细胞工程与分子生物学相结合——野生稻优异种持资源利用的有效途径

野生稻是提供优异基因、拓宽栽培稻遗传基础的重要种质资源库。非ＡＡ染色体组型野生稻优异基因转移和利用的主要难点在于,与栽培稻的亲缘关系无冢由此而产生杂交不实,杂种流通和后代难以利用等问题。细胞工程和分子生物学手段相结合,是实现非ＡＡ型野和稻利用的有效途径。原生质体融合可以克服有效杂交的不亲和性,花药培养能加速后代的纯合和稳定,分子生物学技术可以跟踪目的基因的导入,打破连锁障碍,促进有利基因的重组,提     

细胞工程与分子生物学相结合——野生稻优异种质资源利用的有效途径

野生稻是提供优异基因、拓宽栽培稻遗传基础的重要种质资源库。非ＡＡ染色体组型野生稻优异基因转移和利用的主要难点在于,与栽培稻的亲缘关系远及由此而产生杂交不实、杂种不育和后代难以利用等问题。细胞工程和分子生物学手段相结合,是实现非ＡＡ型野生稻利用的有效途径。原生质体融合可以克服有效杂交的不亲和性,花药培养能加速后代的纯合和稳定,分子生物学技术可以跟踪目的基因的导入,打破连锁障碍,促进有利基因的重组,提高材料的可利用性,并为目的基因的克隆提供基础。     

药用野生稻复合体ITS1和ITS2序列变异及其系统进化分析

通过PCR扩增并测序分析稻属药用野生稻复合体5个野生稻种基因组完整的ITS区及5.8S区,并与栽培稻ITS序列进行比较,构建分子系统进化树,探讨了稻属药用野生稻复合体内不同种间的亲缘关系和系统进化.结果表明,ITS1和ITS2均有较高的G/C含量,ITS1序列的长度多态性相对较高,ITS2序列的碱基突变频率较高.药用野生稻和高秆野生稻亲缘关系很近,而与栽培稻亲缘关系较远;短药野生稻、斑点野生稻、澳洲野生稻与药用野生稻亲缘关系渐近.处于进化的过渡阶段.     

云南野生稻叶茎根组织结构特性的比较研究

采用徒手切片法对云南3种野生稻和栽培稻的叶片、茎秆及根的组织结构进行比较研究,以明确野生稻的内部结构,为进一步揭示其结构与云南野生稻的生长势旺盛、营养吸收能力强、抗某些病虫害能力强的关系奠定基础。结果表明,(1)云南野生稻与栽培稻叶片主脉、茎秆及根的组织结构差异显著,其中景洪疣粒野生稻、景洪药用野生稻与栽培稻的差异最明显。(2)在叶主脉结构中,景洪疣粒野生稻无气腔结构,维管束数量少、面积小;景洪药用野生稻、3个普通野生稻材料存在多个维管束和气腔结构,维管束、束内导管直径及气腔面积较栽培稻大,而栽培稻中的气腔均为2个。(3)在茎秆结构方面,景洪疣粒野生稻茎秆最小,维管束数量最少,其茎壁内的维管束排列方式与栽培稻不同;景洪药用野生稻和普通野生稻茎秆及茎壁较栽培稻粗厚,维管束数量也较栽培稻多,普通野生稻的茎壁中有通气组织。(4)在根的组织结构中,3种野生稻的导管数量较多,导管直径及中柱面积较栽培稻大,外皮层出现了具有凯氏带功能的凯氏点等。     

