利用分子标记研究小麦遗传群体的赤霉病抗性鉴定方法

针对小麦赤霉病抗源苏麦3号构建的两个小麦重组自交系遗传群体苏麦3号／Alondra和苏麦3号／安农8455，采用单花接种、表土接种及自然发病3种不同的接种方法进行小麦赤霉病抗性接种鉴定，并根据苏麦3号赤霉病抗性主效QTL的连锁分子标记Xgwm 493和Xgwm 533．1分别对群体进行抗性连锁分析．检测结果表明，在温室单花接种所获得的鉴定数据中，标记的赤霉病抗性连锁效应最高，P值分别小于0．0001，抗性鉴定结果最为准确．研究表明，对小麦赤霉病这种由数量性状控制，受外界环境影响较大的真菌病害进行抗扩展性的遗传研究，应采用控温控湿条件下的单花滴注接种鉴定方法最为合适．     

Construction of a genetic linkage map for cotton based on SRAP

DNA markers have been widely used in construction of molecular genetic linkage maps in plants. The first genetic linkage map of cotton was constructed by Reinish in 1994 using RFLP (restriction fragment length polymorphism)[1], which included 705 polymorphic loci on 41 linkage groups with a total length of 4675 cM. Afterwards, several genetic linkage maps were constructed[2—7], but no map is comparable to this one in marker density. A high-density genetic linkage map could be applied effec…     

Genetic analysis and fine mapping of a lax mutant in rice

We have analyzed a lax mutant that exhibits altered panicle architecture in rice.The primary and secondary rachis-branches are normally initiated and each branch ends in a terminal spikelet,but all the lateral spikelets are absent and the terminal spikelet displays variegated structures in the mutant.An F2 population from the cross between the lax mutant and a japonica variety,W11,was constructed and analyzed.Using microsatellite and CAPS markers,the lax locus was mapped on the long arm of chromosome 1,co-segregated with a CAPS marker,LZ1,within an interval of 0.28 cM between a CAPS marker,HB2,and a microsatellite marker,MRG4389.RT-PCR analysis revealed that the expressions of the rice B-function MADS-box genes OsMADS2,OsMADS4,OsMADS16 and OsMADS3 were significantly reduced,whereas the expression of the rice A-function gene RAPIA was not altered.     

Genetic analysis and gene mapping of leafy head （lhd）, a mutant blocking the differen-tiation of rachis branches in rice （Oryza sativa L.）

Flowers, fruits and seeds are products of plant re- productive development and provide the important sources of foods for humans. Therefore, the moleculargenetic mechanisms of floral development have been ahotspot of research of plant developmental biology[1]. Rice is one of the most important staple food crops. Theoutcome of its reproductive development would determine the yield and quality of grains. Rice is also a model plantof cereals. Hence, the study of rice reproductivedevelopment, esp…     

PCR—RFLP analysis of mitochondrial DNA ND5／6 region among3 subspecies of common carp（Cyprinus carpio L.）and its application to genetic discrimination of subspecies

Mitochondrial DNA ND5/6 region was studied by PCR-RFLP analysis among ten representative strains belonging to three subspecies (Cyprinus carpio carpio,Cyprinus carpio haematopterus and Cyprinus carpio rubrofuscus) of common carp(Cyprinus carpio L.)A total of 2.4kb fragment was amplified and subjected to restriction endonuclease analysis with nine restriction endonucleases subsequently.The results indicated that each subspecies owned one hyplotype and four restriction enzymes(Dde Ⅰ，HaeⅢ,Taq Ⅰ and MboⅠ)produced diagnostic restriction sites which could be used for discriminating the three subspecies and as molecular genetic markers for assistant selective breeding of common carp.     

