新疆北部棉区黄萎病菌种群致病性分化及变异

采用特异性引物PCR检测技术和鉴别寄主法对新疆北部棉区41个棉花黄萎病菌菌系进行检测,以期明确黄萎病菌种群致病性分化及变异。特异性引物(ND1/ND2和D1/D2)PCR检测结果显示,供试菌系中落叶型菌系16个,占39.0%;非落叶型菌系24个,占58.5%;1个菌系未能检测出致病类型。鉴别寄主法测定结果显示:41个供试菌株中致病性强、中、弱的菌系分别为21、12和8个,分别占51.2%、29.3%和19.5%。落叶型菌系的致病力明显高于非落叶型,平均病情指数分别为39.4和25.8。研究表明,无论落叶型菌系和非落叶型菌系,接种后都可产生落叶症状,但落叶的程度有明显差别,其落叶症状的轻重不仅与菌系的致病类型有关,还与品种的抗病性密切相关。     

不同植棉省区落叶型黄萎病菌的培养特性及致病力比较

近年来落叶型症状的棉花黄萎病对棉花生产的危害越来越大,为明确落叶型棉花黄萎病菌的分化特点,采用特异性分子标记方法,对我国10个主要植棉省区30个落叶型棉花黄萎病菌的培养特性和致病力进行了比较。落叶型黄萎病菌系在我国主要植棉省区已普遍存在,该菌系以菌核型为主,其微菌核呈放射状或环状。63.3%菌系的菌丝发达致密,其余菌系的菌丝较为疏松。落叶型黄萎病菌系之间的产孢量和致病力差异较大,产孢量变幅为3.7×107～18.8×107个孢子/mL;71.9%为强致病力菌系,25.0%为中等致病力。研究表明,不同植棉省区间落叶型黄萎病菌系的产孢量和致病力具有一定差异。     

江苏省水稻品种细菌性条斑病抗性评价与病原菌致病力分化

采用针刺接种法,在水稻孕穗期接种3个不同致病型的细菌性条斑病菌,鉴定134个不同类型的水稻品种对细菌性条斑病的抗感性,并使用6个鉴别品种测定江苏徐淮地区82个细菌性条斑病菌的致病力.结果表明:粳稻品种对细菌性条斑病的抗性明显高于籼稻,常规稻和杂交稻对细菌性条斑病的抗性没有明显差异;根据病菌与鉴别品种的互作反应,将供试菌株区分为8个致病型,大多数菌株和鉴别品种表现为弱互作关系,少数菌株与鉴别品种存在强互作关系;第1致病型的菌株致病力强,6个鉴别品种均呈感病反应,并占供试菌株总数的40.2%.     

我国部分省域甘蓝主要产区黑腐病菌鉴定及致病力分析

 为了明确我国甘蓝主栽区黑腐病菌株种类与致病力水平,为优化抗病性鉴定方法、筛选抗病品种及抗病品种的合理布局提供依据,分别采集了10个省域的黑腐病病叶,经过分离纯化与分子鉴定,获得了26个典型甘蓝黑腐病菌株;选用5个甘蓝抗、感品种作为鉴别寄主,以甘蓝黑腐病菌株的悬浮液为接种体,采用喷雾接种法测定致病力。结果表明:来源于不同省域的黑腐病菌株致病力存在显著差异,致病力最强的是YU,病情指数平均值为38.31;致病力最弱的是SH,病情指数平均值为17.03。来源于不同海拔高度的甘蓝黑腐病菌株致病力最强的是G1500,病情指数平均值为37.93;最弱的是G800,病情指数平均值为19.80。根据鉴别寄主抗感反应将26个黑腐病菌株划分为12类致病型,发现来自不同地域的甘蓝黑腐病菌株间存在着显著的致病性分化现象,对甘蓝品种的致病力存在着显著性差异,其中菌株YU致病力最强,菌株YU可作为甘蓝抗病性鉴定的主要致病菌株,指导抗病品种的选育。     