亚洲栽培稻与AA染色体组稻种的可交配性及F1杂种育性分析

从可交配性和F1杂种育性两方面对亚洲栽培稻与AA染色体组（以下简称AA组）其他7个稻种的系统关系进行了分析。结果表明：栽培稻籼、粳亚种与AA组不同稻种杂交均具有一定的结实率,可交配性不是影响亚洲栽培稻与其他AA组稻种间基因交流的主要生殖障碍。亚洲栽培稻与普通野生稻及尼瓦拉野生稻种间F1花粉育性和小穗育性有不同程度分化,与其他稻种的F1花粉育性和小穗育性均很低,F1杂种不育是AA组内基因交流的主要障碍。综合可交配性和F1小穗育性两方面的因素,初步得出：亚洲栽培稻与AA组稻种的亲缘关系由近及远依次是：普通野生稻、尼瓦拉野生稻、南方野生稻、展颖野生稻、非洲栽培稻、长雄蕊野生稻和短舌野生稻。其中普通野生稻和尼瓦拉野生稻是AA组中可直接利用于水稻育种的野生稻资源。     

RAPD鉴定栽培稻与野生稻体细胞杂种

利用随机引物扩增DNA(RAPD)技术,对栽培稻和野生稻原生质体融合获得的体 细胞杂种进行了鉴定。证实了它们包含有双亲的基因组成分。但来自双亲的基因组成分并不是对等的。一些体细胞杂种含有一个亲本更多的基因组成分,而另一些相反。利用RAPD数据和聚类图讨论了体细胞杂种和双亲的亲缘关系。     

长雄野生稻有利基因的发掘与利用

人类将普通野生稻驯化为亚洲栽培稻,其农艺性状如株高、落粒性、穗型等发生了重要变化,产量也大幅提高,但许多优良性状如抗逆性等却丢失。长雄野生稻与亚洲栽培稻同属AA基因组,蕴藏了许多生物胁迫和非生物胁迫的抗性基因,被认为是亚洲栽培稻遗传改良的潜在基因库。本文总结了长雄野生稻生物及非生物胁迫抗性、地下茎性状以及其他潜在应用价值性状,包括白叶枯抗性、抗旱性、耐热性、自交不亲和性、氮高效利用以及高产等有利性状。基于长雄野生稻地下茎性状开展多年生稻育种实践的应用研究,对长雄野生稻进行从头驯化的策略进行了探讨,以期为长雄野生稻基础研究及栽培稻遗传改良提供理论参考。     

中国野生稻及栽培稻核糖体DNA第一转录间隔区序列分析及其系统学意义

用 PCR技术从产于我国的 3种野生稻和亚洲栽培稻的 2个亚种中特异地扩增和测序了 r DNA的第一转录间隔区。普通野生稻 (Oryza rufipogon)、药用野生稻 (O.officinalis)、疣粒野生稻 (O.granu-lata)和栽培稻的两个亚种 (O.sativa ssp.indica,O.sativa ssp.japonica)的 ITS1序列为 1 93bp、1 94bp、2 1 8bp、1 94bp和 1 94bp,它们的 G/ C含量为 69.3%～ 72 .7% ,序列中位点趋异率为 1 .5%～ 1 0 .6%。序列的相似性比较和简约性分支分析的结果表明 ,普通野生稻与栽培稻的两个亚种之间的亲缘关系最为密切 ;药用野生稻与普通野生稻和与栽培稻的两个亚种的相似性都为 82 % ,说明它与 AA基因组有一定的亲缘关系 ;疣粒野生稻与普通野生稻、药用野生稻和栽培稻两个亚种的亲缘关系相对较远 ,它在稻属中可能是一个系统地位较独特的类群。以 ITS1序列构建的 3种野生稻和 2个栽培稻亚种的系统发育关系与前人用同工酶、叶绿体 DNA、线粒体 DNA和核 DNA资料重建的稻属的系统发育关系基本一致     

2000年间野生稻和栽培稻(O.sativa.L)分布区逆向分离的过程及动力 Ⅱ古今野生稻和栽培稻(O.satival.L)分布区变化的动力分析

人口增加、人口扩散从而促进农业发展是野生稻面积缩小、分布北界南移而栽培稻面积扩大、分布区向北、向东扩张的根本动力。由于野生稻与栽培稻在历史上处于同一生态位,发展栽培稻使野生稻生境破坏。提出生态位恒定假说并解释了野生稻与栽培稻分布区变化的特点。     

