Study on heterosis of intersubspecies between indica and japonica rice （Oryza sativa L.） using chromosome segment substitution lines

Great heterosis exists in the inter-subspecific crossesbetween indica and japonica rice cultivars[1,2] and the ex-ploitation of this heterosis has long been considered as apromising method to further increase rice yield potential[3].Previous studies indicated that there were large differencesbetween the two subspecies with respect to morphology,isozyme, polymorphism of molecular markers and DNAstructure due to long time genetic differentiation[4,5]. Thosedifferences were identified to be clos…     

A draft sequence of the rice (Oryza sativa ssp. indicd) genome

The sequence of the rice genome holds fundamental information for its biology, including physiology, genetics, development, and evolution, as well as information on many beneficial phenotypes of economic significance. Using a “whole genome shotgun” approach, we have produced a draft rice genome sequence ofOryza sativa ssp.indica, the major crop rice subspecies in China and many other regions of Asia. The draft genome sequence is constructed from over 4.3 million successful sequencing traces with an accumulative total length of 2214.9 Mb. The initial assembly of the non-redundant sequences reached 409.76 Mb in length, based on 3.30 million successful sequencing traces with a total length of 1797.4 Mb from anindica variant cultivar93-11, giving an estimated coverage of 95.29% of the rice genome with an average base accuracy of higher than 99%. The coverage of the draft sequence, the randomness of the sequence distribution, and the consistency of BIG-ASSEMBLER, a custom-designed software package used for the initial assembly, were verified rigorously by comparisons against finished BAC clone sequences from bothindica andjapanica strains, available from the public databases. Over all, 96.3% of full-length cDNAs, 96.4% of STS, STR, RFLP markers, 94.0% of ESTs and 94.9% unigene clusters were identified from the draft sequence. Our preliminary analysis on the data set shows that our rice draft sequence is consistent with the comman standard accepted by the genome sequencing community. The unconditional release of the draft to the public also undoubtedly provides a fundamental resource to the international scientific communities to facilitate genomic and genetic studies on rice biology. These authors contributed equally to this work.     

抗稻瘟病细胞突变体筛选技术体系的建立

以稻瘟病菌粗毒素提取液为选择压,选取籼稻材料缙2B、缙恢36和缙恢10进行抗稻瘟病突变体的筛选．结果表明：1）在成熟胚诱导产生愈伤组织过程中,2,4-D是诱导愈伤的关键因子,3种材料在附加2mg／L2,4-D的NB培养基（NBD2）上诱导产生的愈伤较好．2）粗毒素对3种材料的胚根、胚芽、愈伤组织的生长都有着明显的抑制作用,表明粗毒素具有一定的致病力,其毒性并不与浓度完全成正比关系,而是在一定范围内随浓度的增加而增加．在毒素浓度为45％时,缙2B胚根和胚芽生长受到抑制的程度最大,而缙恢36和缙恢10则在30％浓度中生长受到明显抑制．3）粗毒素对3种材料的愈伤组织成活率及再生频率有着明显的抑制作用,其程度随浓度的增加而增大,当稻瘟病粗毒素浓度为60％时,愈伤组织不生长,并变褐死亡,最终选择45％的毒素浓度进行2次继代抗性筛选并获得再生植株．     

Genetic structure and eco-geographical differentiation of cultivated Hsien rice (Oryza sativa L. subsp. indica) in China revealed by microsatellites

Indica is not only an important rice subspecies widely planted in Asia and the rest of the world,but it is also the genetic background of the majority of hybrid varieties in China.Studies on genetic structure and genetic diversity in indica germplasm resources are important for the classification and utilization of cultivated rice in China.Using a genetically representative core collection comprising 1482 Chinese indica landraces,we analysed the genetic structure,geographic differentiation and diversity.Model-based structure analysis of varieties within three ecotypes revealed nine eco-geographical types partially accordant with certain ecological zones in China.Differentiation of eco-geographical types was attributed to local ecological adaption and physical isolation.These groups may be useful for developing heterotic groups of indica.To facilitate the identification of different ecotypes and eco-geographical types,we identified characteristic SSR alleles of each ecotype and eco-geographical type and a rapid index of discrimination based on characteristic alleles.The characteristic alleles and rapid discrimination index may guide development of heterotic groups,and selection of hybrid parents.     

