The Hardness locus on the short arm of chromosome 5D is the main determinant of grain texture in bread wheat. The Pina and Pinb genes are tightly linked at this locus, and the soft kernel texture phenotype results when both genes are present and encode the wild-type puroindoline proteins PINA and PINB. In this study a compensating T5VS 5DL Triticum aestivum-Haynaldia villosa translocation line, NAU415, was characterized by chromosome C-banding, genomic in situ hybridization and molecular markers. Single Kernel Characterization System (SKCS) analysis and scanning electron microscopy indicated that NAU415 had soft endosperm although it lacked the wheat Pina-D1a and Pinb-D1a genes, suggesting the presence of functional Pin gene orthologs on chromosome 5VS. Using a PCR approach, Pina-related (designated Dina) and Pinb-related (Dinb) genes in H. villosa and NAU415 were identified and sequenced. The nucleotide and predicted amino acid sequences showed close similarities to the wild-type puroindolines of T. aestivum cv. Chinese Spring. The tryptophan-rich regions of both Dina and Dinb showed a sequence change from lysine-42 to arginine, a feature that may have an effect on grain texture. The potential of T5VS 5DL translocation line as a source of genes that may be used for modulation of endosperm texture and other valuable traits in wheat breeding is discussed.

脱氧血腐镰刀菌烯醇（deoxynivalenol，DON）在小麦赤霉病发病过程中起重要作用，是一种毒性因子。禾谷镰刀菌的侵染能力依赖于其产生DON的能力，抗病品种能显著降低病穗组织中DON的含量。本研究利用Affymetrix小麦基因组芯片，对抗赤霉病小麦品种望水白经DON诱导后的穗组织基因表达特点进行了分析，结果发现，一个编码PDR型转运蛋白的EST受DON诱导后上调表达45倍。根据该EST设计引物筛选小麦基因组TAC文库，得到一个包含该基因的TAC单克隆。利用染色体walking对该单克隆测序，用Softberry软件进行基因预测，根据预测基因的5′和3′非翻译区设计引物，从DON诱导的小麦望水白穗组织cDNA中克隆出该转运蛋白基因。该基因组全长7377 bp，包含19个外显子，CDS长度为4308 bp，编码长1435 aa且分子量161 kD的蛋白。蛋白序列比对表明，该基因属于PDR蛋白家族，命名为TaPDR1 （Triticum asetivum Pleiotropic Drug Resistance）。利用一套中国春缺体-四体系将TaPDR1基因定位在小麦5A染色体上。半定量RT-PCR表明，TaPDR1在望水白穗中受DON和禾谷镰刀菌诱导表达，表明其参与了植物抗病防御反应。该基因在望水白感病突变体中低水平表达，进一步证明TaPDR1与赤霉病抗性有关。TaPDR1的表达不受与生物胁迫相关的激素（JA和SA）和非生物胁迫因子（热、冷、伤害和NaCl）的诱导，但受到Al3+和游离Ca2+的诱导表达，推测[Ca2+]i介导了TaPDR1的表达信号。

为定位、转移和利用簇毛麦有益基因，通过花粉辐射，获得一批包括小麦-簇毛麦易位染色体的异染色体系。为了鉴定这批材料中的簇毛麦染色体身份，根据水稻、小麦的EST 序列合成了240 对STS 引物，其中34 对引物在普通小麦中国春与簇毛麦间存在多态性；进一步对亲本及簇毛麦二体异附加系进行PCR 扩增分析，标记CINAU32-300可追踪簇毛麦1V 染色体，标记CINAU33-280、CINAU34-510、CINAU35-1100、CINAU36-380 和CINAU37-400 可追踪簇毛麦2V 染色体，标记CINAU38-250 可追踪簇毛麦3V 染色体，标记CINAU39-950 和CINAU40-800 可追踪簇毛麦4V 染色体，标记CINAU41-745 和CINAU42-1050 可追踪簇毛麦5V 染色体，标记CINAU44-765 和CINAU45-495 可追踪簇毛麦7V 染色体。加上本室已开发的2 个6V 染色体特异标记，用这些簇毛麦特异分子标记鉴定辐射诱导材料的部分回交后代，选育出小麦背景中只包含单条簇毛麦染色体的整套1V 至7V 染色体系，同时有18 条易位染色体的簇毛麦身份得到确定，表明这些标记可以用来快速检测普通小麦背景中的簇毛麦染色体或染色体片段。

