两种广西特有报春苣苔属(苦苣苔科)植物传粉生物学研究

通过野外观察和室内试验,对两种广西特有的桂林小花苣苔和阳朔小花苣苔的传粉生物学进行比较研究。结果表明:两种报春苣苔属植物花期从7月底至8月初;单花花期内花粉具有较高的活性,最高可达92.6%和94.5%;柱头可授性最高时可达90%和95%;花粉/胚珠比率(P/O)分别为110.28±17.45和229.65±18.00;柱头与花药之间存在着空间隔离,可防止自花授粉;在单花花冠裂片张开后第3天,花药开始散粉,但雌蕊在花朵刚开始开放时已伸长,待第3天时柱头已伸长到位于花冠筒口部,高于花药,便于接受异花花粉;该两种植物均不存在无融合生殖现象;两种报春巨苔属植物均高度自交亲和,但很难发生自发的自花授粉,必须依靠外力,因此传粉媒介对于结实率有重要影响,自然条件下基本不发生自花授粉;在自然状态下结实率明显低于两种人工授粉的结实率;小蜂和淡脉隧蜂是目前已知仅见的两种传粉者。     

Charadrius squatarola Gl.undTringa cinerea L.in Neu-Vorpommern

Ohne Zusammenfassung     

Morphological, chemical and genetic differentiation of two subspecies of Cistus creticus L. (C. creticus subsp. eriocephalus and C. creticus subsp. corsicus)

Cistus creticus L., an aromatic species from the Mediterranean area, contains various diterpenes bearing the labdane skeleton. The production of essential oil from this species has potential economic value, but so far, it has not been optimized. In order to contribute to a better knowledge of this species and to its differentiation, the morphological characters, volatile chemical composition and genetic data of two subspecies (C. creticus subsp. eriocephalus and C. creticus subsp. corsicus) were investigated. The leaf trichomes were studied using scanning electron microscopy. The chemical composition of Corsican essential oil (C. creticus subsp. corsicus) has been reported using GC, GC/MS and ¹³C NMR; the main constituents were oxygenated labdane diterpenes (33.9%) such as 13-epi-manoyl oxide (18.5%). Using plant material (54 samples) collected from 18 geographically distinct areas of the islands of Corsica and Sardinia, the basis of variation in the headspace solid-phase microextraction volatile fraction and an inter-simple sequence repeat genetic analysis were also examined. It was shown that the two subspecies of C. creticus differed in morphology, essential oil production, volatile fraction composition and genetic data.     

青稞HvBAS1基因的克隆及表达分析

细胞色素P450单加氧酶(CYP450)是参与植物代谢的最大酶家族,其中CYP734A亚家族成员广泛参与植物激素油菜素类固醇(BRs)的失活。该研究以青稞农家品种‘肚里黄’幼苗为实验材料,通过人工合成激素24 表油菜素内酯(24 eBL)和BRs合成抑制剂油菜素唑(BRZ)处理,分析BRs对青藏高原特色作物青稞(Hordeum vulgare L. var. nudum Hook. f.)的影响;采用RT PCR技术从青稞中克隆HvBAS1基因,并运用实时定量PCR检测其表达特征,为深入分析HvBAS1基因的功能奠定研究基础。结果显示：(1)24 eBL能够显著促进青稞幼苗的生长,而BRZ处理后幼苗长势明显减缓。(2)从青稞中成功克隆到2个与拟南芥BRs失活基因BAS1高度同源的CYP734A亚家族基因,即HvBAS1 1和HvBAS1 2;HvBAS1 1开放阅读框全长1 629 bp,编码542个氨基酸;HvBAS1 2长1 689 bp,编码562个氨基酸,二者氨基酸序列相似性为76.42%;亚细胞定位预测结果显示二者均存在于内质网。(3)实时定量PCR检测发现,青稞HvBAS1 1与HvBAS1 2的表达模式完全不同,其中HvBAS1 1在青稞根中的表达量高于叶中,而HvBAS1 2在叶中的表达量高于根,且随着苗龄的增大,HvBAS1 1在根中的表达呈先升高后降低的趋势,HvBAS1 2在叶片中呈先降低后升高的变化趋势;BRZ处理青稞幼苗后,其HvBAS1 1与HvBAS1 2基因的表达较对照均显著下调,且HvBAS1 2下调更为明显。研究表明,HvBAS1 1和HvBAS1 2很可能都参与了青稞内源BRs的失活,但二者的功能存在差异。     