我国部分省域甘蓝主要产区黑腐病菌鉴定及致病力分析

 为了明确我国甘蓝主栽区黑腐病菌株种类与致病力水平,为优化抗病性鉴定方法、筛选抗病品种及抗病品种的合理布局提供依据,分别采集了10个省域的黑腐病病叶,经过分离纯化与分子鉴定,获得了26个典型甘蓝黑腐病菌株;选用5个甘蓝抗、感品种作为鉴别寄主,以甘蓝黑腐病菌株的悬浮液为接种体,采用喷雾接种法测定致病力。结果表明:来源于不同省域的黑腐病菌株致病力存在显著差异,致病力最强的是YU,病情指数平均值为38.31;致病力最弱的是SH,病情指数平均值为17.03。来源于不同海拔高度的甘蓝黑腐病菌株致病力最强的是G1500,病情指数平均值为37.93;最弱的是G800,病情指数平均值为19.80。根据鉴别寄主抗感反应将26个黑腐病菌株划分为12类致病型,发现来自不同地域的甘蓝黑腐病菌株间存在着显著的致病性分化现象,对甘蓝品种的致病力存在着显著性差异,其中菌株YU致病力最强,菌株YU可作为甘蓝抗病性鉴定的主要致病菌株,指导抗病品种的选育。     

棉田土壤中棉花黄萎病菌的致病力分化

为了明确同一棉田生态系中棉花黄萎病菌的群体组成和致病力分化特点,利用病害反应型及病情指数测定法,对来自同一棉田的43个棉花黄萎病分离菌株在5个鉴别寄主上进行了致病力测定。结果表明,43个菌株可划分为落叶型致病力强的Ⅰ型、混合型致病力中等的Ⅱ型和非落叶型致病力弱的Ⅲ型。其中Ⅰ型菌株19个,占44.2%,平均病情指数大于50;Ⅱ型菌株16个,占37.2%,平均病情指数在30～50之间;Ⅲ型菌株8个,占18.6%,平均病情指数小于30。由此证明,同一棉田棉花黄萎病存在落叶型和非落叶型两类病害表现类型,其病原菌存在强、中、弱三种不同致病类型的生理型,揭示出棉花黄萎病菌本身是一个易变异的混合基因型群体,群体中的不同个体组成的亚群体具有不同的致病性。     

宁夏葡萄霜霉病菌致病型鉴定及葡萄品种抗性评价

为合理利用葡萄抗性品种以及田间病害综合治理,采用离体叶盘接种法分别对2018年和2019年自宁夏回族自治区银川市、石嘴山市和吴忠市采集的43株葡萄霜霉病菌Plasmopara viticola菌株进行致病型鉴定及聚类分析,并对17个主栽葡萄品种进行抗性评价及聚类分析。结果表明：2018、2019年供试菌株致病力和供试葡萄品种抗性之间均存在显著差异,菌株平均病情指数与发病率呈显著正相关,皮尔逊相关系数r和回归系数R²分别介于0.45~0.96和0.20~0.92之间;2018、2019年供试菌株的强致病力菌株和弱致病力菌株分别为CS-YL和VI-BYDD、RG-JSJG和CS-YM;2018年和2019年供试菌株致病型被划分为强、中、弱3种类群,2年所占比例分别为10.00%、15.00%、75.00%和34.78%、39.13%、26.09%;供试17个葡萄品种的抗性类型可被划分为感病、抗病、高抗3种类群,2年所占比例均为17.65%、29.41%和52.94%。不同葡萄品种对不同菌株的抗性类型多样化。表明宁夏回族自治区葡萄霜霉病菌菌株致病力分化明显,不同菌株的致病型与其地域来源无关,不同葡萄品种的抗感程度不同。     

