水稻端四体的分子细胞学鉴定及染色体行为分析

在水稻品种中籼3037第9染色体短臂端三体的自交后代中发现了一个变异株。该植株叶片内卷,株型偏散,结实率差。分子细胞学鉴定表明,该植株体细胞染色体数比正常植株多2条,多出的染色体均比较小。进一步用来源于水稻着丝粒特异DNA序列（RCS2）以及位于水稻第9染色体短臂上的特异性DNA序列为探针,进行荧光原位杂交分析,证明该变异株多出的染色体均为第9染色体短臂,故该变异株为第9染色体短臂端四体。对变异株的减数分裂染色体行为进行分析表明,在所观察的25个细胞中,96%的细胞增加的两个端着丝粒染色体可配对形成二价体,一般不与正常的第9染色体配对形成多价体。但额外染色体形成的二价体在中期Ⅰ容易发生提前解离的现象。     

两种水稻四体的分离和细胞学鉴定

 在中籼3037初级三体9和初级三体11的后代中分别发现了一株形态变异株。依据中籼3037减数分裂粗线期核型以及这两个变异株减数分裂粗线期、终变期及后期Ι的染色体联会特征,确定这两个变异株分别为第9染色体和第11染色体的四体。     

Chromosome loops arising from intrachromosomal tethering of telomeres occur at high frequency in G1 (non-cycling) mitotic cells: Implications for telomere capture

BACKGROUND: To investigate potential mechanisms for telomere capture the spatial arrangement of telomeres and chromosomes was examined in G1 (non-cycling) mitotic cells with diploid or triploid genomes. This was examined firstly by directly labelling the respective short arm (p) and long arm subtelomeres (q) with different fluorophores and probing cell preparations using a number of subtelomere probe pairs, those for chromosomes 1, 3, 4, 5, 6, 7, 9, 10, 12, 17, 18, and 20. In addition some interstitial probes (CEN15, PML and SNRPN on chromosome 15) and whole chromosome paint probes (e.g. WCP12) were jointly hybridised to investigate the co-localization of interphase chromosome domains and tethered subtelomeres. Cells were prepared by omitting exposure to colcemid and hypotonic treatments. RESULTS: In these cells a specific interphase chromosome topology was detected. It was shown that the p and q telomeres of the each chromosome associate frequently (80% pairing) in an intrachromosomal manner, i.e. looped chromosomes with homologues usually widely spaced within the nucleus. This p-q tethering of the telomeres from the one chromosome was observed with large (chromosomes 3, 4, 5), medium sized (6, 7, 9, 10, 12), or small chromosomes (17, 18, 20). When triploid nuclei were probed there were three tetherings of p-q subtelomere signals representing the three widely separated looped chromosome homologues. The separate subtelomere pairings were shown to coincide with separate chromosome domains as defined by the WCP and interstitial probes. The 20% of apparently unpaired subtelomeric signals in diploid nuclei were partially documented to be pairings with the telomeres of other chromosomes. CONCLUSIONS: A topology for telomeres was detected where looped chromosome homologues were present at G1 interphase. These homologues were spatially arranged with respect to one-another independently of other chromosomes, i.e. there was no chromosome order on different sides of the cell nuclei and no segregation into haploid sets was detected. The normal function of this high frequency of intrachromosomal loops is unknown but a potential role is likely in the genesis of telomere captures whether of the intrachromosomal type or between non-homologues. This intrachromosomal tethering of telomeres cannot be related to telomeric or subtelomeric sequences since these are shared in varying degree with other chromosomes. In our view, these intrachromosomal telomeric tetherings with the resulting looped chromosomes arranged in a regular topology must be important to normal cell function since non-cycling cells in G1 are far from quiescent, are in fact metabolically active, and these cells represent the majority status since only a small proportion of cells are normally dividing.     

高抗稻瘟病品种粤标5号的遗传背景及农艺性状分析

粤标5号是应用分子标记技术育成的抗病优质水稻新品种,应用水稻12条染色体的237对SSR标记对该品种的遗传背景进行分析,结果发现:93个标记在亲本间有明显的多态性,多态性比例为39.2%;在各染色体上,基因型来自轮回亲本的比例为30.0%~100.0%,来自供体亲本的比例为0.0~70.0%;除染色体1和9外,该品种在其它染色体上均与轮回亲本存在不同程度的差异位点,背景回复率为83.3%,低于理论回复率。此外,对粤标5号的农艺性状分析表明,该品种有多个性状介于双亲之间,但在每穗粒数、结实率、千粒重、粒型等与轮回亲本存在极显著差异。研究结果将为水稻抗病分子育种提供参考依据。     

