泡桐丛枝植原体河北平山和江西吉安株系胸苷酸激酶基因多态性分析

设计引物并 PCR扩增河北平山株系 PaWBPs 和江西吉安株系 PaWBJan 的 tmk 基因,直接和克隆测定tmk序列,利用DNAMAN,MEGA等软件进行序列多样性、序列变异、蛋白功能域、系统进化等比较分析。结果表明：从 PaWBPs和 PaWBJan中克隆测序的93条和41条 tmk-a中,分别有52和24种不同的序列,tmk-a ORF 可被划分为2类,tmk-a-1为639 bp,tmk-a-2为627 bp,PaWBPs株系tmk-a-1与tmk-a-2序列条数的比值约为2.5,而PaWBJan株系为3.3; PaWBPs有5个相同的 tmk-a-1序列与 PaWBJan的一个 tmk-a-1序列及枣疯植原体 tmk-Y 序列完全一致。因多位点突变,PaWBPs含假基因比例达48.1%,PaWBJan的为41.7%; tmk-b基因为单一序列,两株系的 tmk-b核酸序列相似性为99.8%,编码蛋白仅有一个氨基酸差异。TMK-a和 TMK-b中都具有胸苷酸激酶的3个保守功能域。系统进化分析显示,泡桐丛枝植原体的2个株系的所有tmk-a序列都与枣疯植原体tmk-X和tmk-Y等聚为一个进化枝Ⅰ中;而tmk-b与小麦蓝矮tmk-2等聚为另一进化枝Ⅲ,基于tmk-b序列和基于16S rDNA序列构建的系统进化树一致,tmk-b有助于植原体16Sr组水平的分类,而 tmk-a可用于植原体株系变异和遗传多样性分析。     

刺槐实时定量PCR分析中内参基因的选择

The real-time PCR is an important method for analyzing gene expression levels. Selection of reference genes suitable for calibration of the expression of objective gene according to specific experiment...     

油茶查尔酮合酶和异构酶基因的cDNA克隆

查尔酮合酶和查尔酮异构酶是类黄酮代谢与色素苷代谢的关键酶.以油茶近成熟种子cDNA文库和EST文库为材料,通过分子克隆方法鉴定了1条查尔酮合酶基因全长cDNA和1条查尔酮异构酶全长cDNA.结果表明:油茶查尔酮合酶基因的cDNA含1479 bp,编码412个氨基酸,为目前最长的查尔酮合酶,与其它物种的查尔酮合酶具有极高的相似性,在进化上高度同源;油茶查尔酮异构酶基因的cDNA含899 bp,编码206个氨基酸,与茶的查尔酮异构酶基因高度同源,但与其它物种的相似性较低.     

Plus tree of Cryptomeria japonica D. Don with a heterozygous male-sterility gene

To find plus tree clones of Cryptomeria japonica that are heterozygous for a male-sterility gene (Aa), we crossed a homozygous male-sterile tree (aa) with 63 clones. Male sterility in this case is controlled by a recessive allele at a single gene locus and is expressed only in homozygotes. All F₁ seedlings obtained by crossing the male-sterile mother tree and 62 out of the 63 clones produced pollen. In contrast, F₁ seedlings obtained from the crossing between the male-sterile mother tree and a plus tree clone, Ohara 13, produced 64 male-sterile individuals and 52 fertile individuals. The segregation ratio fitted the expected 1 : 1 ratio according to a chi-square test. These results clearly demonstrate that the Ohara 13 clone is heterozygous for a male-sterility gene.     

筇竹QtKAT1基因的克隆与表达分析

为探究竹类植物K+调控机理及K+通道的系统,本研究以筇竹(Qiongzhuea tumidinoda)为试验材料,对筇竹QtKAT1基因分离克隆及表达分析.通过克隆获得筇竹QtKAT1基因,全长为3 124bp,含2 235 bp的最大开放阅读框,编码744个氨基酸.生物信息学分析表明QtKAT1基因预测编码蛋白分子质...     

农杆菌介导法将反义蜡质基因转入杂交稻亲本

通过农杆菌介导法将反义蜡质基因导入特青(OryzasativaL.subsp.indica)和广粳1号(OryzasativaL.subsp.japonica)这两个杂交稻亲本的愈伤组织中,获得了经PCR检测证明外源基因已整合进植物基因组中的再生植株,其中含潮霉素抗性基因的植株有6株,但仅有2株能够扩增出反义蜡质基因的特异条带,其原因可能是在转基因植株中出现了基因丢失或沉默现象。试验表明,粳型稻广粳1号的不同外植体(成熟胚、幼胚、幼穗、花药)的愈伤诱导率比特青的高,且随着继代时间的延长,不同基因型水稻诱导的愈伤之间的转化率存在着极显著性差异(P<0.01);经过转染的水稻愈伤在一定的筛选压力下会出现“逃逸”现象,抗性筛选后成活愈伤PCR检测发现广粳1号和特青的愈伤转化率只有44.4%和29.4%;不同凝固剂对愈伤诱导的质量有着明显的影响,植物凝胶作凝固剂比琼脂作凝固剂时的愈伤褐化率低。     

