基于28S rDNA基因的天牛科部分种类的分子系统发育

对天牛科4亚科32种天牛的28S rDNA基因部分序列进行测定和分析,并结合GenBank数据库中6种天牛的28S rDNA基因部分序列,采用最大简约法和贝叶斯法重建天牛科7亚科38种天牛的系统发育树,探讨它们之间的系统发育关系.在获得的772 bp的序列中,保守位点521个,占全部位点的67.5％;简约信息位点136个,占全部位点的17.6％.G+C的平均含量为60.8％,明显高于A+T的平均含量,碱基组成偏向G和C,转换稍高于颠换.系统发育树表明:天牛亚科、锯天牛亚科、花天牛亚科及沟胫天牛亚科均为单系群,与传统形态分类结果一致.28S rDNA序列是一种有效的解析天牛科高级分类阶元系统发育关系的分子标记.     

基于28S rDNA分析板栗和杉木上针叶小爪螨物种分化原因

【目的】我国经济林树种板栗和杉木上的重要害螨一直被认为是同一种螨——针叶小爪螨,但针叶小爪螨的山东板栗种群和浙江杉木种群间存在生殖隔离,且生殖隔离并非由地理隔离和能调控寄主生殖的内共生菌引起,似乎二者已分化为2个独立的种。本研究目的是明确其成种原因,丰富物种形成理论。【方法】从之前做杂交试验时所采集的针叶小爪螨板栗和杉木种群中各随机取3头雌成螨,提取单头雌成螨的总DNA,使用根据其他小爪螨28S rDNA两端保守序列设计的引物扩增28S rDNA,扩增产物纯化后测序。比较2种群的28S rDNA序列,并基于28S rDNA序列构建小爪螨属系统发育树,结合已有研究分析两种群分化原因。【结果】每个种群的3个个体的28S rDNA序列完全一致,无种群内变异。2种群的28S rDNA序列一致性为98. 3%,遗传距离为1. 7%。在基于28S rDNA序列构建的小爪螨属系统发育树上,浙江杉木种群与采自日本的日本柳杉上的本岛小爪螨亲缘关系最近,山东板栗种群与采自日本的日本栗上的栗小爪螨的亲缘关系最近。【结论】板栗和杉木上的叶螨并非由同一种叶螨因适应不同寄主植物分化而成,很可能是2个独立的物种。     

泰国清迈蘑菇属真菌分子系统学初步研究

文章对泰国清迈蘑菇属真菌进行rDNA ITS区段序列测定和序列特征比较分析,并基于ITS序列进行核酸数据库GenBank同源性检索比对,最终构建系统发育树,旨在为从分子水平上探讨蘑菇属真菌的系统发育、亲缘关系和遗传多样性提供参考.     

乌桕新害虫——中华卡扁蜡蝉的形态及分子鉴定

[目的]介绍发生在贵州省龙里县乌桕上的一种新害虫——中华卡扁蜡蝉的形态及分子鉴定的方法。[方法]对中华卡扁蜡蝉卵、若虫(5龄)及成虫3个虫态的形态特征进行了详细描记;同时通过PCR扩增,获取了中华卡扁蜡蝉的线粒体COI基因序列。利用MEGA 6. 0软件对其序列组成及遗传距离进行分析,以竹鳎扁蜡蝉、红线鳎扁蜡蝉、勐仑鳎扁蜡蝉为外群,采用邻接法(NJ)构建系统发育树。[结果]系统发育树显示中华卡扁蜡蝉10个样品的COI基因序列能较好地聚为一枝;中华卡扁蜡蝉的种内遗传距离为0. 000 0. 065,4种扁蜡蝉科昆虫种间遗传距离为0. 142 0. 202,种内遗传距离与种间遗传距离不存在重叠现象。[结论] COI基因序列可作为DNA条形码片段,实现中华卡扁蜡蝉快速、准确的物种鉴定。初步调查了中华卡扁蜡蝉的发生规律及危害状况。     

降香黄檀DNA提取及其rDNA-ITS序列分子系统发育分析

以核糖体转录间隔区(rDNA-ITS)序列为分子标记,结合GenBank数据库中已有序列,阐明黄檀属内不同物种之间的分子系统发育关系。通过改良十六烷基三甲基溴化铵法(CTAB)提取降香黄檀总DNA,利用引物对rDNA-ITS序列进行聚合酶链式反应(PCR扩增)和序列测定。结果表明,基于rDNA-ITS序列测定、位点分析和系统发育树构建方法,可利用ITS序列进行黄檀属树种准确的分子鉴定,为其种类鉴定和种间分类地位提供分子生物学依据。     

