籼粳交组合培矮64S/ 日本晴F2、F3 及F6 代主要农艺性状分析

采用方差分析和相关分析等方法对籼粳交组合培矮64S/日本晴F2、F3及 F6代分蘖数、有效分蘖数和株高等7个主要农艺性状进行了研究。结果表明, 7个农艺性状在双亲之间均存在显著或极显著差异, 亲本在不同年份和不同地点表现出较大差异, 株高表现变异系数较大, 分别为14.4%和22.8%。各性状在3个世代中除了F2分蘖率、F3齐穗期和F6株高, 其余各性状均呈连续变异, 分布频率大致接近正态分布, 同时存在双向超亲分离现象。各性状不同世代相关系数有一定的变化, 但不改变其方向。这些结果可以为水稻数量性状基因座分析提供有价值的信息, 也可为水稻遗传改良提供理论依据; 本文还对选用测序水稻品种为亲本构建群体进行农艺性状研究的意义进行了讨论。     

培矮64S/爪哇稻F1农艺性状表现和对照优势分析

本文报道了利用原始爪哇稻资源与光温敏雄性不育系培矮64S配制的27个籼爪交组合在长沙的农艺性状和杂种优势表现.从总体上来看,籼爪交组合与对照相比在每穗实粒数和理论产量上无显著差异,在其它性状上均有极显著的差异;籼爪交组合在秆高、穗长、每穗总粒数、每穗实粒数和千粒重方面有正向对照优势,在播始历期、有效分蘖数、结实率、理论产量和实际产量上存在负向对照优势.从个体上来看,籼爪交组合理论产量对照优势＞40%的比例为11.1%.实际产量对照优势＞40%的机率为3.7%,说明爪哇稻资源在籼爪交杂种优势利用中具有利用价值.本文还对爪哇稻资源在籼爪杂种优势利用中的一些问题进行了讨论.     

用微卫星DNA标记分析水稻"培矮64S/Nipponbare"F2、F6群体的遗传结构

群体的构建与遗传结构分析是利用该群体开展进一步研究的基础。选用157对均匀分布在水稻12条染色体上且在双亲间具有多态性的微卫星标记分别对"培矮64S/Nipponbare"F_2群体(180个株系)和F6群体(330个株系)进行分析,分别对单个微卫星位点的群体分布、株系的遗传成分以及纯合进度进行分析。结果表明:各遗传位点和各株系的遗传成分表现连续分布,一些位点呈显著或极显著偏分离,双亲对株系呈不同的遗传贡献率,某些株系对亲本具有偏爱性;各位点和株系的纯合进度呈连续分布,分别与F_2、F_6杂异位点呈极显著正、负相关。这将有助于我们充分的认识籼粳交后代群体遗传结构特征,并为群体结构优化提供依据。     

Identification of Quantitative Trait Loci for Bacterial Blight Resistance Derived from Oryza meyeriana and Agronomic Traits in Recombinant Inbred Lines of Oryza sativa

Bacterial blight (BB) is one of the major diseases that affect rice productivity. In previous studies, BB resistance was transferred to cultivated rice Oryza sativa from wild rice Oryza meyeriana using asymmetric somatic hybridization. One of the resistant hybrid progenies (Y73) has also been shown to possess novel resistance gene(s) different from any of those previously associated with BB resistance. We have mapped quantitative trait loci (QTLs) for BB resistance in a recombinant inbred line (RIL) population derived from a cross between Y73 and a BB‐susceptible cv. IR24. Five QTLs were detected where Y73 alleles contributed to increased BB resistance. Three minor QTLs were identified on chromosomes 3, 10 and 11, and two major QTLs on chromosomes 1 and 5, respectively. QTL on chromosome 5, designated qBBR5, had the strongest effect on BB resistance, explaining approximately 37% of the phenotypic variance. Using the same RIL population, we also mapped QTLs for agronomic traits including plant height (PH), heading date (HD), plant yield (PYD) and PYD component traits. A total of 21 QTLs were identified, of which four were detected for PH, six for HD, three for panicle number per plant (PNPP), one for spikelets per panicle (SPP), six for 1000‐grain weight (TGW) and one for PYD. qPH1 (a QTL for PH) was found in the same interval as qBBR1 for BB resistance, and qHD11 for HD and qBBR11 for BB resistance also shared a similar interval. Additionally, BB resistance was significantly correlated with PH or HD in the RIL population. This suggests that the resistance genes may have pleiotropic effects on, or close linkage to, genes controlling PH or HD. These results will help deduce the resistance mechanisms of the novel resistance gene(s) and provide the basis for cloning them and using them in marker‐assisted breeding.     

