栽培稻与普通野生稻BC2F2群体产量相关性状的QTL分析

以广陆矮4号(Oryza sativa ssp. indica)为母本及轮回亲本,普通野生稻（Oryza rufipogon）为父本,分单株连续回交2次,构建BC2F2群体。首先用241对具有双亲多态性的SSR标记对BC2F1单株进行代换片段分析,在此基础上,根据BC2F1的表型选产量较优的单株自交获得BC2F2群体,用代换片段上具有双亲杂合型基因型的24对SSR标记进行QTL定位。在所选的BC2F1单株上,共检测到分布于7条染色体上的20个野生稻的代换片段,平均每条染色体上有2.86个;代换片段长度最小为0.55 cM,最大为33.00 cM,平均长度为12.36 cM,总覆盖长度为247.20 cM,覆盖率为16.21%。利用BC2F2群体对14个产量相关性状进行QTL定位,共检测到控制8个性状的20个QTL。对性状表型值起增效作用的有11个,占总检出数的55%。控制产量相关性状的QTL存在簇状分布现象,这与表型相关分析结果相符合。     

栽培稻和普通野生稻基因组的随机扩增多态性DNA（RAPD）初步分析

 用35个随机引物对5个籼稻品种、5个粳稻品种和27份中国普通野生稻进行了RAPD分析。60%以上的引物能在籼稻和粳稻基因组间显示差异；中国普通野生稻与栽培稻的差异主要表现在与籼稻的不同，绝大部分供试野生稻的RAPD带型与粳稻的相同。这说明多数中国普通野生稻偏粳，但也存在偏籼的普通野生稻。     

栽培稻和普通野生稻基因组的随机扩增多态性DNA（RAPD）初步分析

用35个随机引物对5个籼稻品种、5个粳稻品种和27份中国普通野生稻进行了RAPD分析。60%以上的引物能在籼稻和粳稻基因组间显示差异;中国普通野生稻与栽培稻的差异主要表现在与籼稻的不同,绝大部分供试野生稻的RAPD带型与粳稻的相同。这说明多数中国普通野生稻偏粳,但也存在偏籼的普通野生稻。     

广东高州普通野生稻与粳稻杂交F1胚囊育性及发育特点

利用整体染色激光扫描共聚焦显微术(WE CLSM), 对广东高州普通野生稻与粳稻台中65杂交F1的成熟胚囊育性、胚囊形成发育及受精特点进行研究。杂种F1成熟胚囊平均育性为64.61%。不同杂种的成熟胚囊均存在不同程度的异常现象, 异常的主要类型有：胚囊退化、小胚囊、雌性生殖单位退化、卵器退化、极核数目或位置异常及其他异常等类型。其中频率最高的异常类型为雌性生殖单位退化（10.49%）,其次是胚囊退化（9.80%）。杂种F1的胚囊发育过程与高州野生稻原种基本一致,育性低的杂种F1胚囊发育过程出现多种异常现象。对3个杂种F1受粉后1 d的胚囊进行观察发现,除正常受精膨大的胚囊外,还存在结构正常未受精和结构异常未受精等异常现象。受粉后7 d的胚囊基本上与受粉后1 d的相似。研究结果表明,广东高州普通野生稻可能具有决定杂种F1胚囊育性的不同基因,包括中性基因等。     

Screening of High kcat Rubisco among Poaceae for Improvement of Photosynthetic CO2 Assimilation in Rice

Abstract

The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a major limitation of photosynthetic CO₂ assimilation in C₃ plants. In order to find useful Rubisco for improvement of photosynthesis in rice under elevated CO₂, we analyzed the catalytic turnover rate (k_cat) of Rubisco in Poaceae including C₃ alpine plants, C₃ cold-resistant plants and C₄ plants. Rubisco in these plants showed 1.1- to 2.8-fold higher k_cat than that in rice. However, the most of high k_cat Rubisco also showed a higher km for CO₂ (Kc) than that of rice, indicating that increase in k_cat led to decrease in the affinity for CO₂. Rubisco in Festuca ovina, Phleum pratense and Sorghum bicolor showed relatively high k_cat to Kc. Although the k_cat of Rubisco in F. ovina and P. pratense was not so high (1.5-1.6 fold relative to rice), the Kc was comparable to that in rice and the amino acid sequence of RbcL shared higher identity to that in rice than that in S. bicolor. By contrast, Rubisco of S. bicolor showed considerably high k_cat (2.5-fold relative to rice), which is considered to be the most important factor for improvement of photosynthesis. In our estimation, the expression of high k_cat Rubisco of F. ovina and S. bicolor in rice could significantly enhance CO₂ assimilation at Ci of 50 Pa, the level assumed to be reached by the middle of this century.     

