湘渝地区栗疫菌低毒力菌株dsRNA的转化研究

通过对采自湘渝两地区板栗上的溃疡斑进行分离，共得到56个菌株，各菌株经检测，有11个中低、低毒力菌株和1个中等毒力菌株含dsRNA，所有供试强毒菌株均不形成电泳带。通过弱毒菌株对毒菌株的转化，结果表明，弱毒力菌株对毒力菌株的转化率表现出较大差异，其中，弱毒力菌株185、618、293对所试的10个毒力菌株转化情况较好，转化率均在90％以上。弱毒力菌株729、518、392对毒菌株的转化差异较大，转化率在20—80％之间不等。     

树木枝干溃疡病菌致病力分化研究

应用人工接种的方法,对不同地理区域、不同寄主上的24个Botryosphaeria dothidea菌株、6个B.berengeriana菌株在不同抗性杨树上接种后的致病力分化进行了研究.结果显示:接种后是否形成愈伤组织是树木抗性的表现,也是真菌致病力大小的表现;B.dothidea菌株存在致病力分化现象,表现为强、中、弱3种类型,中等致病力的菌株是优势类群;以杨树为接种材料,24个B.dothidea菌株的致病力呈现一定的地理分化现象,致病力从强到弱依次为:华东(华南)>西北>华北(华中)>东北,即菌株致病力从我国南方向北方有逐渐变小的趋势;苹果轮纹病菌和干腐病菌的致病力也呈现出南方菌株大于北方菌株的特点.从溃疡病菌株的致病力出发分析了5种杨树的抗病性,其结果与以往的观察结果相一致.     

美国白蛾高毒力白僵菌菌株的紫外线诱变选育

【目的】对分离自美国白蛾幼虫虫尸的1株白僵菌菌株BH01进行紫外线诱变,以获得高毒力突变株,为美国白蛾的生物防治提供新的工程菌株。【方法】将白僵菌的孢子悬浮液置于紫外灯下进行诱变处理,诱变处理后获得的菌株进行培养后以产孢量超过原始菌株2倍以上作为依据筛选正向突变菌株,测定其对美国白蛾5龄幼虫的致病力,筛选高毒力突变株进行继代培养,研究其产孢量和致病力的稳定性。【结果】对原始菌株BH01经紫外线诱变处理后获得28个菌落,孢子校正死亡率为85.5%,将获得的菌落重新接种于PDA平板上得到产孢量高于原始菌株2倍以上的正突变株BH01-5、BH01-12、BH01-25。其中诱变菌株BH01-5对美国白蛾5龄幼虫的校正死亡率明显低于原始菌株,BH01-25与原始菌株相当,而BH01-12的校正死亡率和LT50值分别为原始菌株的1.30和0.68倍,具有显著差异。将突变株BH01-25和BH01-12继代培养6次,发现诱变菌株BH01-25菌株在继代过程中产孢量和致病力明显降低,表现出与原始菌株类似的趋势,但其产孢量始终高于原始菌株,另外,原始菌株培养第4代时即开始降低,BH01-25至第6代时才出现明显的降低,表现出了更好的稳定性。诱变菌株BH01-12在试验的6代继代培养过程中,无论产孢量还是对美国白蛾幼虫的致病力方面均未出现下降,且均明显优于原始菌株。【结论】经过对分离自美国白蛾幼虫的1株球孢白僵菌BH01进行紫外诱变,得到了产孢量和致病力均高于原始菌株的突变株BH01-12,该菌株经过继代培养后,其产孢量和致病力均未出现降低,表现出一定的遗传稳定性,具有很好的生产和应用前景。     

栗疫病菌弱毒性菌株的筛选及其dsRNA的转化稳定性

为获取栗疫病生物防治的基础信息,本研究根据菌株在PDA培养基上培养7天后的菌丝生长速度、分生孢子形成能力等培养特性,从韩国国立山林科学院树木病理研究室保藏的60个栗疫病菌菌株中筛选了2个弱致病力菌株,进行dsRNA检测、弱致病力菌株和强致病力菌株间的细胞融合试验。结果表明:2个弱致病力菌株(KCP-135和KCP-136)中均检测到了dsRNA,弱毒性菌株KCP-22和其他19个强毒性菌株之间的菌落形成明显的隔离带并沿着隔离带产生分生孢子,没有明显的细胞融合现象,而弱毒性菌株KCP-22和强毒性菌株KCP-9之间的菌落则呈现了显著的细胞融合现象,而且其细胞融合菌株的培养特性和转化dsRNA数量均发生了变异。     

利用弱毒力菌株诱导抗板栗疫病初探

在田间通过用弱毒菌株293、185、618及强毒菌株4—7,5—1对板栗大树、嫁接苗、实生苗的诱导接种，结果表明，弱毒菌株293、185的预防效果最好，分别达到86．91％、81．24％：618效果相对较差；并通过F检验，弱毒菌株293、185的效果较好，差异不明显；但与弱毒菌株618差异显著。     

