RFT1与Hd1所在区间对水稻抽穗期、株高和千粒重的作用

 抽穗期是决定水稻品种适应地区和季节的关键性状。水稻抽穗期QTL对产量性状和（或）株高具多效作用是个普遍现象, 但是, 除了Ghd7和DTH8（Ghd8）, 其他水稻抽穗期基因的多效性尚需进一步验证。本研究针对抽穗期基因RFT1 Hd3a所处区间和Hd1所处区间, 以珍汕97B为轮回亲本、密阳46为供体亲本, 构建了遗传背景基本一致的2个BC2F5分离群体;采用Windows QTL Cartographer 2.5进行抽穗期、株高及千粒重的QTL分析, 并根据RFT1 Hd3a下游17 kb处的连锁标记Si2944及Hd1的基因标记Si9337的基因型, 将每个群体中的纯合基因型材料分成4组, 比较其表型差异。结果表明, 这2个区间对抽穗期、株高及千粒重均呈显著作用, 它们之间不呈显著互作, 且Hd1所处区间对3个性状的作用均强于RFT1 Hd3a所处区间。     

水稻抽穗期基因的精细定位、克隆和生物学功能分析

介绍了水稻抽穗期QTL研究的进展,在相同亲本日本晴/Kasalath衍生的不同类型的多个群体中,共检测到15个QTL;应用高世代回交后代,精细定位了其中8个QTL;将在初步定位时同一区间检测到的1个控制种子休眠期QTL(Sdr1)和1个抽穗期QTL (Hd8),分解为两个紧密连锁的基因;将经过精细定位表明可能具有双重功能的单个孟德尔因子Hd3,分解为两个功能不同的紧密连锁的基因Hd3a和Hd3b;根据QTL近等基因系的光周期反应以及这些座位间上位性互作的研究,明确了其中6个QTL的生物学功能;应用图位法克隆了其中3个QTL,研究了它们的表达和调控,并与拟南芥的同源基因进行比较。为水稻其他数量性状以及其他作物数量性状的遗传学研究,提供了一个范例。     

4引物分子标记鉴定水稻高光效基因型hd3a~(Kasa)

水稻的抽穗期关乎水稻的光合效率、适应季节和种植范围,其表现直接决定了水稻能否高产稳产。Hd3a编码的成花素是水稻抽穗调控通路中的关键因子,在短日照下促进抽穗,长日照下推迟抽穗。Hd3a包含多个等位基因,其中来自aus稻品种Kasalath的hd3aKasa相比来自温带粳稻品种日本晴(Nipponbare)的Hd3aNip,在第4个外显子处有2个连续的碱基突变(CC→AA),使得hd3aKasa的功能强于Hd3aNip。hd3aKasa是高光效基因型,一般携带hd3aKasa的水稻品种产量更高,但会导致水稻开花推迟,可能影响其正常生产;而杂合态的Hd3aNip/hd3aKasa则表现出产量高和抽穗延迟适中,相比2种纯合基因型更加有利。由于Hd3a的不同等位基因各具优势,处于杂合状态下还可互补,因此建立可精确选择Hd3a等位基因的分子标记在育种实践中意义重大。本研究利用扩增受阻突变系统(Amplification refractory mutation system,ARMS)的原理,开发出包含4条引物的共显性分子标记hd3afnp,鉴定Hd3a的功能单核苷酸多态性(Functional nucleotide polymorphism,FNP)。hd3afnp同表型完全连锁,1次PCR反应即可精确区分2种纯合等位基因型及其杂合基因型,从而有助于水稻的高光效分子标记辅助选择育种。     

水稻品种桂朝2号抽穗期的基因型分析

应用抽穗期感光基因型明确的秋光（e1e1 e2e2e3e3 Se1eSe1e）、越光 (E1E1E2E2e3e3Se1eSe1e）、日本晴（E1E1e2e2e3e3Se1Se1）和日光（E1E1 E2E2 e3e3Se1Se1）作鉴别品种,分析了中籼水稻品种桂朝2号的抽穗期基因型。结果表明桂朝2号的抽穗期感光基因型为E1E1e2e2E3E3Se1tSe1tiSe1 iSe1, Se1t可能是Se1位点中的一个新的显性感光基因,其效应小于Se1n和Se1u。进一步用抽穗期QTL近等基因系NIL（Hd1）、NIL（Hd2）和NIL（Hd5）进行的实验也验证了桂朝2号存在显性的主效感光基因Se1t及hd2, hd2基因可能与隐性感光抑制基因iSe1等位,其功能是抑制显性主效感光基因Se1t的表达。     

