大丽轮枝菌毒素诱导表达陆地棉cDNA序列的克隆与定位

为获得陆地棉黄萎病抗性相关候选基因,利用棉花黄萎病菌大丽轮枝菌V991毒素粗提物诱导耐黄萎病陆地棉品种‘中棉12’应激基因的表达。在诱导幼根24h时间点提取总RNA,PCR法合成双链cDNA,应用抑制消减杂交技术[1],得到了差异表达的180个克隆。经反Northernblot筛选出15个受毒素粗提物诱导应激表达的阳性cDNA克隆,将其命名为Vdrg(responsegeneinducedbytoxinofVerticilliumdahliae)。本研究对所得阳性cDNA克隆进行了序列分析,并利用PimaS6与AcalaMaxxa海陆杂交四倍体棉花F2群体对Vdrg序列进行了棉花基因组定位。

Preferential gene retention increases the robustness of cold regulation in Brassicaceae and other plants after polyploidization

Cold stress profoundly affects plant growth and development and is a key factor affecting the geographic distribution and evolution of plants.Plants have evolved adaptive mechanisms to cope with cold stress.Here,through the genomic analysis of Arabidopsis,three Brassica species and 17 other representative species,we found that both cold-related genes(CRGs)and their collinearity were preferentially retained after polyploidization followed by genome instability,while genome-wide gene sets exhibited a variety of other expansion mechanisms.The coldrelated regulatory network was increased in Brassicaceae genomes,which were recursively affected by polyploidization.By combining our findings regarding the selective retention of CRGs from this ecological genomics study with the available knowledge of cold-induced chromosome doubling,we hypothesize that cold stress may have contributed to the success of polyploid plants through both increasing polyploidization and selectively maintaining CRGs during evolution.This hypothesis requires further biological and ecological exploration to obtain solid supporting evidence,which will potentially contribute to understanding the generation of polyploids and to the field of ecological genomics.

Comparative Mapping of Cotton and Arabidopsis

A high-density inferred consensus map for 13homoeologous groups of cotton was constructedthrough the integration of three genetic maps(At,Dt and D)of homoeologous chromosomes.The consensus map included 2843 markers andspanned about 2242 cM in 13 linkage groups.1777 mapped probes were sequenced andcompared to the Arabidopsis using the

Toward a Genetically-anchored Physical Map of the Cotton Genomes

We are using a high-density(1-cM)molecularmap of the cotton genome based on RFLP,SSR,and EST markers as a foundation fordevelopment of a robust BAC-based physicalmap.The ’overgo’approach is providing anefficient means by which to accomplishhybridization-based anchoring of genetically-

植物基因组作图

前言由精典遗传学利用分子生物学工具和生物统计学方法合成的一种新概念——基因组作图——是一种研究植物生物学的有效方法。基因组图谱来源于传统的遗传连锁分析,用最新技术帮助对负责简单或复杂表型的基因进行定位作图。植物因增代时间短、易于产生大量群体、及其人工杂交的可控制性使之非常适宜进行基因组作图。广泛收集植物在形态学、生理学及发育方面的变异体,为基因研究提供了丰富的资源。图谱克隆(map-based cloning) (即根据图谱位置克隆构成可识别表型的基因)

Sequencing of Cultivated Peanut, Arachis hypogaea, Yields Insights into Genome Evolution and Oil Improvement

Cultivated peanut (Arachis hypogaea) is an allotetraploid crop planted in Asia, Africa, and America for edible oil and protein. To explore the origins and consequences of tetraploidy, we sequenced the allotetraploid A. hypogaea genome and compared it with the related diploid Arachis duranensis and Arachis ipaensis genomes. We annotated 39 888 A-subgenome genes and 41 526 B-subgenome genes in allotetraploid peanut. The A. hypogaea subgenomes have evolved asymmetrically, with the B subgenome resembling the ancestral state and the A subgenome undergoing more gene disruption, loss, conversion, and transposable element proliferation, and having reduced gene expression during seed development despite lacking genome-wide expression dominance. Genomic and transcriptomic analyses identified more than 2 500 oil metabolism-related genes and revealed that most of them show altered expression early in seed development while their expression ceases during desiccation, presenting a comprehensive map of peanut lipid biosynthesis. The availability of these genomic resources will facilitate a better understanding of the complex genome architecture, agronomically and economically important genes, and genetic improvement of peanut.

Evidence for fine-scale habitat specialisation in an invasive weed

Aims As an exotic species colonises a new continent,it must overcome enormous environmental variation in its introduced range.Local adaptation of introduced species has frequently been observed at the continent scale,particularly in response to latitudinal climatic variation.However,significant environmental heterogeneity can also exist at the landscape scale.A small number of studies have provided evidence that introduced species may also be capable of phenotypic and genetic differentiation at much smaller spatial scales.For example,previously we found US agricultural and non-agricultural populations of Sorghum halepense(Johnsongrass)to be phenotypically and genetically distinct.in this study,we inves-tigated whether this phenotypic differentiation of agricultural and non-agricultural populations of S.halepense is the result of fine-scale local specialisation.Methods We surveyed a nationally collected S.halepense germplasm panel and also collected neighbouring agricultural and non-agricultural sub-populations of S.halepense at four sites throughout Western Virginia,USA,raising seedlings in common conditions mimicking both agricultural and non-agricultural habitats.Important Findings At the national scale,we found evidence of habitat differentiation but not specialisation.However,at the local scale,we found evi-dence of specialisation in two of the four local populations to non-agricultural habitat,but no evidence of specialisation to agricultural habitat.These results show that local specialisation is a possible,but not guaranteed consequence of kilometre-scale habitat heterogen-eity in invasive species.This finding contributes to a growing aware-ness of the importance of fine-scale local adaptation in the ecology and management of introduced and weedy species.