不同地区来源桉树青枯病原菌落生长及幼枝水培接种致病力的差异

不同地区来源的12个青枯病菌株菌落生长特征及桉树幼枝水培接种致病力差异显著,菌落形态存在一定的差异,但是菌株菌落生长与致病值之间没有明显的关联。菌株菌液浓度对致病值影响显著,随浓度提高而加强;用于试验的4个桉树无性系感病性统计上没有显著性差别。菌落生长主要集中在平板划线培养后的4天内;第4天时,平均大小从3.53～27.68 mm。虽然菌株间致病值差异显著,如剔除表现最强及最弱的2个菌株,其余菌株间致病值则没有差别,说明不同地区幼林林木在等同气候环境条件下,受青枯病危害的机率类似,但是,个别立地林分可能因特定病原菌株而受害严重。     

栗疫病菌培养性状及毒力的研究

将采自湖南、重庆两省的56个板栗疫病菌(Cryphonectria parasitica (Murr．)Barr．)的培养性状划分为两类：一种为正常培养性状即：菌落桔黄色或黄色、生长快、形成分生孢子器的菌株，其占菌株总数的58．93％；其它为非正常培养性状，菌落颜色表现出黄褐色、深褐色或白色，其生长速率与正常菌株均不同。致病性测定结果表明，各个菌株可分为强毒力菌株、中等毒力菌株、中低毒力菌株、低毒力菌株。     

板栗疫病菌营养体亲和性研究

通过对湖南、重庆两省11个区县市的栗疫病病原菌菌株进行了营养亲和性(VC)研究。结果表明，菌株间营养体的亲合性可分为菌株间亲合与菌株间不亲合两种类型，亲合性菌株表现为菌丝相互融合，菌落间抗衡区不明显；而不亲和的菌株可分为三种反应类型：I型为强不亲和，抗衡区两侧形成明显的分生孢子器带；Ⅱ型为弱不亲和，抗衡区无分生孢子器产生；Ⅲ型为中等不亲和，分生孢子器带只在抗衡区一侧形成，56个菌株被划分为30个VCC，只含单个菌株的VCG占大多数，并探讨了生物防治栗疫病的可能性，     

杨扇舟蛾幼虫高毒力绿僵菌菌株筛选研究

测定了21株绿僵菌的平板单菌落生长和产孢量情况,证明(Ma1,Ma42,Ma788,Ma789)4菌株产孢量高,通过对这4株绿僵菌菌株的不同温度水浴处理,发现了孢子的萌发条件;并开展了4菌株对杨扇舟蛾幼虫的毒力测定,筛选出Ma789菌株的致病力较强。     

金龟子绿僵菌、球孢白僵菌不同菌株对星天牛成虫的生物测定

在测定8株虫生真菌产孢量的基础上，选用4株金龟子绿僵菌和1株球孢白僵菌菌株，采用爬行接种法对星天牛成虫进行生物测定，旨在筛选出对星天牛成虫具有强致病力的生产菌株。星天牛成虫在产孢充分的平皿上爬行后所接触到的孢子量差异不显著。接种后不同菌株对星天牛成虫的致死趋势较一致，死亡高峰期在9～15d。通过死亡率一时间几率值分析发现，MaYTTR04，MaZPTR01，t3083个菌株的LT50分别为9．14，9．48，9．67d，较另2个菌株要短。最高僵虫率的菌株是MaZFrrR01，为53．3％；其次是MaYTTR04，为40．0％；其余3个菌株均较低。试验结果表明MaYTTR04，MaZPTR012个菌株对星天牛有较高的致死率，僵虫率也较高，可以作为优良菌株进一步的研究、推广。     

杨树溃疡病菌异核体现象的研究

异核体现象是真菌遗传变异和基因流动的基础,在小麦条锈菌毒性变异中起着重要的作用(康振生等,1993).真菌中广泛存在的营养体亲和现象,使异核体现象在真菌的进化、适应性、致病性变异中更具重大意义(余仲东等,2002).本文研究杨树溃疡病菌异核体现象的细胞学及分子生物学证据,及异核体现象在病菌致病性变异中的作用.     

