Cloning of a down-regulated gene encoding small GTP binding protein in hybrid wheat

Previous studies showed that differential gene expression between wheathybrids and their parents was responsible for the heterosis. To provide an insight into the molecular basis of wheat heterosis, one cDNA, designated TaRab, was identified from the cDNA library of wheat seedling leaves. The sequence comparison in GenBank revealed that TaRab is homologous to a group of genes encoding Rab-GTP binding protein. Semi-quantitative RT-PCR analysis indicated that TaRab was expressed in all plant tissues examined, but at slightly higher level in leaves. Further analysis exhibited that TaRab displayed lower expression in hybrid than in its patents in both roots and leaves, which was in agreement with the original results of suppression subtractive hybridization. TaRab was located on chromosome 7B and C-7DS5-0.36 by in silico mapping. The relationship between differential expression of TaRab and the molecular basis of wheat heterosis was also discussed.     

β葡聚糖酶杂合基因bglHAM的克隆及在P.pastoris中的表达

采用PCR的方法,以Bacillus macerans总DNA为模板,构建出β-1,3-1,4葡聚糖酶杂合基因bglHAM,与巴斯德毕赤酵母表达载体pPIC9K重组,得到重组质粒pPIC9K-HAM,电脉冲转化法转化酵母菌GS115,KM71,在MM,MD平板上筛选表型,YPD-G418平板上筛选多拷贝重组子,重组菌株经甲醇诱导后,刚果红平板染色法检测到β-葡聚糖酶活性,SDS-PAGE证明表达产物的分子量约为24kD,摇瓶诱导培养筛选到的重组菌株,胞外每mL发酵液最高酶活达240U。     

Relationship between differ- ential gene expression pat- terns in functional leaves of maize (Zea mays L.) at milk filling stage and heterosis using cDNA-AFLP

The genetic mechanism of heterosis has been one of the most challenging subjects in life science since the 20th century. However, because of the complexity of its genetic basis and the limitations of research methods and means, there was no substantial progress in the research of heterosis from the beginning of the 20th century to the 1990s. The development in molecular biology and bio- technology, especially that in quantitative trait loci (QTL) mapping methods, has made it possible to resea…     

利用SSR 标记正确判断小麦杂交种中的杂株

 正确判断杂交种中混有的杂株, 是准确鉴定小麦杂交种种子纯度的前提。在分析180 份杂交组合的基础上, 以“京麦1100”为例, 提出了利用SSR 标记正确判断小麦杂交种中杂株的方法:1)筛选双亲间有多态性的引物不少于5 对;2)利用该引物检测亲本及杂交种的基因型, 并按照杂交种基因型记录原则记录每个个体的基因型;3)正确判断真实杂交种基因型:不论亲本是否存在非纯合位点现象, 只要某个体同时具备父母本的基因型, 均视为真实杂交种的基因型;4)判断杂株:当某个体在多个SSR 位点上与真实杂交种基因型不同时, 判断为杂株。     

Relationship between differential gene expression patterns in functional leaves of maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) at milk filling stage and heterosis using cDNA-AFLP

To understand the molecular mechanism of maize heterosis ,differential gene expression patterns in the functional leaves of 35 maize hybrids relative to their parents involving 10 elite inbreds at milk filling stage were analyzed hy using cDNA-AFLP,the correlation analyses of various differential expression patterns with the performance and heterosis of main maize agronomic traits were evaluated.The main results were as follows:For uniparental specific expression ,significant positive correlations were detected with the performance of seed weight per ear and 100-seed weight at 0.01 and 0.05 probability levels respectively.For biparental specific expression ,significant negative correlations were detected with the performance of ear diameter and seed weight per ear at 0.01 probability level .For uniparental specific expression ,significant positive correlations were detected with the heterosis of ear diameter and seed weight per ear at 0.01 and 0.05 probability levls rspectively,For biparental specific expression .significant negtive correlation was detected with theheterosis of ear diameter at 0.05 probability level ,However,for F1-spectific expression,for fragments detected only in one parent and F1,and for fragments detected only in two parents or only in F1,no significant correlation was detected with the performance or heterosis of all agronomic traits surveyed.     

