ELE restrains empty glumes from developing into lemmas

Although there is evident homology among reproductive organs when comparing Poaceae(grass)and eudicots,the identity of grass specific organs,such as lodicules,palea,lemma,and glumes has been the subject of a vast and largely inconclusive discussion.Here we provide some direct evidence to support the idea that the empty glumes of rice(Oryza sativa)are counterparts of lemmas.We show that the development of empty glumes is regulated by ELE(elongated empty glume),which belongs to a plant specific novel gene family.Mutations at the ELE locus cause elongated empty glumes,which mimic the lemmas and have the epidermal morphology of lemmas with four or five vascular bundles.As a nuclear-localized gene,ELE is specifically expressed at the empty glumes of immature spikelets,and its ectopic expression causes many floral development defects,including lemma-like palea,extra palea-like structures,elongated lodicules,extra stamens and stigmas.Our result suggests that empty glumes are lemmas of the sterile florets located at the lateral side of the rice spikelet,and ELE acts as a regulator restraining its growth to maintain its small size in wild-type plants.     

蒙古冰草外稃微形态特征的变异式样

采用电镜扫描技术对蒙古冰草（Agropyron mongolicum Keng)6个天然居群和2个栽培品种的外稃进行了观察分析。结果表明,外稃的微形态特征存在有14种变异类型,具有丰富的多态性;从这些变异的分布格局来看,主要存在于居群内的个体间,居群间的分化并不明显,反映出了居群内变异大于居群间变异的特点。     

Phylogenetic systematics of the genus Echinococcus (Cestoda: Taeniidae)

Echinococcosis is a serious helminthic zoonosis in humans, livestock and wildlife. The pathogenic organisms are members of the genus Echinococcus (Cestoda: Taeniidae). Life cycles of Echinococcus spp. are consistently dependent on predator–prey association between two obligate mammalian hosts. Carnivores (canids and felids) serve as definitive hosts for adult tapeworms and their herbivore prey (ungulates, rodents and lagomorphs) as intermediate hosts for metacestode larvae. Humans are involved as an accidental host for metacestode infections. The metacestodes develop in various internal organs, particularly in liver and lungs. Each metacestode of Echinococcus spp. has an organotropism and a characteristic form known as an unilocular (cystic), alveolar or polycystic hydatid. Recent molecular phylogenetic studies have demonstrated that the type species, Echinococcus granulosus, causing cystic echinococcosis is a cryptic species complex. Therefore, the orthodox taxonomy of Echinococcus established from morphological criteria has been revised from the standpoint of phylogenetic systematics. Nine valid species including newly resurrected taxa are recognised as a result of the revision. This review summarises the recent advances in the phylogenetic systematics of Echinococcus, together with the historical backgrounds and molecular epidemiological aspects of each species. A new phylogenetic tree inferred from the mitochondrial genomes of all valid Echinococcus spp. is also presented. The taxonomic nomenclature for Echinococcus oligarthrus is shown to be incorrect and this name should be replaced with Echinococcus oligarthra.     

Analysis of rhizobial endosymbionts of Vicia,Lathyrus and Trifolium species used to maintain mountain firewalls in Sierra Nevada National Park (South Spain)

Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study.     

大陆漂移与白蚁的系统发育

白蚁Termite是属于古老而又原始的一类昆虫。从许多生活习性和形态特征证明,等翅目Isoptera——白蚁与蜚蠊目Blattariae昆虫的亲缘关系十分接近,特别与隐尾蠊科Cryptocercidae的某些类群有着更为密切的关系。它们同以木材纤维为食,并且都是借助于体内共生的细菌和原生动物消化木纤维。当地球上高大乔木出现之后,就已经为这类蛀木昆虫的生存提供必要的生活条件。石炭纪Carboniferous是蜚蠊目昆虫最为繁盛的地质时期(林启彬,1978),为此,白蚁在地质历史上有可能与蜚蠊同时期,或接近     

