云南省马铃薯疮痂病致病链霉菌种类组成研究

 为明确云南省马铃薯疮痂病病原菌(Streptomyces spp.)的种类及其生物学特征,自2013年从云南省13个马铃薯主产区采集疮痂病病样,共分离到200株链霉菌,通过温室盆栽致病性试验筛选出67株致病菌。通过形态学、生理生化指标、致病性测定及16S rDNA序列分析对获得的菌株进行鉴定。结果显示,引起云南地区马铃薯疮痂病的病原为10种链霉菌,分别为S. caviscabies、S. anulatus、S. scabies、S. turgidiscabies、S. acidiscabies、S. europaeiscabiei、S. luridiscabiei、S. enissocaesilis、S. griseus和S. aureofaciens。其中S. enissocaesilis和 S. anulatus为优势种群,S. caviscabies、S. anulatus和S. luridiscabiei为国内首次报道的病原菌。因此,认为云南省马铃薯疮痂病菌种类复杂多样。     

马铃薯疮痂病菌在植株和田间的分布与动态分析

为探明马铃薯疮痂病菌在植株和土壤中的分布情况及种群动态变化特点,利用常规PCR和定量PCR(qPCR)技术对不同环境的马铃薯疮痂病株和田间植株不同生育期的土壤样品进行病原菌的定性定量检测.结果 表明,病田、温室盆栽和微型薯苗床中马铃薯疮痂病重度发病植株的根、匍匐茎、块茎、地上茎、叶片等组织样品均可检测到184 bp的疮...     

Differences in host range, pathogenicity to potato cultivars and response to soil temperature among Streptomyces species causing common and netted scab in France

The pathogenicity and ecology of some isolates representative of the four main Streptomyces species ( S. scabies , S. europaeiscabiei , S. stelliscabiei and S. reticuliscabiei ) identified as pathogenic to potato tubers were investigated. Three pathogenicity groups could be distinguished. Group 1 included all isolates of S. scabies , S. europaeiscabiei and S. stelliscabiei from common scab lesions of potato and other susceptible root crops. All these produced similar symptoms and were pathogenic to potato, carrot and radish. Group 2 included all isolates from S. reticuliscabiei netted scab lesions; they were pathogenic to both tubers and roots of only a few potato cultivars, and did not infect carrot or radish. Group 3 included three isolates of S. europaeiscabiei from netted scab lesions on cv. Bintje, which produced either common or netted scab symptoms depending on the potato cultivar or plant species. In an experiment on a few isolates from each of the three groups, held at various soil temperature regimes, the three from group 1 were most pathogenic at higher temperatures (20°C or 20/30°C), the two from group 2 were most pathogenic at a lower temperature (17°C). The group 3 isolate caused netted scab symptoms on susceptible cultivars at low temperatures (≤ 20°C) and deep-pitted lesions at higher temperatures. Since the groups identified differ in ecological requirements, it is important to adapt the control methods to the pathogenic species present in the soil.     

Phytotoxin produced by Streptomyces sp. causing potato russet scab in Japan

A phytotoxin isolated from the Stretomyces sp. causing potato russet scab in Japan (Kamenoko-byo in Japanese) was identified as a 16-membered macrolide, FD-891. It induced necrosis in potato tuber slices above 50 µg/disk, which is about 1/100 the activity of thaxtomin A. The phytotoxin was detected in potatoes infected by the pathogen and was produced by other pathogenic strains with different geographic origins.     

一个推测的野油菜黄单胞菌Ⅲ型分泌效应子基因XopXccP对寄主植物的致病性分析

 野油菜黄单胞菌野油菜致病变种(Xanthomonas campestris pv. campestris, Xcc)是一种在全球范围内引起十字花科植物黑腐病的重要病原细菌。Xcc中效应蛋白与植物互作机理的研究还不够全面, 在已经测序的菌株Xcc 8004中, Xc_2994基因预测编码一个III型分泌效应蛋白XopXccP, 其生物学功能尚不清楚。为了探索XopXccP的生物学功能, 我们构建了Xcc 8004菌株的XopXccP基因缺失突变体, 结果发现XopXccP基因缺失后, 病原菌在多个甘蓝、花椰菜以及模式植物拟南芥(Col-0)上的致病性显著下降, 甚至几乎不致病。同时, 采用农杆菌侵染拟南芥花序的转化方法, 获得了转XopXccP基因拟南芥纯系, 经过诱导效应蛋白XopXccP在拟南芥中表达, 发现转基因拟南芥出现类似病斑的细胞死亡。本研究结果初步证明, XopXccP是一种毒性蛋白, 是Xcc 8004对多数十字花科植物致病所必须的。     

