普通小麦品种Brock抗白粉病基因分子标记定位

为明确利用Brock转育成的小麦抗白粉病品系3B529(京411*7//农大015/Brock, F₆)抗性的遗传基础,将高感白粉病小麦品系薛早和3B529杂交,获得F₁代、F₂分离群体和F_2:3家系。抗病性鉴定和遗传分析结果表明,3B529对E09小种的抗性受1对显性基因控制,暂被定名为MlBrock。利用BSA和分子标记分析,获得了与MlBrock连锁的3个SSR标记Xcfd81、Xcfd78、Xgwm159和2个SCAR标记SCAR203和SCAR112,根据SSR和SCAR标记在中国春缺体四体、双端体和缺失系的定位结果,将MlBrock定位在小麦染色体臂5DS Bin 0~0.63区间上。MlBrock与Xcfd81和SCAR203共分离,与SCAR112的遗传距离为0.5 cM。这些分子标记的建立有利于今后Brock抗白粉病基因分子标记辅助选择和基因聚合。综合抗白粉病基因MlBrock的染色体定位和抗谱分析结果,推测MlBrock很可能是Pm2基因。     

从野生二粒小麦导入普通小麦的抗白粉病基因MlWE18分子标记定位

野生二粒小麦(Triticum turgidumvar. dicoccoides)是小麦抗白粉病遗传改良的重要基因资源。利用野生二粒小麦WE18与普通小麦品种(系)连续多次杂交和自交,育成对白粉病菌生理小种E09高度抵抗的小麦新品系3D249(京双27//燕大1817/WE18/3/温麦4,F₇)。利用高感白粉病品系薛早和3D249组配杂交组合,获得杂种F₁代、F₂分离群体和F₃代家系,进行苗期白粉病抗性鉴定和遗传分析。结果表明,小麦品系3D249对E09小种的抗性受显性单基因控制,暂命名该基因为MlWE18。利用集群分离分析法(BSA)和分子标记分析,发现4个简单重复序列(SSR)标记(Xwmc525、Xwmc273、Xcfa2040和Xcfa2240)、1个EST-STS标记(Xmag1759)和1个EST-STS序列标记(XE13-2)与抗白粉病基因MlWE18连锁,在遗传连锁图谱上的顺序为Xwmc525–Xcfa2040–Xwmc273–XE13-2–Xmag1759–MlWE18–Xcfa2240。SSR标记的染色体缺失系物理定位结果表明,抗白粉病基因MlWE18位于小麦7A染色体长臂末端的Bin 7AL 16–0.85–1.00。与已知定位于该染色体区域的Pm基因遗传连锁图谱比较表明,MlWE18与抗白粉病基因Pm1、MlIW72、PmU、Mlm2033和Mlm80均位于7AL相同染色体区段。     

水稻半矮秆基因iga-1的鉴定及精细定位

在前期通过空间诱变获得半矮秆隐性突变基因iga-1的基础上,进一步对iga-1进行鉴定。农艺性状调查表明携带iga-1的矮秆株系CHA-2、CHA-2N与原种特籼占13相比存在明显变异。节间长度测量显示CHA-2、CHA-2N节间比例正常,属dn型。外源GA₃处理、内源GA₃测定和α-淀粉酶活性检测揭示iga-1与GA₃调控无关。利用CHA-2与粳稻品种02428杂交获得的F₂群体将iga-1定位在水稻第5染色体两个InDel标记DL18和DL19间32.01 kb的物理距离内。该区域有5个阅读框架,其中包括赤霉素信号传导调控基因D1。序列分析表明CHA-2、CHA-2N和特籼占13在D1位点上基因组序列不存在差异,推测D1并非iga-1的候选基因。比较水稻第5染色体上其他矮秆基因发现iga-1可能与半矮秆基因sd-7来自同一位点。     

