小球藻和莱茵衣藻原生质体的电转化研究

以小球藻及莱茵衣藻原生质体为受体细胞,利用电击法将质粒p CAMBIA1301转入小球藻和莱茵衣藻,摸索电击转化条件并进行分子检测。结果表明:两类藻都对潮霉素敏感,小球藻及莱茵衣藻分别在含25 mg/L和100 mg/L潮霉素的固体培养基上的生长被完全抑制;小球藻和莱茵衣藻原生质体电击转化的最佳电击场强分别为0.8 k V/cm和0.6 k V/cm,最佳脉冲时间均为10 ms;制备原生质体和通过2-脱氧-D-葡萄糖处理可明显提高转化效率;分子检测说明GUS报告基因成功转入两种藻并可稳定遗传。     

Limiting processes for perennial plant reintroduction to restore dry grasslands

In restored grasslands of southern Europe, perennial plants remain highly underrepresented compared with the reference ecosystems. We tested various treatments to reintroduce common perennial plant species (Brachypodium retusum, Poaceae, and Thymus vulgaris, Lamiaceae), which are usually not or poorly reintroduced via soil and hay transfer. Treatments included microenvironmental manipulations (rock cover and plant interactions) and two grazing intensities. Target perennial species were transplanted in 2002 in the reference grassland ecosystem (intact grassland area used as a control) and in two abandoned fields. Survival was assessed in June 2003 and June 2004. Target species shoot and root biomass were measured in June 2004. Grazing greatly reduced the survival and biomass of both target species and its effects were reinforced by summer drought: plants that did not establish well enough during the autumn and spring did not survive summer. The restored rock cover had a mild positive effect, particularly on B. retusum. There were no negative or positive plant neighbor interactions in the steppe, while there was competition in both abandoned fields. Competition was particularly intense in the abandoned melon field, composed of a dense sward of annual grasses (Bromus sp.). In order to reintroduce perennial species to dry grasslands, the ideal combination of treatments is to exclude or reduce grazing during the first year to allow seedlings to establish and to recreate adequate microenvironmental conditions. Reducing competition from arable weeds may help but is not essential in such dry grasslands.     

松鼠分子生态学研究进展

松鼠由于受到非法猎捕、栖息地破坏及欧洲部分地区的北美灰松鼠生态入侵,导致种群数量锐减,现已被世界自然保护联盟(IUCN)列为近危种,我国吉林省已将其列入省重点保护野生动物名录.分子生物学研究方法的快速发展,尤其是基于mtDNA片段开展的相关研究,以及已筛选出并能应用于松鼠研究的微卫星位点的应用,使松鼠分子生态学研究不断深入.本文对松鼠的分子系统发育、遗传多样性和分子系统地理学等分子生态学内容进行了综述,并提出松鼠分子生态学未来研究的展望:进一步探讨松鼠与日本松鼠的系统分化关系;松鼠连续种群、隔离种群和集合种群的遗传多样性比较分析;利用核基因其他标记分析松鼠分子系统地理学问题;探讨亚洲是否存在第四纪冰期避难所.     

Molecular Evidence for the Association of Tomato leaf curl Gujarat virus with a Leaf Curl Disease of Phaseolus vulgaris L.

A leaf curl disease with symptoms typical of begomoviruses was observed in bean (Phaseolus vulgaris) at the Main Research Farm of the Indian Institute of Pulses Research, Kanpur, India. Infected plants had severe distortion of leaves and the plants were unproductive. PCR indicated the involvement of French bean leaf curl virus (JQ866297), a recently described Begomovirus, and Tomato leaf curl Gujarat virus (ToLCGV). The full‐length genome of ToLCGV associated with leaf curl disease of bean was 2757 nucleotides long and had maximum identity (97–98%) with seven isolates of ToLCGV (AY234383, AF449999, EU573714, GQ994098, AY190290, FR819708, AF413671) and is designated as Tomato leaf curl Gujarat virus‐(IN:Knp:Bean:2013) (KF440686). To the best of our knowledge, this is the first record of ToLCGV infecting a leguminous host, P. vulgaris.     

Potential of the bean α‐amylase inhibitor αAI‐1 to inhibit α‐amylase activity in true bugs (Hemiptera)

True bugs (Hemiptera) are an important pest complex not controlled by Bt‐transgenic crops. An alternative source of resistance includes inhibitors of digestive enzymes, such as protease or amylase inhibitors. αAI‐1, an α‐amylase inhibitor from the common bean, inhibits gut‐associated α‐amylases of bruchid pests of grain legumes. Here we quantify the in vitro activity of α‐amylases of 12 hemipteran species from different taxonomic and functional groups and the in vitro inhibition of those α‐amylases by αAI‐1. α‐Amylase activity was detected in all species tested. However, susceptibility to αAI‐1 varied among the different groups. α‐Amylases of species in the Lygaeidae, Miridae and Nabidae were highly susceptible, whereas those in the Auchenorrhyncha (Cicadellidae, Membracidae) had a moderate susceptibility, and those in the Pentatomidae seemed to be tolerant to αAI‐1. The species with αAI‐1 susceptible α‐amylases represented families which include both important pest species but also predatory species. These findings suggest that αAI‐1‐expressing crops have potential to control true bugs in vivo.     