Ester production in E. coli and C. acetobutylicum

Genetic engineering has improved the product yield of a variety of compounds by overexpressing, inactivating, or introducing new genes in microbial systems. The production of flavor-enhancing ester compounds is an emerging area of heterologous gene expression for desired product yield in Escherichia coli. Isoamyl acetate, butyl acetate, ethyl acetate, and butyl butyrate are reported here to be produced by expressing Saccharomyces cerevisiae genes ATF1 or ATF2 and the strawberry gene SAAT in E. coli when the appropriate substrates are provided. Increasing the concentration of alcohol added to the reaction generally resulted in increased ester production. ATF1 expression was found to produce more isoamyl acetate and butyl acetate than ATF2 expression or SAAT expression in the strains and culture conditions examined. Additionally, SAAT expression resulted in greater isoamyl acetate and butyl acetate production than ATF2 expression. Butyl butyrate is produced by cell-free extracts of E. coli harboring SAAT but not ATF1 or ATF2.     

Genome constitutions of Pseudoroegneriageniculata, P. geniculata ssp. scythica and P. geniculata ssp. pruinifera (Poaceae: Triticeae) revealed by genomic in situ hybridization

Genomic constitutions of three taxa of Pseudoroegneria á. L?ve, P. geniculata, P. geniculata ssp. scythica, and P. geniculata ssp. pruinifera, were characterized using genomic in situ hybridization (GISH). The results indicated that ploidy level and genomic constitution in the three Pseudoroegneria taxa studied were as follows: P. geniculata (2n = 4x = 28; genomic formula StSt ^g ), P. geniculata ssp. scythica (2n = 4x = 28; genomic formula ESt), and P. geniculata ssp. pruinifera (2n = 6x = 42; genomic formula EESt). P. geniculata ssp. scythica and P. geniculata ssp. pruinifera should be transferred to Trichopyrum á. L?ve following L?ve’s principles and treated as T. scythicum and T. pruiniferum, respectively.     