利用三个分子标记鉴定大麦Yd2基因型及其在育种辅助选择中的应用

研究分子标记鉴定大麦抗黄矮病基因Yd2的有效性,可为Yd2基因在大麦抗病育种中的广泛应用提供快速有效的分子辅助选择工具。利用与Yd2基因紧密连锁的YLM、CAPS-Ylp和ASPCR-Ylp标记同时检测52份国内外大麦品种(系)与4份大麦F₁杂种的Yd2基因型,同时结合生物学抗性检测的表型分析其有效性。通过对Yd2基因型已知的20份大麦品种(系)及4个F₁杂种的Yd2基因型分析,表明YLM、CAPS-Ylp与ASPCR-Ylp标记可以有效判断大麦Yd2基因型。进一步用这3个标记检测32份Yd2基因型未知的大麦的基因型,鉴定出基因型为Yd2^-/Yd2^-的品种(系) 27份,基因型为Yd2⁺/Yd2⁺的品种(系) 5份。在回交育种的分子辅助选择实例中,从BC₂F₂世代中选出了16个基因型为Yd2⁺/Yd2⁺的单株。3个分子标记结合应用能够快速有效地鉴定大麦Yd2基因型,可用于Yd2基因回交育种中的大规模分子标记辅助选择。     

水稻卷叶基因RL13的遗传分析和分子定位

叶片形态是理想株型的重要指标之一,叶片适度卷曲有利于理想株型的建成,是水稻超高产育种的重要材料。在EMS诱变籼稻缙恢10号群体中发现一个卷叶突变体,表现叶片筒状卷曲,经过多代连续自交,性状稳定,命名为rl₁₃ (rolled leaf 13)。rl₁₃的叶绿素a、叶绿素b和总叶绿素含量均显著高于野生型对照缙恢10号,类胡萝卜素含量在苗期、孕穗期与野生型相比有显著提高,而抽穗期和成熟期则差异不显著。rl₁₃的三片功能叶的卷曲度与野生型相比均达到极显著差异,但rl₁₃的三片功能叶之间差异不显著。通过石蜡切片分析,突变体叶肉细胞层数变薄,野生型含有的一个较大泡状细胞转变为卷叶突变体的两个大小相近的泡状细胞,导致了叶片弯曲。以该突变体为父本,西农1A为母本配制杂交组合构建F₂遗传群体,结果表明,该卷叶性状由一对隐性核基因控制。选用F₂代分离群体中的1 215个隐性单株作为定位群体,将RL₁₃定位在第6染色体短臂上分子标记RM276和SWU6-1之间,遗传距离分别为1.1 cM和0.2 cM。     

棉属野生种克劳茨基棉(Gossypium klotzschianum)基因组向陆地棉的渐渗

 棉花远缘种质是改良栽培种的丰富资源,野生种遗传变异的有效利用依赖于鉴定并渐渗理想的野生种DNA进入栽培种的能力。为了检测二倍体野生种克劳茨基棉染色质在陆地棉中的渐渗情况,构建了一个来自于（陆地棉×克劳茨基棉）×陆地棉的BC₁ F₂群体,并用320个覆盖棉花基因组的SSR标记来监测外源种质的转入;只有38个标记在BC₁F₂群体中显示了分离,这些标记分布于14条染色体,组成了18个渐渗片段;通过比较发表的棉花遗传图谱,这18条渐渗片段的总长为595 cM;同时两个形态性状（黄色花瓣和开放花蕾）被定位于13号染色体。通过分子和形态鉴定,结果证实克劳茨基棉染色质已被渐渗进陆地棉遗传背景中。利用这种特异的标记将会促进理想的外源基因转入栽培棉。     