Destruxin B produced by Alternaria brassicae does not induce accessibility of host plants to fungal invasion

It has been reported that Alternaria brassicae, the causal agent of gray leaf spot in Brassica plants, produces a host-specific or host-selective toxin (HSTs) identified as destruxin B. In this study, the role of destruxin B in infection of the pathogen was investigated. Destruxin B purified from culture filtrates (CFs) of A. brassicae induced chlorosis on host leaves at 50–100 μg ml⁻¹, and chlorosis or necrosis on non-host leaves at 250–500 μg ml⁻¹. Destruxin B was detected in spore germination fluids (SGFs) on host and non-host leaves, but not in a sufficient amount to exert toxicity to host plants. When spores of non-pathogenic A. alternata were combined with destruxin B at 100 μg ml⁻¹ and inoculated on the leaves, destruxin B did not affect the infection behavior of the spores. Interestingly, SGF on host leaves allowed non-pathogenic spores to colonize host leaves. Moreover, a high molecular weight fraction (>5 kDa) without destruxin B obtained by ultrafiltration of SGF had host-specific toxin activity and infection-inducing activity. From these results, we conclude that destruxin B is not a HST and does not induce the accessibility of the host plant which is essential for colonization of the pathogen. In addition, the results with SGF imply that a high molecular weight HST(s) is involved in the host–pathogen interaction.     

黑龙江省部分地区马铃薯疮痂病菌种类及致病性鉴定

为明确黑龙江省马铃薯疮痂病病原菌的种类及其特征,2012-2013年从黑龙江省克山县、绥化市、哈尔滨市、杜尔伯特蒙古族自治县采集具有疮痂病病斑的马铃薯块茎,从中分离纯化病原菌,根据16SrRNA基因的差异采用分子手段对所分离的菌株进行种类和致病性鉴定,并对txtAB阳性菌株采用萝卜幼苗法或马铃薯致病性试验测定其致病性。共分离出74株菌株,鉴定出致病性菌株26株,其中Streptomyces scabies或S.europaeiscabiei 21株,S.turgidiscabies 3株和S.acidiscabies 2株。所有的致病性菌株中共有4种致病岛基因型,即nec1+/tomA+、nec1-/tomA+、nec1+/tomA-和nec1-/tomA。     

水稻种子携带恶苗病菌种类及其致病性研究

水稻恶苗病是水稻上的一种重要病害,每年给我国的水稻生产造成严重的经济损失.本文旨在探究我国主要稻作区水稻种子携带恶苗病菌的种类及其致病性情况.采用洗涤法和平板培养法对收集我国主要稻作区的66份水稻种子样本进行恶苗病病菌分离,共获得111株病菌分离物,并从中选取24株代表性分离物,采用翻译延伸因子TEF-1α序列、形态学...     

Identification and characterization of RB-orthologous genes from the late blight resistant wild potato species Solanum verrucosum

Late blight, caused by the oomycete pathogen, Phytophthora infestans, is a devastating disease of potatoes and tomatoes. A key long-term management strategy for combating this disease is to develop potato cultivars with high levels of durable resistance through identification and integration of major resistance genes. The RBgene, cloned from the Mexican diploid potato species Solanum bulbocastanum, confers broad-spectrum resistance to potato late blight. Here, we have determined the late blight resistance phenotypes of eight accessions of Solanum verrucosum, another wild diploid potato species, using greenhouse inoculations and discovered variability among the accessions. While most accessions were resistant, one accession was notably more susceptible. Transcribed orthologs of the RB gene from the eight S. verrucosum accessions were cloned using a homology-based PCR approach. Sequence analysis revealed that the RB^ver orthologs share up to 83.5% nucleotide identity with RB^blb. Stable introduction of the RB ortholog from late blight resistant S. verrucosum PI275260 into susceptible S. tuberosum confers resistance to P. infestans. Interestingly, this functional RB^ver ortholog contains an insertion of a complete leucine rich repeat when compared to RB^blb, and differs from the RB^ver ortholog from a susceptible accession at only four amino acid residues.     