木本豆科植物根瘤菌16S rDNA的PCR-RFLP研究

为了研究华东地区木本豆科植物根瘤菌种质资源的遗传多样性,采用6种限制性内切酶对53株根瘤菌进行16S rDNAPCR-RFLP多态性分析,共产生35种类型的16S rDNA遗传图谱.聚类分析结果表明,在75%的相似水平上,所有供试菌株可以分为8个系统发育分支.其中,分支3由22个菌株组成,属于中慢生根瘤菌属(Meso-rhizobiura);9个菌株组成分支6和7,属于快生根瘤菌属(Rhizobium);分支5包含7个菌株,属于慢生根瘤菌属(Bradyrhizobium);其余19个菌株与已知菌株亲缘关系较远,可分为4个未知的系统发育分支,这4个新的分支最少有1个新的根瘤菌属存在.结果还表明木本植物根瘤菌存在着极丰富的遗传多样性.     

早竹丛枝病的调查及病原菌的分子鉴定

[目的]对早竹丛枝病进行调查及病原菌分子鉴定,为早竹丛枝病的病害诊断和防治提供科学依据。[方法]采用单株水平和单枝盘水平的2种病害分级标准对早竹丛枝病进行调查。使用植原体16S rDNA和真菌rDNA-ITS序列的特异性PCR引物,对早竹丛枝病的病原菌进行分子鉴定。[结果]调查的6块样地早竹丛枝病的平均发病率为18.59%,平均病情指数为6.67。感病的早竹DNA样品能够扩增出真菌的rDNA-ITS序列,而不能够扩增出植原体的16S rDNA序列;扩增出的序列与报道的竹针孢座囊菌的序列同源性达到99.00%,与其它真菌的序列同源性最高仅为94.00%。[结论]浙江省德清县早竹丛枝病的病原菌为竹针孢座囊菌。     

利用16S rDNA基因序列进行害竹飞虱(半翅目:飞虱科)的分子鉴定

采用DNA测序技术测定了中国飞虱科5属10种15个地理种群的线粒体16S rDNA基因长约480 bp片段的序列,分析了其序列组成及变异特征.所获序列中,A+T约占77.5％,其中,190个核苷酸位点发生了变异(约占39.6％).利用MEGA 4.0软件计算遗传距离,外群与内群的遗传距离平均值(0.317)最高,内群各属间和各属内遗传距离平均值(分别为0.209和0.132)次之,而种内不同地理种群间的遗传距离平均值(0.013)最低.构建了10种飞虱科昆虫的MP和NJ分子系统树,结果显示:各属飞虱基本上形成单系群;各种飞虱各自不同地理种群均聚为一支,构成一单系群,可以很好的区分不同种类的飞虱.上述结果与形态学研究结果非常吻合.     

血皮槭叶绿体DNA非编码区差异序列筛选和分析

[目的]筛选出高变异率的叶绿体DNA序列,以进行血皮槭天然群体的谱系地理学研究。[方法]以血皮槭16个天然群体为试材,对叶绿体基因组20个非编码区序列进行测序研究,并利用筛选出的高变异率cpDNA序列初步分析了其遗传变异。[结果]序列比对和系统发育分析结果显示血皮槭cpDNA种内变异非常低,9个cpDNA序列检测到不同程度的变异位点,其中只有4个序列psbJ-petA、ndhF-rpl32、trnD-trnT和trnH-psbA表现出较高的变异水平。[结论]筛选出的4个高变异率cpDNA序列,可以在分子水平上研究血皮槭种内的系统发育、遗传变异和种群历史动态,为进一步研究濒危种血皮槭的分子谱系地理学奠定基础。     

45S rDNA在7种竹子植物染色体上的定位

编码18-5.8-25S核糖体RNA的45S rDNA基因,是1个简单的多基因家族基因,一般以串联方式相连,对应于核仁组织区(NOR).首次利用荧光原位杂交技术(FISH),研究45S rDNA在散生竹类的毛竹和斑竹,混生竹类的茶秆竹、日本矮竹、菲白竹和铺地竹,以及丛生竹类的白绿竹染色体上的分布.结果表明:本研究所涉及的散生竹和混生竹的几个竹种,只观察到1对随体染色体的次缢痕区域有45S rDNA位点,而丛生竹类的白绿竹除随体染色体具有45S rDNA位点外,某些非随体染色体上也有不同拷贝数的45S rDNA位点存在.     