Sex chromosomes evolved from autosomes. Recombination suppression in the sex-determining region and accumulation of deleterious mutations lead to degeneration of the Y chromosomes in many species with heteromorphic X/Y chromosomes. However, how the recombination suppressed domain expands from the sex-determining locus to the entire Y chromosome remains elusive. The Y chromosome of papaya (Carica papaya) diverged from the X chromosome approximately 2-3 million years ago and represents one of the most recently emerged Y chromosomes. Here, we report that the male-specific region of the Y chromosome (MSY) spans ∼13% of the papaya Y chromosome. Interestingly, the centromere of the Y chromosome is embedded in the MSY. The centromeric domain within the MSY has accumulated significantly more DNA than the corresponding X chromosomal domain, which leads to abnormal chromosome pairing. We observed four knob-like heterochromatin structures specific to the MSY. Fluorescence in situ hybridization and immunofluorescence assay revealed that the DNA sequences associated with the heterochromatic knobs are highly divergent and heavily methylated compared with the sequences in the corresponding X chromosomal domains. These results suggest that DNA methylation and heterochromatinization play an important role in the early stage of sex chromosome evolution.

随机选取定位于小麦和大麦7个部分同源群上的135对EST、27对STS和253对SSR引物对24个可能的普通小麦-纤毛鹅观草二体异附加系的基因组DNA进行扩增。结果表明，55对引物在亲本普通小麦中国春、Inayama Komugi、纤毛鹅观草和Inayama Komugi-纤毛鹅观草双二倍体间有多态性扩增，其中31对引物可以在异附加系中扩增到纤毛鹅观草特异条带。根据PCR扩增结果，异附加系07K02、07K06、07K39、07K201、07K202、07K255和07K256所添加的纤毛鹅观草染色体归属小麦第1部分同源群；07K07、07K08、07K09、07K11、07K14和07K17所添加的纤毛鹅观草染色体归属小麦第2部分同源群; 07K15、07K16、07K21和07K47所添加的纤毛鹅观草染色体归属小麦第6部分同源群。

利用大麦基因芯片筛选差异表达基因并结合RT2PCR 分析技术，对簇毛麦的抗白粉病机制进行了初步研究。基 因芯片杂交试验获得了抗病簇毛麦非诱导叶片、抗病簇毛麦和感病突变体经白粉菌(Blumeria graminis f. sp. tritici)诱导叶片的基因表达谱。抗病簇毛麦经白粉菌诱导前后的表达谱及RT2PCR 分析，结果表明，抗病簇毛麦中乙烯和水杨酸信号途径的部分基因被白粉菌诱导增强表达，参与了白粉病的抗性过程。另外，通过比较诱导的抗病簇毛麦与诱导的簇毛麦感病突变体的表达谱并结合RT2PCR 分析，发现感病突变体中乙烯和茉莉酸途径的部分基因被白粉菌诱导表达参与防卫反应，未观察到水杨酸信号途径参与防卫反应的证据。同时对抗、感簇毛麦经白粉菌诱导不同时间的叶片进行了内源水杨酸含量的测定，结果表明，抗病簇毛麦经白粉菌诱导后水杨酸含量明显上升，而感病突变体中水杨酸含量始终处于较低水平。由于乙烯信号途径是抗、感簇毛麦中共同的信号途径，而水杨酸途径只在抗病簇毛麦中参与抗病反应，所以在簇毛麦的抗病过程中，水杨酸途径是一种最有效的信号传导途径。还筛选出一批与簇毛麦抗白粉病相关的基因，包括病程相关蛋白基因、防卫反应基因、转录因子、信号传导因子和抗病基因类似物等。