质辅助激光解吸电离飞行时间质谱鉴定发现对照种子蛋白质中的No.29特异蛋白与MADS盒转录因子HAM59有23．48％的匹配率。处理种子中的No．279特异蛋白与亮氨酸拉链蛋白的同源蛋白HAHB-4有23.20％的匹配率。     

桃中两个MADS box基因的克隆与表达分析

为研究李属(Prunus sp．)果树生殖调控的相关基因,对国际公共数据库中的李属植物的EST(expressed sequence tags)序列进行了电子拼接,获得了8个MADS box基因的cDNA序列,并利用PCR技术从桃中克隆出其中的两个cDNA,分别命名为PpMDS4和PpMADS6,在GenBank中的登录号为AY705972和AY705973。PpMADS4基因长850bp,包含一个732bp的开放阅读框,编码243个氨基酸。PpMADS6基因长1190bp,包含1个768bp的开放阅读框,编码256个氨基酸。PpMADS4和PpMADS6在序列上分别与拟南芥中的AGAMOUS基因和矮牵牛中的PFG基因高度同源。RT-PCR分析表明,PpMADS4基因在桃的花瓣、心皮、果实及果仁中表达,应属于控制花器官发育的C类MADS box基因。PpMADS6基因在桃的叶、萼片、花瓣、心皮及果实中表达,应属于调控植物由营养生长向生殖生长过渡的A类MADSbox基因。     

转甜菜碱醛脱氢酶基因豆瓣菜的耐盐性

将山菠菜甜苹碱醛脱氢酶（ＢＡＤＨ）基因经根癌土壤杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍｅｆａｃｉｅｎｓ （Ｓｍｉｔｈ ｅｔ Ｔｏｗｎｓｅｎｄ）Ｃｏｎｎ）ＡＧＬ１介导转入豆瓣菜（Ｎａｓｔｕｒｔｉｕｍ ｎｏｆｆｉｃｉｎａｌｅ Ｒ,Ｂｒ．）ＰＣＲ、Ｓｏｕｔｈｅｒｊ ｂｌｏｔｉｎｇ检测呈阳性的再生植株有４６株,对６株再生植株的ＢＡＤＨ活性和Ｎｏｒｔｈｅｒｎ ｂｌｏｔｉｎｇ检测发现,有５株ＢＡＤＨ酶活性明