松树蜂毒液对寄主松树致病性机制的研究进展

松树蜂Sirex noctilio是一种原产于欧洲各国、蒙古国、格鲁吉亚共和国和北非国家的松科林木蛀干害虫,属于国际上重大林业检疫性有害生物。其雌成虫产卵时向寄主树干注射毒液和共生真菌——网隙裂粉韧革菌Amylostereum areolatum。一般认为毒液能削弱寄主林木的防御能力,是导致寄主树木针叶出现变黄、枯萎等早期病理症状的主导因素,也是为共生真菌侵染创造条件的“条件作用剂”。毒液和共生真菌均不能单独致死林木,只有两者联合作用才会对寄主林木有致死性。该文综述了松树蜂毒液成分及性质、寄主松树对毒液的生理响应和松树蜂毒液作用的分子机制,并对植物激素诱导植物防御反应的研究前景进行展望,以期有助于促进毒-菌致寄主林木受害机制的深入研究,有助于基于植物激素免疫诱抗剂等新防控途径的开发。     

49种植物源粗提物对黄瓜灰霉菌的生物活性筛选

黄瓜灰霉病是由灰霉菌Botrytis cinerea引起的重要病害.目前,尚无理想的抗灰霉病黄瓜品种,药剂防治仍然是控制该病害的必要措施.20世纪80年代以前防治灰霉病的杀菌剂如苯并咪唑类的多菌灵、硫代氨基甲酸酯类的甲基托布津、二羧酰亚胺类的异菌脲、腐霉利等已使用了近30年,灰霉病菌对这些药剂均产生了不同程度的抗药性.作者测定了植物源粗提物对黄瓜灰霉病菌的活性,以期研制开发出无公害植物源杀菌剂.     

利用酵母双杂交筛选与马铃薯Y病毒CKVNP互作的寄主蛋白

 马铃薯Y病毒坏死株系(Potato virus Y necrosis strain,PVY^N)侵染烟草后烟草表现叶脉坏死症状,但其致病的分子机制,特别是与病毒互作的宿主蛋白研究鲜有报道。PVY^N(JQ971975)的CKVNP编码区(CI-6K2-VPg-NIa-Pro区域,核苷酸5 540-6 491)与烟草表现叶脉坏死症状相关,研究其与寄主间的分子互作有助于揭示病毒侵染致烟草表现叶脉坏死症状的分子机制。本文将PVY^N的CKVNP编码区定向克隆到含有DNA结合功能域(DNA-binding Domain,BD)载体上,构建与激活功能域(Activation Domain,AD)融合表达的烟草cDNA文库,用CKVNP为诱饵筛选文库寻找与其互作的寄主因子。结果表明:诱饵质粒插入的CKVNP编码区可读框和氨基酸序列均正确,对酵母菌株无自主激活能力;烟草cDNA文库容量为7.0×10⁶ CFU/mL,且插入片段平均大小在1.0 kb以上,质量符合筛选要求;经过筛选和共转化回转验证,有94个候选基因与CKVNP在酵母中互作。挑选22个酵母质粒进行测序得到这些基因的cDNA序列,BLAST分析结果表明,这些基因共编码14种蛋白。     