棉花纤维特异/优势表达基因的染色体定位

 棉纤维是研究植物细胞伸长和细胞壁建成以及纤维素生物合成的优良模型,迄今为止,已经分离了许多纤维特异/优势表达的基因。为了便于这些基因的图位克隆使其能够应用于棉花纤维品质的改良中,本研究采用分离群体定位法和Blast分析法对这些基因进行染色体定位。利用陆地棉、海岛棉BC₁种间分离群体,将GhCFE定位在第6染色体,GhGLP1-250定位在第19染色体。Blast分析将11个基因定位到棉花染色体上。这些基因与棉纤维的伸长和细胞壁的合成相关,与这些基因连锁标记的获得有助于棉花纤维长度和强度的分子标记辅助选择。     

兼抗全蚀病和白粉病小麦新种质的创制与鉴定

TaLTP5是从小麦中分离到的一个脂质转移蛋白编码基因。利用基因枪介导法将TaLTP5表达载体pA25-TaLTP5转入抗白粉病的小麦品种扬麦18 (含抗白粉病基因Pm21)中, 旨在选育兼抗全蚀病和白粉病的小麦新种质。对转基因小麦T₀~T₃代植株中引入TaLTP5基因进行分子检测和抗病性鉴定。PCR检测、Southern杂交分析结果表明, 外源TaLTP5基因已转入、整合到3个转基因小麦株系的基因组中, 并能稳定遗传; 荧光定量RT-PCR的分析以及全蚀病菌的接种与鉴定结果表明, 与受体小麦扬麦18相比, 这3个转基因小麦株系中TaLTP5表达量显著提高, 其对全蚀病的抗性也明显增强。对3个转基因株系的Pm21分子标记和白粉病抗性鉴定表明, 外源TaLTP5基因的导入没有影响受体小麦对白粉病抗性, 说明这些转基因株系为兼抗全蚀病和白粉病小麦新种质。     

一个新的水稻短根毛突变体的遗传分析和基因定位

根毛是植物吸收水分和养分的重要器官。本研究从T-DNA突变体库中获得一个以中花11为遗传背景的水稻短根毛突变体, 命名为ossrh3 (Oryza sativa short root hair 3)。该突变体的根毛伸长严重受阻, 并且伴随株高、主根长、侧根长和侧根数目等性状的改变。遗传分析表明该突变性状受1对隐性单基因控制, 利用ossrh3纯合体和籼稻品种Kasalath杂交构建F₂定位群体, 利用已公布的水稻SSR (simple sequence repeat)和自行设计的STS (sequence- tagged site)标记, 最终将OsSRH3定位在水稻第1染色体上的标记S38978和S39016之间, 物理距离约为37.7 kb, 包含8个候选基因, 为进一步克隆OsSRH3基因和研究禾本科作物根毛发育的分子调控机理提供了依据。     

水稻类病变突变体c5的遗传分析与目标基因的精细定位

水稻类病变突变体c5是由粳稻品种中花11种子经化学诱变剂EMS (甲基磺酸乙酯)诱变处理得到的。该突变体叶片在三叶期开始出现近似圆形褐色斑点，经DAB染色和台酚蓝染色显示这些斑点积累了过多的H₂O₂并引起程序性细胞死亡。与野生型相比，突变体c5的成熟期株高从110.4 cm减少到74.6 cm，有效分蘖数和每穗着粒数分别减少23.7%和28.5%，千粒重和结实率都显著降低，此外，c5还表现出对白叶枯病菌的广谱抗病性，对10个菲律宾生理小种都有强烈的抗性反应。遗传分析表明，c5的突变性状受单隐性核基因控制。利用c5和明恢86配组形成的包含6269个单株的F₂群体和18个分子标记，将c基因限定在水稻第5染色体长臂STS标记S41和S47之间大约102 kb的遗传距离内。序列分析发现该区间内其中有11个编码基因，且它们与现已报道的类病变基因都不同，暗示c5可能是一个新型类病变性状控制基因。     

Mapping of a novel,major late blight resistance locus in the diploid (1EBN) Mexican Solanum pinnatisectum Dunal on chromosome VII