南方稻区弱感光型单季稻的抽穗期基因组合探索

在“双改单”趋势不可避免、农村劳动力越来越紧缺的情况下，选育弱感光型单季稻品种，可缓解单季稻播种期及移栽期劳动力紧缺的问题，有助于稳定并提升单季稻种植面积，从而提高耕地利用率。本研究应用具有hd1Ghd7同质背景的籼稻恢复系D71和中恢161配组衍生的重组自交系，开展分期播种试验，分析DTH8和Hd2各基因型组合的抽穗期变化，筛选弱感光型基因组合。结果显示，在hd1Ghd7背景下的DTH8和Hd2各基因型组合中，dth8hd2和dth8Hd2组合无论播种早晚均表现较短的抽穗期。而DTH8Hd2和DTH8hd2呈现出弱感光性：早播时抽穗期长，保证光温资源的充分利用；迟播时抽穗期缩短，避免秋冬季低温对灌浆结实的影响。尤其是DTH8Hd2组合，早播时其抽穗期较DTH8hd2更长，对光温资源利用更加充分。研究结果为弱感光型单季稻品种培育提供了理论依据。     

水稻新不育系科丰A显性早熟性的遗传机制分析

  籼型细胞质雄性不育系科丰A表现出早熟性,该不育系与晚籼恢复系所配组的F1都呈现不同程度的显性早熟现象。为了解该不育系显性早熟性的遗传机制,利用一整套抽穗期感光基因近等基因系EG0～EG7、ER、LR、T65、T65Eb、T65Ebm、T65m、NIL(Hd1） 和NIL(Hd4) 等对科丰A抽穗期感光基因的基因型进行了初步分析。结果表明,科丰A的抽穗期基因型为E1E1e2e2E3E3Se 1uSe 1uEf 1Ef 1,并带有感光基因E1的显性抑制基因（暂定名为Su E1）和感光基因Se 1u的隐性抑制基因（i Se 1）。分析了由该不育系配组的杂种F1表现早熟现象的原因,并探讨了科丰A所带早熟相关基因的育种利用价值。     

水稻抽穗期QTL及其与产量性状遗传控制的关系

 产量和抽穗期是评价水稻品种应用价值的基本性状。水稻QTL分析已经历了从初定位到基因克隆的发展过程,并以抽穗期和产量性状最受重视。总结了亚洲栽培稻抽穗期QTL的基因组分布,分析了这些QTL与产量性状遗传控制的关系,为进一步筛选和鉴定具有较高育种应用潜力的水稻抽穗期QTL和产量性状QTL提供参考。     

不同水稻品种富硒能力研究

[目的]研究不同水稻品种和施用时期对水稻富硒能力的影响。[方法]以华安501、Y两优7号、新两优6号为试材,采用双因素裂区设计,分别在孕穗期、抽穗期、齐穗期喷施100 mg/kg亚硒酸钠,研究不同品种和施用时期对水稻富硒能力的影响。[结果]两系杂交水稻对外源硒的吸收存在品种间差异;齐穗期喷施外源硒增产显著,一般增产0.5%～12.0%;抽穗期喷施外源硒结实率降低0.1%～2.9%,抽穗期和齐穗期喷施外源硒较孕穗期喷施千粒重增加0.2～0.8 g;水稻抽穗期和齐穗期喷施外源硒稻米硒含量最高。[结论]水稻抽穗期叶面喷硒效果最好。     

水稻抽穗期途径基因的磷酸化、泛素化研究进展

水稻是一种广泛种植的兼性短日照植物.水稻抽穗期是直接影响产量和品种地域适应性的重要农艺性状.因此,研究该性状的影响因素并使植株在适宜的时间抽穗具有重要意义.水稻抽穗期作为一个复杂的数量性状,受内在基因网络和外界光温等条件的共同调控.目前,已经鉴定和克隆出多个控制抽穗期的关键基因,发现磷酸化和泛素化修饰在抽穗期分子机制中...     

黑龙江省主栽水稻品种抽穗模型研究初报

采用黑龙江省生产上主栽的早熟、中熟和晚熟的6个水稻品种,在哈尔滨地区做分期栽培田间试验。调查记载播种、插秧和抽穗期。采取平行观测的气象资料,分析温度对水稻抽穗期和水稻营养生长期的影响。结果表明:不同的插秧期水稻抽穗期变化很大,不同熟期的水稻品种插秧至抽穗期需要的有效积温差别明显,但每个品种需要的有效积温很稳定。     

Quantitative Trait Loci for Yield Traits Located Between Hd3a and Hd1 on the Short Arm of Chromosome 6 in Rice

QTLs for heading date located in the region between Hd3a and Hd1 were detected using an F2:3 population developed from a residual heterozygous line (RHL) identified from the recombinant inbred lines of the indica rice cross Zhenshan 97B/Milyang 46. Linkage in coupling phase between the heading date QTLs and QTLs for yield traits detected in a previous study was found. Four more F2:3 populations were each developed from an RHL, which were homozygous at Hd3a and Hd1 but heterozygous in a portion of the intervals flanked by Hd3a and Hd1. QTLs for grain yield per plant, number of panicles per plant, number of grains per panicle and 1000-grain weight were detected in the heterozygous region. Five sets of near-isogenic lines (NILs) with overlapping heterogenous segments covering the interval RM6119-RM6779 were developed and used to validate and delimitate the QTLs. A QTL having a consistent effect for the number of grains per panicle was located within the interval RM19615-RM19652 that corresponded to a 514.4 kb region on chromosome 6. The same region might have pleiotropic effects on the other three yield traits analyzed, but the effects varied greatly among different populations and across different environments. This study suggests that it is possible to develop a population with little variation on heading date and to identify QTLs for yield traits that might not be associated with heading date by using information of the physical positions of DNA markers and cloned genes.     

