宁波马尾松中松材线虫形态变异研究

从采自宁波北仑的马尾松中分离到一种伞滑刃属线虫,经形态学观察、测量,以及ITS-RFLP图谱比对,鉴定为松材线虫。从原木中分离到的线虫雌虫未见尾端完全呈钝圆的个体,多数都有尾尖突,长约0.5～2.9μm,平均长度约为1.7μm。经实验室灰葡萄孢培养后,雌虫尾端均呈钝圆,其形态特征与相关描述一致。这表明寄主和环境因素对线虫的形态特征有较大影响,应在一致的培养环境下进行形态观察和描述,ITS-RFLP方法是伞滑刃属线虫鉴定有效的辅助手段。     

寄生加勒比松松材线虫的鉴定及其致病性测定

运用线虫比较形态学和rDNA—ITS—PCR-RFLP方法对采自广东省广州市白云山加勒比松上的伞滑刃线虫进行鉴定,结果确定该线虫为松材线虫。致病性测定表明该松材线虫种群对加勒比松苗有较强的致病力,接种的松苗均出现不同程度的枯萎,而且从枯死木中可重新分离到该线虫。     

Bursaphelenchus fungivorus from Pinus pinaster bark in Portugal

Bursaphelenchus fungivorus is reported for the first time in Portugal, identified as associated with Pinus pinaster bark and characterized on the basis of morphological and morphometrical characters for this species. Species identification was confirmed using restriction fragment length polymorphism analysis and sequencing of the internal transcribed spacer (ITS) regions of ribosomal DNA. Intraisolate genetic variability was detected among ITS sequences of the Portuguese B. fungivorus isolate. Phylogenetic analysis, obtained from multiple sequence alignment between ITS sequences of Bursaphelenchus species, revealed that the Portuguese B. fungivorus isolate clusters with other B. fungivorus isolates, forming a separate group close to B. seani highlighting a molecular proximity of these two species.     

松材线虫染病黑松上钻蛀性昆虫生态位的研究

2006年8月和10月,在浙江省舟山市和安徽省滁州市的松材线虫病典型发生区调查了黑松上的钻蛀性害虫的种类,分析了衰弱木上优势虫种的生态位宽度、生态位相似性和生态位重叠值。结果表明:在感染松材线虫病的黑松上共发现7种昆虫,其中钻蛀类害虫5种,天敌2种。在两地生活于松树主干上的昆虫种类不尽相同,而且具有各自不同的生态位宽度,存在不同程度的生态位重叠,对空间和营养资源的利用有不同比例的相似性。依据其各自生物学特性和生活习性的不同达到竞争的平衡和共存。     

Suppression of ectomycorrhizal development in young Pinus thunbergii trees inoculated with Bursaphelenchus xylophilus

In order to study the changes in ectomycorrhizal development during symptom expression of pine wilt disease, root window observations were conducted concurrent with measurements of leaf water potential as well as photosynthetic and transpiration rates of 5‐year‐old Pinus thunbergii trees that were inoculated with the pinewood nematode (PWN) Bursaphelenchus xylophilus. Infected trees were compared with girdled and uninfected control trees. Ectomycorrhizas developed constantly during the experimental period in control trees but did not develop in the girdled trees. Ectomycorrhizal development ceased within 2 weeks in those trees that finally died after PWN infection. In the trees that survived PWN infection, ectomycorrhizal development ceased within 1–4 weeks of inoculation but was resumed thereafter within 3–6 weeks. Ectomycorrhizal development ceased prior to a decrease in both photosynthetic rate and leaf water potential in the inoculated trees.     

松材线虫染病黑松上松褐天牛与褐梗天牛生态位的研究

在对山东威海成山林场松材线虫Bursaphelenchus xylophilus调查中发现,松褐天牛Monocha-mus alternatus Hope和褐梗天牛Arhopalus rusticus Linnaeus是危害黑松的主要蛀干害虫.对老熟幼虫空间生态位研究发现,在4月松褐天牛和褐梗天牛幼虫的空间生态位宽度分别为0.841和0.640,存在一定差异性,生态位重叠值为0.842,在7月和8月空间生态位宽度相似,生态位重叠值和竞争系数增大.衰弱木上松褐天牛幼虫生态位宽度为0.904,比褐梗天牛分布宽.枯立木上松褐天牛在树干2m以下分布最多,与褐梗天牛分布相似,生态位宽度分别为0.53和0.46.     

