一个新的水稻叶形突变体(tll1)的遗传分析与精细定位

利用甲基磺酸乙酯(ethylmethane sulphonate, EMS)诱变粳稻品种日本晴获得了一个遗传稳定的叶形突变体 thread-like leaf 1 (tll1)。该突变体在杭州表现为矮化、窄叶, 极端时仅剩主脉, 呈细丝状。将该突变体分别与籼稻品种南京6号、浙辐802和9311进行正反交配组, 遗传分析表明该突变体性状由1对隐性单基因控制。通过SSR和STS分子标记对F₂代分离群体进行遗传定位, 将该基因初步定位在第12染色体SSR标记RM247和RM101之间。随后利用已公布的粳稻品种日本晴和籼稻品种9311的基因组序列, 发展了7对有多态的STS标记, 最终将该基因定位在FL13和FL14之间约94.3 kb的区间内, 为进一步克隆TLL1基因奠定了基础。     

一个籼稻脆性突变体的生物学特性及基因定位研究

水稻脆性突变体是研究细胞壁组分结构形成机制的重要材料。通过离子束诱变籼稻9311获得1个茎秆、叶片均脆的突变体,命名为bc9311-1。bc9311-1突变体与野生型9311相比,分蘖数减少,结实率显著降低,其他农艺性状无明显差异。叶片和茎秆的细胞壁成分分析表明,与野生型相比,bc9311-1突变体茎秆中的纤维素和木质素含量明显降低,半纤维素和SiO2含量显著增加;叶片中的纤维素含量降低,半纤维素和木质素含量增加,SiO2含量无明显差异。遗传分析表明,该脆性突变体脆性性状受单隐性基因控制。以bc9311-1突变体与02428杂交的F2群体为基因定位群体,利用SSR标记将bc9311-1突变位点定位在水稻第1染色体上,位于SSR分子标记的RM1095和RM3632之间,遗传距离分别为0.6cM和3.4cM,与其中的标记RM1183表现共分离。这些结果为进一步克隆突变基因,揭示脆性性状的分子机制奠定坚实基础。     

一个新水稻温敏感叶色突变体的遗传分析及其基因分子定位

在粳稻品种嘉花1号（Oryza sativa L.ssp.japonica＇ Jiahua No.1＇）种子经60Coγ射线辐照处理的后代中,发现了1个低温敏感叶色突变体mr21。在较低温度（〈25.0°C）条件下,该突变体幼苗叶色呈黄色;随着温度逐渐升高,叶色由黄转绿,其临界温度约为27.5°C;在低温条件下,突变体幼苗总叶绿素含量以及叶绿素a、b的含量均较野生型嘉花1号明显下降,表明该突变体的叶色性状具有明显的温敏感性。遗传分析表明,该突变体叶色性状受1对隐性核基因控制,暂将该突变基因命名为thermo-sensitive leaf-color1（tsl-1）。以该突变体与籼稻9311（Oryza sativa L.ssp.indica＇ 9311＇）杂交的F2代分离群体作为定位群体,利用SSR分子标记将tsl-1基因初步定位在水稻（Oryza sativa）第1号染色体短臂上的MM1799与RM8132分子标记之间,其遗传距离分别为2.4cM和3.0cM;然后,进一步利用扩大F2代群体及新发展的分子标记将tsl-1基因定位在分子标记InDel2与InDel4之间的198kb内。研究结果为今后对该基因的克隆和功能分析奠定了基础。     

