苹果分子标记及辅助育种研究进展

从基于集群分离分析法、杂交群体、全基因组关联分析和功能基因分子标记4个方面对苹果相关的分子标记及其在辅助育种上的应用进行了综述,为苹果分子标记辅助育种和揭示重要性状的遗传提供依据。     

Molecular mapping of soybean seed tocopherols in the cross ‘OAC Bayfield’ × ‘OAC Shire’

Soybean (Glycine max [L.] Merr.) is cultivated primarily for its protein and oil in the seed. In addition, soybean seeds contain nutraceutical compounds such as tocopherols (vitamin E), which are powerful antioxidants with health benefits. The objective of this study was to identify molecular markers linked to quantitative trait loci (QTL) that affect accumulation of soybean seed tocopherols. A recombinant inbred line (RIL) population derived from the cross ‘OAC Bayfield’ × ‘OAC Shire’ was grown in three locations over 2 years. A total of 151 SSR markers were polymorphic of which a one‐way analysis of variance identified 42 markers whereas composite interval mapping identified 26 markers linked to tocopherol QTL across 17 chromosomes. Individual QTL explained from 7% to 42% of the total phenotypic variation. Significant two‐locus epistatic interactions were identified for a total of 122 combinations in 2009 and 152 in 2010. The multiple‐locus models explained 18.4–72.2% of the total phenotypic variation. The reported QTL may be used in marker‐assisted selection (MAS) to develop high tocopherol soybean cultivars.     

Survey and new insights in the application of PCR‐based molecular markers for identification of HMW‐GS at the Glu‐B1 locus in durum and bread wheat

Wheat, among all cereal grains, possesses unique characteristics conferred by gluten; in particular, high molecular weight glutenin subunits (HMW‐GS) are of considerable interest as they strictly relate to bread‐making quality and contribute to strengthening and stabilizing dough. Thus, the identification of allelic composition, in particular at the Glu‐B1 locus, is very important to wheat quality improvement. Several PCR‐based molecular markers to tag‐specific HMW glutenin genes encoding Bx and By subunits have been developed in recent years. This study provides a survey of the molecular markers developed for the HMW‐GS at the Glu‐B1 locus. In addition, a selection of molecular markers was tested on 31 durum and bread wheat cultivars containing the By8, By16, By9, Bx17, Bx6, Bx14 and Bx17 Glu‐B1 alleles, and a new assignation was defined for the ZSBy9_aF1/R3 molecular marker that was specific for the By20 allele. We believe the results constitute a practical guide for results that might be achieved by these molecular markers on populations and cultivars with high variability at the Glu‐B1 locus.     

棉花纤维中木质素的相对分子量

分子量是聚合物的重要特性之一,木质素的分子量及其分布是研究苯丙烷类结构的反应、物理化学特性和评价其改性产物质量的内容之一。本研究以陆地棉TM-1成熟纤维为材料,分别利用酶解-温和酸解木质素法和二氧六环法提取棉纤维中木质素,结合凝胶渗透色谱法(gel permeation chromatography,GPC)调查和评价2种方法获得的棉纤维中木质素的相对分子量。结果表明,经二氧六环处理提取的棉花纤维中的木质素(dioxane lignin,DL)的重均分子量为2924g mol~(–1)、数均分子量2403 g mol~(–1),略高于由酶解-温和酸解处理提取的木质素(enzymatic hydrolysis-mild acidolysis lignin,EMAL)的重均分子量(2169 g mol~(–1))和数均分子量(1970 g mol~(–1)),EMAL的多分散系数稍低,说明木质素的均一性比DL高。表明EMAL法提取的木质素更适用于分析棉纤维中木质素的相对分子量。利用EMAL法分析棉纤维中木质素相对分子量表明,不同棉花品种的木质素重均分子量分布范围为938~2169 g mol~(–1),数均分子量分布范围为857~1970 g mol~(–1),多分散性系数在1.09~1.74间,均小于2。重均分子量与纤维马克隆值呈显著负相关,数均分子量与纤维长度呈显著负相关,与纤维马克隆值呈极显著负相关。     

甜橙精油分子蒸馏组分的成分分析及其抗菌活性研究

应用分子蒸馏技术加工冷压甜橙精油,分离得到轻相与重相两个组分,采用气相色谱-质谱联用技术(GC-MS)分析其化学成分,鉴定出甜橙精油轻相组分中含22种化合物,重相组分中含40种化合物。抑菌试验结果表明,甜橙精油轻相和重相组分对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和酵母菌均具有较好的抑菌效果,最低抑菌浓度(MIC)范围为0.78~3.125μL/m L。抑菌活性受不同p H和温度条件的影响,酸性环境下轻相组分的抑菌效果较好,碱性环境下重相组分的抑菌活性更强。在高温处理下,轻相组分对细菌的抑菌效果具有较好的热稳定性,重相组分的抑菌效果有所减弱。     

