水稻(Oryza sativa)核型分析

水稻(Oryza sativa)核型分析结果:在12对染色体中,具中部着丝点的有5对,近中部着丝点的有6对(包括随体染色体),1对近端部着丝点。本文还着重讨论了随体的数目及所在的染色体。     

Characterization of recombinant β-amylases from Oryza sativa

Four putative β-amylase genes found in the Oryza sativa cDNA sequence database (KOME) were expressed in Escherichia coli. Recombinant proteins from two of these genes showed β-amylase activity. Similarly to β-amylases from other plants, the optimum pH of the recombinant rice β-amylases was about 5.5-6.0, but they exhibited inferior heat stability to soybean β-amylase.     

水稻(Oryza sativa L.)的受精作用

本文对四个水稻品种的双受精过程作了细胞形态学的观察。作者看到,水稻在受精过程中常常有多条花粉管相继伸向珠孔,并把花粉管内含物注入胚囊。注入胚囊的内含物进入两助细胞之一,在卵细胞的一侧形成钩状构造。当合子发育成原胚时,钩状构造就逐渐消失。卵细胞与极核,除了通常的单精受精以外,有少数可能是属于多精受精的现象。卵细胞多精受精时,超数精子不但进入细胞质,而且进入细胞核。精子还可能进入原胚的胚胎细胞。     

野生稻Oryza nivara和O. rufipogon DNA甲基化多样性

本文调查研究了野生稻群体内及群体间的DNA甲基化多样性。选取与亚洲栽培稻近缘的两个野生种Oryza nivara和O. rufipogon作为研究对象, 采用改进的MSAP (methylation-sensitive amplification polymorphism)技术对其基因组CCGG位点的甲基化多样性进行了分析。结果表明: 在同一个IRGC(the International Rice Germplasm Center)编号群体内的不同个体间, 基因组甲基化条带高度一致; 而在不同编号群体间, 甲基化条带表现为多态。其中后者又可以分为两类: 条带模式高度一致的Class I和条带模式呈多态性的Class II。将上述两类甲基化片段的编码基因与栽培稻粳稻(O. sativaL. subsp. japonica)和籼稻(O. sativa L. subsp. indica)两个亚种的同源基因进行序列比对发现, 在进化趋势上Class I表现得比较保守, 而Class II较为活跃。DNA甲基化多样性作为标志遗传多样性的一种信息来源, 其在群体分化及物种进化过程中的作用还需要进一步探讨。     

植酸在水稻(Oryza sativa L.)细胞培养中的促进作用

植酸(C_6H_(18)O_(24)P_6)添加到固体和液体培养基中,能显著降低多酚氧化酶活性,稳定培养基中pH值和mV值,并能促进水稻细胞生长,增强细胞抗褐化和水渍化能力,从而改善细胞状态。在培养基中植酸的最佳添加量为0.1%,配合使用MES可以增强其稳定pH值的效果。     

Identification and Validation of Quantitative Trait Loci for Agronomic Traits in Advanced Backcross Breeding Lines Derived from Oryza rufipogon × Oryza sativa Cultivar MR219

A backcross breeding strategy was used to identify quantitative trait loci (QTLs) associated with 14 traits in a BC₂F₂ population derived from a cross between MR219, an indica rice cultivar and an accession of Oryza rufipogon (IRGC 105491). A total of 261 lines were genotyped with 96 microsatellite markers and evaluated for plant morphology, yield components and growth period. The genetic linkage map generated for this population with an average interval size of 16.2?cM, spanning 1,553.4?cM (Kosambi) of the rice genome. Thirty-eight QTLs were identified with composite interval mapping (CIM), whereas simple interval mapping (SIM) resulted in 47 QTLs (LOD >3.0). The O. rufipogon allele was favourable for 59% of QTLs detected through CIM. Of 261 BC₂F₂ families, 26 advanced backcross breeding lines (BC₂F₅) were used for QTL validation. These lines were selected on the basis of the yield traits potentiality in BC₂F₃ and BC₂F₄ generations. The field trial was conducted at three different locations in Malaysia using randomized complete block design with three replications. Trait based marker analysis was done for QTL determination. Twenty-five QTLs were detected in BC₂F₅ generation whereas 29 QTLs were detected in BC₂F₂ generation of the same population. Two QTLs (qPL-1 and qSPL-7) were not considered for validation due to their low R ² values and two QTLs (qPSS-3-2 and qGW-3-2) were not detected in the BC₂F₅ population. Fifteen QTLs showed the beneficial effect to enhance the trait value of the breeding lines. QTL validation aided to select the promising lines for further utilization.     

