山羊mtDNA多态性及其遗传结构的研究*

 对中国6个山羊品种（辽宁绒山羊,内蒙古绒山羊,西藏山羊,中卫山羊,济宁青山羊和龙陵山羊）的52个样本进行mtDNA的D-Loop区的全序列测定,用来研究中国山羊品种的线粒体DNA遗传多态性及系统发育。用NJ法构建单倍型系统发育树,结果发现6个山羊品种的线粒体DNA控制区聚类后得到了4个很明显的分支,即单倍型A,B,C,D.品种间遗传结构分析发现内蒙古绒山羊、辽宁绒山羊两个绒山羊品种与西藏山羊、中卫山羊3个可产绒的山羊品种聚在一起,接着与产羔皮的济宁青山羊聚在一起,最后与产肉性能强的龙陵山羊聚在一起。     

A new Fusarium lineage within the Gibberella fujikuroi species complex is the main causal agent of mango malformation disease in Brazil

Mango malformation is a serious disease in tropical and subtropical areas of the world and has been attributed to various Fusarium spp., including F. mangiferae , F. proliferatum , F. sacchari , F. sterilihyphosum and F. subglutinans . Isolates of Fusarium associated with mango malformation from Brazil, Egypt, India, South Africa and the United States were evaluated through amplified fragment length polymorphisms (AFLPs) and partial DNA sequences of the genes encoding β-tubulin ( tub2 ) and translation elongation factor 1-α ( tef1 ). These techniques were used to delimit species and to estimate the genetic and phylogenetic relatedness of the isolates. In the AFLP analysis, most of the Brazilian isolates formed a unique cluster. Additionally, one small cluster was formed by isolates of F. sterilihyphosum from Brazil and South Africa, and another by isolates of F. mangiferae from Egypt, India, South Africa and the United States. In the phylogenetic analysis, most of the Brazilian isolates represented a new phylogenetic lineage in the Gibberella fujikuroi species complex, where they formed a sister clade to F. sterilihyphosum. Representatives of both clades were pathogenic to mango (cv. Tommy Atkins) and Koch's postulates were completed for isolates belonging to the new lineage and to F. sterilihyphosum . Thus, most of the mango malformation disease in Brazil is due to a distinct phylogenetic lineage of Fusarium , and to a lesser extent by F. sterilihyphosum. The new phylogenetic lineage identified in this study, together with F. mangiferae and F. sterilihyphosum , are the only known taxa of Fusarium proven to be capable of causing mango malformation.     

A new root-knot nematode, Meloidogyne silvestris n. sp. (Nematoda: Meloidogynidae), parasitizing European holly in northern Spain

High infection rates of European holly ( Ilex aquifolium ) feeder roots by an unknown root-knot nematode were found in a holly forest at Arévalo de la Sierra (Soria province) in northern Spain. Holly trees infected by the root-knot nematode showed some decline and low growth. Infected feeder roots were distorted and showed numerous root galls of large (8–10 mm) to moderate (2–3 mm) size. Morphometry, esterase and malate dehydrogenase electrophoretic phenotypes and phylogenetic trees of sequences within the ribosomal DNA (rDNA) demonstrated that this nematode species differs clearly from other previously described root-knot nematodes. Studies of host-parasite relationships showed a typical susceptible reaction in naturally infected European holly plants, but did not reproduce on a number of cultivated plants, including tomato, grapevine, princess-tree and olive. The species is described here, illustrated and named as Meloidogyne silvestris n. sp. The new root-knot nematode can be morphologically distinguished from other Meloidogyne spp. by: (i) roundish perineal pattern, dorsal arch low, with fine, sinuous cuticle striae, lateral fields faintly visible; (ii) female excretory pore level with stylet knobs, or just anterior to them, EP/ST ratio about 0·8; (iii) second-stage juveniles with hemizonid located 1 to 2 annuli anterior to excretory pore and short, sub-digitate tail; and (iv) males with lateral fields composed of four incisures, with areolated outer bands. Phylogenetic trees derived from maximum parsimony analysis based on 18S, ITS1-5·8S-ITS2 and D2–D3 of 28S rDNA showed that M. silvestris n. sp. can be differentiated from all described root-knot nematode species, and it is clearly separated from other species with resemblance in morphology, such as M. ardenensis , M. dunensis and M. lusitanica .     