Assessment of molecular detection of Fusarium circinatum in insects and passive spore traps in Pinus radiata plantations

Fusarium circinatum is the causal agent of pitch canker, a destructive disease that threatens natural and planted pine forests around the world. Although pitch canker has caused problems in Spain and Portugal, concerning Europe as a whole, the fungus is not established across the pine distribution area. Its dispersion by wind and/or insect vectors could nevertheless play a role in the colonization of currently uninfected stands. It is therefore crucial to develop monitoring tools for its detection. To this end, we assessed the molecular detection of the pathogen in environmental samples of bark beetles and passive spore traps, collected in two infected Pinus radiata plantations in Basque country, Spain. The spread pattern of F. circinatum was assessed by an experimental design that included insect and spore traps installed at the centre, at the edge and outside the plots. Our results showed that F. circinatum was detected in both types of samples, at almost all collection dates. In both type of samples, positive detections were mainly found at the centre of the plots, a lower proportion at the edge, and very few outside. This suggests that long‐distance dispersion of Fusarium circinatum does not rely on wind spore dispersal neither on insect flight. Our study also shows that molecular methods are a powerful tool to monitor the pathogen in environmental samples.     

生物学自主设计型实验探索——以叶绿体DNA提取为例

指出了分子生物学是生命科学相关学科的主干课程,具有很强的实践性。同时,学生掌握分子生物学的实验方法和技术手段,对培养自身科研能力具有重要意义。结合当前高校对于绿色植物叶绿体DNA提取的实验,从丰富教学方法、更新教学手段、改进考核方式等方面进行了改革与探索。以期提高学生学习质量,强化实验技能及综合能力培养,为高校培养高素质创新型人才奠定基础。     

东北黑土nirS型反硝化细菌群落和网络结构对长期施用化肥的响应

【目的】探明长期施用氮磷钾化肥对东北黑土农田土壤nirS型反硝化细菌群落和网络结构的影响,为更加合理的肥料配施提供理论依据。【方法】基于农业农村部黑龙江耕地保育与农业环境科学观测实验站平台,选取不施肥(NoF)、氮肥(N)、磷肥(P)、钾肥(K)、氮钾肥(NK)、氮磷肥(NP)、磷钾肥(PK)、氮磷钾肥(NPK)8个施肥处理,借助荧光定量PCR、Illumina MiSeq高通量测序和分子生态网络技术,分析东北黑土nirS型反硝化细菌丰度、群落及网络结构,及影响反硝化细菌群落变异的主要环境因子。【结果】1)长期施用氮肥均在显著增加nirS基因拷贝数的同时,降低了nirS型反硝化细菌的群落多样性,而磷、钾肥对其影响并不显著。2)Proteobacteria是所有处理中的优势反硝化细菌门,相对丰度为16.96%~27.34%,且氮肥的施用促进了隶属于该菌门中Bradyrhizobium的生长。3)PCoA分析结果显示,8个施肥处理nirS型反硝化细菌群落主要分成施氮肥和不施氮肥两组,说明长期氮肥的施用显著改变了东北黑土反硝化细菌的群落结构。结合Mantel test的结果可知,土壤pH是影响nirS型反硝化细菌群落改变的主要因素。4)分别构建施氮肥和不施氮肥的反硝化细菌分子生态网络,发现施氮肥和不施氮肥网络结构存在很大差异,长期施用氮肥明显简化了nirS型反硝化细菌的网络结构,同时使其网络结构稳定性降低,易受外界环境扰动。【结论】尽管施用化学氮肥有利于土壤养分的增加,但其土壤nirS型反硝化细菌群落及网络结构发生了较大改变,而磷、钾肥的施用对反硝化细菌群落无显著影响。本试验结果为进一步研究东北黑土区农田土壤反硝化微生物对不同施肥管理的响应机制提供了重要科学依据。     

硬骨鱼类黄色素细胞的研究进展

色素细胞是动物体内产生色素的一类特化细胞,其色素颗粒可选择性吸收或反射特定波长的光,产生多种颜色,从而形成动物的体色。色素细胞由胚胎神经嵴细胞分化形成,在动物警戒、求偶、伪装、拟态、隐蔽以及环境适应性等一系列生物学过程中起着关键作用。黄色素细胞的受关注度仅次于黑色素细胞,其合成含有类胡萝卜素和蝶啶成分的红/黄色素小体,可以形成从白色到红色等一系列的颜色,是研究色素细胞互作、色素沉着以及生物进化机制的理想模型。本文综述了鱼类色素细胞的来源和分布、黄色素细胞的发育和分化以及蝶啶色素合成代谢机制三个方面,并提出了现阶段黄色素细胞研究中存在的缺陷,为鱼类体色形成、色素细胞分化及体色性状分子选育提供参考依据。