栗疫病菌的致病力分化

采用树皮下接种和打孔接种的方法,在板栗树苗和离体栗枝上测定了栗疫病菌的致病力。结果表明,两种接种方法测定病菌致病力比较一致;据此可将菌株分为强致病力和低致病力两类。对低致病力菌株分生孢子后代的不同培养型也进行了致病力测定,野生型单孢菌株的毒力明显比亲本型单孢菌株的强。讨论了低致病力菌株的毒力降低的原因。     

攀西地区烟草黑胫病菌对甲霜灵的抗药性

为了评估攀西地区烟草黑胫病菌对甲霜灵的抗药性,对从不同地点采集的89个黑胫病菌菌株进行甲霜灵抗药性检测。结果表明,供试菌株中有3株对甲霜灵敏感,22株对甲霜灵敏感性处于中间状态,64株抗甲霜灵。敏感菌株、中间菌株和抗性菌株分别占总体的3.37%、24.72%和71.91%。不同地区的菌株对甲霜灵的敏感性存在差异,其中以仁和地区的菌株最为敏感,EC50值最低0.676 2 mg/L,平均为1.478 4 mg/L;而其他地区的菌株表现出一定的抗药性,平均EC50为3.085 7 mg/L,最高达6.318 1 mg/L。     

一种用于板栗疫病菌基因打靶系统的新型抗性筛选标记

板栗疫病菌是研究病原真菌的模式物种之一。目前应用于板栗疫病菌遗传转化的筛选标记有潮霉素、苯菌灵和G418抗性基因。随着板栗疫病菌致病分子机理研究的深入,需要更多的遗传筛选标记用于多重基因的遗传转化分析。本研究通过融合PCR技术,成功利用博莱霉素抗性基因Bleor进行了板栗疫病菌高丰度分泌表达基因的打靶实验,证实了Bleor作为板栗疫病菌基因筛选标记的可行性。     

应用二维液相色谱评价低毒病毒感染对板栗疫病菌总蛋白表达的影响

根据丝状真菌自身的特点,本文建立了一套完整的适合于板栗疫病菌蛋白质组分析的总蛋白质提取方法,并使用二维液相系统对野生强毒株EP155和受低毒病毒感染的弱毒株EP713进行了差异蛋白质组的比较。用ProteoVue和DeltaVue软件进行分析,得到了重复性较好的二维模拟凝胶图谱,在EP155和EP713之间共找到296个峰值差异强度在2倍以上的蛋白质紫外吸收峰：以EP155为标准,病毒感染导致蛋白上调的209个,下调的87个。根据蛋白质分子量,使用SDS-PAGE聚丙烯酰胺凝胶电泳可以得到纯度更高的蛋白质条带,本研究为大规模质谱鉴定丝状真菌差异表达蛋白质提供了一种新方法。     

In vitro inhibition of mycelial growth of Phytophthora nicotianae Breda de Haan from different hosts by Brassicaceae species. Effect of the developmental stage of the biofumigant plants

BACKGROUND: The hydrolysis products of glucosinolates in Brassicaceae tissues are potentially useful for the control of fungal pathogens. The in vitro activity of these products against Phytophthora nicotianae Breda de Haan was studied, with the isolates exposed to the volatile products released from the brassica tissues. RESULTS: The four species of Brassicaceae tested inhibited the mycelial growth of P. nicotianae isolates. The most effective developmental stage was different, depending on the species: buds yellowing in Sinapis alba L. and Brassica carinata A. Braun; seeds enlarging and all buds open in Brassica nigra (L.) W.D.J. Koch; cauliflower still covered by leaves in Brassica oleracea L. var. botrytis. At this stage, B. nigra and S. alba were the most effective (53.6 and 52.5% inhibition respectively). With all the biofumigants species tested, isolates from pepper plants were more susceptible to the brassica effect than those from tomato isolates. CONCLUSION: The developmental stage of plants has an influence on the biofumigant potential of Brassicaceae species against P. nicotianae. The isolates differ in susceptibility to compounds released, depending on their host of origin, suggesting the differentiation of populations of P. nicotianae in relation to the host of origin. Copyright © 2012 Society of Chemical Industry     

Genetic Analysis of Resistance to Phytophthora Root Rot in Tomato (Lycopersicon esculentum Mill.)