水稻短根毛突变体Ossrh2的表型分析与基因定位

在粳稻品种中花11为遗传背景的T-DNA突变体库中筛选获得一个遗传稳定的水稻（Oryzasativa）短根毛突变体Ossrh2（Oryza sativa short root hair2）。突变体在苗期表现为根毛数量减少,为野生型的61.4%,根毛长度明显变短,只有野生型的22.8%,同时根毛增粗,根毛形态也发生了变异,局部扭曲膨胀和分叉,除此之外突变体的地上部和根部生长情况与野生型相比没有显著差异。遗传分析表明,该突变性状受1对隐性单基因控制。通过对突变体T2和F2代的分子检测发现,该突变体表型非T-DNA插入引起。利用Ossrh2纯合体和籼稻品种Kasalath杂交构建的F2群体对OsSRH2进行基因定位,发现其与第10号染色体短臂上的SSR（simple sequence repeat）标记RM6370和RM474连锁,遗传距离分别为1.1cM和3.0cM。通过在两标记间发展3个新的STS（sequence-taggedsite）标记,将OsSRH2基因定位于标记S1227和S1531之间,物理距离约为304kb,为进一步克隆OsSRH2打下了基础。     

水稻叶状颖壳突变体Oslh的遗传分析和OsLH基因的定位

通过γ射线诱变,从粳稻品种9522的M2代中筛选出一株具有叶状颖壳的突变体,定名Oslh(1h=leafy hull).Oslh突变体的开花时间要比野生型晚15 d左右,内外稃和浆片发育成了叶片状器官.Oslh突变体与粳稻品种9522回交结果表明Oslh突变性状可能由单核基因隐性突变造成.以Oslh突变体与籼稻品种广陆矮4号杂交的F2代群体为基因定位群体,利用SSR和InDel分子标记将Oslh突变位点定位在3号染色体上的SSR标记RM5475和InDel标记GY305之间,遗传距离分别为2.5 cM和1.9 cM.这些结果为克隆OsLH基因和研究花器官发育的调控机理奠定了基础.     

一个新水稻温敏感叶色突变体的遗传分析及其基因分子定位

在粳稻品种嘉花1号(Oryza sativa L. ssp. japonica ‘Jiahua No.1’)种子经⁶⁰Co γ射线辐照处理的后代中, 发现了1个低温敏感叶色突变体mr21。在较低温度(<25.0°C)条件下, 该突变体幼苗叶色呈黄色; 随着温度逐渐升高, 叶色由黄转绿,其临界温度约为27.5°C; 在低温条件下, 突变体幼苗总叶绿素含量以及叶绿素a、b的含量均较野生型嘉花1号明显下降, 表明该突变体的叶色性状具有明显的温敏感性。遗传分析表明, 该突变体叶色性状受1对隐性核基因控制, 暂将该突变基因命名为thermo-sensitive leaf-color 1(tsl-1)。以该突变体与籼稻9311(Oryza sativa L. ssp. indica ‘9311’)杂交的F₂代分离群体作为定位群体, 利用SSR分子标记将tsl-1基因初步定位在水稻(Oryza sativa)第1号染色体短臂上的MM1799与RM8132分子标记之间, 其遗传距离分别为2.4 cM和3.0 cM; 然后, 进一步利用扩大F₂代群体及新发展的分子标记将tsl-1基因定位在分子标记InDel2与InDel4之间的198 kb内。研究结果为今后对该基因的克隆和功能分析奠定了基础。     

水稻生长发育多效基因DDF1的遗传分析与基因定位

植物中存在许多多效性基因,它们在调控植物的营养生长与生殖发育过程中起着关键性作用。文章在籼稻育种材料中发现了一个植株显著矮化且花器官明显变异的突变体ddf1(dwarf and deformed flower 1)。遗传分析表明,该突变体由单基因隐性突变所致,这说明该基因是一个同时控制营养生长和生殖发育的多效性基因,暂命名为DDF1。为了定位该基因,将ddf1杂合体与热带粳稻品种DZ60杂交,建立了F2定位群体,利用水稻RM系列微卫星标记,通过混合分离分析(BSA)和小群体连锁分析,将DDF1初步定位在水稻第6号染色体RM588和RM587标记之间,与两标记的遗传距离分别为3.8 cM和2.4 cM。进一步利用已经公布的水稻基因组序列,在初步定位的区间内开发新的SSR标记,将DDF1定位在165 kb的区间内。该结果为克隆DDF1奠定了基础。     

