植物多倍体诱导育种研究进展

概述了多倍体中领域中多倍体产生途径,特征、特性及鉴定方法等研究现状,展望了植物多倍体诱导育种的应用和发展前景。     

三倍体枇杷花期调控基因EjAGL6的表达特性和功能分析

以三倍体枇杷(Eriobotrya japonica) ‘华玉无核1号’的花芽为材料,采用基因克隆技术获得EjAGL6基因,分析其序列、亚细胞定位特性以及在二倍体和三倍体枇杷早晚花品种中的表达水平。采用花序浸染转化拟南芥,并利用实时荧光定量PCR分析转基因拟南芥植株的EjAGL6基因表达量,进一步观察野生型与EjAGL6转基因拟南芥的表型差异,分析EjAGL6基因的功能,为解析EjAGL6基因参与三倍体枇杷花期调控机制提供理论依据。结果显示：(1)成功获得MADS box基因EjAGL6;该基因的编码区序列(CDS)为732 bp,编码243个氨基酸,分子质量为27.88 kD,等电点为 9.05,脂溶指数为 79.05;系统进化树分析表明,枇杷EjAGL6与苹果MdAGL6蛋白质的相似性较高,聚在同一分支。(2)蛋白序列比对发现,EjAGL6的M区有57个氨基酸,I区有30个氨基酸,K区有82个氨基酸,C区有74个氨基酸,其中C区包含高度保守的AGL6基序Ⅰ和AGL6基序Ⅱ。(3)亚细胞定位分析表明,EjAGL6蛋白定位在细胞核,具有典型的MADS box转录因子亚细胞定位特性。(4)实时荧光定量PCR分析表明,EjAGL6基因在二倍体和三倍体枇杷早、晚花品种中均有表达,主要集中于小花分化期(S6)、花蕾露白期(S7)和盛花期(S8),且EjAGL6基因在二倍体和三倍体早花品种中的花蕾露白期的表达量均较高。(5) 转基因拟南芥株系的EjAGL6基因表达量显著高于野生型拟南芥;转EjAGL6基因植株表型观察显示,EjAGL6基因在拟南芥中过量表达能够使转EjAGL6基因拟南芥的开花时间提前1周左右。研究认为,EjAGL6基因可促使枇杷开花时间提前,推测EjAGL6基因在花蕾露白期发挥调控花期的关键作用。     

植物外源基因组成分鉴定方法的研究进展

具外源基因组成分(外源染色体/染色体片段/基因)植株是目前进行基因组学研究以及作物改良的重要材料。迄今为止,已建立了基于性状观测、染色体分析、特异蛋白、DNA序列4种鉴定外源基因组成分的策略。其中,基于DNA序列的分子标记技术是当前鉴定外源基因组成分的主要手段,文中归纳了用于小麦、甘蓝等重要作物外源基因组成分的分子标记,且对简单重复序列(Simple sequence repeat, SSR)、插入缺失(Insertion-deletion,InDel)、单核苷酸多态性(Single nucleotide polymorphism,SNP)等9种标记进行了系统的比较。相比单一的鉴定方法,组合法更全面精准,文中对各组合法的应用情况进行统计和分析,提供了小麦族、芸薹族等作物的最佳鉴定组合。新一代分子标记InDel、SNP易实现高通量检测,对于外源渗入基因的精细定位展现了一定的优越性。此外,可以考虑一些新鉴定方法的加入,如微阵列比较基因组杂交(Microarray-based comparative genomic hybridization,array-CGH)、抑制差减杂交(Suppression subtractive hybridization,SSH)。     

涪陵磨盘沟自然保护区桫椤种群分布格局的分形特征

利用分形理论中的计盒维数探讨了重庆市涪陵磨盘沟桫椤种群的分形特征。结果表明,桫椤种群的分布格局具有分形特征。桫椤种群在不同海拔高度分布格局的计盒维数各不相同,与生境密切相关。在6个不同植物群落中,桫椤种群的计盒维数大小依次为黄牛奶树淡竹叶>黄杞水麻>盐肤木腹水草>血桐芒>白栎扁穗莎草>毛叶木姜子火炭木。计盒维数定量地反映了该自然保护区桫椤种群占据生态空间的能力,随机型的桫椤种群对空间占有能力比聚集型的低。     

Taxonomical revision of “Arctonyx” fossil remains from the Liucheng Gigantopithecus Cave (South China) by means of morphotype and morphometrics,and a review of Late Pliocene and Early Pleistocene Meles fossil records in China