Derivation and dispersal of Acacia (Leguminosae), with particular reference to Australia, and the recognition of Senegalia and Racosperma

The morphology of seedlings, leaves, flowers and inflorescences, anatomy of the pod, the occurrence of extra-floral nectaries, free amino acids of the seeds, flavonoid compounds in heartwoods, cyanogenic compounds and porate, colporate and extraporate pollen, and susceptibility to rusts, all indicate that three genera, Acacia Miller, Senegalia Raf. and Racosperma Martius, should be recognized. These correspond to currently accepted subgenera of Acacia. The size of these more narrowly circumscribed genera is in keeping with the size of genera of other tribes of low diversity in Leguminosae. Acacia and Senegalia arose independently from the Ingeae, with Racosperma being derived from Senegalia. Section Filicinae is more advanced than section Senegalia of Senegalia , and sections Racosperma and Pukhella , both with at least some species with bipinnate foliage, are the most advanced of Racosperma , while the other sections Pleurinervia and Lycopodiifolia have only phyllodinous species. Long-range dispersal of Racosperma from the Australian region has occurred, but the broad pattern of distribution is interpreted in terms of plate tectonics. Racosperma was present in Australia in the late Cretaceous but did not become widespread until the general drying of the continent in the Miocene. The flora of SW Australia has been isolated from the rest of the continent by climatic barriers since the late Tertiary and has a high proportion of endemic species. Barriers to plant migration in the east have operated only intermittently and there is no area comparable in endemism to the southwest.     

Two new species of Neosartorya isolated from soil in Xinjiang, China

Two new species, Neosartorya shendaweii and N. tsunodae, isolated from soil in Xinjing, China and in Pernambuco, Brazil, are described and illustrated. The first species is characterized by its ascospores with two widely separated equatorial crests and tuberculate to verrucose convex surfaces. This species has affinities with several known species of the genus, bearing ascospores with a similar ornamentation, but can be distinguished from these species by other morphological characteristics such as smaller cleistothecia and conidiophores, spathulate vesicles and rather ellipsoidal conidia. The second species is characterized by its unique ascospores with two low equatorial crests, an evident furrow as a deep depression, and finely reticulate convex surfaces. The validation of these new species is supported further by analyses of the β-tubulin, calmodulin and actin gene sequences.     

骨舌鱼超目的系统发育关系

通过对中国化石骨舌鱼类及骨舌鱼类现生主要类群的比较研究,用 PAUP 软件对31个分类单元的65个特征进行了分析,得到了16个最简约的分支图(步长为206,一致性指数为 0．4320,保留指数为0．7194)。严格合意树显示,中国早白垩世的骨舌鱼类(酒泉鱼、狼鳍鱼、固阳鱼、吉南鱼、同心鱼、西夏鱼、昆都仑鱼和华夏鱼)主要为骨舌鱼超目中不同等级的干群;与一般的观点不同,始舌齿鱼与蛟河鱼组成了姊妹群关系;骨舌鱼目由 Thaumaturus、弓背鱼亚目和骨舌鱼亚目组成;弓背鱼类与象鼻鱼类关系更近;Ostariostoma 为弓背鱼科的姊妹群;副狼鳍鱼与[骨舌鱼亚科+犁齿鱼亚科]组成了姊妹群,该姊妹群关系的建立,将骨舌鱼科的历史延伸到了早白垩世。     

Definition of two new symbiovars,sv. lupini and sv. mediterranense, within the genera Bradyrhizobium and Phyllobacterium efficiently nodulating Lupinus micranthus in Tunisia