Morphology and mapping analysis of rice (Oryza sativa L.) clustered spikelets( Cl) mutant

The rice clustered spikelets (Cl) mutant exhibits a phenotype that most of branch apical have 2-3 spikelets clustered together,SEM (scanning electron microscope )observation suggested that the Cl gene controlled branch apical development,and influenced the terminal spikelets elongation,The spikelet number was reduced in mutant,indicating that Cl may also have an effect on spikelet number,To map Cl locus,two F2 mapping populations derived from the crosses between the Cl and ZhongHua11,and Cl and ZheFu802 were constructed ,respectively,The Cl locus was roughly mapped between two CAPS markers CK0214 and SS0324,A further fine mapping analysis showed that the Cl locus was mapped between makers R0674E and Cl12560,with genetic distances of 0.2 and 2.1 cM,respectively ,Then we found a PAC conting spanning Cl locus,the region was delimited to 196 kb.This results was useful for cloning of the Cl gene,Allelism test demonstrated that Cl was allelic to Cl2 another rice clustered spikelets mutant.     

Characterization and mapping of a lesion mimic mutant in rice （Oryza sativa L.）

A rice initiation-type lesion mimic mutant (lmi) was identified, which was isolated from an indica rice Zhongxian 3037 through γ radiation mutagenesis. Trypan blue staining and sterile culture revealed that the mutant spontaneously developed lesions on the leaves in a developmentally regulated and light-dependent manner. Genetic analysis indicated that the lesion mimic trait was controlled by a single resessive locus. Using public molecular markers and an F2 population derived from lmi and 93-11, we mapped the lmi locus to the short arm of chromosome 8, nearby the centromere, between two SSR markers RM547 and RM331. The genetic distance was 1.2 and 3.2 cM, respectively. Then according to the public rice genomic sequence between the two SSR markers, lmi was further finely tagged by three CAPS markers: C4135-8, C4135-9 and C4135-10. And lmi locus was a co-segregated with marker C4135-10, providing a starting point for lmi gene cloning.     

Characterization and molecular marker screening of a rice bacteria-resistant gene Xa-min(t)

To test the resistant spectrum of the Xa-min(t) gene introgressed from Oryza minuta, thirty-four isolates of different bacterial blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo), from 11 countries were used to inoculate the Xa-min(t) introgression line 78-15. Four rice cultivars, IR24, C64 (IRBB21), Nipponbare and Zhonghua 11 were used as controls. The results showed that the Xa-min(t) gene was broad-spectrum and highly resistant to diverse Xoo isolates. The methods of bulk segregant analysis (BSA), randomly amplified polymorphic DNA (RAPD) and sequence characterized amplified regions (SCAR) were used to analyze F2 individuals of the hybrid IR24×78-15 and molecular genetic markers linked to Xa-min(t) gene were identified. A total of 800 arbitrary decamer oligonucleotide primers were used for RAPD analysis. Two RAPD markers, BE05300 and BE061400, produced by primers BE05 and BE06 respectively, were closely linked to the Xa-min(t) gene. Based on the sequences of these two markers, sequence specific primers were designed and used to screen all F2 plants. One RAPD marker, BE05300, was converted into a stable SCAR marker (ScBE05300). Linkage analysis was carried out using markers ScBE05300 and BE061400 on 948 and 719 F2 individuals of the hybrid IR24×78-15. Our results indicate that the genetic distances from Xa-min(t) to ScBE05300 and BE061400 are 2.2 cM and 3.7 cM respectively on the same side. This study may facilitate the construction of the fine physical map of the Xa-min(t) gene.     

中国的黄管藻属

报道了我国黄管藻属植物共10种1变种，其中有1个新变种，3个中国新记录种。它们是多变黄管藻Ophiocytium variabile Bohlin，埃尔卡黄管藻O ilkae（Istvanffi）Heering和罕见黄管藻O maius Nageli,以及一个新变种－罕见黄管藻小型变种O maius var minor H L Li et Q X Wang。     

一种新的分子标记--单核苷酸多态(SNP)

单核苷酸多态(SNP)为同一物种不同个体间染色体上遗传密码单个碱基的变化，是继限制性片段长度多态性(RFLP)、微卫星标记(SSR)之后的又一种新的分子标记，通常呈双等位基因多态。在此从SNP的特点、SNP的搜寻、SNP的确认与检测、SNP数据库、SNP作图、SNP的研究前景等方面对其研究进展进行综述。