籼型光敏核不育水稻的RAPD分析

以籼型光敏核不育水稻８９０２ｓ及其可育近等基因系材料８９０２的核ＤＮＡ为模板，进行ＲＡＰＤ分析，从检测过的１５个引物中发现引物ＯＰＡ－０４在可育品系和不育品系中扩增出１个１０００ｂｐ的差异带，并初步认为此差异与育性相关     

一个新的水稻矮秆突变体sd-sl的遗传与基因定位研究

新的矮秆基因的发掘、研究和利用对水稻育种和植物生长发育机制研究有重要的作用.用60Coγ射线辐照粳稻9522,获得一个能稳定遗传的突变体.该突变体表型为株高较野生型矮,叶片短而微卷.将该突变体与籼稻广陆矮杂交,F2代呈3∶1分离,说明该突变体受隐性单基因控制.通过InDel分子标记对F2代分离群体进行遗传定位,将该基因定位于第6染色体InDel标记OS604附近.随后又发展了多对有多态性的InDel分子标记,将该基因座位精细定位在InDel标记XL6-6和XL6-1之间,AP003490和AP005619上,两个引物之间的物理距离为118 kb.本研究为该克隆基因及其作用机理的探究奠定了基础.     

微卫星标记分析籼粳亚种间的遗传多样性

208对引物中具有多态性的引物123对,占所用引物的59．13％,不同染色体的微卫星分析的多态性不同,染色体9,10微卫星的多态性高于其它染色体,染色体12上的微卫星标记的多态性最差,仅为46．15％．聚类分析表明,所有的供试材料可分为两群,即籼稻群和粳稻群,聚类结果与亲本材料亲缘关系基本一致,说明微卫星标记能较好地区分籼稻和粳稻,由于农艺性状是基因表达的结果,易受环境影响,聚类结果不能从整体上充分反应品种间的遗传变异,42份常用杂交水稻亲本材料聚类分析表明,恢复系和不育系遗传基础均较狭窄,但恢复系和不育系之间的遗传距离相对较远,从一定程度上反映了遗传距离与杂种优势正相关。     

紫外线B(UV-B)辐射增强对水稻影响的研究进展

紫外线是到达地面的太阳光的一部分.20世纪以来,由于多种原因,导致平流层臭氧层变薄,因而到达地表的紫外线B(UV-B)的辐射增强,对地球生物产生严重影响.本文综述了紫外线辐射增强对水稻生长发育,产量和品质影响,以及水稻的自我防护与修复机制的研究现状与动态,展望了今后紫外辐射增强对水稻影响的研究重点与研究方向.     

Origin of the Chinese cultivated rice (Oryza sativa L.)

The following new research progresses are summarized and discussed, which are related to 3 main problems in origin of rice cultivation in China: 1. new hypothesis of rice cultivation in China— middle Yangtze River and upper Huai River regions; 2. primitive cultivated rice and the strengthen period of domestication; 3. genetic diversity centers of cultivated rice in China; 4. China and South Asia might be two independent systems of origin and differentiation of Asian cultivated rice; 5. morphological classification of common wild rice of China; 6. primitive progenitor of common wild rice; 7. direct progenitor of cultivated rice; 8. present or not the annual wild rice in China; 9. differentiation or not the common wild rice into Indica and Japonica; 10. origin and differentiation of Indica and Japonica.     

一个新矮秆水稻突变体的光合特性研究

从T-DNA插入的水稻突变体库发现了一个新的水稻矮秆突变体,平均株高约是野生型的37％,茎节间长度明显低于野生型,其叶片直立生长并呈暗绿色,边缘卷曲的性状。光合特性分析表明,单位重量叶片ChlaxChlb和B-Car色素含量显著高于野生型,Chla／b与野生型没有差异。与野生型相比,突变体最大光化学效率（Fv／Fm）、实际光化学效率（φesu）和光化学淬灭系数（qP）与野生型并没有显著差异,但其非光化学淬灭系数显著低于野生型,说明突变体光合效率优于野生型。电镜分析发现了突变体细胞内部出现衰老症状但叶绿体结构正常。     

水稻光敏核不育基因分子标记的研究

石明松（１９７３）从晚粳品种农垦５８大田中发现了具有光周期敏感核不育性状的水稻农垦５８Ｓ,并被正式命名为湖北光周期敏感核不育水稻（ＨＰＧＭＲ）,它的发现及利用可以将杂交水稻种子的生产方式由“三系法”改变为更经济的“二系法”,这将对杂交水稻的生产起到十...     

Characterization and fine mapping of an early senescence mutant （es-t） in Oryza sativa L.