应用东乡野生稻回交重组自交系群体分析糙米矿质含量QTL

【目的】 强化粮食作物的必需矿物质有利于缓解人们矿质营养缺乏症。【方法】 从协青早B//协青早B/东乡野生稻BC₁F₅群体中挑选到1个单株A58,与协青早B回交,构建了BC₂F_4:5群体。采用电感耦合等离子体原子发射光谱仪ICP-AES测定132个BC₂F_4:5株系的糙米Mg、Ca、Zn、Fe、Mn和Cu含量,应用Windows QTL Cartographer 2.5进行糙米矿质QTL分析。【结果】 共检测到17个糙米矿质含量QTL,分别位于第1、4、6、8、9和11等6条染色体上,包括Mg含量1个、Ca含量4个、Zn含量4个、Fe含量2个、Mn含量2个和Cu含量4个。这些QTL解释表型变异的5.0%~47.2%,其中8个QTL的增效等位基因来自东乡野生稻。【结论】 12个QTL聚集于5条染色体上的5个QTL簇,表明不同矿质营养元素涉及到共同遗传生理机制,可通过分子标记辅助选择方法将有利等位基因应用于稻米营养品质改良。     

Physio-morphological Studies of F1 Hybrids in Rice (Oryza sativa L.): Photosynthetic ability and yield

Summary

Photosynthetic ability in terms of CO₂ exchange rate and leaf area, dry matter accumulation (dry weight) and other important growth components along with yield and yield contributing characters in two F₁ hybrids of Akebono × Chiyonishiki (A × C) and Zenith × Akebono (Z × A) were studied. The photosynthetic rate at the flowering stage was lower than that at the panicle initiation stage in all the inbred parent cultivars and F₁ hybrids. Heterosis in photosynthetic rate was higher at the panicle initiation stage than that at the flowering stage. Pre-anthesis leaf area in the F₁ hybrid was significantly larger than that in the parent cultivars. However, the post- anthesis decline in leaf area was more rapid in the F₁ hybrids than in the parent cultivars and its magnitude was the highest in the F₁ hybrid of Z × A which was tall having long and curved panicles. Pre-anthesis dry matter accumulation in both hybrids was significantly higher in the F₁ plants than the parental cultivars, but post-anthesis dry matter accumulation in the F₁ hybrid was lower than the mid-parental value in Z × A. The degree of heterosis in grain yield varied with the hybrid combination, an average heterosis being 1.03. Heterosis in grain yield was closely associated with heterosis in harvest index.     

栽培稻杂交后代保护酶活性的变化

以抗水稻细菌性条斑病（简称细条病）的普通野生稻DY3和感病轮回亲本9311组合构建了BC2F2群体．分蘖期用针刺法人工接种广西细菌性条斑病菌优势致病型菌株JZ28,选取其中的1、3、5、7、9级植株为材料,在孕穗期接种第2次,研究接种细条病后水稻叶片防御酶活性的变化动态及其与抗病性的关系。结果表明：高抗病1级与高感病9级材料的苯丙氨酸解氨酶（PAL）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）的活性和丙二醛（MDA）含量与对照亲本时间动态变化趋势相似,而过氧化物酶（POD）活性变化不一致;不同抗病等级之间,苯丙氨酸解氨酶活性和过氧化氢酶活性在极端抗感材料之间差异显著．超氧化物歧化酶、过氧化物酶活性和丙二醛含量差异不显著．     

Identification of QTLs for Improvement of Plant Type in Rice (Oryza sativa L.) Using Koshihikari / Kasalath Chromosome Segment Substitution Lines and Backcross Progeny F2 Population

Abstract

Thirty-nine chromosome segment substitution lines (CSSLs) population derived from a Koshihikari / Kasalath cross was used for quantitative trait locus (QTL) analysis of plant type in rice (Oryza sativa L.). Putative rough QTLs (26.2～60.3cM of Kasalath chromosomal segments) for culm length, plant height, panicle number, chlorophyll content of flag leaf blade at heading and specific leaf weight, were mapped on the several chromosomal segments based on the comparison of CSSLs with Koshihikari in the field experiment for 3 years. In order to verify and narrow QTLs detected in CSSLs, we conducted QTL analyses using F₂ populations derived from a cross between Koshihikari and target CSSL holding a putative rough QTL. The qPN-2, QTL for panicle number was mapped on chromosome 2. In traits of flag leaf, the qCHL-4-1 and qCHL-4-2 for chlorophyll content was mapped on chromosome 4, and the qSLW-7 for specific leaf weight on chromosome 7. All QTLs were detected in narrow marker intervals, compared with rough QTLs in CSSLs. The qPN-2, qCHL-4-1 and qCHL-4-2 had only additive effect. On the other hand, the qSLW-7 showed over-dominance. It could be emphasized that QTL analysis in the present study with the combination of CSSLs and backcross progeny F₂ population can not only verify the rough QTLs detected in CSSLs but also estimate allelic effects on the QTL.