海南山栏稻遗传基础的研究Ⅱ．核型与异染色质特征

海南山栏稻体细胞染色体数与普通栽培水稻相同，即２ｎ＝２４，并同属２Ｂ核型。山栏稻染色体组中有９对中部着丝点染色体（水稻对照品种为５－６对），１－２对亚中部着丝点染色体（水稻为４－５对）．１－２对亚端部着丝点染色体。这表明山栏稻核型比水稻更为对称。山栏稻染色体组的异染色质含量平均为４６．１％，低于水稻对照（平均为５０．１％）。异染色质在染色体上的分布形式与水稻对照基本相同，多数是位于着丝点两侧（或再加一个短臂），只有少数（１－２对）染色体表现异染色质化。     

Genome-wide Association Analysis of Rice Heading Date and Yield-related Traits Based on MAGIC Population

【Objective】The objective of the study is to identify new genes related to heading date and yield related traits in rice, and to screen the elite rice lines carrying favorable alleles, therefore providing new genes and excellent germplasm for molecular marker-assisted (MAS) breeding.【Method】The multi-parent generation inter-crosses (MAGIC) population MAGIC-Hei was planted in 2017 and 2018 in Changsha, Hunan Province. Genome-wide association analysis was performed to detect the quantitative trait loci associated with heading date, number of tillers per plant, grain number per panicle, seed setting rate, 1000-grain weight and grain yield per plant based on genotyping by sequencing (GBS).【Results】Totally, 26 QTLs that control heading date and yield related traits were identified on all the chromosomes except chromosome 10 in the two years. Of these, 11 are new and qNTP9, associated with the number of effective panicles, was detected in the two years. qNTP9 was less affected by environment and could be used for further fine mapping and gene cloning. Based on the phenotypic and the SNP genotypes five elite lines carrying favorable alleles were selected, which could be used for future high-yielding rice breeding. 【Conclusion】The loci associated with heading date and yield related traits could be used for rice breeding.     

应用DNA标记分析稻飞虱的抗性基因

简要地回顾了水稻抗飞虱的遗传位点定位和作图的新进展.来自具有不同基因组的野生稻渗入系的4个抗褐飞虱基因Bph 1、 bph 2、 bph 4和Bph 9,以及4个暂定名抗褐飞虱基因Bph 10(t)、bph 11(t)、bph 12(t)和Bph 13(t),目前已被定位于水稻12条染色体中的5条.其中,Bph 1、 bph 2、 Bph 9和Bph 10(t)在水稻第12染色体的长臂上形成1个连锁区段,位于bph 2位点附近约25 cM.检测出几个对田间抗性和杀卵作用有影响的QTL.抗白背飞虱基因Wbph 1、 Wbph 2和Wbph 6(t)已经或暂时定位了.粳稻中对白背飞虱具有杀卵抗性的QTL已进行了详细的分析,在第6染色体的短臂上检测到有效的QTL,在同一位点鉴定出1个显性的杀卵基因Ovc.在杀卵基因Ovc存在时,第1染色体上的1个QTL和第5染色体上的2个QTL增加白背飞虱的卵死亡率.用DNA标记进行QTL作图可以加深人们对作物抗虫性中复杂的生理和遗传机理的理解.标记辅助选择可以加速培育具多基因抗虫性的作物,还可以将野生种中的有利抗虫特性转入改良品种中,增加作物抗虫性的持久性和遗传多样性.     

水稻第6染色体短臂株高及产量性状QTL的分解

针对第6染色体短臂上一个对产量性状遗传具有重要作用的区间RM587-RM19715,从珍汕97B/密阳46重组自交系群体中筛选到1个剩余杂合体,自交衍生获得一个由195个个体组成的F2群体,检测控制株高和产量性状的QTL。经分析,在目标区间的上部和下部分别检测到1个QTL簇,分别对除单株穗数以外的产量性状因子具显著作用,单个QTL对群体性状表型变异的贡献率为5.0%~55.5%。将第6染色体上的产量性状QTL分解到更小的区间中,为产量性状QTL的精细定位和克隆打下了基础。     