Vertebrate and insect pests and hemi-parasitic plants of Parkia biglobosa and Vitellaria paradoxa in Nigeria

This study investigated the occurrence and diversity of hemi-parasitic plants, vertebrate and insect pest species of Parkia biglobosa (Keay), and Vitellaria paradoxa (Gaertn.) as well as the strategies for their control in the parklands of the Nigerian humid savanna. Results indicated that of the two major hemi-parasitic plants encountered, Tapinanthus globiferus was the more widespread with wider host range than T. dodonifolius. Mechanical control by cutback of infested branches was ineffective for both species. The major vertebrate pests consist of 6 avian species from 3 families: Nectaridae, Plocidae and Cuculidae; a fruit bat, Epomops frangueti and an unidentified squirrel. The species fed on both the fruits of the trees and the seeds of the hemi-parasitic plants. Twenty insect species from 14 families were encountered on P. biglobosa compared to 33 species from 17 families on V. paradoxa in all the ecological zones covered in the study. Species diversity was comparatively higher in the fallow than in the cultivated land. The majority of the insects encountered was of little significance and may not warrant application of control. Cirina forda (Saturnidae:lepidoptera) was a major pest causing 60%–90% defoliation of mature trees of V. paradoxa. All larval stages were destructive but control at this stage is not advised because it provides incidental source of food to locals. Control after pupation using a slow-release insecticide with a soil penetration depth of 15–20 cm is suggested.This revised version was published online in November 2005 with corrections to the Cover Date.     

Dry matter production and allocation in Eucalyptus cloeziana and Eucalyptus argophloia seedlings in response to soil water deficits

Effects of soil water availability on seedling growth, dry matter production and allocation were determined for Gympie (humid coastal) and Hungry Hills (dry inland) provenances of Eucalyptus cloeziana F. Muell. and for E. argophloia Blakely (dry inland) species. Seven-month-old seedlings were subjected to well-watered (100% field capacity, FC), moderate (70% FC) and severe (50% FC) soil water regimes in a glasshouse environment for 14 wk. There were significant differences in seedling growth, biomass production and allocation patterns between species. E. argophloia produced twice as much biomass at 100% FC, and more than three times as much at 70% and 50% FC than did either E. cloeziana provenance. Although the humid provenance of E. cloeziana had a greater leaf area at 100% FC conditions than did the dry provenance, total biomass production did not differ significantly. Both E. cloeziana provenances were highly sensitive to water deficits. E. argophloia allocated 10% more biomass to roots than did E. cloeziana. Allometric analyses indicated that relative biomass allocation patterns were significantly affected by genotype but not by soil water availability. These results have implications for taxon selection for cultivation in humid and subhumid regions.     

Aboveground biomass and nitrogen in four short-rotation woody crop species growing with different water and nutrient availabilities

We quantified the effect of water and nutrient availability on aboveground biomass and nitrogen accumulation and partitioning in four species from the southeastern United States, loblolly pine (Pinus taeda), slash pine (Pinus elliottii), sweetgum (Liquidambar styraciflua), and sycamore (Platanus occidentalis). The 6-year-old stands received five levels of resource input (control, irrigation with 3.05 cm water week⁻¹, irrigation + 57 kg N ha⁻¹ year⁻¹, irrigation + 85 kg N ha⁻¹ year⁻¹, and irrigation + 114 kg N ha⁻¹ year⁻¹). Irrigation significantly increased foliage, stem, and branch biomass for sweetgum and sycamore, culminating in 103% and 238% increases in total aboveground biomass. Fertilization significantly increased aboveground components for all species resulting in 49, 58, 281, and 132% increases in total aboveground biomass for loblolly pine, slash pine, sweetgum, and sycamore, respectively. Standing total aboveground biomass of the fertilized treatments reached 79, 59, 48, and 54 Mg ha⁻¹ for loblolly pine, slash pine, sweetgum, and sycamore, respectively. Fertilization increased foliar nitrogen concentration for loblolly pine, sweetgum, and sycamore foliage. Irrigation increased total stand nitrogen content by 6, 14, 93, and 161% for loblolly pine, slash pine, sweetgum, and sycamore, respectively. Fertilization increased total nitrogen content by 62, 53, 172, and 69% with maximum nitrogen contents of 267, 212, 237, and 203 kg ha⁻¹ for loblolly pine, slash pine, sweetgum, and sycamore, respectively. Growth efficiency (stem growth per unit of leaf biomass) and nitrogen use efficiency (stem growth per unit of foliar nitrogen content) increased for the sycamore and sweetgum, but not the loblolly or slash pine.     

Trees and shrubs as sources of fodder in Australia

Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline.     