复轮生暗孢小克银汉霉新变种及其与原变种之间的配合

多年前分离自湖北神农架林中采回的一份土样的一株小克银汉霉Cu137最近经我们研究定名为复轮生暗孢小克银汉霉新变种(Cunninghamella phaeospora Boedijn var.multiverticillata var. nov.)。它与暗孢小克银汉霉原变种(Cunninghamella phaeospora Boedijnvar. phaeospora)的异同在于:(1)两者均具有单轴分枝、分枝单生或成对的孢子枝,不同的是新变种的孢子枝除单轴分枝外还可轮状分枝,或单轴与轮状混合分枝,轮状分枝可多达3轮,每轮由3-8分枝组成,原变种则完全不形成轮状分枝;(2)两者的孢子枝主轴上的顶生泡囊均具各种形状并略呈棱角状,但新变种的侧枝上的饱囊常常是棒形的,原变种的侧枝上的饱囊则很少棒形;(3)新变种的假根很发达,可自菌丝、匍匐菌丝、孢子枝、泡囊等部位发生,而原变种的假根一般不很发达,而且只从菌丝或甸旬菌丝发生;(4)两者的小型孢子囊在形状、大小、刺等方面一致,但新变种的小型孢子囊无色至淡褐色,原变种的小型孢子囊则为淡褐色至深褐色;(5)新变种的菌落白色,至多在老后污白色至极浅的淡褐色,原变种的菌落自始即为深灰色。除暗孢小克银汉霉原变种外,同属中还有另外三个分类群与复轮生暗孢小克银汉霉较为接近:印度小克银汉霉(Cunninghamella indica Baijal & B. S. Mehrotra)与印度刺孢小克银汉霉[Cunninghamella echinulata(Thaxt.) Thaxt. ex Blakeslee var. indica Baijal & B. S. Mehrotra]因菌落白色及孢子枝分枝棒形,轮生小克银汉霉(Cunninghamella verticillaata Paine)因孢子枝具数轮轮生分枝而与复轮生暗孢小克银汉霉这个新变种有一定的相似。但是,新变种无论是顶生泡囊还是侧生泡囊的直径都较上述三个分类群小得多;新变种的顶生饱囊往往不规则形状且略带棱角,而上述三个分类群则不是这样。还有,新变种的孢子枝分枝方式与印度小克银汉霉的颇为不同,新变种的小型孢子囊比印度刺孢小克银汉霉的小得多,其小型孢子囊主要球形至近球形,与轮生小克银汉霉的椭圆形至卵形也不一样。此外,新变种的假根系统极其发达,与同属中任何一种均不相同。将复轮生暗孢小克银汉霉新变种Cu137(+)与暗孢小克银汉霉原变种的一株分离自香港山边土壤的Cu 136(一)配合时只形成配子囊,但与原变种的模式菌株CBS 692.68(-)配合时则可形成少量的接合孢子囊。为了获得更多的接合孢子囊以观察它们是否可育的,我们将Cu 137和CBS 692.68同时接种到许多培养皿上,然后制片观察。用姆指轻轻、重复压盖玻片,可使接合孢子囊破裂以观察其内含物。结果,从100个以上的接合孢子囊中,仅在其中4个发现有接合孢子的形成,其余的都是空的和不育的。由于原变种尚未发现(+)配合型菌株,新变种则未发现(-)配合型菌株,原变种与原变种之间及新变种与新变种之间配合形成的有性型尚未获得,而且全世界均未见有报道,无法和新变种与原变种之间配合形成的有性型相比较,因此目前尚不能肯定新变种与原变种之间形成的有性型在形态上是否能代表这个种的有性型。但是,尽管如此,暗孢小克银汉霉的这两个变种之间配合形成的有性型的形态仍然是很有特征性的,足以把它与其它种的已知有性型相区别。     

Phytophthora captiosa sp. nov. and P. fallax sp. nov. causing crown dieback of Eucalyptus in New Zealand

A locally severe crown disease of exotic plantation Eucalyptus trees has been recorded periodically in New Zealand since 1986. Symptoms include leaf spots, petiole infection and twig and small branch lesions. Outbreaks of disease are episodic and individual trees may show marked variation in crown symptoms ranging from unaffected to total defoliation. Two previously unknown species of Phytophthora are associated with the disease. These are described and formally designated here as P. captiosa, from Eucalyptus botryoides and E. saligna; and P. fallax, from E. delegatensis, E. fastigata, E. nitens and E. regnans. Both P. captiosa and P. fallax have non-papillate, non-caducous sporangia and both are self-fertile. Phylogenetic analysis on the basis of ITS rDNA sequence data indicates they are closely related to each other but evolutionarily distant from the majority of described Phytophthora taxa. They share a common ancestor with another assemblage of Phytophthora lineages that includes P. insolita, P. macrochlamydospora and P. richardiae. Sporulation of P. captiosa and P. fallax has not been observed in the field. The mode of infection and spread of these non-caducous Phytophthora species in the eucalypt tree canopy remains unknown. This issue, and the possible geographic origins of these two Phytophthora species are discussed.     

Description of Tropicibacter mediterraneus sp. nov. and Tropicibacter litoreus sp. nov.

