辣椒黄绿苗突变体生物学特性及生长动态研究

对96－140牛角辣椒及96－140辣椒黄绿苗突变体（96－140YBM）生物学特性、生长动态、抗病性等方面进行了测定，试验收结果表明96－140辣椒黄绿苗突变体不仅在生长势，叶片、株重、单果重等方面强于96－140，而且在抗疫病方面明显强于96－140牛角辣椒。96－140YBM性状遗传稳定，苗期遗传标记性状明显，在杂交育种及纯度鉴定上有较大的利用价值。     

Effect of mutant β-catenin gene on the proliferation of hepatocytes

AIM:The β-catenin is a key molecule in the Wnt signal pathway, which plays a critical role in normal development and tumorigenesis. However, the mechanisms of the β-catenin on the cell growth control are still not completely defined. The aim of this study was to test the hypothesis that the mutant β-catenin may regulate the hepatocyte proliferation. METHODS: The immortalized murine hepatocyte cell line, AML12, was used for this study. A plasmid that contain mutant β-catenin S33Y was transfected into the AML12 cells and a stable cell line AML12S33Y was established. The cell growth property of this cell line and the parental cell were compared by flow cytometry analysis and direct cell count. The cells were also tested for the ability to form soft agar colonies, and the ability to form tumors in the severe immune deficient mice (SCID). RESULTS:1. The mutant β-catenin containing cell line AML12S33Y has higher proliferating index compared with the parental AML12 cells (P<0.01), suggesting that mutant β-catenin promotes cell growth. 2. The mutant β-catenin cells formed small colonies in soft agar after 4 weeks of culture, but did not generate tumor in SCID mice. CONCLUSION:The mutant β-catenin promotes liver cell growth.     

甲基磺酸乙酯诱变西瓜种子的条件优化

为探明EMS诱变西瓜种子的最佳条件,以石红为试材,设置种子切口与不切口2种处理方式,采用6个诱变浓度(0.40%,1.00%,1.20%,1.40%,1.60%和2.00%)和5个诱变时间(4、10、12、14、16 h)共30个不同处理组合对西瓜种子萌发的影响进行研究。结果表明,切口处理能显著提高西瓜种子对EMS诱变剂的敏感性,共筛选出6个处理组合,诱变效果最接近半致死剂量,分别是1.20%+12 h、1.20%+14 h、1.20%+16 h、1.40%+12 h、1.40%+14 h和1.40%+16 h,对应的西瓜种子相对发芽率分别为50.38%、52.21%、51.97%、48.95%、49.97%和48.82%。以用量少且用时短为原则,确定EMS诱变西瓜种子的最佳组合是1.20%EMS诱变12 h。     

大豆突变体库构建研究进展

大豆突变体库是大豆农艺性状变异的重要来源,可以作为选育新品种资源和大豆基因功能研究的基础。综述了几种常用大豆突变体库的构建方法及其构建特点和应用范围,介绍了一些突变体库构建的新方法及其优缺点,并对这些新方法在大豆突变体库构建应用中进行了展望,为大豆育种实践和基因功能研究拓宽思路和提供参考。     

Mutation Techniques for Gene Discovery and Crop Improvement

One of the most important breakthroughs in the history of genetics ）was the discovery that mutations can be artificially induced in organisms （van Harten, 1998）. Artificially induced mutations, by physical and chemical mutagens, have greatly advanced the understanding of genetics of higher organisms. Starting in the late 1960＇s, the International Atomic Energy Agency （IAEA） and the Food and Agriculture Organization （FAO） of the United Nations sponsored extensive research on mutation induction and their application to breeding of food and indnstrial crops that resulted in the introduction of new varieties of rice, wheat, barley, apples, citrus, sugar cane, banana, and others （more than 2 500 officially released new varieties are to be found in the FAO/IAEA Mutant Varieties Database） （hitp：//www-mvd.iaea.org/MVD/default.htm）. However, the usefulness of mutation techniques has been underappreciated in research communities, particularly during the last decade, when more and more researchers and breeders were rushing into molecular marker techniques and transgenic plants. In this paper, after a brief review of the past accomplishments of mutation induction and its application, we discuss the uniqueness of induced mutations in gene discovery and how to integrate induced mutants into functional genomics programs;     