Research and application of hybrid wheat in China

Hybrid wheat is recognized as a preferred approach to improve wheat yield,and it will be a competi-tion focus in high-tech seed industry in the future. We have made a breakthrough for the first time in...     

The relationship of differential expression of genes in GA biosynthesis and response pathways with heterosis of plant height in a wheat diallel cross

Heterosis in internode elongation and plant height is commonly observed in hybrid plants, but the molecular basis for the increased internode elongation in hybrids is unknown. In this study, midparent heterosis in plant height was determined in a wheat diallel cross involving 16 hybrids and 8 parents, and real-time PCR was used to analyze alterations in gene expression between hybrids and parents. Significant heterosis of plant height and the first internode in length were observed for all 16 hybrids, but the magnitude of heterosis was variable for different cross combinations. Analysis revealed that the heterosis of the first internode was significantly correlated to that of plant height （r = 0.56, P 〈 0.05）, suggesting that the increased elongation of the first internode is the major contributor to the heterosis in plant height. Real-time PCR analysis exhibited that significant difference in heterosis of gene ex- pression was observed among all cross combinations. Moreover, heterosis of the first internode in length was correlated significantly and positively with expression heterosis of KS, GA3ox2-1, GA20ox2, GA20ox1D, GA-MYB and GID1-1, but significantly and negatively with expression heterosis of GAI and GA2ox-1, which is consistent with our recently proposed model of GAs and heterosis in wheat plant height, suggesting the alteration of GA biosynthesis and response pathways might be responsible for the observed heterosis in plant height.     

Analysis of IGF2 mRNA expression and its methylation status between cattle yaks and their parents

s irrelevant to the lower expression of IGF2 in cattle yaks;other factors perhaps play roles in its expression.     

3-酮基嘌呤还原酶(TSC10)表达载体的构建及其在毕赤酵母中的表达

目的：Tsc10基因所编码的3-酮基嘌呤还原酶是酵母中神经酰胺合成的重要因子,本文研究从酵母中提取神经酰胺经济、便捷、高效的方法。方法：1.利用构建含有tsc10基因的毕赤酵母GS115表达载体pPIC3.5K-tsc10。2.电转化法将该表达质粒转化到GS115感受态细胞中。3.用G418筛选以及PCR鉴定。4.使用qRT-PCR和SDS-PAGE进行检测。结果：经过G418筛选以及PCR鉴定后确定获得了包含tsc10基因的毕赤酵母转化子,经过qRT-PCR和SDS-PAGE进行检测后发现tsc10基因在20个阳性菌株中均可以稳定、高效表达。结论：本方法成功构建了3-酮基嘌呤还原酶高表达的毕赤酵母菌株,并为后续获得高收率神经酰胺奠定了基础。     

High expression of EPO gene using un-dhfr negative cell

Erythropoietin (EPO) genomic gene was cloned and its expression vector pOP13/EPO was constructed. CHO_K12 cell was transfected by this vector using lipofectin method. A stable expression cell strain C10 cell with the EPO production at 160IU/d in 10\+6 cells were obtained at 400 μg/mL G418. Based on the C10 cell, another vector pHY/dhfr (dihydrofolate reductase) that carries a dhfr gene and a selecting marker of hygromycin B resistant gene was transferred to this cell. Several cell clones were obtained at 200 μg/mL hygromycin B. These cell clones that can express both EPO gene and exogenous dhfr gene were selected under the progressively increased concentration to 1 μmol methotrexate(MTX). Some high EPO expression cell clones were obtained, the highest expression was 2 400 IU/d in 10\+6 cells, 15 times higher than that without MTX pressure. Then, a method of EPO high expression by using un_dhfr negative cell was primarily established. EPO bioactivity was found by using TF_1 cell.     