An es-t (early senescence-temporary) mutant, produced by ethylene methylsulfonate treatment of strain Nipponbare, was identified in rice. The leaves of es-t appeared yellow at the seedling stage, and had decreased chlorophyll content. Rust spots were found during growth in es-t, especially at the leaf margin and tip. The plants showed a typical early-senescence phenotype at the milky stage. The leaf surface of es-t appeared smoother than wild-type leaves under a scanning electron microscope, because the lea...     

水稻花粉Profilin基因启动子的克隆及序列分析

作者使用两次染色体步移（Genome walking)法，从灿稻（Oryza sativa subsp.indica)IR36中克隆到长度为569bp的花粉proiflin基因的启动子片段，并进行了全序列测定和分析。结果表明：在该段序列中含有3个TATA box，3个CAAT box和2个G－box。通过EPD（The Eukaryotic Promoter Database)的比较发现，序列的＋2－-71区域与番茄（Lycopersicon esculentum)花粉特异基因LAT52，向日葵（Helianthus annuus)花药特异基因SF2启动子关键序列的同源性为50％左右。     

Genetic analysis and mapping of rice （Oryza sativa L.） male-sterile （OsMS-L） mutant

A rice male-sterile mutant OsMS-L of japonica cultivar 9522 background, was obtained in M4 population treated with ^60Co γ-Ray. Genetic analysis indicated that the male.sterile phenotype was controlled by a single recessive gene. Results of tissue section showed that at microspore stage, OsMS-L tapetum was retarded. Then tapetal calls expanded and microspores degenerated. No matured pollens were observed in OsMS-L anther locus. To map OsMS-L locus, an F2 population was constructed from the cross between the OsMS-L (japonica) and LongTeFu B(indica). Firstly, the OsMS-L locus was roughly mapped between two SSR markers, RM109 and RM7562 on chromosome 2. And then eleven polymorphic markers were developed for further fine fine-mapping. At last the OsMS-L locus was mapped between the two lnDel markers, Lhsl0 and Lhs6 with genetic distance of 0.4 cM, respectively. The region was delimited to 133 kb. All these results were useful for further cloning and functional analysis of OsMS-L.     

Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L. and Oryza meyeriana L

Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O.sativa and O.meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance.     

Morphology and mapping analysis of rice (Oryza sativa L.) clustered spikelets( Cl) mutant

The rice clustered spikelets (Cl) mutant exhibits a phenotype that most of branch apical have 2-3 spikelets clustered together,SEM (scanning electron microscope )observation suggested that the Cl gene controlled branch apical development,and influenced the terminal spikelets elongation,The spikelet number was reduced in mutant,indicating that Cl may also have an effect on spikelet number,To map Cl locus,two F2 mapping populations derived from the crosses between the Cl and ZhongHua11,and Cl and ZheFu802 were constructed ,respectively,The Cl locus was roughly mapped between two CAPS markers CK0214 and SS0324,A further fine mapping analysis showed that the Cl locus was mapped between makers R0674E and Cl12560,with genetic distances of 0.2 and 2.1 cM,respectively ,Then we found a PAC conting spanning Cl locus,the region was delimited to 196 kb.This results was useful for cloning of the Cl gene,Allelism test demonstrated that Cl was allelic to Cl2 another rice clustered spikelets mutant.     

NaCl对高蛋白糯稻品系H1701胚培养力的影响

以糯稻Ｈ１７０１为材料,通过胚培养诱导愈伤组织,继代培养并分化,实验结果表明,ＮａＣｌ对胚性愈合伤组织的诱导和生长有不同程度的抑制作用,ＮａＣｌ浓度越高,抑制越明显,转人发化培养基后以后,除含１０ｇ／Ｌ及以上浓度ＮａＣｌ的诱导培养基中愈伤组织分化为零外,其余均能分化出苗,其中,含ＮａＣｌ２ｇ／Ｌ的诱导培养基中诱导出愈伤组织分化率最高。     

籼粳杂交稻主要农艺性状之间的遗传相关分析

用混合线性模型方法对舢粳亚种间杂交组合农艺性状的相关性进行了遗传研究,结果表明：被测性状之间大都存在一定程度的相关．其中,株高与实粒数、结实率,穗长与总粒数、实粒数,总粒数与实粒数和结实率,以及实粒数与结实率之间具有显著的表型相关,总粒数与实粒数,实粒数与结实率,以及穗长与株高和结实率之间具有显著的遗传相关．进一步的分析表明,性状之间的遗传相关大多归因于显性效应,而粒重与穗长、总粒数和实粒数之间,以及总粒数与实粒数之间还具有极显著的加性相关