松材线虫入侵的黑松内栖真菌区系初步研究

松材线虫（Bursaphelenchus xylophilus（Steiner ＆ Buhrer）Nickle）是毁灭性森林病害——松材线虫病的病原物,主要危害针叶树种,尤其是松属（Pinus spp．）树种。黑松（Pinus thunbergii Pad．）原产日本及朝鲜半岛东部沿海地区,因其耐海雾、抗海风、可在海滩上生长等特性,在我国辽宁、山东、河北、江苏、安徽、浙江、福建、湖北、广东等省大量栽植,总面积约159300hm^2。研究证明,黑松是松材线虫病的高度感病树种,一旦松材线虫入侵,后果是毁灭性的,将给森林造成严重的、不可挽回的损失。     

Identification and genetic analysis of the pinewood nematode Bursaphelenchus xylophilus from Pinus yunnanensis

In China, pinewood nematode (PWN), Bursaphelenchus xylophilus, was first discovered from Pinus thunbergii in 1982. Thus far, 14 species in the genus Pinus have been reported to be infected by PWN under natural conditions. Pinus yunnanensis, a pine species native to south‐western China, is considered a pioneer tree for barren hill afforestation in areas undergoing rocky desertification. In this study, we detected PWN in dead P. yunnanensis trees in Anlong County, Guizhou Province, China, using both morphological and molecular methods. To our knowledge, this is the first report of PWN from P. yunnanensis in China. To investigate the possible origin of this new outbreak, mitochondrial cytochrome oxidase gene subunit I and cellulase gene sequences were used to evaluate genetic relationships among worldwide PWN isolates. Phylogenetic tree and haplotype networks revealed that the Anlong isolate (BxChQAL008) sequence was identical to those of seven Chinese isolates collected from Sichuan, Chongqing, Zhejiang, Anhui and Shandong (372–1500 km from Anlong County), but different from the isolate BxChQZY030 collected from the same province (330 km from Anlong County). It is suggested, therefore, that more than one introduction of PWN into Guizhou Province has taken place. The Anlong isolate was likely introduced from neighbouring or more distant provinces rather than from outside China. Moreover, the absence of a correlation between geographic and genetic distance was observed using Mantel test analysis, providing evidence that human‐induced dispersal plays a fundamental role in the spread of the PWN in this region.     

松材线虫对黑松几个生理生化指标的影响

8～9年生黑松经4种处理(接种松材线虫、100μg苯甲酸水溶液处理、无菌水处理并环剥主干中部树皮以及单独无菌水处理)后,研究了其流脂量、蒸腾作用及叶部过氧化物酶同工酶的变化.结果显示,接种后12天,所有接虫株松脂分泌停止;接种后27天,接虫株蒸腾作用下降最明显,其平均蒸腾强度为0.0145ml·g     

First record of Ektaphelenchoides pini associated with Ips sexdentatus on Pinus nigra laricio in Italy

In February 2015, an unexpected windstorm downed five hectares of a European black pine Pinus nigra subsp. laricio forest formation located close to Vallombrosa, Florence (Central Italy). In the following spring, an extensive survey was conducted in the area. Felled trees, stumps and all the suitable plant material were screened for the presence of the pinewood nematode (PWN), Bursaphelenchus xylophilus, by sampling wood and bark. Bark beetles were then collected from the gallery systems on the inner side of bark samples and observed in the laboratory. The following bark beetles were morphologically identified: Ips sexdentatus, Orthotomicus erosus, O. laricis and Pityogenes bidentatusa. The dissection of Ips sexdentatus allowed the extraction of numerous nematodes that were morphologically and molecularly identified as Ektaphelenchoides pini. Conversely, only few nematode specimens were isolated from either pine bark or wood. These individuals could be only molecularly identified and belonged to an undescribed nematode taxon. Even though no PWN was recorded in the investigated sites, our survey allowed the detection of a new association between E. pini and I. sexdentatus on P. nigra.     