Virulence and double‐stranded RNA in Sphaeropsis sapinea

Forty wildtype isolates of Sphaeropsis sapinea were grouped into the morphotypes A and B based on previously defined differences in cultural and morphological criteria as well as restriction sites for Dde I and Bst UI endonucleases in nuclear ribosomal DNA amplicons. Thirteen of 20 type A isolates and nine of 20 type B isolates contained detectable dsRNA (55%) of different molecular weight and size. dsRNA was transmitted into conidia at a frequency of 71–100%. By selecting single conidia, dsRNA‐free subcultures were obtained from six of 22 isolates containing dsRNA. Pathogenicity tests on expanding buds of landscape trees of three species of Pinus showed highly significant statistical interactions between isolate virulence, Pinus species, and year. Pine species‐year had a profound impact on virulence. The pattern in the interactions was revealed by principal component analysis of the interaction sums of squares of the anova (Additive Main Effects and Multiplicative Interaction; AMMI). Pinus sylvestris was highly interactive in its susceptibility to S. sapinea with seasonal effects. P. nigra and P. resinosa were more stable. The interactivity analysis was used to apportion interaction to specific isolates to improve the accuracy of the estimates of virulence. Estimates of the relative virulence of isolates were predicted over five different Pinus species‐years. Isolates were ranked in virulence and interactivity using the AMMI model. This model permitted mean separation tests of the relative virulence among isolates over the combined Pinus species‐years. One isolate was identified as potentially having dsRNA‐mediated hypovirulence based on the significantly greater virulence of its isogenic, dsRNA‐free subculture, as expressed over the three Pinus species and 2 years. Type A isolates containing dsRNA ranged from stable to highly interactive and from low to high in virulence. Type B isolates containing dsRNA were similar in interactivity but virulence ranged from avirulent to moderate, seldom exceeding the mean for S. sapinea. dsRNA‐free isogenic subcultures tended not to express higher virulence than their dsRNA‐containing parent strains but often changed in interactivity. Therefore, in one year a dsRNA‐free subculture might be more virulent than its dsRNA‐containing parent. In another year the dsRNA‐free subculture might be less virulent.     

马鞍山林场松墨天牛病原微生物种类调查鉴定及毒力测定研究

在马鞍山市马鞍山林场,对松材线虫病(Bursaphelenchus xylophilus)的传媒昆虫松墨天牛(Monochamus alternatus)的病原微生物进行调查,结果鉴定了8种真菌和1种细菌.对松墨天牛幼虫的致病率测定显示不同的微生物种类和同一种白僵菌(Beauveria bassiana)的不同菌株均有显著差异.白僵菌的高毒力菌株营养生长无明显差异,而产孢量有明显差异.通过测定,白僵菌菌株226可能是优良菌株,对生物防治松黑天牛方面有潜在的实用价值.     

黑龙江省露地西瓜细菌性果斑病病原菌的分离与鉴定

从黑龙江省西瓜主产区分离露地西瓜果斑病病原菌18份,经过致病性测定,其中有8份对西瓜具有致病性。通过培养性状观察、显微形态观察、染色及生理生化测定,证明这8个菌株为燕麦食酸菌西瓜亚种。这8个菌株的寄主范围不尽相同。     

An inoculation experiment of Japanese <Emphasis Type="Italic">Bursaphelenchus</Emphasis> nematodes on Japanese black and red pine, <Emphasis Type="Italic">Pinus thunbergii</Emphasis> and <Emphasis Type="Italic">P. densiflora</Emphasis>

The pinewood nematode (PWN) Bursaphelenchus xylophilus is an invasive pathogen that was introduced from North America to Asian countries and Portugal and is devastating native pine forests. Some native European and Asian Bursaphelenchus nematodes also have weak to moderate pathogenicity to native pine species. To evaluate the potential risk of native Bursaphelenchus species, we inoculated ten Japanese Bursaphelenchus species into native pine species (the dominant forest species) in Japan, and evaluated their pathogenicity using mortality and tracheal tissue damage as indices. Inoculation was conducted on August 3, 2007, and the symptoms were observed every 2 weeks until February 1, 2008. None of the inoculated trees, excluding the pathogenic PWN inoculated control, showed external disease symptoms; however, four species [a less pathogenic PWN isolate, B. luxuriosae, Bursaphelenchus sp. NK215 (undescribed), and NK224 (undescribed)] caused tracheal tissue damage in inoculated seedlings and showed weak pathogenicity. Therefore, we conclude that there are some potentially pathogenic native species of nematodes distributed in Japan. Interestingly, two of these weakly pathogenic species, B. luxuriosae and NK215, are not associated with Pinaceae trees, suggesting that nematode pathogenicity may be a pre-adaptive character. More experimental studies under different conditions are necessary to accurately evaluate the potential risk of these pathogens.     

藤茎的轴向抗拉强度试验

藤茎的轴向抗拉强度试验蔡则谟（中国林业科学研究院热带林业研究所广州５１０５２０）关键词藤茎，轴向抗拉强度大部分商品藤茎加工成藤皮和藤芯，用于编织生活用品及工艺品，因此须有一定的轴向抗拉强度，这方面的研究记载很少，仅见Ｙｕｄｏｄｉｂｒｏｔｏ［’‘、吴顺...     

