一个籼稻脆性突变体的生物学特性及基因定位研究

水稻脆性突变体是研究细胞壁组分结构形成机制的重要材料。通过离子束诱变籼稻9311获得1个茎秆、叶片均脆的突变体,命名为bc9311-1。bc9311-1突变体与野生型9311相比,分蘖数减少,结实率显著降低,其他农艺性状无明显差异。叶片和茎秆的细胞壁成分分析表明,与野生型相比,bc9311-1突变体茎秆中的纤维素和木质素含量明显降低,半纤维素和SiO2含量显著增加;叶片中的纤维素含量降低,半纤维素和木质素含量增加,SiO2含量无明显差异。遗传分析表明,该脆性突变体脆性性状受单隐性基因控制。以bc9311-1突变体与02428杂交的F2群体为基因定位群体,利用SSR标记将bc9311-1突变位点定位在水稻第1染色体上,位于SSR分子标记的RM1095和RM3632之间,遗传距离分别为0.6cM和3.4cM,与其中的标记RM1183表现共分离。这些结果为进一步克隆突变基因,揭示脆性性状的分子机制奠定坚实基础。     

水稻多分蘖矮秆突变体htd1-2的遗传分析和基因定位

文章所采用的多分蘖矮秆突变体为htd1-2(high-tillering dwarf 1-2), 是野生型籼稻品种9311经350Gy的60Co- g射线辐射处理后产生的后代中选育出来的稳定多分蘖矮秆突变体。遗传分析表明, 突变体htd1-2多分蘖矮秆性状是由一对隐性核基因的突变造成的。文章利用简单重复序列(Simple sequence repeat, SSR)、酶切扩增多态性序列(Cleaved amplified polymorphic sequence, CAPS)和衍生型CAPS(derived CAPS, dCAPS)等分子标记的方法, 最终将多分蘖矮秆基因HIGH-TILLERING DWARF1-2(HTD1-2)定位在水稻第4号染色体116 kb的物理区间内。在该物理区间内有一个已经克隆的控制水稻分蘖的基因HIGH-TILLERING DWARF1(HTD1), 经过测序比对和dCAPS特异性分析, 认为HTD1就是HTD1-2基因。尽管突变体htd1与突变体htd1-2是等位基因的不同位点发生突变, 但是由于遗传背景的不同, 两者表型并不完全相同。此外, 通过去除分蘖芽的实验证明了突变体htd1-2的矮化部分是由于分蘖过多造成的。     

Global gene expression analysis of a rice high-tillering dwarf mutant

Plant height and tiller number are indispensible for the establishment of grain production in rice (Oryza sativa L.). A new rice mutant high-tillering dwarf 3 (htd3) exhibiting more tiller number and shorter culm length than the wild-type Guichao 2 (GC2, an indica cultivar) was used to investigate the global gene expression patterns at days after germination 25 (DAG25) and DAG60. In this study, we identified 305 and 987 genes with at least twofold change in gene expression level at DAG25 and DAG60 respectively using the rice microarray chip. Gene ontology enrichment analysis of these twofold change regulated genes revealed that large numbers of genes were involved in binding activity, catalytic activity and metabolic process. The chip results also showed that some of the regulated genes involved in diverse molecular pathways, including gibberellin pathway, brassinosteroid pathway and auxin signal, had significant differences in gene expression abundance at DAG60. This genome-wide gene expression analysis could provide a new opportunity to uncover the regulation mechanisms of the development of culm and tiller, two important components of yields in rice.     

水稻多分蘖突变体ht1的遗传分析和分子定位

在水稻品种新稻18中发现了一个多分蘖植株,经过多代自交获得了稳定的多分蘖突变株,突变体ht1在整个生育期最显著的特点就是分蘖数目多,是其野生型新稻18的3倍以上.遗传分析表明该基因受1对显性核基因控制,命名为HT1.利用微卫星标记将HT1初步定位于第10号染色体RM25435和RM25552之间,进一步利用极端个体定位法把HT1精细定位于标记RM25523和RM25532之间,HT1基因距它们的遗传距离均为0.05 cM,这两标记问的物理距离约为130kb.     