浙江省不同寄主植物上烟粉虱寄生蜂之调查

为明确浙江省不同地区以及不同寄主植物上的烟粉虱Bemisia tabaci寄生蜂种类,更好地利用寄生蜂对烟粉虱进行生物防治,通过对浙江省8个地区进行田间烟粉虱末期若虫或伪蛹采样,并将其带回实验室内饲养直至寄生蜂成蜂羽化进行形态学鉴定。结果表明,在浙江省8个地区共采集到3 490头烟粉虱寄生蜂,其中蒙氏桨角蚜小蜂Eretmocerus mundus Mercet、狄氏桨角蚜小蜂Eretmocerus debachi RoseRosen和浅黄恩蚜小蜂Encarsia sophia(GiraultDodd)的数量最多,比例分别达到了53.0%、27.8%和9.9%;在温州发现的寄生蜂种类最多,共有10种;在20种寄主植物种类或品种上共发现10余种烟粉虱寄生蜂,其中17种寄主植物上共有的烟粉虱寄生蜂有蒙氏桨角蚜小蜂、12种寄主植物上共有的是浅黄恩蚜小蜂、10种寄主植物上共有的是狄氏桨角蚜小蜂;表明这3种寄生蜂是浙江省广泛分布的优势种类。     

FpStuA参与假禾谷镰孢的产孢和致病性

 假禾谷镰孢是一种土传真菌,其引起的小麦茎基腐病已成为威胁我国小麦生产的重要病害。APSES蛋白是真菌中保守存在的一类转录因子,参与多种细胞生理过程。本研究,我们在假禾谷镰孢中鉴定到StuA同源蛋白FpStuA。qRT-PCR分析发现FpStuA在假禾谷镰孢分生孢子和侵染阶段诱导表达。通过PEG介导的原生质体转化方法获得3个FpStuA基因缺失的突变体。与假禾谷镰孢野生型菌株相比,Δfpstua突变体的生长速度明显减慢,气生菌丝减少;分生孢子的产生比野生型减少70%,且Δfpstua突变体分生孢子变短、分隔减少;Δfpstua突变体对大麦叶片、小麦胚芽鞘和小麦根的致病性均显著降低,脱氧雪腐镰刀菌烯醇(DON)合成明显减少。综上结果,转录因子FpStuA对假禾谷镰孢的生长、产孢和致病性都非常重要。     

红颈常室茧蜂对绿盲蝽及其为害寄主植物的选择行为

为明确红颈常室茧蜂Peristenus spretus Chen et van Achterberg定位寄主绿盲蝽Apolygus lucorum(Meyer-Dür)时利用的挥发性信息物质来源,利用Y型昆虫嗅觉仪测定了红颈常室茧蜂雌雄成虫对绿盲蝽3龄若虫及其为害寄主植物棉株以及雌性红颈常室茧蜂成虫、绿盲蝽成虫对苗期和花期的棉花、蓖麻的选择行为。结果表明,与干净空气(空白对照)相比,雌性红颈常室茧蜂对绿盲蝽3龄若虫、健康棉株的选择行为无显著差异,绿盲蝽3龄若虫为害的棉株对雌性红颈常室茧蜂具有显著的吸引作用,但在为害后去虫和未去虫处理间无显著差异;雄性红颈常室茧蜂对各处理均无明显的选择行为。与健康或为害后去虫的苗期棉花相比,雌性绿盲蝽成虫显著趋向花期蓖麻;而雌性红颈常室茧蜂只趋向于为害后的花期蓖麻。雌性红颈常室茧蜂对为害后去虫的花期棉花和花期蓖麻的选择行为显著高于相应的苗期植株。这表明雌性红颈常室茧蜂主要利用绿盲蝽若虫为害后寄主植物释放的挥发性信息物质来定位寄主绿盲蝽,且其对花期寄主植物的选择行为与绿盲蝽成虫具有一致性。     

西花蓟马对不同花卉寄主的产卵选择性

为探讨不同寄主对西花蓟马Frankliniella occidentalis产卵的影响,采用非自由选择法研究了其对黄花美人蕉、黄花槐、凤尾兰及夹竹桃4种寄主的产卵选择性。结果表明,西花蓟马单雌总产卵量在黄花美人蕉的花上最大为77.65,凤尾兰的叶上最小为19.00;日均产卵量在黄花槐的花上最大为2.58,凤尾兰的叶上最小为0.91;净生殖率、内禀增长率和子代雌性比均在黄花美人蕉的花上最大,分别为46.07、0.136和0.74,在凤尾兰的叶上最小,分别为5.94、0.065和0.55。西花蓟马在花上的产卵量等参数显著高于叶,表明其对花的产卵选择性高于叶,对花的产卵选择性依次为黄花美人蕉黄花槐凤尾兰夹竹桃,对叶的产卵选择性为黄花美人蕉≈黄花槐夹竹桃凤尾兰。表明西花蓟马对不同寄主有不同的产卵偏好,对寄主不同部位也有不同偏好。     

