江西省油菜根肿菌小种鉴定与油菜品种抗性分析

明确江西省油菜根肿病病菌类型及油菜品种对病害的抗性,对指导油菜生产及景区观光业的发展具有重要意义。为了探明油菜根肿病的分布及其病菌的致病性分化,于2011年至2016年持续对江西省油菜根肿病的地理分布进行调查,并对病区油菜根肿病株进行生理小种鉴定。结果表明,江西油菜根肿病主要分布在赣东北局部区域,致病菌为4号和9号生理小种,其中4号小种仅发现在赣东北区域分布。在4号和9号小种的病区分别设置田间病圃进行200余个油菜品种的抗性鉴定,结果表明,测试的全部油菜品种对9号小种表现抗病,而94.74%油菜品种对4号小种表现感病;萝卜籽花和59-013等12个品种对4号小种具中抗以上水平。本研究筛选到生理小种特异性的抗病资源或品种,可为油菜抗根肿病育种提供抗源。     

芸薹根肿菌侵染早期甘蓝型油菜转录组分析

根肿病是油菜最为严重的病害之一。为探索根肿病菌和油菜互作中的抗性分子机制,采用RNA-seq技术对根肿病早期侵染中抗病品系ZHE-226(R)和感病油菜10159(S)进行转录组分析。与感病材料S相比,在0、12、48和72h 4个接种时间点,抗性材料R中共有809个基因上调表达,1082个基因下调表达。模式识别受体、几丁质酶、R基因、WRKY、水杨酸和茉莉酸等抗性相关(PRR)基因在抗病材料R和感病材料S中诱导表达并表现出不同的表达模式。抗病材料R中PRR相关基因主要表现为下调表达,R基因上调表达,水杨酸表现为前期下调后期上调表达,茉莉酸、几丁质酶和WRKY因子在R和S中均诱导表达。结果表明PRR介导的PTI(病原相关分子模式触发的免疫反应)在感病材料S中显著诱导,在抗病材料R中作用不明显;R基因介导的ETI(效应蛋白触发的免疫反应)和水杨酸介导的抗病信号途径对根肿病抗性起重要作用。     

二醇型、三醇型人参皂苷对白菜白斑菌和菜豆菌核菌的影响

为了探讨人参二醇型、三醇型皂苷对白菜白斑菌和菜豆菌核菌的影响,本文采用菌丝生长率法和孢子萌发实验研究人参二醇型、三醇型皂苷对2种病原菌的影响.结果表明:不同质量浓度的人参二醇组皂苷和三醇组皂苷对白菜白斑菌、菜豆菌核菌的影响结果大致相同,在培养初期(24 h)均表现出一定的促进效果,且低质量浓度处理尤其明显;随着培养时间增加,各处理按照质量浓度高低的顺序先后表现出不同程度的抑制作用,并且抑制效果逐渐增强;所有处理中的高质量浓度人参皂苷对病原菌生长的抑制作用最为显著;不同质量浓度的人参二醇组皂苷和三醇组皂苷对2种病原菌孢子或菌核萌发的作用总体上呈低促高抑,且与皂苷质量浓度关系密切.可见,高质量浓度的人参三醇型皂苷有防治白菜白斑菌流行的潜力,而高质量浓度的人参二醇型皂苷有防治菜豆菌核菌流行的潜力.     