Quantitative trait loci for yield and yield components in an Oryza sativa×Oryza rufipogon BC2F2 population evaluated in an upland environment

An advanced backcross breeding strategy was used to identify quantitative trait loci (QTLs) associated with eight agronomic traits in a BC₂F₂ population derived from an interspecific cross between Caiapo, an upland Oryza sativa subsp. japonica rice variety from Brazil, and an accession of Oryza rufipogon from Malaysia. Caiapo is one of the most-widely grown dryland cultivars in Latin America and may be planted as a monoculture or in a multicropping system with pastures. The objectives of this study were: (1) to determine whether trait-enhancing QTLs from O. rufipogon would be detected in 274 BC₂F₂ families grown under the drought-prone, acid soil conditions to which Caiapo was adapted, (2) to compare the performance with and without pasture competition, and (3) to compare putative QTL-containing regions identified in this study with those previously reported for populations adapted to irrigated, low-land conditions. Based on analyses of 125 SSLP and RFLP markers distributed throughout the genome and using single-point, interval, and composite interval mapping, two putative O. rufipogon derived QTLs were detected for yield, 13 for yield components, four for maturity and six for plant height.We conclude that advanced backcross QTL analysis offers a useful germplasm enhancement strategy for the genetic improvement of cultivars adapted to stress-prone environments. Although the phenotypic performance of the wild germplasm would not suggest its value as a breeding parent, it is noteworthy that 56% of the trait-enhancing QTLs identified in this study were derived from O. rufipogon. This figure is similar to the 51% of favorable QTLs derived from the same parent in crosses with a high-yielding hybrid rice cultivar evaluated under irrigated conditions in a previous study. In conclusion, parallel studies in rice using AB-QTL analysis provide increasing evidence that certain regions of the rice genome are likely to harbor genes of interest for plant improvement in multiple environments. Received: 3 September 1999 / Accepted: 16 May 2000     

植酸在水稻（Oryza sativaL.）细胞培养中的促进作用

植酸（Ｃ６Ｈ１８Ｏ２４Ｐ６）添加到固体和液体培养基中,能显著降低多酚氧化酶活性,稳定培养基中ＰＨ值和ｍＶ值,并能促进水稻细胞生长,增强细胞抗褐化和水渍化能力,从而改善细胞状态。在培养基中植酸的最佳添加量为０．１％,配合使用ＭＥＳ可以增强其稳定ＰＨ值的效果。     

Subspecies — Specific Microsatellite Markers for Rice (Oryza sativa L)

Subspecific classification of Asian rice (Oryza sativa L) into indica and japonica has always been a subject of interest althrough for rice breeders and geneticists. The present study aims at identifying subspecies specific microsatellite markers in six genotypes, each of indica and japonica using 372 microsatellite primers covering the entire genome. Only 36 primers gave clear polymorphism on 3% agarose gel and these can be used as diagnostic markers for routine and easy identification of the subspecies.     

水稻(Oryza satica L.)干旱胁迫响应转录因子研究进展

干旱胁迫是水稻生长发育和产量的重要限制因子。转录因子在水稻对干旱胁迫响应中起关键调控作用。水稻中参与干旱胁迫的转录因主要有DREB转录因子、NAC转录因子、b ZIP转录因子、锌指蛋白转录因子、MYB转录因子、WRKY转录因子和TIFY转录因子等。这些转录因子与特异的靶基因的顺式作用元件结合调控水稻抗旱相关基因的表达,增强水稻对干旱胁迫的适应能力,本综述对这些转录因子在干旱胁迫中的表达调控和功能进行简要概述。     