亚种间杂交稻根系伤流强度变化动态及影响因素

以亚种间杂交稻为材料 ,研究了在不同生育期及不同处理条件下其根系伤流强度的变化 ,认为根系伤流量的变化可以很好地反映稻株根系活力在品种及生育进程上的差异 ,并指出亚种间杂交稻根系活力的衰退主要发生在灌浆中后期     

拟南芥HIS1-3基因克隆及表达载体构建

文章提取拟南芥植株总RNA,通过RT-PCR扩增出HIS1-3基因的cDNA片段,连接到pEASY-T1Simple载体上,转化到Trans1-T1感受态细胞内,筛选阳性单克隆并抽提质粒。利用限制性内切酶Eco91Ⅰ和NcoⅠ对质粒pEASY-T1-HIS1-3和植物表达载体pCAMBIA2301进行完全双酶切,通过电转化法,将重组表达载体pCAMBIA2301-HIS1-3导入根癌农杆菌C58中以期获得携带HIS1-3基因的根瘤农杆菌株,为研究HIS1-3基因的抗逆分子机理以及遗传改良作物抗逆性奠定了基础。     

高丹草及其亲本种子胚差异蛋白质组学分析

 高丹草是综合高粱和苏丹草双亲优良性状的一年生禾本科饲草,其杂种优势特别明显,但杂种优势形成机理还不明确。为了揭示高丹草杂种优势形成机理,本研究以杂种高丹草及其亲本的成熟胚为试材,利用Label free结合质谱技术,采用生物信息学分析方法在蛋白质组学水平进行研究。研究结果鉴定出差异蛋白124个,其中加性积累蛋白48个,占差异蛋白总数的38.71%,加性积累蛋白中上调蛋白19个,下调蛋白29个。鉴定出非加性积累蛋白为76个,占差异蛋白总数的61.29%,非加性积累蛋白的表达模式以超高亲表达所占比例最大（29个）,其次是偏高亲表达模式（18个）,偏低亲表达模式次之（14个）,另外还有超低亲表达模式（10个）,以及不属于该四种表达模式蛋白5个,因此,加性积累蛋白在高丹草成熟胚杂种优势形成上起主导作用。加性与非加性积累蛋白涉及多个功能组,主要是胁迫响应、碳水化合物代谢、转录调控、发育调控、信号转导、蛋白质代谢等功能类别。     

Generation of transgenic wheat resistant to wheat yellow mosaic virus and identification of gene silence induced by virus infection

The plasmid containing the promoter Act1, the coat protein (cp) gene of wheat yellow mosaic virus (WYMV) and the selectable bar gene, was delivered via particle bombardment, directly into immature embryos of a wheat cultivars. PCR and PCR-RFLP were employed to screen the existence of the cp gene in T0 and T1 generations. Seeds from the positive T1 plants were sowed in fields heavily contaminated with WYMV to detect their resistance. In field trial of virus infection, one of the transgenic wheat lines, P8-T2, exhibited highly disease-resistance. Western blot and RT-PCR analysis showed that the expression level of cp gene in the resistant transgenic line was reduced greatly compared to those susceptible to WYMV infection. This provided evidence to presume that the resistance obtained by the transgenic wheat line was stimulated by the mechanism of the virus induced gene silencing.     

Molecular mapping of a novel yellow rust resistance gene of wheat using microsatellite markers

Identification and genetic analysis of yellow rust resistance have suggested that wheat line R55 carries single dominant gene conferring yellow rust resistance. The bulked segregant analysis (BSA) for an F₂ population using microsatellite marker technique has indicated that the yellow rust resistance gene is located on the short arm of chromosome 1B, tightly linked to the microsatellite markers WMS11-193 bp and WMS18-184 bp, the linkage distance between the markers and the gene is 1.9 cM. This gene has been formally namedYr26. It is inferred from the pedigree, resistance and gene locus analysis that theYr26 has been transferred fromTriticum turgidum L. and is different from the other known yellow rust resistance genes.