马铃薯黄萎病病原菌营养亲和群、生理小种、交配型鉴定以及致病力差异分析

为明确引起马铃薯黄萎病的大丽轮枝菌Verticillium dahliae的遗传变异和致病力的差异,对从内蒙古及其周边地区马铃薯发病株上分离得到的29株大丽轮枝菌的营养亲和群、生理小种和交配型进行了测定,利用伤根接种法进行致病力分化研究。结果表明,供试的29株马铃薯大丽轮枝菌菌株被划分为VCG2B、VCG4B和VCG4A三个营养亲和群,其菌株数分别为11、2和16株;供试的29株菌株均鉴定为单一的2号生理小种和MAT1-2-1交配型。供试的29株大丽轮枝菌菌株间致病力存在一定的差异,其中NCP-1菌株的致病力最强,病情指数为83.33;而NWS-5菌株的致病力最弱,病情指数仅为10.85;不同营养亲和群菌株的平均致病力也存在显著差异,VCG4B型菌株的平均致病力最高,平均病情指数为67.18;其次为VCB2B型菌株,平均病情指数为42.50,而VCG4A型菌株致病力最弱,平均病情指数仅为20.54。     

棉花黄萎病菌致病力测定及评价方法研究

 棉花黄萎病菌致病力测定及评价是抗病育种及病害综合防治的基础。本文以我国三大棉区的167个黄萎菌菌株为对象,研究致病力测定及评价中不同批次之间病情指数的校准及致病力类型划分标准等关键技术环节。结果表明,以中等致病力类型菌株Vd076为校正菌株,以感病性稳定的冀棉11为校正鉴别寄主,以校正菌株在校正鉴别寄主上病情指数达到50.0±5.0时的调查结果进行各菌株的致病力评价,可获得较好的校正效果,使不同批次试验数据具有可比性;依据聚类分析结果,制定了致病力类型划分标准,强、中、弱3种致病力类型的平均校正病指分别为﹥40.0、20.1~40.0和20.0;通过对不同鉴别寄主组合的分析,推荐陆地棉中棉所41号、豫棉21、鲁棉研28、中棉所35号、中棉所8号、冀棉11作为鉴别寄主。该研究为棉花黄萎病菌致病力变异等相关研究工作提供了技术支撑。     

江苏省大丽轮枝菌的培养、遗传及致病特性分析

由大丽轮枝菌引起的黄萎病是我国棉花和茄子的主要病害之一,对棉花和茄子的生产造成巨大损失。为了研究大丽轮枝菌的群体遗传变异以及对棉花和茄子的交互致病性,本文对分离自江苏省的63个棉花黄萎菌和10个茄子黄萎菌进行了培养、遗传和致病特性分析。根据菌株在PDA培养基上生长时形成微菌核的多少来划分培养类型,结果菌核型占83.6%,成为主要的培养类型。用PCR技术检测菌株的致病类型、交配型以及是否具有无毒基因Ave1,结果落叶型菌株占86.3%,为优势种群,但是10株茄子黄萎菌100%都是非落叶型菌株;供试的所有江苏菌株交配型都是MAT1-2型,并且都没有无毒基因Ave1。选择江苏省的6个棉花黄萎菌和4个茄子黄萎菌在室内苗期接种棉花和茄子,进行交互致病性测定,结果这10个菌株都可以侵染棉花和茄子,而且来源于不同寄主作物的菌系之间致病力分化明显,表现在不同菌株对同一寄主的致病力不同,同一菌株对不同寄主的致病力也不同。研究结果为深入研究大丽轮枝菌群体遗传结构和制定黄萎病防治措施提供了理论支持。     

枯草芽胞杆菌对离体荔枝果实霜疫霉病、炭疽病的防治效果

为了进一步明确从土壤中筛选得到的拮抗细菌OR-1、OR-2、OR-3、ON-6的分类地位和生防效果,采用形态学观察、理化特性结合分子生物学方法,鉴定这4株细菌皆为枯草芽胞杆菌Bacillussubitilis.拮抗菌对荔枝霜疫霉菌、炭疽菌菌丝生长均具有明显抑制作用,ON-6菌株的发酵液对菌丝生长的抑制率最高,分别为92.34％和70.36％,其次是OR-1菌株.拮抗菌处理组褐变指数均小于对照组以及杀菌剂处理组,且差异达显著水平(P＜0.05),OR-1菌株防褐变效果最好.常温下,拮抗菌发酵液对离体鲜果病害防治效果优于对照组和杀菌剂处理组,其中ON-6菌株的防治效果最佳;4℃低温储藏处理40天后,拮抗菌发酵液处理组的防治效果高于对照和杀菌剂处理组,且差异显著(P＜0.05),以ON-6和ON-3菌株的防治效果最佳.表明拮抗菌发酵液对荔枝鲜果上的霜疫霉菌和炭疽病菌有一定的抑制作用.     