水稻(Oryza sativa L.)原生质体分离与培养的进一步研究

在过去工作的基础上,改进了原生质体的分离技术、培养基及培养条件,成功地获得了大量水稻原生质体再生的愈伤组织。讨论了得到实验重复结果所需要的主要条件。     

差异显示法分离赤霉素调控的水稻（Oryza sativa）cDNA

赤霉素是植物生长发育过程中一类重要的调节激素。本文运用反转录和聚合酶链式反应建立了一套旨在分离差异表达ｃＤＮＡ的差异显示方法。ＤＤＦ１所对应的基因是一个单拷贝基因,可被高浓度的ＧＡ３诱导并获得高水平表达。     

RFLP Analysis of Progeny from Hybrid of Oryza alta×O.sativa

Oryza alta Swallen is a species of allotetraploid wild rice (CCDD, 2n = 48) with high biomass production and resistant to several insects and diseases. The high polymorphism (RFLP) between O. alta and O. sativa L. (average 90%) reveals the long phylogenical distance between these two species which may impede the crossing. The chromosome constitutions of several progeny from O. alta × O. sativa were analyzed with 22 mapped rice RFLP markers. The results showed that almost all triploid sterile plants which had 36 chromosomes were, as expected, composed of the chromosomes from two parents. But the two partial fertile regenerated plants from 02428 (O. sativa) × WHS601-2 (O. alta) which had only 24 and 25 chromosomes respectively, in most cases, had RFLP patterns similiar to their O. sativa parent. Therefore the chromosomes constituted their genomes were mainly from O. sativa or have high homology with the chromosomes of O. sativa. It seems evident that chromosome elimination had occurred during the wide hybridization as O. alta RFLP patterns could be found in them. Furthermore, that the introgression of O. alta chromosome fragment into that of O. sativa in an F2 plant was indicative that some kind of recombination also occurred. Regarding the rare chromosome pairing in PMCs, the probability of the existence of a nonconventional mechanism for the wild rice chromosomes (chromosome fragments ) to introgressing into cultivated rice genomes in a relatively short time was discussed.     

普通野生稻（Oryza rufipogon Griff．）的SSR遗传多样性研究

利用SSR标记对分布在我国7个省的17个居群普通野生稻(Oryza rufipogon Griff．)的种质资源进行研究,结果表明：17个居群普通野生稻的遗传多样性有着显著的差异,从UPGMA聚类结果可以看出普通野生稻的遗传多样性与其生态地理分布有显著的相关性,遗传多样性指数高的地区极有可能是栽培稻的起源中心;用筛选出的7对SSR引物对336份：DNA样品进行扩增,得到60条特异条带,在分子水平上进一步证明普通野生稻的起源为两广地区;本研究也表明SSR是进行遗传资源多样性研究的一种切实有效的研究方法。     

广东特殊生境的普通野生稻(Oryza rufipogon Griff)遗传变异研究

选择来自广东佛冈县地处山林区远离稻田的一个普通野生稻生境中的25份野生稻样本,以国外多年生、一年生普通野生稻7份样本和广东地方栽培稻8个品种为对照进行种植观察,调查了21个形态生物学性状,对调查数据作方差分析表明,有20个性状表现极显著差异,1个性状表现显著差异.通过模糊聚类分析,可将25份样本分为4类,各类与对照材料之间表现不同的遗传差异,说明该生境野生稻存在较丰富的遗传变异,但从形态生物学和生育期观察,从中尚未发现一年生型、栽培型、粳型等变异类型的分化.     

广东特殊生境的普通野生稻（Oryza rufipogon Griff）遗传变异研究

选择来自广东佛冈县地处山林区远离稻田的一个普通野生稻生境中的25份野生稻样本,以国外多年生、一年生普通野生稻7份样本和广东地方栽培稻8个品种为对照进行种植观察,调查了21个形态生物学性状,对调查数据作方差分析表明,有20个性状表现极显著差异,1个性状表现显著差异。通过模糊聚类分析,可将25份样本分为4类,各类与对照材料之间表现不同的遗传差异,说明该生境野生稻存在较丰富的遗传变异,但从形态生物学和生育期观察,从中尚未发现一年生型、栽培型、粳型等变异类型的分化。