Late blight caused by the oomycete Phytophthora infestans (Mont.) de Bary (Pi) is the most important foliar disease of potato worldwide. An intraspecific hybrid between individuals of a resistant and a susceptible S. pinnatisectum accession was backcrossed to the susceptible parent to generate a segregating population for late blight resistance consisting of 84 plants. In detached‐leaflet assays, reaction to late blight segregated in a 1r:1s manner in BC₁ progeny indicating the presence of a single dominant resistance gene. A genetic map was constructed based on 1,583 DArT/SSR markers which were allocated to 12 linkage groups, covering 1,793.5 cM with an average marker distance of 1.1 cM. The late blight resistance locus derived from S. pinnatisectum was mapped on chromosome VII. In comparison with the previously reported resistance genes Rpi1 and Rpi2, the new target resistance locus most likely is located on the opposite arm of chromosome VII. Results of this study will serve as a basis for future fine mapping of the late blight resistance locus and the development of locus‐specific markers for marker‐assisted selection.     

The potato R10 resistance specificity to late blight is conferred by both a single dominant R gene and quantitative trait loci

The R10 late blight differential of potato, 3681ad1, exhibits good field resistance. Progeny from the cross between 3681ad1 and the susceptible cultivar ‘Katahdin’ were assessed for late blight resistance to three Phytophthora infestans isolates, using a detached leaf assay. Progeny differed in response to the three isolates. Resistance to isolates IPO‐0 and 99018 was controlled by quantitative trait loci (QTL), whereas resistance to isolate 89148‐9 was inherited as a dominant R gene, designated as R10 in this study. Statistical analysis revealed that one of the resistance QTLs to isolates IPO‐0 and 99018 is linked to the R10 gene, which maps to chromosome 11 in a region where a complex late blight resistance locus has been reported previously. A high‐resolution map of R10 was constructed using a large segregating population, and the gene was delimited to a genetic interval of 0.26 cM. The clustering of the qualitative gene R10 with resistance QTLs could explain the field resistance observed with 3681ad1.     

水稻抗白叶枯病新基因Xa32（t）的鉴定和初步定位

通过多菌系接种鉴定及抗谱分析,并与目前国际上已知抗白叶枯病基因比较,证明在水稻抗源C4064中含有一个新的抗白叶枯病基因,暂命名为Xa32(t)。应用分离集团分析法(BSA),借助SSR和EST等分子标记,对该基因进行了分子标记定位。通过对F₂分离群体及F₃家系单株进行遗传连锁性检测,发现6个位于水稻第11染色体长臂末端的分子标记RM27256、RM27274、RM2064、ZCK24、RM6293和RM5926与Xa32(t)基因连锁。它们与Xa32(t)基因间的遗传距离分别为2.1、1.0、1.0、0.5、1.5和2.6 cM。其中标记RM6293和RM5926位于染色体近端粒一侧,其他4个标记RM27256、RM27274、RM2064和ZCK24位于基因的另一侧。将Xa32(t)定位在水稻第11染色体长臂末端2.0 cM范围内。     

水稻抗白叶枯病新基因Xa32（t）的鉴定和初步定位

通过多菌系接种鉴定及抗谱分析,并与目前国际上已知抗白叶枯病基因比较,证明在水稻抗源C4064中含有一个新的抗白叶枯病基因,暂命名为Xa32(t)。应用分离集团分析法(BSA),借助SSR和EST等分子标记,对该基因进行了分子标记定位。通过对F₂分离群体及F₃家系单株进行遗传连锁性检测,发现6个位于水稻第11染色体长臂末端的分子标记RM27256、RM27274、RM2064、ZCK24、RM6293和RM5926与Xa32(t)基因连锁。它们与Xa32(t)基因间的遗传距离分别为2.1、1.0、1.0、0.5、1.5和2.6 cM。其中标记RM6293和RM5926位于染色体近端粒一侧,其他4个标记RM27256、RM27274、RM2064和ZCK24位于基因的另一侧。将Xa32(t)定位在水稻第11染色体长臂末端2.0 cM范围内。     

