花莲种质资源的遗传多样性及品种间亲缘关系的探讨

利用17个随机引物对来自中国和美国的29份花莲种质资源材料进行了RAPD分析。扩增形成207条谱带,多态带122条,多态率为58．94％。说明中国花莲具有较丰富的遗传多样性。结果还显示：（1）花莲种质资源可被分为2个品种群：品种群Ⅰ以大花型为主,少量小花型。品种群Ⅰ以中小型花为主。又在欧氏遗传距离11．01处分为7个亚品种群。（2）美洲黄莲与中国莲的花莲之间在DNA水平上没有显著差异,与中小型花关系更近。     

应用SRAP标记对莲藕资源的聚类分析

利用一种新的分子标记SRAP技术对17个莲藕品种进行了DNA多态性分析。选取7对引物扩增基因组DNA,共获得168条带,其中159条为多态性条带,每对引物平均提供24个标记信息。由UPMGA方法得到的聚类分析结果表明了17个品种间的遗传关系:(1)亚洲莲与美洲莲之间有明显的差异;(2)在亚洲莲内部,藕莲和花莲有明显的遗传分化,在花莲内部亚洲莲与美洲莲的杂交后代和其它花莲品种之间存在明显的差异;(3)SRAP标记是作分子图谱的好标记,但很难区分遗传关系较近的品种。     

Isolation and Identification of a Sexual Hormone in Yeast

5-Fluorotryptophan (5FT), indolmycin (IM), 4-fluorotryptophan and 7-azatryptophan were found on screening to be tryptophan antagonists among various chemically synthesized and naturally occurring tryptophan analogues for the isolation of l-tryptophan (l-Trp) producing mutants of Bacillus subtilis K.

From among 5FT resistant mutants, potent l-Trp producers were obtained using an improved isolation medium. Growth of the isolated 5FT-resistant l-Trp producer, AJ 11709, was inhibited by IM. From among 5FT and IM resistant mutants, the best strain, AJ 11979, which produced 9.0 g/liter of l-Trp from 13% glucose on 120hr cultivation, was selected.     

Relative contribution of rainfall and coconut hybrids to the abundance and composition of the Auchenorrhyncha community as potential vectors of phytoplasmas in the state of Sergipe,Brazil

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The evolution of plant microRNAs: insights from a basal eudicot sacred lotus

microRNAs (miRNAs) are important noncoding small RNAs that regulate mRNAs in eukaryotes. However, under which circumstances different miRNAs/miRNA families exhibit different evolutionary trajectories in plants remains unclear. In this study, we sequenced the small RNAs and degradome from a basal eudicot, sacred lotus (Nelumbo nucifera or lotus), to identify miRNAs and their targets. Combining with public miRNAs, we predicted 57 pre‐eudicot miRNA families from different evolutionary stages. We found that miRNA families featuring older age, higher copy and target number tend to show lower propensity for miRNA family loss (PGL) and stronger signature of purifying selection during divergence of temperate and tropical lotus. Further analyses of lotus genome revealed that there is an association between loss of miRNA families in descendent plants and in duplicated genomes. Gene dosage balance is crucial in maintaining those preferentially retained MIRNA duplicates by imposing stronger purifying selection. However, these factors and selection influencing miRNA family evolution are not applicable to the putative MIRNA‐likes. Additionally, the MIRNAs participating in lotus pollen–pistil interaction, a conserved process in angiosperms, also have a strong signature of purifying selection. Functionally, sequence divergence in MIRNAs escalates expression divergence of their target genes between temperate and tropical lotus during rhizome and leaf growth. Overall, our study unravels several important factors and selection that determine the miRNA family distribution in plants and duplicated genomes, and provides evidence for functional impact of MIRNA sequence evolution.     