In this study, a polyphasic approach was used to analyze three representative strains (LmiH4, LmiM2 and LmiT21) from a collection of six previously described strains isolated in Tunisia from root nodules of Lupinus micranthus. The phylogenetic analysis of the concatenated rrs, recA and glnII genes showed that strain LmiH4 had 100% concatenated gene sequence identity with the type strain Bradyrhizobium retamae Ro19T. Similarly, strain LmiM2 shared 100% concatenated gene sequence identity with the species Bradyrhizobium valentinum LmjM3T. However, strain LmiT21 showed an identical concatenated gene sequence with reference strain Phyllobacterium sophorae CCBAU03422T. The recA-glnII concatenated protein-coding genes used produced incongruent phylogenies compared with 16S rDNA phylogeny. The nodC gene analysis showed that the strains were phylogenetically divergent to the Bradyrhizobium symbiovars defined to date, and represented two new symbiovars. Plant infection analysis revealed that the three strains showed moderate host range and symbiotic specificities.Based on their symbiotic characteristics, we propose that the three strains isolated from Lupinus micranthus nodules belong to two new symbiovars, with the first denominated lupini within the two species Bradyrhizobium valentinum (type strain LmiM2) and B. retamae (type strain LmiH4), and the second denominated mediterranense within the species P. sophorae (type strain LmiT21).     

Phylogeny and maternal donor of Kengyilia (Triticeae: Poaceae) based on chloroplast trnT–trnL sequences

The chloroplast DNA regions trnT–trnL was used to analyze to phylogenetic relationships and maternal donor of Kengyilia species and their closely related species. The Neighbor-Joining phylogenetic reconstructions partitioned the species into two reciprocally monophyletic groups. Kengyilia melanthera was related to species of Agropyron, whereas the other species were related to species of Pseudoroegneria and Roegneria. These results indicate that there have been at least two phylogenetically divergent maternal donors within Kengyilia, i.e. Agropyron (P genome) and Pseudoroegneria (St genome). In addition, the St genome of Kengyilia had several origins and diverse species of Pseudoroegneria might have taken part in the formation of polyploid species of Kengyilia.     

五个遗传学实验的一次杂交试验设计

FiveGeneticExperimentsinOneCrossingTestChenZongli(DepartmentofBiology,Yan'anUniversity,Yan'an,ShanxiProvince716000)在遗传学实验课教学中,有关遗传现作的验证性实验,例如分离现律、自由组合规律、连锁与互换、伴性遗传及三点洲交等这5个实验,基本上都是以果蝇为材料的杂交实验,它们是最基本的,也是最经典的．然而,在现行的所有遗传学实验教材中,都要分别进行5次杂交设计实验,有的实验历时约40天．显然,在有限的实验课教学中,采用传统的实验设计方法,是不能完全计学生掌握这些实验知识的,这既造成了实验材料和时…     

Phylogenetic analysis of the genus Microbacterium based on 16S rRNA gene sequences

Abstract 16S rRNA gene (rDNA) studies of the six species of the genus Microbacterium, M. lacticum, M. laevaniformans, M. dextranolyticum, M. imperiale, M. arborescens and M. aurum , were performed and the primary structures were compared with those of 29 representative actinobacteria and related organisms. Phylogenetic analysis indicated that six species of the genus Microbacterium and representative four species of the genus Aureobacterium appear to be phylogenetically coherent as was suggested by Rainey et al., although the peptidoglycan types of these two genera are different (peptidoglycan type B1 or B2). Thus, the phylogenetical analyses revealed that members of actinobacteria with group B-peptidoglycan do not cluster according to their peptidoglycan types, but form compact cluster different from actinobacteria or actinomycetes with group A-peptidoglycan.     

蕨类植物起源与系统发生关系研究进展

蕨类植物是一群非常古老的植物,在其漫长的演化历史中丢失了大量的系统发生信息,因此重建其系统演化关系是蕨类植物学家所面临的重要任务之一.近年来的分子系统学研究已经确立了一些类群的系统关系,但现存的蕨类分类系统和系统发生关系还有很多谜团有待揭开.化石记录表明蕨类植物最早出现于大约4亿多年前,但大部分现代真蕨类缺少足够的化石证据.它们的起源时间和方式及其内部各类群的系统发生关系等诸多问题的解决,还有待于大量形态学和不同分子水平上的实验数据的进一步积累,并结合其直接的化石证据进行综合研究.