水稻矮秆突变体dtl1的分离鉴定及其突变基因的精细定位

文章通过对所构建的水稻突变体库进行大规模筛选,获得一个稳定遗传的矮秆突变体,与野生型日本晴相比,该突变体表现为植株矮化、叶片卷曲、分蘖减少和不育等性状,命名为dtl1(dwarf and twist leaf 1)。dtl1属于nl型矮秆,激素检测表明,矮秆性状与赤霉素和油菜素内酯无关。遗传分析显示,突变性状受单一隐性核基因控制。利用dtl1与籼稻品种Taichung Native 1杂交构建F2群体,将该突变基因DTL1定位于水稻第10染色体长臂2个SSR标记RM25923和RM6673之间约70.4 kb区域内,并与InDel标记Z10-29共分离,在该区域预测有13个候选基因,但未见调控水稻株高相关基因的报道,因此,认为DTL1基因是一个新的控制水稻株高的基因。     

基于CSSL的水稻抽穗期QTL定位及遗传分析

抽穗期是水稻（Oryza sativa）品种的重要农艺性状之一,适宜的抽穗期是获得理想产量的前提。鉴定和定位水稻抽穗期基因/QTL,分析其遗传效应对改良水稻抽穗期至关重要。以籼稻品种9311（Oryzasativa ssp.indica‘Yangdao 6’）为受体,粳稻品种日本晴（Oryza sativa ssp.japonica‘Nipponbare’）为供体构建的94个染色体片段置换系群体为材料,以P≤0.01为阈值,对置换片段上的抽穗期QTL进行了鉴定。采用代换作图法共定位了4个控制水稻抽穗期的QTL,分别位于第3、第4、第5和第8染色体;QTL的加性效应值变化范围为–6.4––2.7,加性效应百分率变化范围为–6.4%––2.7%;qHD-3和qHD-8加性效应值较大,表现主效基因特征。为了进一步定位qHD-3和qHD-8,在目标区域加密16对SSR引物,qHD-3和qHD-8分别被界定在第3染色体RM3166–RM16206之间及第8染色体RM4085–RM8271之间,其遗传距离分别为13.9cM和6.4cM。研究结果为利用分子标记辅助选择改良水稻抽穗期奠定了基础。     

云南栽培稻种SSR遗传多样性比较

采用64个SSR标记对96份云南水稻（Oryza sativa）地方品种和选育品种的遗传多样性进行比较分析。结果发现64个标记都具有多态性,共检测到741个等位基因,每个多态性位点检测到的等位基因数为2—29个,平均11．57个：Nei基因多样性指数（He）范围在0．345（RM321）-0．932（RM1）之间,平均为0．56。水稻品种的遗传多样性并非按地理位置均匀分布,而是在相似系数为0．17的水平上明显分为2个不同类群,即籼稻类群和粳稻类群,且籼粳亚种间的SSR多样性差异不明显,籼稻平均等位基因数（Ap）和Nei基因多样性指数（Ap=10．6,He=0．46）与粳稻品种（Ap=10．7,He=0．48）十分接近,可能与这些品种间存在一定频率的基因交流有关。糯稻和非糯稻在籼稻群和粳稻群中都有表现,没有特别的分布规律。云南栽培稻选育品种与地方稻亲缘关系较近,其遗传基础可能来源于云南水稻地方品种。本研究结果表明,SSR标记能较好地区分云南栽培稻品种,且云南水稻地方品种遗传多样性丰富,存在大量的优质性状可供育种实践选择。     