小麦-黑麦1BL/1RS易位系中的染色体结构变异

用黑麦(Secale cereale L.)自交系Kustro与普通小麦(Triticum aestivum L.)品种绵阳11杂交,获得了八倍体小黑麦MK,再用绵阳11与MK回交,用基因组原位杂交(GISH)和荧光原位杂交(FISH)的方法从回交后代中筛选到含1条1BL/1RS易位染色体的植株13FT-100。为了筛选含有变异染色体的姊妹1BL/1RS易位系,用FISH方法对植株13FT-100的自交后代进行了分析。结果表明,在1个后代植株中,1条6B染色体在核仁组织区断裂,造成6BS端部缺失;而在另1个后代植株中,1条1BL/1RS易位染色体的1BL端部Oligo-p Sc119.2-1信号缺失。变异6B染色体可以用来研究6BS臂从核仁组织区到端部区段的功能,变异1BL/1RS易位染色体可以用来研究1BL的变异对1BL/1RS易位染色体发挥功能的影响。本研究结果提示,对于小麦远缘杂交后代,应多留意小麦染色体结构的变化,获得具有新型结构的小麦染色体或易位染色体可能对小麦育种研究更具重要意义。     

水稻籼粳交DH群体中影响白背飞虱抗虫性QTL的检测

分析了水稻籼粳交加倍单倍体(DH)群体中影响白背飞虱抗虫性和感虫性的QTL.虽然DH株系的亲本窄叶青8号和京系17没有拒取食抗性,但是白背飞虱在6个DH株系中的取食受到了强烈的抑制,可能属超亲分离.在第3染色体的粳型片段中检测到1个影响蜜露分泌的微效QTL.粳稻亲本京系17具有杀卵抗性.DH株系中的杀卵特性是通过叶鞘上杀卵反应产生的坏死症状表现的.在DH株系分蘖早期和中期,将4个杀卵作用的QTL定位在第1、2、6和8染色体的粳型片段上.出现在分蘖中期的另一个QTL被定位在第9染色体的籼型片段上.在分蘖盛期至孕穗期,杀卵位点减少至2个.整个试验期间对每个DH株系的最高杀卵级别的分析显示,在染色体2、6和9上共有4个QTL.两个主效QTL位于近邻第6染色体的粳型片段.在第1、3和5染色体上检测到3个影响第2代白背飞虱若虫密度的QTL.第3染色体上起主要作用的QTL源自粳稻亲本;第5染色体上的微效QTL源自籼稻亲本.两个白背飞虱为害的QTL位于第8和第10染色体的籼型片段,另一个QTL位于第3染色体的粳型片段.这些QTL被认为与水稻品种对白背飞虱田间抗性表达有关.     

Inheritance and QTL Mapping of Salt Tolerance in Rice

An F2 population derived from the cross between Jiucaiqing (japonica) and IR36 (indica) was used to analyze the inheritance of salt tolerance in rice by genetic model of major-genes plus polygenes, and to map the corresponding QTLs by SSR molecular markers. Rice plants of P1, P2, F1 and F2 at 5- to 6- leaf stage were treated under 140 mmol/L NaCI for 10 days. Three indices representing the ability of salt tolerance of rice seedlings were measured, including salt tolerance rating (STR), Na^ /K^ ratio in roots and dry matter weight of shoots (DWS). STR, Na^ /K^ and DWS were all controlled by two major genes with modification by polygenes. Heritability of these traits from major genes was 17.8, 53.3 and 52.3%, respectively. The linkage map constructed by 62 SSR molecular markers covered a total length of about 1 142 cM. There were three QTLs detected for STR located on chromosome 1, 5 and 9, two QTLs for DWS on chromosomes 8 and 9, and two QTLs for Na^ /K^ on chromosomes 2 and 6, one on each chromosome respectively. Single QTL accounted for 6.7 to 19.3% of phenotypic variation. Identification method of salt tolerance in rice and breeding of rice varieties with salt tolerance based on molecular markers assisted selection had been discussed.     

用培矮64S/日本晴F2群体对水稻6个农艺性状的QTL定位

 用水稻测序品种培矮64S和日本晴配组建立了由180个单株组成的F2群体，构建了含137个SSR标记的连锁遗传图谱，对水稻的分蘖数、有效分蘖数、分蘖率、株高、剑叶长和穗长等6个相关农艺性状进行了QTL定位分析。共检测到14个QTL，分布在第1、2、4、5、6、7染色体的11个区间。检测到1个控制株高的主效QTL(qPH1 2),位于第1染色体，其表型贡献率为24.0%；1个控制剑叶长的主效QTL(qFL4）,位于第4染色体，其表型贡献率为30.5%。对所定位QTL的价值、QTL在染色体上的区域分布等进行了探讨。     

