水稻多胚品系9003的胚胎发生

水稻多胚品系9003具有6％左右的多胚频率，且多胚苗中有单倍体和多倍体出现，对胚胎发生过程的观察发现，大多数除了行正常的发育途径外，还有多卵卵器、原胚提前发育、助细胞发育成胚、合子异常分裂等现象，讨论了多胚和倍性变异体的起源，认为在栽培稻中存在生殖多样性。     

Identification of salt-tolerance QTL in rice (Oryza sativa L.)

Quantitative trait loci (QTLs) controlling salt-tolerance at the seedling stage in rice (Oryza sativa L.) were identified by interval mapping (SIM) and composite interval mapping (CIM) using a doubled haploid population ZJDH and its high resolution genetic linkage map. The population was derived from an inter-subspecific cross between an indica variety Zhaiyeqing8 (ZYQ8) and a japonica variety Jingxi17 (JX17). Analysis of survival days of seedlings treated with 0.7% NaCI revealed that a major salt-tolerance quantitative trait locus (QTL), Std, was present between markers RG612 and C131 on chromosome 1 when using both MAPMAKER/QTL 1.1 and PLABQTL 1.0 (SIM). Its allele which contributes to salt-tolerance was from ZYQ8. In addition, seven more QTLs which give additive effect on salt-tolerance are identified when using PLABQTL (CIM), and most of them were from JX17.     

一个新水稻低温敏感叶色突变体tcm11的鉴定及基因定位

对粳稻"嘉花1号"经~(60)Coγ诱变处理获得的稳定遗传低温敏感叶色突变体tcm11(thermo-sensitive chloroplast mutant 11)进行了表型鉴定与遗传分析.在20℃条件下,该突变体三叶期之前幼苗均表现为黄色,光合色素含量明显下降,叶绿体发育不完整,从第4叶开始逐渐转为浅黄绿色直至最后死亡.而在32℃条件下,其表型与野生型相比没有明显差异,具有低温敏感属性.通过对培矮64S与tcm11杂交的F_2代分离群体进行遗传分析,发现该低温敏感突变体性状是受单个隐性核基因(tcm11)控制,利用图位克隆技术对tcm11进行定位,将其定位在第11号染色体的InDel分子标记ID13252与SSR分子标记MM1361之间一个约1 566 kb的区域内.这也为后续的研究奠定了基础.     

着丝粒串联重复序列RCS2对亚洲栽培稻和非洲栽培稻的比较分析

为了揭示中高度重复序列在同为AA基因组的亚洲栽培稻和非洲栽培稻基因组中的差异以及重复序列在.栽培稻种的分化过程中可能起到的作用,利用水稻着丝粒串联重复序列RCS2作为探针分别对籼稻广陆矮4号、粳稻日本晴和非洲栽培稻的体细胞染色体进行荧光原位杂交(FISH)实验,并对其核型进行同源性聚类和比较分析,杂交结果显示:RCS2序列位于在3种栽培稻染色体组中,RCS2序列位于每条染色体的着丝粒位置,但有不同的分布特点,表明该3种栽培稻基因组的RCS2序列有不同的进化方向.探讨了RCS2序列结合Cot-1 DNA FISH方法对水稻染色体组进行核型分析的可行性和优势.     

水稻矮化突变体G蛋白α亚基基因的结构和表达

利用γ-Co60辐射诱发水稻特光矮-2(Oryza sativa L.cv.TGA-2)产生变异,获得一种稳定遗传的新型水稻矮化突变体dwarf69.dwarf69和TGA-2及其杂交后代F1、F2、F3成熟期的株高数据表明矮化表型受一对隐性基因控制.进一步研究发现,虽然dwarf69和TGA-2的G蛋白α亚基基因(Rice G protein alpha-subunit,RGA)编码区核苷酸序列只有一个核苷酸的差异,但RGA在野生型TGA-2中的表达量明显高于在突变体dwarf69中的表达量.对矮化突变体dwarf69和野生型TGA-2的RGA基因5＇上游区的序列分析表明,dwarf69 RGA 5＇上游区比TGA-2RGA5＇上游区多出1076bp.首次报道水稻矮化突变体中的RGA5＇上游区序列与其野生种的RGA5＇上游区序列存在显著的差异.     