水稻F2不育和抽穗期QTL分析

对台中65（粳稻）/Bhadua（籼稻）杂交F2代群体构建了RFLP连锁图谱,含94个分布较为均匀的标记。对F2小穗不育性状进行单点分析和区间分析的结果基本一致：有两个F2小穗不育QTL座位分别位于染色体1的XNpb113～XNpb346之间和染色体8的G187～XNpb397之间,而且该两个QTL均为新检测出的座位;检测出5个抽穗期TQL,其中3个座位在单点分析和区间分析中的结果一致,分别位于染色体1的XNpb113～XNpb346,染色体4的C891～C335,染色体的8的C166～C1121,另外,染色体6的XNpb27为单点分析结果,染色体10的R716～C405为区间分析结果。由于染色体1上的F2不育QTL和抽穗期QTL重叠,该QTL座位是由于遗传效应所至还是由于环境因素（迟抽穗）所至有待构建近等基因系进一步研究。;位于染色体1和10上的抽穗期QTL座位为新检测的座位。对新检测的F2不育和抽穗期QTL座位正在建立相应的近等基因系以精确定位和克隆上述基因。     

小麦抗病基因Lr46/Yr29/Pm39、Sr2/Yr30和Lr68的遗传特性及其与主要农艺性状的关联分析

利用与抗病基因Lr46/Yr29/Pm39、Sr2/Yr30和Lr68等紧密连锁的分子标记,对小麦品种(系)‘RL6077’和‘西农979’构建的BC1F1和F2群体进行抗病基因遗传分析,结合主要农艺性状分析,探究小麦抗病基因Lr46/Yr29/Pm39、Sr2/Yr30和Lr68的遗传特性及其与主要农艺性状的关联性;并对检测的聚合有3个抗慢锈病基因(Lr68+Sr2/Yr30+Lr46/Yr29/Pm39)位点的聚合体进行SSR标记遗传背景回复率检测。结果表明:(1)F2群体中Lr68基因的传递率(65.41%)比理论值(75%)偏低,Lr46/Yr29/Pm39基因和Sr2/Yr30基因的传递率(分别为75.83%、74.53%)与理论值(75%)相符合;BC1F1群体中Lr68基因的传递率(44.27%)比理论值(50%)偏低,Lr46/Yr29/Pm39基因和Sr2/Yr30基因的传递率(分别为56.64%、55.11%)均比理论值(50%)偏高。(2)Lr46/Yr29/Pm39和Sr2/Yr30基因位点均与株高、穗长、穗下茎长、穗下节长呈极显著正相关关系;Lr68和Sr2/Yr30基因位点均与穗粒数呈显著或极显著正相关关系;Lr46/Yr29/Pm39基因位点与千粒重呈显著负相关、与单株成穗数呈显著正相关关系。(3)对BC1F1群体中聚合有Lr68+Sr2/Yr30+Lr46/Yr29/Pm39基因位点的92个聚合体的遗传背景回复率检测发现,轮回亲本‘西农979’遗传背景回复率最高达91.67%,其中遗传回复率达90%以上的聚合体有3株,占回交群体(655株)总体的0.46%。该研究结果为优异抗病基因资源‘RL6077’的进一步利用提供了理论参考,对创制小麦多种抗病新种质具有重要意义。     

粳稻龙锦1号/香软米1578杂交组合F_5家系群糙米总花色苷含量变异及相关性分析

随着环境污染加剧和人们对自身健康关注度的提高,功能性食品在全球范围内蓬勃发展。彩色稻米作为稻米家族中的一员,由于富含微量元素、花色苷、生物碱等功能性成分,已成为当前功能性食品研究开发的热点之一。本研究利用粳稻品种龙锦1号/香软米1578杂交组合214个F_5家系,对水稻糙米总花色苷含量、粒色等级和千粒重的变异及其相关性进行了分析。糙米粒色等级变异范围为1~9,平均值为4.98,变异系数为57.87%;糙米总花色苷含量变异范围为0~5459.34 mg/kg,平均值为834.47 mg/kg,变异系数为191.96%;糙米千粒重变异范围为11.96~26.24 g,平均值为17.75 g,变异系数为12.89%。糙米总花色苷含量、粒色等级和千粒重在F5家系中不符合正态分布,表现为右偏态,其中糙米总花色苷含量的偏斜程度最大。糙米总花色苷含量和千粒重的峰度系数为正值,表明为尖顶峰;而糙米粒色等级的峰度系数为负值,表明为平顶峰。糙米总花色苷含量与粒色等级呈极显著正相关,相关系数为0.69;糙米总花色苷含量、粒色等级均与千粒重呈极显著负相关,相关系数分别为-0.20和-0.34。与高亲龙锦1号相比,27个家系的糙米总花色苷含量极显著提高,占214个F_5家系的12.62%,为高花色苷水稻种质创新奠定了基础。     