Effects of a lectin-like protein isolated from Acacia farnesiana seeds on phytopathogenic bacterial strains and root-knot nematode

Acacia farnesiana lectin-like protein (AFAL) showed bacterioestatic effects against Xanthomonas axonopodis pv. passiflorae (Gram-negative) and Clavibacter michiganensis michiganensis (Gram-positive), with the latter being more sensitive. This effect is probably due to the ability of AFAL to interact with the bacterial cell wall where we observed that AFAL induced macroscopic change. The maximum bacterial growth inhibition was approximately 78% when incubated with Gram-negative strains, and as high as 92% percent for the Gram-positive one. The antibacterial effect of flavonoids (rutin, quercetin and morin) was also observed using low concentrations against both bacterial strains. Prior incubation of both with AFAL at high concentrations increases the inhibitory effect of flavonoids on bacterial growth. The potential use of AFAL as a control agent against the root-knot nematode Meloidogyne incognita was investigated as well, showing anti-nematode properties involving both egg hatching and motility. In the juvenile second-stage, AFAL showed reduction in larval mobility when measured against a control group. The results suggest that AFAL is effective against M. incognita and could be used as a component of integrated pest management programs. These data also suggest that lectins probably play a role in plant defense not only against invertebrate phytopathogens, herbivores and fungi but also against bacteria.     

苏云金杆菌亚致死浓度对美国白蛾及其寄生蜂生长发育的影响

为阐明苏云金杆菌Bacillus thuringiensis(Bt)与白蛾周氏啮小蜂Chouioia cunea Yang的协同作用,分别用103~108孢子/m L的6个Bt浓度处理美国白蛾Hyphantria cunea 2龄幼虫后,通过室内试验测定了Bt对其致死、亚致死效应,及亚致死浓度Bt对寄生蜂子代出蜂的影响。结果表明,浓度106孢子/m L处理组美国白蛾均未能化蛹;而106孢子/m L处理组均能化蛹并羽化,且幼虫发育历期随Bt浓度的增加而延长,平均蛹重在74.92~92.18 mg之间,均高于对照的68.66 mg,但蛹重不呈线性规律变化。当Bt对美国白蛾平均校正死亡率低于17.17%时,幼虫发育历期延迟不明显,但平均蛹重为101.11~124.34 mg,均高于对照;接蜂后能够正常出蜂,出蜂率为33.13%~51.25%,每蛹出蜂量为117.43~143.42头,均显著高于对照。表明用平均校正死亡率低于20%的Bt处理对白蛾周氏啮小蜂的寄生有利,2种生防措施协同作用存在增效潜力。     

Analysis of two acetylcholinesterase genes in Bombyx mori

Two acetylcholinesterases (AChE, EC 3.1.1.7) cDNAs were identified and cloned from silkworm, Bombyx mori. One of those, BmAChE-o cDNA, is comprised of 3197 nucleotides which encode 638 amino acids, having an amino acid sequence homology of 72% with Drosophila melanogaster Ace-orthologous AChE (AO-AChE). In some species, another AChE group based on the sequence, Drosophila Ace-paralogous AChE (AP-AChE) has been recognized in relation to organophosphate- or carbamate-resistance, but there have been few reports of AP-AChE among lepidopteran species. However, we isolated the AP-AChE from lepidopteran silkworm, and cloned full ORF as BmAChE-p, which cDNA consisted of 2465 nucleotides that encode 683 amino acids. The homologies with other AP-AChEs were over 60% when compared. Although silkworm is not a target of pesticides, the genomic information obtained in this study will contribute to insecticide-resistance study on lepidopteran pest species.     