Biodiversity of Fusarium species in ears and stalks of maize plants in Belgium

In order to investigate the pre-harvest contamination of maize plants by Fusarium species in Belgium, a three-year survey has been performed in five fields in which three hybrids differing in susceptibility to maize stalk rot were sampled at four different physiological stages. An extensive collection of 5,659 Fusarium isolates characterized at the species level was established during the 2005, 2006, and 2007 growing seasons, with a total of 23 different Fusarium species identified to occur on ears and stalks. A high number of plants was already contaminated by Fusarium spp. at the anthesis stage, although no symptoms were visible on ears or on stalks. As the season progressed, the incidence of Fusarium-infected maize plants reached 100% in several fields. At the end of the growing season, the most frequently isolated species in maize ears were F. graminearum, sometimes associated with F. avenaceum, F. crookwellense, F. culmorum, F. poae, and F. temperatum, a new species recently described on maize. The predominant Fusarium species detected in stalks at the end of the growing season were F. graminearum and F. crookwellense, often associated with F. culmorum and F. temperatum. Year-to-year variability observed for the incidence of F. graminearum can most likely be associated with differences in climatic conditions among the three years.     

拮抗水稻白叶枯病菌链霉菌的筛选、鉴定和防效研究

为寻找水稻白叶枯病天然生防药剂,本研究利用共培养和牛津杯法分离筛选植物根际土壤放线菌,共分离纯化获得65株放线菌菌株.在8株能够拮抗水稻白叶枯病菌Xanthomonas oryzae pv.oryzae(Xoo)放线菌菌株中,Sr-63菌株对水稻白叶枯病菌拮抗能力最强,其发酵液抑菌圈直径为46.4 mm±2.3 mm....     

一株PVYNTN-NW黑龙江马铃薯分离物的检测鉴定

 马铃薯Y病毒(Potato virus Y,PVY)是马铃薯、烟草等茄科作物上的重要病毒,在与寄主共同进化过程中产生了许多株系。本文从黑龙江马铃薯样品中得到PVY分离物A12。ELISA结果表明A12被PVY^O的单克隆抗体特异性识别。A12开放阅读框为9 186个核苷酸,编码3 061个氨基酸,与SYR-II-Be1分离物的核苷酸和氨基酸序列一致率均最高,分别为98.3%和99.2%。系统发育分析发现A12与PVY^NTN-NW株系SYR-II型的分离物聚类到一起;重组分析表明,A12是N-605和O_z的重组体,重组类型与SYR-II-Be1相同。综合以上结果表明,A12属于PVY^NTN-NW株系SYR-II型。但与常见PVY^NTN-NW株系分离物在珊西烟引起叶脉坏死不同,A12产生花叶症状。A12辅助成分-蛋白酶在182位和245位的氨基酸均为精氨酸,而其它PVY^NTN-NW株系分离物为赖氨酸。本研究结果可为黑龙江马铃薯PVY的早期检测和有效防控提供理论指导。     

寄主植物对草地螟种群增长的影响

根据草地螟对寄主植物的选择性和转主取食的特性,研究了寄主植物对草地螟种群增长的影响.结果表明,不同寄主植物不仅影响草地螟的生长发育,而且也影响其产卵量和交配率.如幼虫取食灰菜和大豆苗时发育历期较短(约17天),存活率高,蛹重较大;雌蛾产卵量分别达到238、222 粒/头,交配率分别为75%、67%,其种群增长指数较高.而取食玉米和马铃薯苗时发育历期则延长到24天,存活率不足40%,蛹重较轻;其雌蛾产卵量分别为93、50粒/头,交配率均为40%,种群增长指数较低.转主取食有利于草地螟的生长和繁殖,而且提高其种群增长指数.如低龄幼虫取食灰菜至3龄再转食玉米或马铃薯苗,其发育历期、蛹重、产卵量和交配率均比仅取食玉米或马铃薯苗的有明显改善.寄主植物对成虫干重及甘油酯含量的影响亦表现出类似的结果.