特矮稻ED基因的遗传定位和分析

赤霉素（GA3）鉴定表明,一种新型特矮稻（命名为‘特矮稻-2’）的GA3信号转导途径正常,施加外源GA3不能恢复到正常植株的高度,说明此种矮稻的矮化机制与GA3无关。来源于组合‘特矮稻-2’ב日本晴’的F2群体的遗传分析表明,‘特矮稻-2’的特矮性状受1对隐性基因控制。采用SSR分子标记,将该矮秆基因定位于第12染色体上的RM519和RM235标记之间,遗传距离分别为15.9和22.0cM,该基因暂命名为ED。     

一份新型水稻极度分蘖突变体的遗传分析及分子标记定位

在三系杂交水稻保持系绵香1B（M1B）和一个雄性不育材料GMS-1的杂交后代中发现一株极度分蘖突变体（命名为ext．M1B）,其分蘖数为121。对ext-M1B与5个正常分蘖水稻品种杂交F1和F2代的遗传分析表明,ext-M1B的极度分蘖特性受一对隐性核基因控制。以2480B／ext-M1B的F2代作定位群体,用分子标记将ext-M1B的突变基因定位于水稻第6染色体短臂,该基因与微卫星标记RM197、RM584和RM225的遗传距离分别为3．8cM、5．1cM和5．2cM,认为ext-M1B突变基因是一个新的水稻极度分蘖基因,暂命名为ext-M1B（t）。     

矮泰引-3中半矮秆基因的分子定位

矮泰引-3的矮生性状受两对独立遗传的半矮秆基因控制,利用SSR标记将这两个矮秆基因分别定位到第1和第4染色体上。等位性测交的结果表明,位于第1染色体上的矮秆基因与sd1是等位的,所以仍然称其为sd1;而位于第4染色体上的矮秆基因是一个新基因,暂命名为sdt2。利用SSR标记将sd1定位于RM297、RM302和RM212的同一侧,而与OSR3共分离,它们之间的位置关系可能是RM297-RM302-RM212-OSR3-sd1,遗传距离分别为4．7cM、0cM、0．8cM和0cM,这与sd1在第1染色体长臂上的确切位置是基本一致的。利用已有的SSR标记和拓展的SSR标记将sdt2定位于SSR332、RM1305和RM5633、RM307、RM401之间,它们的排列位置可能是SSR332-RM1305-sdt2-RM5633-RM307-RM401,它们之间的遗传距离分别为11．6cM、3．8cM、0．4cM、0cM和0．4cM。     

Genetic Analysis and Molecular Tagging on a Novel Excessive Tillering Mutant in Rice

A rice (Oryza sativa L.) mutant with an excessive tiller number, designated ext-M1B, was found in the F₂ progenies generated from the cross between M1B and GMS-1 (a genetic male sterile), whose number of tillers was 121. The excessive tillering mutant also resulted in significant changes in plant height, flag leaf, stem, filled grains per panicle, and productive panicles per plant. The inbreeding progenies of ext-M1B exhibited the same mutant phenotype. The crosses from ext-M1B/M1B, M1B/ext-M1B, 2480B/ext-M1B, D62B/ext-M1B, G46B/ext-M1B, and G683B/ext-M1B expressed normal tillering in F₁, and segregated into two different phenotypes of normal tillering type and excessive tillering type in a ratio of 3:1 in F₂. Inheritance analysis indicated that the excessive tillering character was controlled by a single recessive nucleic gene. By BSA (bulked segregants analysis) and microsatellite makers with the F₂ population of 2480B/ext-M1B as the mapping population, RM197, RM584, and RM225, all of which were located on the short arm of rice chromosome 6, were identified to be linked with the excessive tillering gene with genetic distance of 3.8 cM, 5.1 cM, and 5.2 cM, respectively. This gene is probably a new excessive tillering gene in rice and is designated tentatively ext-M1B (t).     

Characterization of a common wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) high-tillering dwarf mutant

Key message

A novel high-tillering dwarf mutant in common wheat Wangshuibai was characterized and mapped to facilitate breeding for plant height and tiller and the future cloning of the causal gene.

Abstract

Tiller number and plant height are two major agronomic traits in cereal crops affecting plant architecture and grain yield. NAUH167, a mutant of common wheat landrace Wangshuibai induced by ethylmethyl sulfide (EMS) treatment, exhibits higher tiller number and reduced plant height. Microscope observation showed that the dwarf phenotype was attributed to the decrease in the number of cells and their length. The same as the wild type, the mutant was sensitive to exogenous gibberellins. Genetic analysis showed that the high-tillering number and dwarf phenotype were related and controlled by a partial recessive gene. Using a RIL_2:6 population derived from the cross NAUH167/Sumai3, a molecular marker-based genetic map was constructed. The map consisted of 283 loci, spanning a total length of 1007.98 cM with an average markers interval of 3.56 cM. By composite interval mapping, a stable major QTL designated QHt.nau-2D controlling both traits, was mapped to the short arm of chromosome 2D flanked by markers Xcfd11 and Xgpw361. To further map the QHt.nau-2D loci, another population consisted of 180 F₂ progeny from a cross 2011I-78/NAUH167 was constructed. Finally, QHt.nau-2D was located within a genetic region of 0.8 cM between markers QHT239 and QHT187 covering a predicted physical distance of 6.77 Mb. This research laid the foundation for map-based cloning of QHt.nau-2D and would facilitate the characterization of plant height and tiller number in wheat.