利用Pi-1基因邻近SSR标记鉴定稻瘟病抗性

Pi-1是具有广谱抗性的水稻显性主效抗稻瘟病基因,位于水稻11号染色体末端。本研究选择靠近此处的SSR标记15对,用含有Pi-1基因的Lac23与不含Pi-1基因恢复力强的N优69-1进行检测。检测出有差异条带5对引物,分别为RM224、RM254、RM2136、RM6094和RM6293。另外,以N优69-1为母本,以LAC23为父本进行杂交至F8代群体,利用上述差异分子标记,在F8趋亲单株中选择与Lac23标记一致的单株,与田间稻瘟病鉴定结果相比较。结果显示,RM6293对含有Pi-1基因材料的选育有较大的准确度,其次为RM254RM224RM2136RM6094。本实验与其它研究不同的是采用了F8代群体,认为多次自交重组后的遗传稳定株系才可能得到稳定的标记。     

A high-resolution map of the rice blast resistance gene Pi15 constructed by sequence-ready markers

The gene Pi15 for resistance of rice to Magnaporthe grisea was previously mapped to a ≈0.7-cM region on chromosome 9. To further define the chromosomal region of the Pi15 locus, a contig spanning the locus was constructed, in silico , through bioinformatics analysis using a reference sequence of the cultivar 'Nipponbare'. One simple sequence repeat marker adopted from the International Rice Microsatellite Initiative and six candidate resistance gene (CRG) markers, developed from gene annotation of the reference sequence of the contig, were used for linkage analysis in a mapping population consisting of 504 extremely susceptible F₂ plants. The Pi15 locus was delimited to a ≈0.5-cM region flanked by the markers CRG5 and CRG2 and co-segregated with the markers BAPi15₇₈₂, CRG3 and CRG4, which was physically converted to a 44-kb interval.     

Assessing genetic diversity of sweet potato (Ipomoea batatas (L.) Lam.) cultivars from tropical America using AFLP

The sweet potato genebank at the International Potato Center (CIP) maintains 5,526 cultivated I. batatas accessions from 57 countries. Knowledge of the genetic structure in this collection is essential for rational germplasm conservation and utilization. Sixty-nine sweet potato cultivars from 4 geographical regions (including 13 countries) of Latin America were randomly sampled and fingerprinted using AFLP markers. A total of 210 polymorphic and clearly scorable fragments were generated. A geographic pattern of diversity distribution was revealed by mean similarity, multidimensional scaling (MDS), and analysis of molecular variance (AMOVA). The highest genetic diversity was found in Central America, whereas the lowest was in Peru-Ecuador. The within-region variation was the major source of molecular variance. The between-regions variation, although it only explains 10.0% of the total diversity, is statistically significant. Cultivars from Peru-Ecuador, with the lowest level of within region diversity, made the most significant contribution to the between region differentiation. These results support the hypothesis that Central America is the primary center of diversity and most likely the center of origin of sweet potato. Peru-Ecuador should be considered as a secondary center of sweet potato diversity.     

Residual effects of the Xa-4 resistance gene in three rice cultivars when exposed to a virulent isolate of Xanthomonas campestris pv. oryzae

Summary F₂ plants of five, and F₃ plants of three, crosses between genotypes carrying the race-specific resistance gene Xa-4 and genotypes not carrying this gene were inoculated with two isolates of Xanthomonas campestris pv. oryzae. Half the tillers of each plant received isolate PX061, avirulent on the Xa-4 gene, the other half of the tillers received isolate PX099, virulent for the Xa-4 gene. The F₂ and F₃ populations segregated for a single dominant resistance gene, Xa-4.The parental, F₂ and F₃ genotypes not carrying Xa-4 had mean lesion lengths between 28 and 29 cm for both isolates. The Xa-4 carrying parents showed a mean lesion length of 2.7 cm with the avirulent isolate and of 12.4 cm with the virulent isolate. The Xa-4 carrying F₂ and F₃ genotypes had mean lesion lengths of 5.2 and 20.1 cm for the two isolates, respectively. These observations strongly indicate that the Xa-4 gene, carried by the rice genotypes studied (IR28, Cisadane and BR51-282-8), had a considerable residual effect when exposed to virulent isolate PXO99.