松材线虫与拟松材线虫的几种鉴别方法

在形态、生化与分子以及致病性3个方面综述了松材线虫和拟松材线虫的鉴别方法,旨在为松材线虫病的防治和进出口检疫提供更多更安全的检疫方法,同时为更好的区别两种线虫提供理论依据。     

福建省马尾松枯死木中线虫检测结果分析

对2001~2005年福建省9个(地)市48个县(市、区)采集来的5 751个马尾松枯死木进行线虫分离镜检,结果表明:松枯死木中含有线虫率平均为91.29%,其中拟松材线虫占67.56%,其它线虫(线虫种类有待进一步鉴定)占23.73%,无线虫的占8.71%。应用木材小棍分离的线虫密度平均为1 028条.g-1,显著高于应用木屑分离的线虫平均密度286条.g-1。在垂直分布上,不同季节拟松材线虫在松枯死木树干中广泛分布,均表现为3种类型:Ⅰ型为树干上部线虫密度大于中、下部;Ⅱ型为树干中部线虫密度大于上、下部;Ⅲ型为树干下部线虫密度大于上、中部。在水平分布上,不受季节的影响,不管是秋季还是春季,均是内材的线虫密度863~1 563条.g-1(平均1 138条.g-1)6、89~1 463条.g-1(平均986条.g-1)高于相应的外材线虫密度342~631条.g-1(平均586条.g-1)、209~431条.g-1(平均325条.g-1)。因此,在对我省各地在松材线虫病监测时,应在树干上、中、下不同部位,并靠近树干中间同时取样,以木材小棍分离线虫较准确。     

Interspecific hybridization between Bursaphelenchus xylophilus and Bursaphelenchus mucronatus

Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe.Bursaphelenchus mucronatus is closely related to B. xylophilus in morphology and host plant specificity. A longrunning debate has existed regarding whether these two species can successfully produce hybrid offspring. In the present study, we performed in the laboratory, hybridization of two B. xylophilus nematode isolates from China and Japan and three B. mucronatus isolates from China, Japan and France. Nematode isolates of B. xylophilus were successfully crossed with B. mucronatus isolates, and the rate of hybridization was relatively high; however, some hybrid offspring died. Successful hybridization occurred between B. xylophilus and B. mucronatus isolates from China, and 22 generations of hybrids were produced. All F1 hybrids could be backcrossed with their parents and produce offspring. Variation in mucro length among the hybrid offspring and their parents was observed. The hybrid offspring and their parents were inoculated into 3-months-old black pine(Pinus tunbergii) seedlings. Weaker pathogenicity of hybrid offspring was observed compared with that of their parents, and significantly fewer offspring nematodes than parents were reisolated from pines. Therefore, the offspring of B. xylophilus and B. mucronatus may exist in the forest and could influence disease epidemics.     

Population structure of Bursaphelenchus xylophilus within single Pinus thunbergii trees inoculated with two nematode isolates

A study was performed to clarify the population structure of the pinewood nematode, Bursaphelenchus xylophilus, within single Pinus thunbergii trees after double infection of nematode populations using the polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method. Two nematode isolates, which had different levels or the same level of virulence, were inoculated into 6‐year‐old trees at the same or different times and then the propagated nematodes were collected from the trees after 1, 6 and 9 months. When a virulent and an avirulent isolate were inoculated into a single tree, an overwhelming propagation of the virulent isolate was observed there irrespective of the inoculation order of isolates or collection time of nematodes. However, when two virulent isolates were inoculated, propagation through the interbreeding between the two isolates was observed. In the case of the staggered inoculations with two virulent isolates, the frequency of nematodes with a PCR‐RFLP pattern of the primarily inoculated isolate increased with the time after nematode inoculations. This suggested that the population structure of B. xylophilus within a single tree varied by the virulence level of nematode populations transmitted and their transmission order.     