木霉对多菌灵的生物降解特性研究

从耐药性木霉菌株的诱变选育过程中,得到一株能在含多菌灵2 000 mg L-1培养基上生长的变异菌株T32。该菌株在以多菌灵为唯一碳源的无机盐培养基中,于25℃、200 rm in-1振荡培养5 d,对多菌灵的降解率达到61.4%。在pH6.0、25℃、5%接种量和加入0.5%酵母粉为最适降解条件下,该菌株对多菌灵、速克灵、扑海因、甲基布托津和三唑酮这5种常用化学农药的降解率分别达到91.4%、92.1%、55.3%、40.1%和86.5%。对原土壤、自然风干土壤和高温烘干土壤中的多菌灵进行室内降解实验,在25~28℃、5%接种量、含水量维持15%的条件下处理10 d,对多菌灵的降解率分别达到78.6%、75.3%和70.5%。     

采用两种突变方法对甘蓝黑腐病菌XC_1348基因的功能解析

为研究甘蓝黑腐病菌Xcc8004基因组中一个功能未知的假定蛋白XC_1348的基因功能,本研究用自杀质粒pK18mob和pK18mobSacB分别通过同源单交换和同源双交换构建XC_1348的非极性整合突变体1348nk和有标记的缺失突变体DM1348Gm,并对两种突变体的表型进行检测,结果显示该基因突变后不影响细菌的胞外多糖（EPS）产量、胞外酶活性以及细菌游动性.有趣的是该基因的两种突变体的致病力存在较大差异,原因可能是Xcc经两种方法定点突变后分别具有的不同基因组结构而影响到某些基因的表达所致.通过研究初步了解了XC_1348基因的功能并为今后改进定点突变方法提供现实依据.     

矮秆基因Rht_NM9在小麦株高建成中对内源激素含量的影响

普通小麦品种"南农9918"经甲基磺酸乙酯(ethyl methanesulfonate,EMS)诱变获得一个矮秆、多蘖、长穗突变体"NM9",在该突变体中定位到一个新的矮秆突变基因Rht_NM9。内源激素在普通小麦株高建成的过程中发挥重要的调节作用,为了解析Rht_NM9致矮的生理机制,本研究以南农9918及其矮秆突变体NM9为材料,利用酶联免疫吸附分析法(enzyme-linked immunosorbent assays,ELISA)测定了不同生育期各节间内源赤霉素(GA)、生长素(IAA)、脱落酸(ABA)和玉米素核苷(ZR)的含量,分析小麦发育关键时期的内源激素含量变化与株高的关系。结果表明,在孕穗期和抽穗期,矮秆突变体NM9中GA、ABA含量均显著高于南农9918,而ZR含量则显著低于南农9918,IAA含量在南农9918和突变体NM9之间无明显差异。此外,突变体NM9各节间中GA/ABA比值显著高于南农9918,而IAA/ABA、(IAA+GA)/ABA、ZR/ABA比值显著低于南农9918。以上结果表明小麦株高受多种激素调控,突变体中内源ABA含量升高,IAA/ABA和ZR/ABA比值降低会抑制植物株高伸长。     

一个新的水稻生育期延迟T-DNA插入突变体

从水稻突变体库中筛选到一个生育期延迟突变体,主要表现为生育期延迟、植株矮化、叶色变深、叶角张大、根系变短。遗传分析表明该突变体受1对隐性单基因控制。对突变体及其后代分离群体做Basta抗性检测,证实该突变体是由T-DNA插入引起的,突变性状与T-DNA共分离。PCR和Southern杂交结果进一步证实了上述观点。该材料可用于插入座位的基因克隆和生育期调控机理的研究。     

理化诱变小豆京农6号突变体的鉴定

选用小豆品种京农6号种子,分别采用甲基磺酸乙酯(EMS)(0.5%、0.9%和1.4%处理12h和24h)、电子束(100、300、600Gy)、60Co-γ(400Gy)诱变处理,将处理后的种子种于大田,鉴定后代植株性状的变异。观察表明,EMS诱变的变异类型最丰富、60Co-γ射线次之、电子束产生的变异类型较单一。EMS处理小豆以浓度0.5%和0.9%处理24h为宜;0.5%EMS处理的粒色和荚色变异突出,有鲜红、黄白、绿白粒色和黑荚、褐荚、黑褐荚变异;0.9%处理的叶形变异突出,有鸡爪叶、剑叶、肾形叶、小密叶等突变类型;电子束诱变后,M2变异率分别为4.09%、3.64%和2.22%。400Gy60Co-γ射线处理种子,后代变异率为7.23%。通过两年的鉴定筛选,获得937个EMS诱变M3代株系,934个60Co-γ射线和电子束诱变M2代株系,已得到株高、叶形、叶色、粒形、粒色、荚色、无分枝、多分枝、叶簇生、分枝簇生、光叶、蔓生、有限结荚习性、株型松散、育性、成熟特性等突变体材料1490份。本研究为小豆基因遗传分析、基因定位与克隆及其进一步的基因功能分析奠定了基础,为小豆育种提供了重要的材料。