溴氰虫酰胺和氯虫苯甲酰胺对三种鳞翅目害虫的毒力作用比较

为比较溴氰虫酰胺和氯虫苯甲酰胺对甜菜夜蛾、玉米螟和小地老虎的作用差异,采用浸卵法、浸叶法、饲喂毒营养液法等测定了溴氰虫酰胺和氯虫苯甲酰胺对3种害虫的卵、3龄幼虫和成虫的毒力,以及对其3龄幼虫的拒食活性。结果表明,溴氰虫酰胺和氯虫苯甲酰胺均无杀卵作用,但能降低初孵幼虫存活率。溴氰虫酰胺对甜菜夜蛾、玉米螟和小地老虎3龄幼虫的LC₅₀值分别为0.11、0.05和0.13 mg/L,相对毒力分别是氯虫苯甲酰胺的2.8、2.7和5.1倍。溴氰虫酰胺对3种害虫成虫的LC₅₀值分别为0.11、0.09和0.22 mg/L,相对毒力分别是氯虫苯甲酰胺的3.9、3.8和2.7倍。溴氰虫酰胺在亚致死浓度0.10、0.05和0.14 mg/L的剂量下分别对甜菜夜蛾、玉米螟和小地老虎3龄幼虫表现出较强的拒食作用,处理48 h后达到最高,拒食率分别为85.58%、81.91%和86.11%。药剂处理试虫虫体皱缩,体节缩短,体重增加率明显低于对照处理。表明溴氰虫酰胺对3种鳞翅目害虫的毒力作用比氯虫苯甲酰胺好,可作为氯虫苯甲酰胺的替代药品。     

Biological and biochemical responses of Biomphalaria alexandrina to some extracts of the plants Solanum siniacum and Artemisia judaica L.

The molluscicidal activity of cold water, boiled water, methanol, ethanol, acetone and chloroform extracts of Solanum siniacum and Artemisia judaica L. plants against Biomphalaria alexandrina snails was carried out. The tests revealed plant’s ethanol extract was more toxic to the snails than the other tested extracts. Therefore, it was tested against snails’ fecundity (M_x), reproduction rate (R₀) and their infection with Schistosoma mansoni miracidia. In addition, biochemical parameters and the activities of some enzymes in tissues of snails treated with the two tested plants were determined. As well, glucose concentration in snails’ hemolymph was evaluated. Exposure of B. alexandrina snails to plant’s ethanol extract led to a significant reduction in their survival and snails’ fecundity, reproduction rate. In addition, it caused a considerable reduction in the infectivity of S. mansoni miracidia to the snails. Also, it caused a reduction in number of cercariae per snail during the patent period and in the period of cercarial shedding. The results revealed that the glucose concentration in hemolymph and Lactate level in soft tissues of treated snails were increased (P < 0.001) while glycogen, total protein, the lipid content and the pyruvate level in snail’s tissues decreased (P < 0.001). The activities of lactic dehydrogenase (LDH), pyruvatekinase (PK) and cytochrome oxidase (CY) enzymes in homogenate of snail’s tissues were reduced (P < 0.001) in response to treatment with the two tested plants while protease (PR) activity increased (P < 0.001). It is concluded that the application of LC₂₅ of ethanol extract of S. siniacum and A. judaica L. may be helpful in snail control as it interferes with the snails’ biology and physiology.     

The effects of Artemisia annua L. and Achillea millefolium L. crude leaf extracts on the toxicity, development, feeding efficiency and chemical activities of small cabbage Pieris rapae L. (Lepidoptera: Pieridae)

The biological effects of two important medicinal plants, Artemisia annua L. and Achillea millefolium (L.) (viz, mortality, growth, and feeding indices as well as enzyme and non-enzymatic activities) were studied on small white Pieris rapae L a deleterious pest of cruciferous plants under controlled conditions (16:8 h L:D at 25 ± 1 °C and 65 ± 5% RH). The LC₅₀ and LC₂₅ values were 9.387% and 3.645% for A. annua L. and 4.19% and 1.69% for A. millefolium (L.), respectively. At the lowest concentration (0.625%), the deterrency was 29.826% and 44.185% for A. annua L. and A. millefolium (L.), respectively. Feeding indices were variously affected with changes in a number of parameters and an increase in larval and pupal duration. The activity level of alkaline phosphatase increased sharply while alanin and aspartate aminotransferases showed a sharp decrease. For non-enzymatic compounds, the amount of glucose and uric acid increased, but total protein and cholesterol decreased. These results indicate that these two medicinal plants might possess potential secondary metabolites that may be useful for controlling potential insect pests.     