水稻着丝粒特异组蛋白CENH3抗体的制备与应用

【目的】着丝粒是真核生物染色体的基本功能元件之一,其功能是在细胞有丝分裂和减数分裂时期精确地调控染色体配对和分离并维持染色体的稳定。着丝粒结构是由DNA和蛋白质形成的一种复合体。着丝粒特异组蛋白(centromere-specific histone H3,CENH3)是功能着丝粒是否具有活性的最基本特征。所以制备CENH3的相关抗体是进行着丝粒结构与功能研究的前提条件之一。【方法】通过设计短肽进行兔免疫实验,制备了水稻着丝粒特异组蛋白CENH3兔源抗体,利用ELISA和蛋白免疫荧光(immunofluorescence,IF)等检测方法对抗体有效性进行了鉴定。【结果】ELISA检测显示制备的CENH3抗体有效稀释度为1:40万,并且蛋白免疫荧光信号在水稻体细胞每条染色体的着丝粒区域均能检测到。同时,该抗体也可以应用于玉米等其他物种。通过染色质免疫沉淀(ChIP)技术获得与CENH3相结合的DNA分子,并进行PCR扩增和FISH定位分析,结果显示相应的Ch IP-DNA位于水稻功能着丝粒区域。【结论】本研究制备的水稻CENH3兔源抗体能满足着丝粒研究中相关实验的要求,可进一步应用于着丝粒的结构与功能研究。     

Evaluation of Agronomic Traits in Chromosome Segment Substitution Lines of KDML105 Containing Drought Tolerance QTL under Drought Stress

Drought is a major abiotic constraint to rice production in rainfed lowland and insufficiently irrigated areas.The improvement of drought tolerant varieties is one of the strategies to reduce the negative effects of drought.Quantitative trait loci(QTLs) for primary and secondary traits related to drought tolerance(DT) on chromosomes 1,3,4,8 and 9 that determined from double haploid lines derived from a cross between CT9993 and IR62266 were introgressed and dissected into small pieces in the genetic background of Khao Dawk Mali 105(KDML105) to develop chromosome segment substitution line(CSSL) population.The CSSLs were evaluated at the reproductive stage for their agronomic performance and yield components under drought stress,and results were compared with irrigated condition.The flowering of CSSL lines was 6 to 7 d earlier than KDML105.The mean values of grain yields in the CSSLs were higher than KDML105 under drought and irrigated conditions.At irrigated condition,the grain yields of introgression lines carrying DT-QTLs from chromosomes 4 and 8 were higher than that of KDML105,whereas other traits showed little difference with KDML105.Analysis indicated that grain yield has positive correlation with plant height,tiller and panicle number per plant,and total grain weight per plant under drought stress while negatively correlated with days to flowering.As mentioned above,CSSLs showing good adaptation under drought stress can be used as genetic materials to improve drought tolerance in Thai rainfed lowland rice breeding program,and as materials to dissect genes underlying drought tolerance.     

小麦-中间偃麦草蓝粒代换系的创制与鉴定

小麦的蓝粒性状可作为表型标记用于小麦育种和遗传学研究,来自中间偃麦草的蓝粒种质材料尚鲜见报道。本研究通过八倍体小偃麦中5 (2n=8x=56, AABBDDXX)与中国春缺-四体系列材料杂交,在中5×N4BT4A和中5×N7BT7D杂交组合后代中获得了两份蓝粒材料,编号分别为Zh5-a2-1和Zh5-c13-2。利用细胞遗传学和分子标记方法对这两份蓝粒材料进行了染色体组成分析。以中间偃麦草基因组DNA为探针的GISH分析显示,这两份蓝粒材料的染色体数均为2n=42,包括40条小麦染色体和两条中间偃麦草染色体。利用重复序列探针pSc119.2和pAs1进行的FISH分析表明,Zh5-a2-1和Zh5-c13-2均为二体代换系,被代换的一对小麦染色体分别为4B和4D。通过用St、E~e和E~b基因组DNA作探针进行GISH分析,证明这两份蓝粒代换系中的中间偃麦草染色体均为St组染色体,但与中5中的中间偃麦草染色体比较发现这对St组染色体的短臂端部发生了缺失。利用二倍体长穗偃麦草E~e基因组的SNP标记分析证明,两份蓝粒代换系中的中间偃麦草染色体与长穗偃麦草的4E~e染色体同源,即Zh5-a2-1和Zh5-c13-2分别为4St(4B)和4St(4D)代换系,命名为SubZh5-4St(4B)和SubZh5-4St(4D)。同时说明,中间偃麦草的4St染色体上带有蓝粒基因。通过对450个小麦SSR标记进行筛选,获得了4个可跟踪鉴定4St染色体的特异SSR标记。研究结果可用于蓝粒小麦品种的培育和中间偃麦草蓝粒基因的遗传学研究。     