Studies on the host range of the barley strain of Wheat dwarf virus using an agroinfectious viral clone

Comparative analysis of the host ranges of the barley and wheat strains of Wheat dwarf virus (WDV; family Geminiviridae ; genus Mastrevirus ) in Europe has been severely hampered by the lack of an infectious clone of the barley strain. To remedy this situation an agroinfectious clone of a Hungarian isolate of the barley strain (WDV-Bar[HU]) was constructed and its virulence tested in barley ( Hordeum vulgare ), wheat ( Triticum aestivum ), rye ( Secale cereale ) and oat ( Avena sativa ) by agroinoculation. Although all four species could be systemically infected by the isolate, infections were asymptomatic in the rye and oat cultivars tested. WDV-Bar[HU] induced chlorosis and stunting symptoms typical of WDV in barley, while in wheat low infection rates but high mortality of infected seedlings were observed. In contrast, a much higher percentage of wheat plants agroinoculated with a wheat-strain isolate (WDV-[Enk1]) became systemically infected. WDV-[Enk1] in wheat caused symptoms similar to those caused by WDV-Bar[HU] in barley. WDV-Bar[HU] was leafhopper-transmissible to barley seedlings, in which it caused typical WDV symptoms; geminate virus particles were isolated from the infected leaves. Comparison of the genomic sequences of 11 barley strain isolates from Europe and Turkey revealed that whereas WDV-Bar[HU] represents a typical barley-strain isolate that is not detectably recombinant, the Turkish barley isolate (WDV-Bar[TR]) is probably a recombinant between a barley-strain isolate and an as-yet-undescribed WDV-like mastrevirus species.     

利用RAPD进行茶组植物遗传多样性和分子系统学分析

对张宏达系统山茶属茶组植物24种、变种的遗传多样性和分子系统学进行了RAPD分析。从冬梢中获得了高质量和高得率的基因组DNA, A260/A280平均为1.71,平均得率为331μg/g鲜重。从Operon技术公司的61个十聚体随机引物中筛选出15个用于茶组植物的RAPD扩增,在所扩增得到的107条可重现谱带中(平均7.1条/引物)有102条(平均6.8条/引物)是多态的,多态性程度是95.3%。每个引物扩增的谱带数在211条之间,相对多态性频度在0.04—0.96之间,不过总平均多态性频度只有0.30,     

林木分子标记研究进展

分子标记技术大大促进了林木有关研究的发展,林木分子标记研究主要包括林木遗传连锁图谱构建,比较基因组研究,数量性状位点定位,标记辅助选择,系统演化及群体遗传变异和多样性等内容。迄今,已有近２０个树种构建了基因组遗传连锁图谱,少数树种还进行了基因研究。     

Distribution and phylogeny of Potamophila parviflora R.Br. a wild relative of rice from eastern Australia

Potamophila parviflora is a wild relative of rice from Eastern Australia. The species was found in the Richmond, Clarence, Macleay and Hastings River systems of northern New South Wales. Existing populations had wider leaves (10–15 mM) than those previously reported (4–6 mM). This species and North American wild rice, Zizania palustris were investigated as genetic resource for rice improvement. Both species, Potamophila , and Zizania , occur in colder climates than rice (Oryza sativa). Sequencing of the ITS1 of the ribosomal genes of these two species indicated that Zizania and Potamophila were more closely related to each other than either was to Oryza sativa. Potamophila has a similar number of chromosomes (n=12) and a greater sequence homology to rice and may thus be a better source of useful genes for rice improvement.     

An isolate and sequence database of infectious haematopoietic necrosis virus (IHNV)

In the field of fish diseases, the amount of relevant information available is enormous. Internet‐based databases are an excellent tool for keeping track of the available knowledge in the field. Fishpathogens.eu was launched in June 2009 with the aim of collecting, storing and sorting data on fish pathogens. The first pathogen to be included was the rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Here, we present an extension of the database to also include infectious haematopoietic necrosis virus (IHNV). The database is developed, maintained and managed by the European Community Reference Laboratory for Fish Diseases and collaborators. It is available at http://www.fishpathogens.eu/ihnv .     

中国鲷科鱼类分类和系统发育研究进展

鲷科(Sparidae)隶属于硬骨鱼纲(Osteichthyes),鲈形目(Perciformes),鲈亚目(Percoidei).目前已报道世界有34属133种,广泛分布于大西洋、印度洋和太平洋的温带至热带水域,在世界海洋渔业中占有重要地位.虽然此类群系统学研究已有250多年历史,但是在亚科、属、种(亚种)等不同分类阶元上仍然存在颇多争议和疑问,有必要对其进行深人研究.本文总结了近百年来有关鲷科鱼类的分类和系统发育研究的文献资料,厘定了中国鲷科鱼类的有效物种和种名,修订了过去文献中出现的主要同物异名和错误的命名种,初步确认中国鲷科鱼类现有7属18种(或亚种);在探讨鲷科鱼类分类地位的基础上,指出了当前中国鲷科鱼类系统分类研究中存在的问题,展望了今后研究的方向,旨在为深入研究M科鱼类以合理保护和利用其资源提供参考依据.