     

水稻粒长基因GL3的遗传分析和分子标记定位

为了解析水稻粒长的遗传机制,以大粒水稻品种‘80018-TR161-2-1’和小粒水稻品种‘日本小黑稻’及其F2代200个株系和F2：3家系为材料,分析水稻粒长的遗传学性状。结果表明,谷粒长度的分离比在F2及F2：3家系中都表现为3：1,长粒性状受1对隐性核基因控制,命名为GL3。用简单重复序列（simple sequence repeat,ssR）分子标记结合群体分组混合分析的方法,将此种基因定位在水稻第3号染色体上SSR标记PSM379和RM16之间,它们的遗传距离分别为4．0cM和11．2cM。     

萍乡显性核不育水稻育性相关基因的定位和遗传分析

萍乡显性核不育水稻(Pingxiang Dominant Genic Male Sterile Rice,PDGMSR)是在水稻中首次发现的显性核不育材料,其育性由两对显性基因互作控制,一对是萍乡显性核不育基因Ms-p,另一对是显性上位恢复基因(dominant epistatic fertility restorer gene,Rfe)。两者共同存在时显性上位恢复基因能抑制不育基因的表达,从而使育性表现可育。本实验用一个对萍乡显性核不育水稻有恢复能力的水稻品种E823与萍乡显性核不育水稻配制杂交组合,将(萍乡核不育水稻/E823)F2作为定位群体,根据F3株系的育性分离,选择育性分离株系对应F2单株(基因型为Ms-pMs-pRefrfe和Ms-pms-pRferfe)构建可育池,用对应F2株系中的不育单株(基因型为Ms-pMs-prferfe或Ms-pms-prferfe)构建不育池,将显性上位恢复基因Rfe定位在水稻10染色体RM311和RM3152一侧,遗传距离分别为7.9cM和3.6cM。根据已有的Ms-p的定位结果,合成10染色体部分微卫星引物,对不育单株进行分析,发现RM171和RM6745位于Ms-p的两侧,距离分别为0.3cM和3.0cM。根据10染色体的测序结果,将Ms-p界定在约730kb的范围内,并构建了Ms-p的电子重叠群。植物显性核不育的育性恢复机理存在“复等位基因”和“显性上位互作”两种假说,贺浩华等用经典的遗传学方法证明了萍乡显性核不育水稻育性恢复的遗传机理属于“显性上位互作”。理论上认为,确定其遗传机理最为有效的方法是基因定位,如果不育基因和恢复基因位于同一位点,则其遗传机理属于“复等位基因”,否则为“显性上位互作”。本实验将不育基因和恢复基因定位在水稻10染色体不同的位点,用基因定位的方法证实了萍乡显性核不育水稻育性恢复的遗传机理属于“显性上位互作”。     

一个水稻显性高秆突变体的遗传分析和基因定位

从水稻(Oryza sativa L.)的两个半矮秆籼稻品种6442S-7和蜀恢881杂交F2代群体中发现一个高秆突变体D111,其株高和秆长分别比亲本蜀恢881增加63.0%和87.0%.用205个微卫星标记分析D¨1及其原始亲本6442S-7和蜀恢881之间的基因组DNA多态性,结果未发现D111具有2个原始亲本都没有的新带型,证明D1¨的确是6442S-7和蜀恢881的杂交后代发生基因突变产生的.将D111分别与蜀恢881、蜀恢527、明恢63、9311、IR68、G46B等6个半矮秆品种和高秆对照品种南京6号杂交,分析F1和F2代株高的遗传行为,结果表明D1¨的高秆性状由一对显性基因控制,且该基因与南京6号的高秆基因紧密连锁或等位.以蜀恢527/D111 F2群体为定位群体,运用微卫星标记将D111显性高秆突变基因定位于水稻第一染色体长臂,与RM212、RM302和RM472的遗传距离分别是27.7 cM、25.5 cM和6.0 cM,该基因暂命名为LC(t).认为D111是首例从半矮秆品种自然突变产生的水稻显性高秆突变体,LC(t)为首次定位的水稻显性高秆突变基因.此外,将上述基因定位结果与Causse等(1994)和Temnykh等(2000,2001)发表的水稻分子连锁图谱进行比较,发现LC(t)基因恰巧位于与水稻"绿色革命基因"sd1相同或十分相近的染色体区域,因此,还就LC(t)基因与sd1基因之间的可能关系进行了讨论.     