Genetic Analysis and Molecular Mapping of a Rolling Leaf Mutation Gene in Rice

A rice mutant with rolling leaf, namely γ-rl, was obtained from M2 progenies of a native indica rice stable strain Qinghuazhan （QHZ） from mutagenesis of dry seeds by γ-rays. Genetic analysis using the F2 population from a cross between this mutant and QHZ indicated the mutation was controlled by a single recessive gene. In order to map the locus for this mutation, another F2 population with 601 rolling leaf plants was constructed from a cross between y-rl and a japonica cultivar 02428. After primary mapping with SSR （simple sequence repeats） markers, the mutated locus was located at the short arm of chromosome 3, flanked by RM6829 and RM3126. A number of SSR, InDel （insertion/deletion） and SNP （single nucleotide polymorphism） markers within this region were further developed for fine mapping. Finally, two markers, SNP121679 and InDe1422395, were identified to be flanked to this locus with genetic distances of 0.08 cM and 0.17 cM respectively, and two SNP markers, SNP75346 and SNPl10263, were found to be co-segregated with this locus. These results suggested that this locus was distinguished from all loci for the rolling leaf mutation in rice reported so far, and thus renamed rl10（t）. By searching the rice genome database with closely linked markers using BLAST programs, an e-physical map covering rl10（t） locus spanning about a 50 kb region was constructed. Expression analysis of the genes predicted in this region showed that a gene encoding putative flavin-containing monooxygenase （FMO） was silenced in γ-rl, thus this is the most likely candidate responsible for the rolling leaf mutation.     

Characterization and Fine Mapping of a Novel Rice Narrow Leaf Mutant nal9

A narrow leaf mutant was isolated from transgenic rice （Oryza sativa L.） lines carrying a T-DNA insertion. The mutant is characterized by narrow leaves during its whole growth period, and was named nal9 （narrow leaf 9）. The mutant also has other phenotypes, such as light green leaves at the seedling stage, reduced plant height, a small panicle and increased tillering. Genetic analysis revealed that the mutation is controlled by a single recessive gene. A hygromycin resistance assay showed that the mutation was not caused by T-DNA insertion, so a map-based cloning strategy was employed to isolate the nal9 gene. The mutant individuals from the F2 generations of a cross between the nal9mutant and Longtepu were used for mapping. With 24 F2 mutants, the nal9 gene was preliminarily mapped near the marker RM156 on the chromosome 3. New INDEL markers were then designed based on the sequence differences between japonica and indica at the region near RM156. The nal9 gene was finally located in a 69.3 kb region between the markers V239B and V239G within BAC OJ1212_C05 by chromosome walking. Sequence and expression analysis showed that an ATP-dependent CIp protease proteolytic subunit gene （CIpP） was most likely to be the nal9 gene. Furthermore, the nal9 mutation was rescued by transformation of the CIpP cDNA driven by the 35S promoter. Accordingly, the CIpP gene was identified as the NAL9 gene. Our results provide a basis for functional studies of NAL9 in future work.     

水稻剑叶部分形态生理特性QTL分析以及它们与产量、产量性状的关系

光合产物是水稻产量的主要来源,因此对水稻后期功能叶片尤其是剑叶形态生理性状的遗传分析对水稻高产育种很重要。利用来源于籼／粳交后代的重组自交系群体为材料对水稻剑叶形态（叶片长、宽、面积）和生理性状（叶绿度、持绿性）进行了QTL定位,并对这些性状与产量、产量性状的相关性进行了分析。两年分别定位了17、6和14个与剑叶形态性状、叶绿度和持绿性有关的QTL,其中10个QTL在两年中共同检测到。相关分析表明,较大的剑叶可以增加穗粒数并显著增加产量,然而叶绿度和持绿性与产量、产量性状无关或呈显著负相关。叶绿度与剑叶大小呈显著负相关以及籼／粳交群体后代半不育是叶绿度和持绿性与产量、产量性状无关或呈显著负相关的可能原因。染色体4上的RM255-RM349区域同时控制3个剑叶形态性状并且解释的变异也较大,该区域可用于遗传改良以提高水稻产量。染色体3上的RM422-RM565区域重叠了3个与持绿性有关的QTL,它们对产量的贡献有待于通过构建近等基因系进行深入研究。     