Root diseases in bareroot and container nurseries of the Pacific Northwest: epidemiology, management, and effects on outplanting performance

In forest and conservation nurseries in the Pacific Northwest USA, seedling production can be limited by root diseases caused by fungi in the genera Fusarium Link:Fr., Cylindrocarpon Wollenw., Phytophthora de Barry, and Pythium Pringsh. Fusarium, Cylindrocarpon, and Pythium are the most ubiquitous, whereas incidence of Phytophthora is mostly associated with coastal bareroot nurseries. All of these root pathogens are encouraged by water saturated soils or media. Seedlings infected with Fusarium, Phytophthora, or Pythium often appear chlorotic or necrotic with extensive root decay. Cylindrocarpon often causes serious root decay without shoot symptoms. The best approach to mitigate losses from these diseases is to use a holistic integrated pest management program. This program should combine chemical controls with cultural practices, particularly those that increase soil permeability and drainage and reduce potential sources of inoculum, especially by disinfesting seeds and containers reused for crops. In general, we found that seedlings meeting nursery specifications for outplanting on forest soil (proper height, root collar diameter, healthy shoot color, lack of disease symptoms) but having these disease organisms on their root systems perform as well as non-infected seedlings.     

Populations of adult fungus gnats and shore flies in British Columbia container nurseries as related to nursery environment,and incidence of fungi on the insects

Adult fungus gnat and shore fly populations were monitored in four container nurseries near Victoria, British Columbia. In general, populations of both insects were larger in summer than in winter. Also, both insects were more abundant in the nursery with a plastic-covered, soil floor, which favored moisture accumulation and build up of algae, liverworts and mosses, than in nurseries with other types of floors such as cement. Results of fungus isolations revealed that gnats and flies both harbor the seedling pathogens Botrytis cinerea and species of Fusarium and Phoma, plus several non-pathogenic fungi. The results are discussed in relation to nursery sanitation practices, their effects on gnat and fly populations, and some possible roles of these insects in seedling disease epidemiology.     

Growth, nitrogen fixation and mineral acquisition of Alnus sieboldiana after inoculation of Frankia together with Gigaspora margarita and Pseudomonas putida

The role of tetrapartite associations among Frankia, Gigaspora margarita (an arbuscular mycorrhizal fungus), Pseudomonas putida (rhizobacterium), and Alnus sieboldiana in growth, nitrogen fixation, and mineral acquisition of A. sieboldiana was investigated. Seedlings of A. sieboldiana were inoculated with Frankia isolated from root nodules of alder, followed by inoculation of G. margarita and P. putida, and were grown for 5 months in a greenhouse. The seedlings inoculated with Frankia and G. margarita together produced the highest biomass of shoots and root nodules. Nitrogen-fixation activity, measured by acetylene reduction assay, was observed when Frankia was inoculated. The activity, on a per-nodule gram basis, decreased after G. margarita inoculation, but on a per-plant basis there was no significant difference in the activity among inoculation treatments. The mineral content in the seedlings changed after inoculation with Frankia, but not after inoculation with P. putida and/or G. margarita. The results showed a synergistic interaction among Frankia, the mycorrhizal fungus, and the rhizobacterium on the growth of A. sieboldiana.     

Fusarium spp. and Pinus strobus seedlings: root disease pathogens and taxa associated with seed

Eastern white pine (Pinus strobus L.) seeds weresown in soil infested with Fusarium proliferatum, rootnecrosis developed on seedling roots, and F. proliferatumwas reisolated from symptomatic roots; thus, demonstrating thatF. proliferatum is pathogenic toeastern white pine seedlings. Soils infested with F.acuminatum or F. sporotrichioides resulted infew diseased seedlings. Seedlings with root rot generally showed reductions inseedling height. All Fusarium species tested wererecoveredfrom rhizosphere soil samples. Three seedlots of Pinusstrobus were examined for Fusarium infestation.Fusarium species were recovered from most seeds in twoseedlots. Fusarium proliferatum and F.sporotrichioides were the predominant species isolated. Additionalspecies not previously reported from P. strobus included:F. acuminatum, F. chlamydosporum,F. equiseti, F. graminearum,F. moniliforme, F. poae, F.polyphialidicum, F. heterosporum, F.sambucinum, and F. semitectum.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.     

Antinephritis and radical scavenging activity of prenylflavonoids

Antinephritis activity of 5 prenylflavonoids similar to glabridin (1-5), isolated from Morus alba, Artocarpus communis, Glycyrrhiza uralensis and G. inflata, was evaluated in mice with glomerular disease (Masugi-nephritis). Oral administrations of artonin E (2) or licochalcone A (4) for 10 days (30 mg kg(-1) day(-1)) reduced the amount of urinary protein excretion compared to nephritic mice. ESR spectroscopy demonstrated that morusin (1) and licorisoflavan A (5) increased the radical intensity of sodium ascorbate by about two times. Morusin, licoricidin (3), licochalcone A and licorisoflavan A showed weak scavenging activity against superoxide anion radical.