分子标记技术在马铃薯晚疫病研究中的应用

马铃薯是世界上重要的粮食作物之一,晚疫病则是当今危害马铃薯生产最为严重的病害。重点介绍了四种常用的分子标记技术RFLP、RAPD、AFLP和SSR,以及国内外利用这些标记技术在马铃薯晚疫病研究中的应用。分析了马铃薯晚疫病菌的遗传多样性、菌株抗药性、有性杂交后代的遗传分离以及抗病种质资源的遗传多样性,介绍了遗传图谱的构建、抗性基因及与晚疫病抗性相关的QTL定位、体细胞杂种及回交后代的晚疫病抗性检测。这些对今后中国学者开展相关领域的研究具有重要的借鉴意义。     

马铃薯资源晚疫病抗性的全基因组关联分析

广谱抗性基因的挖掘是马铃薯高抗晚疫病品种选育的基础。本研究以288份国际马铃薯中心筛选的晚疫病抗性群体为试验材料,经过连续2年田间调查,计算AUDPC和sAUDPC值,评估群体晚疫病抗性;利用SLAF-seq方法进行群体简化基因组测序,通过对晚疫病抗性表型数据的全基因组关联分析,挖掘晚疫病抗性相关的遗传位点和候选基因,为晚疫病抗性品种选育和抗病机理研究提供一定的理论和材料基础。结果表明,晚疫病抗性在288份材料间存在着广泛的遗传差异;基于5种分析模型,共鉴定到82个与晚疫病抗性显著关联的位点;在关联区间关联到54个已知或可能与晚疫病抗性相关的基因。其中,23个基因为抗性基因,包括晚疫病抗性基因R1同源基因、Sw-5同源基因(R8)和Rpi-vnt1以及编码多效性耐药蛋白基因;5个基因编码MAPK蛋白和WRKY转录因子;1个基因参与茉莉酸途径;3个基因与水杨酸途径相关;6个基因是病程相关的基因;3个基因参与苯基丙酸类合成途径;其他与晚疫病抗性相关的基因,如HMGR基因(2个)、细胞色素P450(21个)。     

Linkage analysis of rice bacterial blight resistance gene xa20 in XM6, a mutant line from IR24

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is an important disease constraining rice (Oryza sativa L.) production worldwide. The XM6 line was induced by N-methyl-N-nitrosourea from IR24, an Indica cultivar that is susceptible to Philippine and Japanese Xoo races. XM6 was confirmed to carry a recessive gene named xa20, resistant to six Philippine and five Japanese Xoo races. The chromosomal gene location was found using 10 plants with the shortest lesion length in an F₂ population consisting of 298 plants from a susceptible Japonica variety Koshihikari × XM6. Analysis using PCR-based DNA markers covering the whole rice genome indicated the gene as located on the distal region of the long arm of chromosome 3. The IKC3 line carries IR24 genetic background with Koshihikari fragment on chromosome 3 where a resistance gene was thought to be located. The F₂ population from IKC3 × XM6 clearly showed a bimodal distribution separating resistant and susceptible plants. Further linkage analysis conducted using this F₂ population revealed that xa20 is located within the 0.8 cM region flanked by DNA markers KIC3-33.88 (33.0 Mb) and KIC3-34.06 (33.2 Mb). This study yields important findings for resistance breeding and for the genetic mechanism of Xoo resistance.     