籼-粳稻特异插入／缺失分子标记揭示的稻属植物遗传分化

籼-粳分化在亚洲栽培稻(Oryza sativa L.)的驯化过程中非常重要,但其分化机制仍不清楚.有的学者认为水稻籼-粳分化是亚洲栽培稻在驯化过程中适应不同生境的结果,也有人认为籼-粳分化在水稻的野生祖先种中就已经存在.为了研究普通野生稻的籼-粳分化,并解析稻属(Oryza)植物的籼-粳遗传变异,利用34对籼-粳特异插入/缺失分子标记(InDel)引物,研究了50份典型籼稻(O.sativa L.subsp.Indica Kato)和粳稻(O.sativa L.subsp.japonica Kato)样本以及来源于35个国家的348份稻属其他种材料.结果表明,亚洲栽培稻存在明显的籼-粳分化,普通野生稻复合体(O.rufipogon complex)中存在"偏籼"和"偏粳"类型,而稻属的其他种均未出现籼-粳分化,普通野生稻复合体中"偏籼"和"偏粳"类型的地理分布格局与籼稻和粳稻的地理分布格局相吻合.考虑到大部分普通野生稻复合体的样本取自邻近有栽培稻种植的普通野生稻群体,推测得出部分普通野生稻样本中表现出的"偏籼"和"偏粳"类型可能是栽培稻的籼稻品种和粳稻品种在普通野生稻的长期协同进化过程中基因交流的结果.     

Morphological and physiological analysis of narrow and striped leaf 1 （nsl1） mutant of rice （Oryza sativa L.） and the gene mapping

The shape and color of rice leaves are impor- tant agronomic traits that directly influence the proportion of sunlight energy utilization and ultimately affect the yield and quality. A new mutant exhibiting stable inheritance was identified as derived from ethyl methane sulfonate （EMS）-treated restorer Jinhui 10, tentatively named as narrow and striped leaf 1 （nsll）. The nsll displayed pale white leaves at the seeding stage and then white striped leaves in parallel to the main vein at the jointing stage. Meanwhile, its leaf blades are significantly narrower than the control group of Jinhui 10. The chloroplast structures of cells in the white striped area of the nsll mutant break down, and the photosynthetic pigments are significantly lower than that of the wild type. Moreover, fluorescence parameters, such as Fo, Fv/Fm, ФpsⅡ, qP, and ETR, in the nsll mutant are significantly lower than those of the wild type, and the photosynthetic efficiency is also significantly decreased. These changes in leaf color and shape, together with physiological changes in the nsll, result in smaller plant height and a decrease in the most important agro- nomic traits, such as the number of grains per panicle, grain weight, etc. Genetic analysis shows that the narrow and striped traits of the nsll mutant are controlled by a single recessive nuclear gene, which is located between InDel 16 and InDel 12 in chromosome 3. The physical distance is 204 kb. So far, no similar genes of such leaf color and shape in this area have been reported, This study has laid asolid foundation for the gene cloning and function analysis of NSL 1.     

一个水稻白化致死突变体abl25鉴定及其基因定位

经Co60辐照的粳稻嘉花1号得到一个新的致死白化突变体albino lethal 25(abl25),该突变体从发芽至4叶期表现为白化苗,之后逐渐死亡.与野生型嘉花1号相比,abl25突变体的叶绿素含量和类胡萝卜素的含量大大降低,叶绿体结构不正常,说明其叶绿体发育受到严重阻碍,导致植物死亡.遗传分析表明:该突变体受一对隐性核基因(abl25)控制,进一步利用abl25与广占63S杂交的F2分离群体,将该突变体基因(abl25)定位于第2染色体上SSR标记RM424与Indel分子标记ID7330之间,随后利用新开发的分子标记和扩大群体将其定位在Indel分子标记ID9111和ID9261之间的150 kb内,发现abl25是一个新的水稻苗期白化致死基因.     

利用粳稻基因组DNA和C_ot-1 DNA探针对普通野生稻和亚洲栽培稻的比较分析

以粳稻日本晴基因组DNA和Cot-1 DNA为探针,分别对日本晴、籼稻广陆矮4号和普通野生稻的染色体组进行了基因组原位杂交(GISH)和Cot-1 DNA荧光原位杂交(FISH)分析,并对3种染色体组进行了同源聚类和比较研究.结果表明:粳稻基因组DNA和Cot-1 DNA探针信号在3种水稻染色体组中的分布状况和覆盖率相似,Cot-1 DNA的覆盖率分别为(47.13±0.18)%、(45.89±0.22)%、(44.24±0.21)%,3种水稻基因组同源性高,亲缘关系接近.Cot-1 DNA在3种水稻染色体上的杂交信号分布各有特点,中高度重复序列的变异在普通野生稻向栽培稻进化和亚洲栽培稻籼、粳分化过程中具有重要意义,中高度重复序列含量较低的2、5、8号染色体是水稻染色体组进化过程中相对活跃的成分.