栽培稻与其野生近缘种的可交配性研究

通过人工授粉方法研究栽培稻与二倍体和四倍体野生稻之间的可交配性.以栽培稻为对照,用光学显微镜观察不同野生稻花粉在同一栽培种柱头上的萌发生长情况.结果表明,在栽培稻柱头上普通野生稻(AA)花粉萌发最好,与对照萌发情况相近.药用野生稻(CC)萌发差,表现为柱头上花粉附着量少,开始萌发时间迟,萌发量少,花粉管扭曲、缠绕、伸长慢等.四倍体野生稻未观察到有萌发现象.说明普通野生稻与栽培稻亲缘关系近,可交配性好;药用野生稻与栽培稻可交配性差;四倍体野生稻与栽培稻可交配性极差.由此推断,转基因水稻与普通野生稻通过花粉途径发生基因漂移的可能性很大,而与药用野生稻和其他基因组野生稻发生基因漂移的可能性很小.     

野生稻与栽培稻及种间杂种F1叶表面亚显微结构的研究

用扫描电镜对原产中国的３种野生稻、２个栽培稻品种及栽培稻与野生稻间的杂种Ｆ１,就气孔频度、气孔器乳突、大瘤状乳突及本栓细胞乳突等叶片表面亚显微结构作了比较观察研究。结果显示这些性状具有种的特性,发现种间杂种的亚星微性状与两个亲本 特性及亲缘关系远近有关。     

The Oryza Map Alignment Project: The Golden Path to Unlocking the Genetic Potential of Wild Rice Species

The wild species of the genus Oryza offer enormous potential to make a significant impact on agricultural productivity of the cultivated rice species Oryza sativa and Oryza glaberrima. To unlock the genetic potential of wild rice we have initiated a project entitled the ‘Oryza Map Alignment Project’ (OMAP) with the ultimate goal of constructing and aligning BAC/STC based physical maps of 11 wild and one cultivated rice species to the International Rice Genome Sequencing Project’s finished reference genome – O. sativa ssp. japonica c. v. Nipponbare. The 11 wild rice species comprise nine different genome types and include six diploid genomes (AA, BB, CC, EE, FF and GG) and four tetrapliod genomes (BBCC, CCDD, HHKK and HHJJ) with broad geographical distribution and ecological adaptation. In this paper we describe our strategy to construct robust physical maps of all 12 rice species with an emphasis on the AA diploid O. nivara – thought to be the progenitor of modern cultivated rice.     

ITS1 Sequences of Nuclear Ribosomal DNA in Wild Rices and Cultivated Rices of China and Their Phylogenetic Implications

he first internal transcribed spacer (ITS1) of nuclear ribosomal DNA of three wild rice species and two subspecies of cultivated rice, which are distributed in China, was amplified using PCR technique and sequenced with automated fluorescent sequencing. The sequences of ITS1 ranged from 193 bp to 218 bp in size and G/C content varied from 69.3%to 72.7%. In pairwise comparison among the five taxa, sequence site divergence ranged from 1.5 % to 10.6%. Phylogenetic analysis of ITS1 sequences using Wagner parsimony generated a single well-resolved tree, which revealed that Oryza rufipogon was much more closely related to cultivated rice species than to the other two wild species. Oryza granulata was less closely related to either cultivated rice species or the other two wild species, and might be a unique and isolated taxon in the genus Oryza. The phylogenetic relationships of the three wild rice species and two cultivated rice subspecies inferred from ITS1 sequences is highly concordant with those based on the molecular evidence from isozyme, chloroplast DNA (cpDNA), mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) of the genus Oryza.     