Genetic and Microsatellite Analyses of a New Elongated Uppermost Internode Gene Teui2 of Rice

Two mutants possessing elongated uppermost internode, Xieqingzao eB-1 (XQZeB-1) and Xieqingzao eB-2 (XQZeB-2), were identified from M 2 population of Xieqingzao B-line (XQZB) treated with γ-ray. The proportion of uppermost internode length to entire culm length of XQZeB-2 and XQZeB-1 were 65.3%and 54.8%, respectively. Compared with the original XQZB, the increased length of uppermost internode of XQZeB-2 contributed to the total increased culm length by 90.2% as well as XQZeB-1 by 53.3%. Genetic analysis showed that the characters of elongated uppermost internode in the two mutants were governed by one pair of recessive gene respectively. The recessive gene of XQZeB-1 is allelic to the reported eui , but that of XQZeB-2 is non-allelic to it by allelic test. Therefore, the elongated-uppermost-internode gene of XQZeB-2 is a new gene, designated as eui2. Microsatellite markers RM258, RM269, RM271 and RM304, which were linked with eui2 and located on chromosome 10, were identified. The genetic distances from the four markers to eui2 were 12.0 cM, 12.9 cM, 35.1 cM, 1.4 cM, respectively. It could be concluded that eui2 gene was located on the middle of the long arm of chromosome 10.     

水稻(Oryza sativa L.)苗期低温白化突变体al12的超微结构与基因定位

水稻苗期低温白化突变是水稻在发育早期对低温胁迫的一种适应性,是一种受发育和温度控制的条件表达,它与其他水稻白化突变有本质的不同.本研究利用便携式叶绿素测量仪测定了白化时期植株的叶绿素含量和用透射电镜观察了叶绿体的结构变化.结果发现叶绿素平均含量仅为1.2(SPAD),而叶绿体也不能正常发育仅有囊泡状结构.通过与9311的正反交实验及子代的分离表现证明该性状受一个隐性核基因的控制.另外利用SSR分子标记技术将该基因定位在第8染色体上,两侧最近的SSR标记RM5068和RM3702分别距基因0.5～1.1 cM和4.9 cM,基因被定位在约6个cM的区间内.我们将该基因暂时命名为al12.     

Ultrastructure and Gene Mapping of the Albino Mutant al12 in Rice (Oryza sativa L.)

Seedling albino mutation resistant to low temperature is an adaptability of rice (Oryza sativa L.) to cold. The mutant, a conditional expression controlled by development and temperature, differs from other albino mutants. The chlorophyll content of the mutant was measured using a portable chlorophyll meter, and the ultrastructure of the chloroplast was observed using a transmission electron microscope. Chlorophyll content was 1.2 SPAD, and the chloroplast did not develop, with only small vesicle-like structures. A segregation analysis of the reciprocal crosses between the albino mutation line with the rice line 9311 demonstrated that the albino trait was controlled by a single recessive gene, which was flanked by SSR markers RM5068 and RM3702 on the short arm of chromosome 8 with a distance of 0.5-1.1 cM and 4.9 cM, respectively. This gene was mapped within a 6 cM interval region and was tentatively referred to as al12.     

水稻窄叶突变体nal(t)的表型分析与基因定位

在水稻(Oryza sativa)缙恢10号的EMS诱变群体中发现一个窄叶突变体nal(t), 表现出叶片变窄不变短、植株半矮化、节间变细变短和穗长缩短等特性。突变体苗期和成熟期叶片平均宽度为0.99 cm和1.42 cm, 分别为野生型的76%和74%,均达到极显著差异。nal(t)成熟期倒一、倒二、倒三节间长和宽分别为9.16 cm、6.97 cm、3.57 cm和0.31 cm、0.36 cm、0.45 cm, 仅为野生型的63%、83%、71%和78%、72%、79%。遗传分析表明该突变性状受1对隐性核基因控制, 利用SSR标记将NAL(T)定位在第12染色体长臂RM6869和RM28537之间, 遗传距离分别为3.1 cM和9.0 cM。     

Genetic interaction between 2 tillering genes, reduced culm number 1 (rcn1) and tillering dwarf gene d3, in rice

Mutant genes, reduced culm number 1 (rcn1) and bunketsuwaito tillering dwarf (d3), affect tiller number in rice (Oryza sativa L.) in opposite directions. The d3 mutant was reported to increase tiller number and reduce plant stature. Our objective was to compare the phenotype of the d3rcn1 double mutant with each single mutant and parental rice cultivar "Shiokari" and to clarify whether the Rcn1 gene interacted with the D3 gene. We recovered a new rcn1 mutant from Shiokari and developed d3rcn1 double mutant with Shiokari genetic background. A new rcn1 mutant, designated as "S-97-61" exhibited a reduction in tiller number and plant stature to about the same level as the previously reported original rcn1 mutant. Three near-isogenic lines, rcn1 mutant, d3 mutant, and d3rcn1 double mutant, were grown together with the parental Shiokari. The reduction in tillering by the rcn1 mutation was independent of the d3 genotype, and tillering number of d3rcn1 double mutant was between those of the d3 and rcn1 mutants. These results demonstrated that the Rcn1 gene was not involved in the D3-associated pathway in tillering control.