两株棒束孢菌的鉴定及其对茶卷叶蛾和茶小卷叶蛾的致病力

为明确分离自茶卷叶蛾和中华大刀螳僵虫的2株虫生真菌的归属及生防潜力,采用形态学特征和rDNA-ITS序列分析其分类地位,测定了其对茶卷叶蛾和茶小卷叶蛾幼虫的致病力,并初步筛选了其最适培养条件.结果表明:2株真菌均为环链棒束孢Isaria cateniannulata,分别命名为ICBS918和ICTL911.在1.0×10⁸孢子/mL浓度下,ICBS918和ICTL911对茶卷叶蛾幼虫的累计校正死亡率均达100%,LT₅₀分别为3.13 d和3.15 d;对茶小卷叶蛾幼虫的累计校正死亡率分别为100%和95%,LT₅₀分别为3.25 d和3.31 d.接菌后8 d,2菌株对茶卷叶蛾幼虫的LC₅₀分别为0.47×10⁵孢子/mL和1.01×10⁵孢子/mL;对茶小卷叶蛾幼虫的LC₅₀分别为2.20×10⁵孢子/mL和1.34×10⁵孢子/mL.2菌株23 ℃下最适生长培养基均为综合马铃薯培养基,最适产孢培养基均为蛋白胨马铃薯葡萄糖琼脂培养基;在萨氏培养基上,菌株ICBS918和ICTL911分别在24~30 ℃及24 ℃时生长速度最快,在27 ℃和21 ℃时产孢量最大.表明2株环链棒束孢对茶卷叶蛾和茶小卷叶蛾幼虫均具有较好的生防潜力,可作为生防菌进行开发和应用.     

Molecular analysis of resistance in a deltamethrin-resistant strain of Musca domestica from China

We investigated the molecular basis of resistance in a strain of house fly (BJD) from Beijing, China. This strain showed 567-fold resistance to commonly used deltamethrin. Flies were 64-fold resistant to deltamethrin synergized by piperonyl butoxide (PBO). The 5′-flanking sequence of the cytochrome P450 gene CYP6D1 in BJD strain had a 15-bp insert as in the LPR strain. Two mutations (kdr, super-kdr) in the voltage sensitive sodium channel (VSSC) were also detected in the BJD strain. Our results showed that a combination of resistance alleles for CYP6D1 and VSSC existed in deltamethrin resistant house flies in China.     

Assessment of Cyfluthrin commercial formulation on growth, photosynthesis and catalase activity of green algae

Aquatic environments of the pampasic region of Argentina are severely affected by agricultural contamination due to an increase in a glyphosate tolerant transgenic variety of soybean crops. The present study is aimed to determine the effects of a commonly used Cyfluthrin commercial formulation (CCF) on growth, some physiological and biochemical parameter of four species of green algae. Significant inhibition of algal growth was observed from 0.1 mg Cyf/l. 96 h IC₅₀ were between 0.92 and 4.85 mg Cyf/l. CCF caused algicidal effects. Photosynthesis was stimulated by 50% in Scenedesmus quadricauda cultures exposed to the lowest concentration (hormesis). Algal photosynthesis inhibition was observed at higher concentrations with IC₅₀ values between 1.7 and 8.9 mg Cyf/l. Similar toxicity endpoints were found as a consequence of applying the traditional methodology of short-term chronic toxicity test of 96 h of exposition and the methodology developed using the Clark type photosynthetic oxygen evolution method. CAT activity was significantly increased between 23% and 33% considering the four species, at a lower concentration than those affecting algal growth and photosynthesis, indicating a potential biomarker. Taking into account that the extent of the soybean crops in the region is about fourteen million hectares, the improvement and extension of environmental tools for early detection of the action of pesticides on this essential group of organisms are discussed.