NRL3 Interacts with OsK4 to Regulate Heading Date in Rice

NRL3 is essential for the growth and development of rice leaves. In this study, we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions. The yeast two-hybrid and the bimolecular fluorescence complementation proved that NRL3 interacts with OsK4, a Snf1-related kinase. OsK4 localized to the nucleus and expressed in various rice tissues. The rhythmic expression pattern of OsK4 was similar to NRL3 under long daylight and short daylight conditions. Knock-out mutants of OsK4 exhibited early heading under long daylight conditions, indicating that it acts as a negative regulator of heading date in rice. Interestingly, the OsK4 mutant under the nrl3 mutant background rescued the late heading phenotype of nrl3 under long daylight conditions, suggesting that OsK4 functions downstream of NRL3. Moreover, both NRL3 and OsK4 controlled heading date through regulating the expression of Hd3a and RFT1 genes. These findings shed light on the heading date regulation in rice and provide a sound theoretical base to improve regional adaptability of rice.     

Mapping of Hd-6-2 for Heading Date Using Two Secondary Segregation Populations in Rice

Heading date is one of the most important traits for rice adaption to different cultivation areas and crop seasons. In this study, two single segment substitution lines(SSSLs), W31-41-61-3-11-3-6-7(W31-SSSL) and W32-59-80-2-11-1-10(W32-SSSL) with substituted intervals derived from the donor parents IR66897 B(W31) and IR66167-27-5-1-6(W32), respectively, with Huajingxian 74(HTX74) were found to comprise a gene for extremely late-heading date, and the gene was tentatively designated as Hd-6-2. Two secondary F2 segregating populations were developed by crossing the two heterozygous SSSLs with HJX74 to map Hd-6-2 gene. According to phenotype analysis of the two mapping populations, the late heading date trait was controlled by a major recessive gene. In the segregation population derived from W31-SSSL, Hd-6-2 was mapped on chromosome 6 between PSM677 and RM204 with the genetic distances of 1.3 and 2.7 c M, respectively. In the population of W32-SSSL, the gene for heading date was mapped to the similar region as Hd-6-2 and co-segregated with PSM672. The sequence alignment of Hd3 a in the coding domains and promoter regions of HJX74 and W31-SSSL are completely consistent, whereas there was a great difference between W32-SSSL and HJX74, suggesting that Hd3 a could hardly be the main cause of the heading date variation in W31-SSSL, but it was probably the main reason for the change of heading stage in W32-SSSL.     

Genetic Mechanism of Dominant Earliness in Kefeng A, a New Rice Cytoplasmic Male Sterile Line

Kefeng A is an early maturing indica cytoplasmic male sterile (CMS) line of rice. Combinations derived from Kefeng A and late maturing indica restorer lines showed dominant earliness to various extents. To understand the genetic basis of dominant earliness, the genotype of photoperiod-sensitive genes in Kefeng A was analyzed using a complete set of heading time near isogenic lines (NILs) EG0 to EG7, ER, LR, T65, T65Eb, T65Ebm, T65m, NIL(Hd1) and NIL(Hd4). Results indicated that Kefeng A contained two dominant photoperiod-sensitive alleles E1 and Se-1u on E1 and Se-1 loci, respectively, and the genotype of photoperiod-sensitivity genes for heading time in Kefeng A was E1E1e2e2E3E3Se-1uSe-1uEf-1Ef-1. Based on the detected heading time genotype, in combination with the heading time of Kefeng A and the early maturing phenomenon in its derived F1 hybrids, it is speculated that Kefeng A might carry a dominant inhibitor gene Su-E1 for the dominant photoperiod- sensitive gene E1, and a recessive inhibitor gene i-Se-1 for another dominant photoperiod-sensitive gene Se-1. The reason why F1 hybrids from Kefeng A exhibited early maturing was hereby analyzed and the breeding value of dominant earliness related genes in Kefeng A was discussed.     

我国华北地区粳稻品种抽穗期遗传分析

 设置长、短日照和高、低温共4种环境,分析了我国华北地区14份主栽粳稻品种的抽穗期光、温敏感性及基本营养性。结果表明,华北地区多数粳稻品种表现出感光性,但感光性大都偏弱,抽穗期长短与品种的感光性呈显著线性相关。此外,大多数品种对温度也比较敏感。并利用一套抽穗期主基因近等基因系对这些品种抽穗期基因型进行了分析。结果表明,所有华北地区粳稻品种都携带主效感光基因E1,而在Se 1位点,有11个品种为非感光的Se 1e,同时,有13个品种都携带早熟基因Ef 1,另外,有9个品种还携带具有一定感光抑制效应的hd2。这些结果从基因型角度揭示了华北地区粳稻品种具有一定的感光性和较短的基本营养生长期的原因,为华北地区选育适宜抽穗期的粳稻品种提供了依据。