应用微卫星标记定位水稻恢复系密阳46的主效和微效恢复基因

应用由704个株系组成的珍汕97A/(珍汕97B/密阳46)F6测交群体,针对水稻第10染色体和第1、11染色体短臂构建了微卫星标记连锁图谱,检测到控制野败型细胞质雄性不育育性恢复的4个QTL,其中位于第10染色体长臂中下部的Rf4具有主效效应,位于第1染色体短臂的Rf3具有较大效应,位于第10染色体长臂近着丝粒处的qRf10和第11染色体短臂近着丝粒处的qRf11表现出微效作用。研究还表明,在主效基因Rf4存在时,其他3个基因仍具有提高结实率的作用,但在Rf3和Rf4同时存在时,qRf10和qRf11的效应不明显。     

总DNA导入水稻后变异系及供体特异带DNA片段的核苷酸序列比较

将小粒野生稻（Oryza minuta)总DNA导入杂交水稻保持系V20B获得变异系，经RAPD分析找到了受体中不存在而变异系及供体中存在的特异常。将自变异系与供体扩增出的长均为975bp的特异DNA片段分别回收、克隆、测序，发现两者核苷酸序列极为相似，从而进一步证明了远缘资源特异DNA片段向水稻的转移；同时发现两者间存在29个碱在差异（包括转换、颠换、插入及缺失4种类型），表明供体特异DNA片段的导入不仅可能使供体特异性状在变异系中表达，也可能由于个别碱基的突变而使受体产生新性状。     

基于粳稻F2和F2:6群体的连锁图谱及剑叶性状QTL比较分析

 以粳稻沈农265和丽江新团黑谷 (LTH) 为亲本,分别构建了F2群体和F2:6群体,分析并比较了两群体的遗传信息和控制剑叶相关性状(剑叶长、宽和比叶重)的数量性状基因座。结果表明：1)多数标记在染色体上的顺序相同,但标记间距不同。F2群体中30个标记显著偏离预期的1∶2∶1孟德尔分离比例,13个标记极显著偏离预期的1∶2∶1孟德尔分离比例,其中19个偏向沈农265,11个偏向LTH。F2:6群体中62个标记显著偏离预期的1∶1孟德尔分离比例,38个标记极显著偏离预期的1∶1孟德尔分离比例,其中43个偏向沈农265,19个偏向LTH。偏分离标记共形成10个偏分离区域,其中有6个区域同时出现在两个群体中。2) F2:6群体检测QTL的能力强于F2群体。F2群体共检测到7个控制剑叶性状的QTL (2个控制剑叶长,4个控制剑叶宽,1个控制比叶重),而F2:6群体共检测到17个控制剑叶性状的QTL (7个控制剑叶长,5个控制剑叶宽,5个控制比叶重),其中有4个QTL在两群体中同时检测到,分别是第9染色体上控制剑叶长的qFLL9,第4染色体上控制剑叶宽的qFLW4,第12染色体上控制剑叶宽的qFLW12.1和第6染色体上控制比叶重的qSLW6。其中,控制比叶重的qSLW6 (加性效应值为1.956 mg/cm2),极富研究与应用价值。     

Dissection of QTLs for Yield Traits Using Near Isogenic Lines Derived from Residual Heterozygous Lines in Rice

Three residual heterozygous lines (RHLs) carrying heterozygous segments in the intervals RM587-RM225, RM204-RM6119 and RM6119-RM402 on the short arm of rice chromosome 6, respectively, were selected from a rice population derived from an RHL for the interval RM587-RM402. Ten maternal homozygotes, 10 paternal homozygotes and 20 heterozygotes were selected from each of the F2 populations derived from the three RHLs. The three sets of near isogenic lines (NILs) were grown to detect the grain yield per plant, n...     

水稻巨大胚基因的分子定位

 应用粳稻金南风巨大胚突变体和籼稻南京11杂交F₂群体58个植株构建了包含74个分子标记位点的遗传连锁图。 对巨大胚基因进行了分子定位, 结果发现巨大胚基因与第7染色体上RG678紧密连锁,两者之间的遗传距离为6.2 cM,与同一染色体上的另一探针RZ395之间的遗传距离为13 cM。根据巨大胚(ge)、褐色果皮(Rc)基因经典连锁图上的位置,将第7染色体分子图谱与经典图谱进行了整合