莲品种DNA指纹图谱的构建

为了克服单纯依据形态特性鉴定品种的局限性, 我们开展了莲品种DNA指纹图谱构建研究, 旨在对其品种的快速准确鉴定及专利权保护等起一定作用。本研究以圆明园保存的72个莲品种为实验材料, 用来自不同地点的1,409份野生莲(Nelumbo nucifera)和58份美洲黄莲(N. lutea)群体样本作遗传背景参照。从104对核微卫星引物(nSSR)中筛选出15对, 从17对叶绿体微卫星(cpSSR)引物中筛选出2对, 共17对引物作为72个莲品种DNA指纹鉴定的条码。15对nSSR引物共检测到94个等位基因(平均6.27个), 其中11个属于美洲黄莲, 65个属于野生莲, 18个不能区分; 多态信息含量(PIC)介于0.3899-0.8023之间 (平均0.5748)。2对cpSSR引物共检测到13个单倍型, 其中9个属于野生莲, 4个属于美洲黄莲。全部17对引物标记结果显示, 共有19个品种含有美洲黄莲遗传组分, 其中8个母系来源于美洲黄莲; 有36个品种(涉及12对引物)具有至少1个特有基因型; 最少8对引物组合可完全区分开68个品种。有2组共4个品种组内全部17对引物均不能区分。本研究通过核心引物组合法使68个莲品种获得特异性DNA指纹。推荐13对nSSR和2对cpSSR共15对引物作为莲品种鉴定的核心条码, 并建议将形态特征与DNA指纹相结合作为莲品种的鉴定标准。     

荷花品种比较试验

从始蕾、始花期、群体花期、着花密度、株型、花型等方面对41个荷花品种进行比较试验。结果表明,大株型荷花品种以祝福、西湖红莲最好;中小株型以金珠落玉盘、小精灵、绿云、小碧台、玉碗、红宝石、醉半熏、淡云、雨花、桃红小碗、红碗莲、瑶池春暖等12个品种最好,具有较高的观赏价值和商品价值。     

莲属(Nelumbo Adans.)的系统学研究进展和莲科的确立

本文介绍了莲属的系统学研究的历史和最新研究成果．综述了莲属从睡莲科中独立出来,单独成科的形态学、解剖学、细胞学、孢粉学、胚胎学、植物化学、分子生物学及花器官发生等多方面的证据,并对莲科的系统学地位进行了总结。     

Induction of host‐plant preference in Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle, Brontispa longissima, is a serious invasive pest of coconut palm (Cocos nucifera) in Southeast Asia and the Pacific region. Recently, however, it has been reported that on Ishigaki Island, Japan, where C. nucifera is rare, the endemic palm Satakentia liukiuensis serves as a regular host. To explore this phenomenon, we examined the preferences of the beetle for the two palm hosts by choice tests and measurements of feeding amount using four different groups: naïve adults obtained from a colony reared on C. nucifera (NC); naïve adults from a colony reared on S. liukiuensis (NS); wild adults collected on C. nucifera on Ishigaki Island (WC); and wild adults collected on S. liukiuensis on Ishigaki Island (WS). Both NC and NS consumed significantly more C. nucifera leaves than S. liukiuensis leaves and were observed more often on the leaves of C. nucifera. These results suggest that B. longissima has an innate preference for C. nucifera. In contrast, field‐collected adults (WC, WS) initially showed preferences for the species on which they were collected, but after exposure to the other host plant for 2 weeks, their preferences for that host increased. These results suggest that the feeding experience of B. longissima adults affected their subsequent host preferences. This flexible host preference may have facilitated the beetle’s successful establishment in novel Japanese habitats where the original host plant was rare.     

莲幼苗的胚根发育及其筛分子研究

报道了莲无初生根型幼苗的胚根发育过程,其胚根由分生组织转化成贮藏组织,致使胚根不突破种皮;莲幼苗初生维管系统中的筛分子为筛管分子。莲的子叶和胚根连为一体的特殊结构与其生活环境和系统演化密切相关。