Four strains (M15∅_3, M17^T, M49 and R37^T) were isolated from Mediterranean seawater at Malvarrosa beach, Valencia, Spain. Together with an older preserved isolate (strain 2OM6) from cultured oysters at Vinaroz, Castellón, Spain, the strains were thoroughly characterized in a polyphasic study and were placed phylogenetically within the Roseobacter clade in the family Rhodobacteraceae. Highest 16S rRNA sequence similarities of the five strains to the types of any established species corresponded to Tropicibacter multivorans (95.8–96.4%), Phaeobacter inhibens (95.9–96.3%) and Phaeobacter gallaeciensis (95.9–96.2%). On the other hand, whole genome (ANI) and protein fingerprinting (MALDI-TOF) data proved: (i) non clonality among the strains, and (ii) the existence of two genospecies, one consisting of strains M15∅_3, M17^T, M49 and 2OM6 and another one consisting of strain R37^T. Phenotypic traits determined allow differentiating both genospecies from each other and from closely related taxa. In view of all data collected we propose to accommodate these isolates in two species as members of the genus Tropicibacter, Tropicibacter mediterraneus sp. nov. (type strain M17^T = CECT 7615^T = KCTC 23058^T) and Tropicibacter litoreus sp. nov. (type strain R37^T = CECT 7639^T = KCTC 23353^T).     

Proposal of Ensifer psoraleae sp. nov., Ensifer sesbaniae sp. nov., Ensifer morelense comb. nov. and Ensifer americanum comb. nov

In a survey of rhizobia associated with the native legumes in Yunnan Province, China, seven and nine strains isolated from the root nodules of Psoralea corylifolia, Sesbania cannabina and Medicago lupulina were respectively classified into the novel genomic species groups I and II in the genus Ensifer (former Sinorhizobium) based on the sequence analyses of the 16S rRNA gene. Analyses of concatenated housekeeping genes (atpD, recA and glnII) further revealed that they were distinct lineages in the genus, and group I was most similar to Ensifer terangae and Ensifer garamanticus (both with 94.2% similarity), while group II was most similar to Ensifer adhaerens (94.0%). These groups could be distinguished from closely related species by DNA–DNA relatedness, MALID-TOF MS, cellular fatty acid profiles and a series of phenotypic characters. Therefore, two novel species were proposed: Ensifer psoraleae sp. nov. (seven strains, type strain CCBAU 65732^T = LMG 26835^T = HAMBI 3286^T) and Ensifer sesbaniae sp. nov. (nine strains, type strain CCBAU 65729^T = LMG 26833^T = HAMBI 3287^T). They had a DNA G + C mol% (T_m) of 58.9 and 60.4, respectively. Both of the type strains formed effective nodules on common bean (Phaseolus vulgaris) and their hosts of origin. In addition, the previously described species Sinorhizobium morelense and Sinorhizobium americanum were renamed as Ensifer morelense comb. nov. and Ensifer americanum comb. nov. according to the accumulated data from different studies.     

Staphylococcus petrasii sp. nov. including S. petrasii subsp. petrasii subsp. nov. and S. petrasii subsp. croceilyticus subsp. nov., isolated from human clinical specimens and human ear infections

Thirteen coagulase-negative, oxidase-negative, and novobiocin-susceptible staphylococci were isolated from human clinical specimens. The isolates were differentiated from known staphylococcal species on the basis of 16S rRNA, hsp60, rpoB, dnaJ, tuf, and gap gene sequencing, automated ribotyping, (GTG)₅-PCR fingerprinting, and MALDI-TOF MS analysis. Phylogenetic analysis based on the 16S rRNA gene sequence indicated phylogenetic relatedness of the analyzed strains to Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus devriesei, and Staphylococcus lugdunensis. DNA–DNA hybridization experiments between representative strains CCM 8418^T, CCM 8421^T, and the closest phylogenetic neighbors confirmed that the isolates represent novel Staphylococcus species, for which the name Staphylococcus petrasii sp. nov. is proposed. Genotypic and phenotypic analyses unambiguously split the strains into two closely related subclusters. Based on the results, two novel subspecies S. petrasii subsp. petrasii subsp. nov. and S. petrasii subsp. croceilyticus subsp. nov. are proposed, with type strains CCM 8418^T (=CCUG 62727^T) and CCM 8421^T (=CCUG 62728^T), respectively.