马尾松抗松材线虫病候选无性系的抗病性测定

为筛选抗松材线虫病强的马尾松无性系,以前期筛选获得的抗松材线虫病强的马尾松实生苗为接穗,使用湿地松作为砧木培育嫁接苗,开展无性系2次接种松材线虫抗病性测定。结果表明:使用湿地松作为砧木培育马尾松抗性无性系苗木,经过对马尾松无性系嫁接苗2次接种松材线虫测定,获得健全率较火炬松高的无性系。抗病性第1次、第2次测定的健全率超过火炬松的合格无性系分别为77.7%、66.2%,平均健全率分别为81.4%、94.5%,对照树种火炬松平均健全率分别为61.3%和82.1%,获得的无性系抗病性显著提高。为了减小误差,应该选用嫁接成活苗数量相对多的无性系间进行抗病性强弱次序评价。采用了10株以上无性系间抗病性强弱次序评价进行对照,减少了抗性强弱无性系两极分化,抗性能力中等的无性系相应增多,在选拔植株营建抗性种子园过程中应给予重视,尽量选择接种测定数量较多的高抗无性系。     

辽宁抚顺樟子松松材线虫分离与鉴定

2019年4-7月在辽宁省抚顺市对樟子松Pinus sylvestris var.mongolica枯死、濒死树取样调查,发现树体内含有线虫,经形态学比较、测量以及核糖体DNA序列分析,鉴定为松材线虫Bursaphelenchus xylophilus。樟子松是欧洲赤松Pinus sylvestris的变种,我国早期的接种试验表明樟子松为人工接种感病树种,但始终未见樟子松自然感染现象,此文是我国自然条件下樟子松感染松材线虫的首次报道。     

Comparative study on the mRNA expression of Pinus massoniana infected by Bursaphelenchus xylophilus

Pine wilt disease(PWD)is a devastating disease affecting the growth of Pinus massoniana,often leading to withering and death.To reveal the changes involved during disease progression,we investigated the mRNA expression profile of P.massoniana infested by Bursaphelenchus xylophilus.The infestation resulted in the downregulation of genes involved in interactions with pathogenic pathways such as disease resistance gene,CC-NBS-LRR resistancelike protein,and the gene encoding a putative nematode resistance protein.Increased infestation pressure(number of nematodes inoculated)caused a continuous decline in the gene expression of stem samples.An infestation of P.massoniana also resulted in a pathway enrichment of genes involved in phenylpropanoid metabolism and flavonoid biosynthesis,which in turn reduced the levels of total phenols and total flavonoids.A downregulation of auxin responsive family protein was observed in infested samples,which resulted in a suppression of plant growth.Thus,upon B.xylophilus infestation,a downregulation of genes associated with the recognition of pathogens,PWD resistance,and growth regulation was observed in P.massoniana,together with a decrease in the levels of phytoalexinlike secondary substances,all of which resulted in withering and ultimately death of P.massoniana.     

药剂防治松线虫病的研究

用呋喃丹、克线磷、涕灭威等杀线虫剂进行沟施,防治松树线虫病的效果达９６％～１００％;氧化乐果、果树宝杀虫剂,注射防治松树线虫病的效果为９２％以上;林间应用呋喃丹、涕灭威,其防治效果达６７．５％～１００％,防治后的松林不但枯死率下降,而且生长良好,枝茂叶盛,郁郁葱葱。     

Correlation of seedling size and branch number with disease resistance of Pinus thunbergii seedlings to Bursaphelenchus xylophilus

Japanese black pine (Pinus thunbergii) seedlings resistant to pine wood nematode (PWN; Bursaphelenchus xylophilus) are routinely selected in Japanese field inoculation trials. Correlations between morphological factors (such as height, stem diameter at ground level and number of branches on seedlings) and disease resistance were examined to improve the production efficiency of 1‐year‐old black pine seedlings for inoculation. Family relatedness and environmental conditions strongly affected seedling resistance; accordingly, logistic regression analysis was used to separate effects of these two variables. Height and stem diameter at ground level significantly correlated with disease resistance in seedlings inoculated with PWN. Because (a) interactions between stem diameter at ground level and environmental condition were significant and (b) height did not interact with any other factor, it was concluded that height of 1‐year‐old Japanese black pine seedlings independently correlated with PWN resistance. Thus, field inoculation tests should use tall seedlings to achieve enhanced survival rates.