The resistant accession, LA1312, and the susceptible cultivar ‘Peto 343′, were crossed to develop F₁, F₂ and BC₁ populations for genetic analysis of resistance in tomatoes to Phytophthora parasitica Dastur, the causal agent of Phytophthora root rot. There was no maternal effect on resistance. Generation means analysis indicated that tolerance to Phytophthora root rot was under genetic control with both simple (additive and dominance) and digenic interaction (additive × additive and additive × dominance) effects contributing to the total genetic variation among generation means. Weighted least square regression analysis indicated that the majority (ca. 96 %) of the genetic variation could be explained by simple additive effects alone. Narrow sense heritability was estimated as 0.22. Based on effective factor formulae, at least five effective factors controlled the resistance. Implications for breeding procedures are discussed.     

栗疫病菌低毒力菌株的生物学特性研究

本文研究了栗疫病菌低毒力菌株的培养性状及其低毒力的转化,结果表明低毒力菌株培养性状与强毒力菌株有所不同,而且单孢后代发生分化。光照不能提高低毒力的转化率,但能提高识别转化是否发生的能力;基质对不同营养体亲和组(VCG)菌株间的转化有影响,对相同CCG菌株间的转化无作用。     

The effects of logging and disease on American chestnut

Disturbance histories drive spatiotemporal patterns of species distributions, and multiple disturbances can have complex effects on these patterns of distribution. The introduction of the chestnut blight (Cryphonectria parasitica (Murril.) Barr.) to the eastern United States in the early 1900s coincided with an increase in logging, thus presenting an ideal situation for studying the effect of two disturbance events, logging and disease. The purpose of this study was to compare chestnut (Castanea dentata) abundance and the prevalence of chestnut blight among (1) sites that were and were not logged for chestnuts during the blight pandemic and (2) sites that varied in time since the last logging event. Current chestnut abundance and chestnut blight prevalence were assessed in areas where chestnut was known to occur before the blight. Elevation, soil pH, slope, aspect, age of canopy trees, and presence or absence of chestnut stumps indicating selective logging of chestnuts were recorded at each site. Chestnuts were more abundant on sites that had not been selectively logged for pre-blight chestnuts. Chestnut presence was more likely at high elevations (857 m ± 33 m). Chestnut abundance was greater at high elevations (>1000 m) and acidic soils (pH 4-5). Chestnut blight prevalence was not correlated with any measured environmental variable. Rather, 15.1% of all chestnut stems were infected with blight regardless of chestnut density. Thus, higher chestnut abundance is not due to lower mortality from the chestnut blight, although the temporal dynamics of blight infection and stem recovery were not within the scope of this study. This research shows that local rates of chestnut population decline differ between locations with different chestnut logging histories. Chestnut site preferences are better understood within the context of history, and thus teasing apart the effects of disease, logging, and environment will result in more successful chestnut restoration efforts.     

不同土壤理化性质对板栗疫病的影响

采用线性回归模型,对不同土壤理化性质与板栗疫病之间的关系作定量的研究。结果表明：土壤中有机质、速氮、速钾、全氮、全磷、全钾的含量对板栗疫病有极显著的影响,速磷对板栗疫病有较显著的影响,板栗疫病的发病率和感病指数随它们的升高而降低;土壤的容重和质地对板栗有极显著影响,板栗疫病的发病率和感病指数随其升高而升高。     

广西烟草黑胫病菌对甲霜灵的敏感性检测

【目的】研究广西烟草黑胫病菌对甲霜灵的敏感性,为烟草黑胫病药剂防治提供科学依据。【方法】采用菌落生长速率法对从广西主要烟区采集分离到的196株烟草黑胫病菌株进行对甲霜灵的敏感性测定。【结果】甲霜灵对196株菌株的EC50在0.0691-1.0243μg/mL,平均EC50为0.3618±0.0297μg/mL;来自田林县的菌株TL05为最敏感菌株,EC50为0.0691μg/mL;来自靖西县画洞镇的菌株ZXHD12为最耐药菌株,EC50为1.0243μg/mL;各烟区烟草黑胫病菌对甲霜灵的敏感性有一定差异,其中南丹、田林县的菌株较敏感,而隆林、靖西、德保、富川县的部分菌株较耐药;196株菌株中,敏感型、一般耐药型和耐药型菌株分别占1.53%、66.84%和31.63%。【结论】广西烟草黑胫病菌已对甲霜灵产生不同程度的抗性,甲霜灵作为生产上防治烟草黑胫病的主要药剂具有较大的风险,建议生产上甲霜灵与其他杀菌剂进行轮换使用。