野生稻和栽培稻的随机多态DNA(RAPD)分析

应用 RAPD方法对药用野生稻、普通野生稻、粳稻和籼稻进行基因组多态性分析。 1 2个随机引物共扩增出 1 3 2条 RAPD带 ,片段大小在 3 0 0～ 3 5 0 0 bp之间 ,其中有 1 0 6条表现出多态性 ,占总扩增片段的86.4%。根据遗传距离分析 ,用 UPGMA法构建了聚类树状图 ,结果表明 ,普通野生稻的遗传特性比药用野生稻更接近于栽培稻。     

Gene flow from cultivated rice (Oryza sativa) to its weedy and wild relatives

BACKGROUND AND AIMS: Transgene escape through gene flow from genetically modified (GM) crops to their wild relative species may potentially cause environmental biosafety problems. The aim of this study was to assess the extent of gene flow between cultivated rice and two of its close relatives under field conditions. METHODS: Experiments were conducted at two sites in Korea and China to determine gene flow from cultivated rice (Oryza sativa L.) to weedy rice (O. sativa f. spontanea) and common wild rice (O. rufipogon Griff.), respectively, under special field conditions mimicking the natural occurrence of the wild relatives in Asia. Herbicide resistance (bar) and SSR molecular finger printing were used as markers to accurately determine gene flow frequencies from cultivated rice varieties to their wild relatives. KEY RESULTS: Gene flow frequency from cultivated rice was detected as between approx. 0.011 and 0.046 % to weedy rice and between approx. 1.21 and 2.19 % to wild rice under the field conditions. CONCLUSIONS: Gene flow occurs with a noticeable frequency from cultivated rice to its weedy and wild relatives, and this might cause potential ecological consequences. It is recommended that isolation zones should be established with sufficient distances between GM rice varieties and wild rice populations to avoid potential outcrosses. Also, GM rice should not be released when it has inserted genes that can significantly enhance the ecological fitness of weedy rice in regions where weedy rice is already abundant and causing great problems.     

Evolutionary Genomics of Weedy Rice in the USA

Red rice Is an Interfertlle, weedy form of cultivated rice （Oryza sativa L.） that competes aggressively with the crop In the southern US, reducing yields and contaminating harvests. No wild Oryza species occur In North America and the weed has been proposed to have evolved through multiple mechanisms, Including ＂de-domestication＂ of US crop cultlvars, accidental introduction of Asian weeds, and hybridization between US crops and Asian wild/weedy Oryza strains. The phenotype of US red rice ranges from ＂crop mimics＂, which share some domestication traits with the crop, to strains closely resembling Asian wild Oryza species. Assessments of genetic diversity have Indicated that many weed strains are closely related to Asian taxa （Including indica and aus rice varieties, which have never been cultivated In the US, and the Asian crop progenitor O. ruflpogon）, whereas others show genetic similarity to the tropical Japonica varieties cultivated In the southern US. Herein, we review what Is known about the evolutionary origins and genetic diversity of US red rice and describe an ongoing research project to further characterize the evolutionary genomlcs of this aggressive weed.     

Evolutionary Genomics of Weedy Rice in the USA

Red rice is an interfertiie, weedy form of cultivated rice (Oryza sativa L.) that competes aggressively with the cropin the southern US, reducing yields and contaminating harvests. No wild Oryza species occur In North America andthe weed has been proposed to have evolved through multiple mechanisms, including "de-domestication" of UScrop cultivars, accidental introduction of Asian weeds, and hybridization between US crops and Asian wild/weedyOryza strains. The phenotype of US red rice ranges from "crop mimics", which share some domestication traitswith the crop, to strains closely resembling Asian wild Oryza species. Assessments of genetic diversity haveindicated that many weed strains are closely related to Asian taxa (including indica and aus rice varieties, whichhave never been cultivated in the US, and the Asian crop progenitor O. rufipogon), whereas others show geneticsimilarity to the tropical japonica varieties cultivated in the southern US. Herein, we review what is known aboutthe evolutionary origins and genetic diversity of US red rice and describe an ongoing research project to furthercharacterize the evolutionary genomics of this aggressive weed.     

Characterization of Interspecific Hybrids Between Oryza sativa L. and Three Wild Rice Species of China by Genomic In Situ Hybridization

In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.