“Arctonyx” fossil remains from the Liucheng Gigantopithecus Cave, Guangxi, are redescribed and analysed in details. Detailed tooth character differences between Arctonyx and Meles are analysed. It is shown that materials from the Liucheng Gigantopithecus Cave actually belong to two species of Meles: Meles minor and Meles magnus n. sp. At the same time, a review of Late Pliocene and Early Pleistocene Meles records in China is made. During Late Pliocene, Meles are only represented by M. chiai and one archaic form. During Early Pleistocene, Meles from northern and central part of China are represented by two nearly sympatric species Meles chiai and Meles teihardi. Meles from South China are represented by M. minor and M. magnus n. sp., though the distribution of the two species is still unclear. M. magnus n. sp. is so far only known from the Liucheng Gigantopithecus Cave, whereas M. minor is probably also known from Longgupo, Chongqing in the central part of China besides Liucheng. Great diversity of Meles in Early Pleistocene in China indicates that the genus radiated earlier than previously thought. Phylogenetic analysis suggests M. magnus n. sp. is sister group to living M. leucurus, whereas M. minor and M. chiai are early branches in Meles evolution.     

不同树形龙安柚冠层特性

以开心形、Y字形、双层分层形和自然圆头形的龙安柚为试验材料,比较不同树形的冠层特性、叶片结构和生理特征,以期为龙安柚果园小环境的调控提供理论基础。结果表明:(1)开心形间隙分数阈值最高,是自然圆头形的4.33倍。开心形与Y字形的冠层光合辐射与透射系数均显著高于其他树形,但二者无显著差异,表明开心形和Y字形的冠层通风透光特性较好。(2)开心形与Y字形叶片厚度增加,叶面积和气孔密度较大,栅栏/海绵组织厚度和组织紧密度较高,叶片组织疏密度较低,且二者无显著差异,表明开心形与Y字形利于提高叶片的光合作用,降低蒸腾作用。(3)Y字形和开心形净光合速率、水分利用率、最大表观电子传递速率、初始斜率和半饱和光强较高,而蒸腾速率较低,二者对强光的耐受能力较强;其中开心形蒸腾速率最低为2.43 mmol m~(-2)s~(-1),且其结果枝光抑制参数最小,为0.629。说明开心形为最佳的高光效树形。(4)冠层微环境因子、叶片结构及光合生理指标之间多呈极显著相关关系,但开心形叶片结构和生理的大部分指标与冠层环境因子之间相关性较低,说明开心形树形不同部位的营养枝和结果枝的叶片性状差异较小,其光渗透性好,整个冠层的光截获能力和有效光辐射的分布差异较小,笔者认为开心形是龙安柚栽培中的适宜高光效树形。     

Information in morphological characters

The construction of morphological character matrices is central to paleontological systematic study, which extracts paleontological information from fossils. Although the word information has been repeatedly mentioned in a wide array of paleontological systematic studies, its meaning has rarely been clarified nor specifically defined. It is important, however, to establish a standard to measure paleontological information because fossils are hardly complete, rendering the recognition of homologous and homoplastic structures difficult. Here, based on information theory, we show the deep connections between paleontological systematic study and communication system engineering. Information is defined as the decrease of uncertainty and it is the information in morphological characters that allows distinguishing operational taxonomic units (OTUs) and reconstructing evolutionary history. We propose that concepts in communication system engineering such as source coding and channel coding, correspond to the construction of diagnostic features and the entire character matrices in paleontological studies. The two coding strategies should be distinguished following typical communication system engineering, because they serve dual purposes. With character matrices from six different vertebrate groups, we analyzed their information properties including source entropy, mutual information, and channel capacity. Estimation of channel capacity shows character saturation of all matrices in transmitting paleontological information, indicating that, due to the presence of noise, oversampling characters not only increases the burden in character scoring, but also may decrease quality of matrices. We further test the use of information entropy, which measures how informative a variable is, as a character weighting criterion in parsimony‐based systematic studies. The results show high consistency with existing knowledge with both good resolution and interpretability.     

Antigenic Drift of the Hemagglutinin from an Influenza A (H1N1) pdm09 Clinical Isolate Increases its Pathogenicity In Vitro

Virologica Sinica - The influenza A (H1N1) pdm09 virus emerged in 2009 and has been continuously circulating in humans for over ten years. Here, we analyzed a clinical influenza A (H1N1)...     

定量研究晚白垩世以来陆地生态系统演化格局和过程的新进展

陆地植物的起源和演化与全球气候环境存在着密不可分的关系,而且地质历史时期全球气候环境和植被均呈动态变化,被子植物在白垩纪开始出现,并发生强烈分化,成为植物界的主宰,对这全球陆地生态系统的演化格局和过程产生重要影响,大量保存在地层中具有叶相特征的被子植物叶化石对认识这一过程提供了极为重要的生物学信息,简述了利用被子植物的叶相对古气候,古地理等进行定量分析的研究历史,“气候与叶片多变量分析程序”（Climate-Leaf Analysis Multivariate Program CLAMP）颇具特色,运用CLAMP在定量解释古气候等方面可以得到准确而精确的结果,这对定量重建晚白垩世以来全球陆地气候环境变化的格局与过程具有十分重要的意义,并对今后的深入研究作了展望。