Characterization and genetic analysis of a light- and temperature-sensitive spotted-leaf mutant in rice

A rice spotted-leaf mutant was isolated from an ethane methyl sulfonate (EMS) -induced IR64 mutant bank. The mutant, designated as spl30 (spotted-leaf30), displayed normal green leaf color under shade but exhibited red-brown lesions under natural summer field conditions. Initiation of the lesions was induced by light and the symptom was enhanced at 33 (°) C relative to 26 (°) C. Histochemical staining did not show cell death around the red-brown lesions. Chlorophyll contents in the mutant were significantly lower than those of the wild type while the ratio of chlorophyll a/b remained the same, indicating that spl30 was impaired in biosynthesis or degradation of chlorophyll. Disease reaction patterns of the mutant to Xanthomonas oryzae pv. oryzae were largely unchanged to most races tested except for a few strains. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively named spl30(t), which co-segregated with RM15380 on chromosome 3, and was delimited to a 94 kb region between RM15380 and RM15383. Spl30(t) is likely a novel rice spotted-leaf gene since no other similar genes have been identified near the chromosomal region. The genetic data and recombination populations provided in this study will enable further fine-mapping and cloning of the gene.     

Quantitative trait loci mapping of flag-leaf ligule length in rice and alignment with ZmLG1 gene

A doubled haploid (DH) population,which consists of 120 lines dedved from anther culture of a typical Indica and japonica hybrid 'CJ06'/'TN1',was used in this study.Ligule lengths of flag leaf were investigated for quantitative trait loci (QTL) mapping using the DH population.Five QTLs (qLL-2,qLL-4,qLL-6,qLL-10 and qLL-12) controlling the ligule length (LL) were detected on chromosomes 2,4,6,10 and 12,with the variances explained 11.4%,13.6%,27.8%,22.1% and 11.0%,respectively.Using four known genes of ZmGL1,ZmGL2,ZmGL3 and ZmGL4 in maize from the MaizeGDB,their homologs in rice were aligned and integrated into the existing simple sequence repeats linkage map by in silico mapping.A ZmLG1 homolog gene,OsLG1 encoding a squamosa promoter binding protein,was located between the markers RM255 and RM280,which is just identical to the interval of qLL-4 on the long arm of chromosome 4.The results are beneficial to dissection of the ligule molecular mechanism and the study of cereal evolution.     

Characterization and fine mapping of the glabrous leaf and hull mutants (gl1) in rice (Oryza sativa L.)

The glabrous leaf and hull (gl1) mutants were isolated from M₂ generation of indica cultivar 93-11. These mutants produced smooth leaves and hairless glumes under normal growth conditions. By analyzing through scanning electron microscope, it was revealed that the leaf trichomes, including macro and micro hairs, were deficient in these mutants. Genetic analysis indicated that the mutation was controlled by a single recessive gene. Using nine SSR markers and one InDel marker, the gl1 gene was mapped between RM1200 and RM2010 at the short arm of chromosome 5, which was consistent with the mapping of gl1 in previous studies. To facilitate the map-based cloning of the gl1 gene, 12 new InDel markers were developed. A high-resolution genetic and physical map was constructed by using 1,396 mutant individuals of F₂ mapping population. Finally, the gl1 was fine mapped in 54-kb region containing 10 annotated genes. Cloning and sequencing of the target region from four gl1 mutants (gl1-1, gl1-2, gl1-3 and gl1-4) and four glabrous rice varieties (Jackson, Jefferson, Katy and Lemont) all showed that the same single point mutation (A→T) occurred in the 5′-untranslated region (UTR) of the locus Os05g0118900 (corresponding to the 3′-UTR of STAR2). RT-PCR analysis of the locus Os05g0118900 revealed that its mRNA expression level was normal in gl1 mutant. RNA secondary structure prediction showed that the single point mutation resulted in a striking RNA conformational change. These results suggest that the single point mutation is most likely responsible for the glabrous leaf and hull phenotypes in rice.