一个粳稻来源抗稻瘟病基因的鉴定、遗传分析和基因定位

7001S是一个广谱抗稻瘟病的粳稻两用核不育系,对来自全国不同稻区的22株稻瘟病菌系均表现为高度抗性。通过构建7001S/80-4B F2群体的遗传分析和初步定位表明,F2分离单株对稻瘟病菌的抗性呈明显的抗、感双峰分布,抗感分离符合3﹕1的理论比例,说明粳稻7001S对稻瘟病菌的抗性由1对显性核基因或一个显性QTL位点控制,并将该基因初步定位于第11染色体长臂末端。进一步通过扩大遗传群体和分子标记开发,利用基于BSA的隐性群体分析技术,将目的基因精细定位于P21-2415和RM27322之间约310 kb的范围内,并获得了可用于分子标记辅助选择的紧密连锁和共分离分子标记,同时对目标基因所在区域进行基因预测,初步确定了候选基因。为进一步开展该抗稻瘟病基因的克隆、功能验证和抗病机理研究,以及通过分子标记辅助选择技术培育抗稻瘟病水稻新品种等工作奠定了基础。     

Half-sib progeny evaluation and selection of potatoes resistant to the US8 genotype of Phytophthora infestans from crosses between resistant and susceptible parents

The objectives of this study were to evaluate the use of potato (Solanum tuberosum L.) late blight (Phytophthora infestans (Mont.) de Bary) resistant parents in cultivar development and identify superior clones possessing moderate to high late blight resistance combined with acceptable maturity and tuber quality. Ninety-five crosses were made between eight unadapted parents with reported late blight resistance (B0718-3, Bertita, Bzura, Greta, Libertas, Stobrawa, Tollocan and Zarevo) and susceptible parents (cultivars or advanced breeding clones) adapted to North American growing conditions. A total of 408 field selected clones were assessed for late blight resistance in the greenhouse and in the field using a mixture of US8 P. infestans isolates (A2 mating type, metalaxyl resistant) that overcame all known R-genes except R8 and R9. Clones with ≤ 10% infected foliar area in the greenhouse test or ≤ 0.30 RAUDPC (relative area under the disease progress curve) value in the field in 1998 were re-tested in 1999. A total of 118 (29% of 408) putative late blight resistant clones were selected. The eight late blight resistant parents differed in both the ability to transmit late blight resistance and in the level of resistance transmitted to the progeny. The Tollocan and B0718-3 families (half-sib progeny) had the greatest degree of resistance and frequency of resistant clones. Scott-Knott cluster analysis ranked 79 clones (67% of 118) in the high and moderate late blight resistant groups. Among these 79 clones, 19 clones had vine maturity equal to or earlier than mid-season combined with acceptable tuber quality. Further selection in 2000 resulted in eight advanced selected clones (six from Tollocan and two from B0718-3 families) with the same level of resistance as the parent combined with vine maturity and tuber quality equivalent to Atlantic, a standard cultivar for chip processing in North America. The results indicate that this breeding approach can be used to select parents for late blight resistance breeding and to identify superior clones with high levels of late blight resistance and marketable vine maturity and tuber quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis and identification of SSR marker linked to Phomopsis blight resistance in eggplant (Solanum melongena L.)

The present investigation was carried out to decipher inheritance of resistance and to identify linked SSR markers for Phomopsis blight resistance in eggplant. An F₂ population comprising 161 plants was developed from the cross of Pusa Kranti and BR-40-7. Genetic analysis was carried out using Chi square test. Artificial inoculation of fruits was carried out using pin prick method, and scoring was done as per the standard scoring scale. The F₂ plants segregated into 92 susceptible (77—highly susceptible, 15—susceptible): 69 resistant (17—highly resistant, 27—resistant, 25—moderately resistant) suggesting complimentary epistasis with ratio of 9:7. To identify the putatively linked markers to resistance gene, parental polymorphic markers were subjected to bulk segregant analysis (BSA), and two markers (emk03O04 and emf11A03) could differentiate resistant and susceptible bulk and co-segregated with resistance gene. The genetic distance between the identified markers was found to be 18.12 cM using QTL IciMapping V3.2 software depicting two new QTLs on chromosome number 6. The identified QTLs have great significant importance in marker assisted breeding programme.