Monoallelic intragenic POU3F2 variants lead to neurodevelopmental delay and hyperphagic obesity,confirming the gene’s candidacy in 6q16.1 deletions

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航天诱变水稻抗褐飞虱新种质的培育、遗传分析与生物学特性

利用"实践八号"育种卫星搭载"玉香油占"干种子,在褐飞虱爆发条件下,从M2代中首次获得农艺综合性状优良的抗褐飞虱水稻突变体PR955。遗传分析表明,PR955的抗褐飞虱性状受1对显性基因控制。米质检测分析表明,PR955的出糙率、精米率、整精米率均达国家一等优质米标准,综合评定为二等优质米。     

Redox Properties of Iron in the Binding Site(s) of F1ATPase from Mammalian Mitochondria and Thermophilic Bacterium PS3: A Comparative Study

Iron ions in the two iron centers of beef heart mito-chondrial F, ATPase, which we have been recently characterized (FEBS Letters 1996,379, 231-235), exhibit different redox properties. In fact, the ATP-dependent site is able to maintain iron in the redox state of Fe(II) even in the absence of reducing agents, whereas in the nucleotide-independent site iron is oxidized to Fe(III) upon removal of the reductant. Fe(III) ions in the two sites display different reactivity towards H₂O₂, because only Fe(III) bound in the nucleotide-independent site rapidly reacts with H₂O₂ thus mediating a 30% enzyme inactivation. Thermophilic bacterium PS3 bears one Fe(III) binding site, which takes up Fe(III) either in the absence or presence of nucleotides and is unable to maintain iron in the redox state of Fe(II) in the absence of ascorbate. Fe(III) bound in thermophilic F₁ATPase in a molar ratio 1:1 rapidly reacts with H₂O₂ mediating a 30% enzyme inactivation. These results support the presence in mitochon-drial and thermophilic F₁ATPase of a conserved site involved in iron binding and in oxidative inactivation, in which iron exhibits similar redox properties. On the other hand, at variance with thermophilic F₁ATPase, the mitochondrial enzyme has the possibility of maintaining one equivalent of Fe(II) in its peculiar ATP-dependent site, besides one equivalent of Fe(III) in the conserved nucleotide-independent site. In this case mitochondrial F, ATPase undergoes a higher inactivation (75%) upon exposure to H₂O₂. Under all conditions the inactivation is significantly prevented by PBN and DMSO but not by Cu, Zn superoxide dis-mutase, thus suggesting the formation of OH radicals as mediators of the oxidative damage. No dityrosines, carbonyls or oxidized thiols are formed. In addition, in any cases no protein fragmentation or aggregation is observed upon the treatment with H₂O₂.     

Isolation and Expression Analysis of Plastidic Glucose-6-phosphate Dehydrogenase Gene from Rice (Oryza sativa L.)

Glucose-6-phosphate dehydrogenase is a rate-limiting enzyme of pentose phosphate pathway, existing in cytosolic and plastidic compartments of higher plants. A novel gene encoding plastidic glucose-6-phosphate dehydrogenase was isolated from rice (Oryza sativa L.) and designated OsG6PDH2 in this article. Through semiquantitative RT-PCR approach it was found that OsG6PDH2 mRNA was weakly expressed in rice leaves, stems, immature spikes or flowered spikes, and a little higher in roots. However, the expression of OsG6PDH2 in rice seedlings was significantly induced by dark treatment. The complete opening reading frame (ORF) of OsG6PDH2 was inserted into pET30a (+), and expressed in Escherichia coli strain BL21 (DE3). The enzyme activity assay of transformed bacterial cells indicated that OsG6PDH2 encoding product had a typical function of glucose-6-phosphate dehydrogenase.