Armillaria species distribution on symptomatic hosts in northern hardwood and mixed oak forests in western Massachusetts

Armillaria spp. are some of the most important forest pathogens in mixed hardwood forests of southern New England, yet their role as prominent disturbance agents is still not fully appreciated. We investigated the distribution of Armillaria species across eight separate stands of northern hardwood and mixed oak forests in western Massachusetts. We were specifically interested in the Armillaria species distribution from live, symptomatic hosts and not in determining overall incidence in the forest. From 32 plots (16 within each forest type), 320 isolates were collected. Armillaria was routinely encountered causing disease of live trees. In total, 89% (286/320) of all isolations came from live hosts exhibiting symptoms of root and butt rot. Overall, A. gallica was the dominant species in each forest type, making up 88/160 (55%) isolates from northern hardwood and 153/160 (96%) of all isolations from mixed oak stands. However, northern hardwood forests showed much greater species diversity, as A. calvescens, A. gemina, A. ostoyae, and A. sinapina were all found. At one site, a northern hardwood forest surrounding a high elevation spruce-fir forest, A. ostoyae was the most abundant species encountered. All five Armillaria species were found causing disease of live hosts, including A. gemina, a species considered by some as weakly virulent. Armillaria gallica was found on 22/23 tree species’ sampled, and was found most often causing butt rot.     

切梢小蠹伴生真菌发生及病害特征的初步研究

小长喙霉 ( Ophiostoma minus Hedgc.)于 190 6年作为新种定名为 Ceratostomella minorHedgc,1981年更名为 Ophiostoma minus Hedgc.,此后一直沿用至今 [1]。小长喙霉以小蠹虫( Tomicus spp.)为媒介 ,通过小蠹虫对树木的蛀害 ,被携带进入到寄主植物组织内 ,进行自身生命过程并危害寄主植物[2 ] ,故也被称为小蠹虫伴生真菌 [3,4] 。该菌的寄主植物主要是松树( Pinus spp.) [4] ,它在协助小蠹虫蛀害松树树木中扮演着重要的角色 [3,4]。80年代以来 ,纵坑切梢小蠹 ( Tomicus piniperda Linnaeus)在云南 8个地州大面积暴发成灾 ,10余万 hm2 …     

Comparative virulence of blue-stain fungi isolated from Japanese red pine

 We made inoculations to determine the comparative virulence of blue-stain fungi isolated from Japanese red pine (Pinus densiflora Sieb. & Zucc.). Based on the symptoms caused by each fungus, the most virulent fungus was Leptographium wingfieldii. Also, Ophiostoma minus was relatively virulent while lesions induced by some species did not differ from those in the control treatment. Based on the results, we concluded that the pathogenicity of the blue-stain fungi varied widely, and thus their impact on the host most likely varies too. Received: June 7, 2002 / Accepted: October 4, 2002 Present address: JST Domestic Research Fellow, Forest Pathology Laboratory, Tohoku Research Center, Forestry and Forest Products Research Institute, 92-25 Nabeyashiki, Shimo-Kuriyagawa, Morioka 020-0123, Japan Tel +81-19-648-3961; Fax +81-19-641-6747 e-mail: H_masu@hotmail.com Acknowledgments We thank Drs. Ohtaka and Usuki, Plant Pathology and Mycology Laboratory, Institute of Agriculture and Forestry, University of Tsukuba, for technical assistance. Contribution No. 174, Plant Pathology and Mycology Laboratory, Institute of Agriculture and Forestry, University of Tsukuba. Correspondence to:H. Masuya     

木麻黄青枯菌的根表吸附及根内增殖与其致病性关系

对 3个不同致病的青枯菌菌株和 7个不同抗病性的木麻黄无性系苗的研究得出 ,各菌株对寄主根表吸附量具有显著差异 ,吸附量与致病性呈负相关 :各菌株在寄主根内的增殖量差别明显 ,增殖量与致病性呈正相关。病菌脂多糖 (LPS)对幼苗根的预处理 ,可使其供体菌的吸附量减少5 8.5 %　 97.3% ,但胞外多糖 (EPS)对供体菌的吸附量无明显影响。洗去EPS和LPS的菌体较完整菌体对根表的吸附量减少 6 3.3%　 74 .2 %。而仅洗去EPS的菌体对根表的吸附有所增加 ,最高达19.1%。各菌体SDS PAGE电泳图谱显示出一定差异 ,其中强毒菌株 6 0 1B具有Rf=0 .35的特异谱带。结果表明青枯菌对木麻黄的致病性与其在寄主根表的吸附情况和在根内的快速增殖具有密切关系。LPS在此病理系统中 ,起着细菌识别因子的作用 ,EPS对LPS进行掩盖 ,二者都是病菌致病性的重要因子