Lectin-like proteins accumulate as fragmentation products in bean seed protein bodies

The gene sequence of the Phaseolus vulgaris L. seed lectin-like protein (LLP) and its precursor ( 40 kDa) which is associated with the endoplasmic reticulum has been described, while the molecular characteristics of the mature protein and its cellular localization are still unknown. Our data, obtained using antibodies raised against a fusion protein, which was produced in Escherichia coli and contained most of the LLP sequence, indicate that mature LLP accumulates in the protein bodies of cotyledon cells. LLP consists of several polypeptides in the M_r range 15 000 to 20 000, which are a result of proteolytic fragmentation of the protein precursor.     

Growth control by phytochrome of de-etiolated bean hypocotyls mediated by chlorophyll fluorescence

The elongation of hypocotyls excised from de-etiolated seedlings of beans (Phaseolus vulgaris L. cv. British Wax) is inhibited by light, blue and red irradiations being equally effective. Conditions which decrease chlorophyll fluorescence, such as CO₂-free air, abolish the inhibitory effect of blue irradiation and enhance the inhibition by red light. Conversely, conditions which increase chlorophyll fluorescence, such as a N₂ atmosphere or irradiation through a chlorophyll filter, abolish the inhibitory effect of red light and enhance the inhibition by blue irradiation. The inhibitory effect of blue light is reversible by red irradiation under increased fluorescence as well as by far red. We propose that the chlorophyll fluorescence excited by blue and red irradiations in λ_F > 660 nm and λ_F > 720 nm, respectively, is responsible for the inhibitory effect of blue light and the reduction of the inhibitory effect of non fluorescing red light. Both red and blue wavelengths seem, therefore, to control hypocotyl elongation through phytochrome.     

‘巴斗杏’组培快繁体系建立与耐盐植株筛选

以淮北黄里‘巴斗杏’茎段为外植体,MS为基本培养基,通过茎段诱导植株再生及进行耐盐筛选。结果表明:采用4、5月‘巴斗杏’茎段用0.1%升汞灭菌8 min较适宜;在含有1.0 mg/L 6-BA和0.1 mg/L IBA的MS培养基上茎段增殖较快,生长旺盛;较理想的生根培养基为MS+NAA 0.1 mg/L+IBA 0.2 mg/L,生根率达46.3%;‘巴斗杏’组培苗进行耐盐筛选的适宜盐浓度为0.4%～0.8%,筛选植株与对照相比差异显著。     

Microsatellite Markers Reveal Genetic Variation within Sclerotinia sclerotiorum Populations in Irrigated Dry Bean Crops in Brazil

Microsatellites are powerful markers to infer population genetic parameters. We used 10 microsatellite loci to characterize the genetic diversity and structure of 79 samples of Sclerotinia sclerotiorum isolated from four Brazilian dry bean populations and observed that eight of them were polymorphic within populations. We identified 102 different haplotypes ranging from 6 to 18 per locus. Analyses based on genetic diversity and fixation indices indicated variability among and within populations of 28.79% (F_ST = 28793) and 71.21%, respectively. To examine genetic relatedness among S. sclerotiorum isolates, we used internal spacer (ITS1‐5.8S‐ITS2) restriction fragment length polymorphism (PCR‐RFLP) and sequencing analysis. PCR‐RFLP analysis of these regions failed to show any genetic differences among isolates. However, we detected variability within the sequence, which does not support the hypothesis of clonal populations within each population. High variability within and among populations may indicate the introduction of new genotypes in the areas analysed, in addition to the occurrence of clonal and sexual reproduction in the populations of S. sclerotiorum in the Brazilian Cerrado.     

Location of demographic sources affects the distributions of a vulnerable native fish in invaded river networks

1. Invasive predators negatively affect native prey to varying degrees across landscapes, and spatial configuration of invader‐free refugia may affect prey distributions across invaded river networks. In New Zealand, introduced trout (Salmo trutta and Oncorhynchus mykiss) create source‐sink dynamics in native Galaxias vulgaris populations, and their co‐occurrence with trout may be enhanced by immigration from trout‐free reaches. 2. We investigated how network configuration of trout‐free demographic sources affected the distribution of G. vulgaris across trout‐invaded riverscapes. Using quantitative biomass surveys and spatially extensive presence–absence surveys, the interaction between habitat variability and location relative to sources in limiting distributions of G. vulgaris in trout‐invaded reaches was assessed. 3. Galaxias vulgaris biomass at invaded sink sites decreased with increasing network distance to the nearest trout barrier. The maximum distance to barriers at which G. vulgaris occurred in the riverscape was limited, so that galaxiids were excluded from small and stable streams far from sources. 4. Large predatory trout (i.e. >150 mm fork length) occurred in high densities at stable sites all year round and were seasonally excluded from sites disturbed by flooding. Large streams probably provide increased refugia for galaxiids to avoid predation from trout, but narrowness and habitat stability may act synergistically to extirpate G. vulgaris from sites that are too far from sources to receive regular immigrants. 5. The interaction between immigration and habitat configuration in mediating effects of trout on G. vulgaris distributions indicates the spatial dependency of predator–prey interactions in river networks. 6. These results indicate creating new invader‐free source habitat should enhance co‐occurrence in nearby invader‐occupied reaches. Moreover, adding source habitat in sink streams far from existing sources, and ensuring barriers prevent future invasion, will also allow native fish dispersal between sources and sinks and will maximise the conservation gains from management across invaded riverscapes.