水介导十字花科作物根肿病的传播及其化学防治

以感病的大白菜品种为供试材料,采用漂浮育苗池水和人工接种不同菌量的芸薹根肿病菌(Plasmo-diophora brassicae Woronin)休眠孢子悬浮液,分析病菌在水和土壤环境中的致病性差异,观察病菌在不同含水量土壤中的传播距离、侵染程度和带菌水浇灌处理后的病情,并在水培育苗池中进行药剂筛选。结果表明:人工接种漂浮育苗有利于根肿病传播,且发病程度与接种的孢子悬浮液带菌量呈正相关,当以103、104、105、106、107个/g的菌量接种时,漂浮育苗植株的发病率分别为9.51%、19.88%、44.31%、63.65%、76.00%,传统旱育苗植株的发病率分别为5.33%、15.00%、20.67%、43.33%、45.00%;在土壤含水量为38%～115%的基质上种植大白菜苗,接种根肿病菌后均能发病,其中以土壤含水量为77%时植株的发病率最高,当植株距离病菌5cm时,植株发病率达20.43%,距离病菌10cm时,植株发病率达10.23%;在水培育苗池中分别施入375.0mg/L的百菌清WP、250.0mg/L的多菌灵WP、25.0mg/L的氰霜唑SC、125.0mg/L的氟啶胺SC和262.5mg/L的BAS651FSC,其防治效果分别达96.65%、94.19%、87.93%、80.18%和88.02%,但所用剂量的氟啶胺SC和BAS651FSC对大白菜苗有药害作用。     

甘蓝夜蛾核型多角体病毒某些生化特性的测定

本文报道不连续系统的 SDS-PAGE 法对甘蓝夜蛾核型多角体病毒(Mamestrabrassicae nuclear polyhedrosis virus MbNPV)的多角体蛋白,病毒粒子结构多肽进行分析。结果表明,经热处理和温和碱解的多角体蛋白呈现一条带,分子量为28.2×10~3±500道尔顿。病毒粒子至少有15种多肽.MbNPV 多角体蛋白富含天门冬氨酸、谷氨酸。未检出色氨酸、限制性内切酶 ECoR Ⅰ,HindⅢ,BamH Ⅰ和 Pst Ⅰ分别把 MbNPV-DNA 酶解成15,13,7和10个限制性片段.由片段积加法计算得平均分子量为95.905±2.164Kbp.     

大白菜黑斑病芸薹链格孢鉴别寄主筛选的研究

采用黑龙江省各地的大白菜黑斑病芸薹链格孢 ( Alternaria brassicae ( Berk.) Sacca.) 2 2个单孢菌株 ,对国内当前生产上应用的大白菜、萝卜、甘蓝、油菜等十字花科蔬菜的品种 (其中含自交系和杂种一代 )共 51份进行苗期接种鉴定。试验结果表明 ,各品种对不同的菌株抗感反应差异明显。根据同一品种在相同条件下对不同菌株抗感反应存在差异 ,而在不同条件下对同一菌株抗感反应趋近一致 ,采用模糊聚类分析的方法 ,筛选出 5个鉴别寄主 ,它们是 ,二牛心大白菜、97- 3- 114大白菜、牡丹江一号大白菜、新一号大白菜和四九菜心     

Synthesis of spiroketal enol ethers related to tonghaosu and their insecticidal activities

This paper describes the syntheses and biological activities of a number of spiroketal enol ethers which are analogues of the plant extract tonghaosu. The insecticidal potential of this spiroketal system is assessed.     

Electron microscopic studies on the root hairs and cortex of a susceptible and a resistant variety of Brassica campestris infected with Plasmodiophora brassicae

The cortex of the roots of a susceptible and a resistant variety ofBrassica campestris var.rapa infected with sterile resting spores ofPlasmodiophora brassicae from senescent callus was studied at a stage prior to disease symptom development. Electron micrographs show the presence of amoeboid structures within the cortical cells of the susceptible variety 10 days after inoculation. Cell wall perforations, hypertrophied host cell nuclei, nucleoli and broken tonoplasts were frequently found in the susceptible variety. It has been concluded that amoeboid structures of the parasite penetrate the cell wall and disrupt the cortical cells.Electron micrographs of the resistant variety show the presence of zoosporangia with secondary zoospores in the root hairs nine days after inoculation. Two to four days later a large number of dead host cells can be observed in the outer cortical layer of the resistant variety, whereas no apparent changes are found in the inner cortex. The results suggest the occurrence of a hypersensitive host reaction which terminates further growth ofPlasmodiophora brassicae.Samenvatting Kiemplanten van een vatbare en een resistente variëteit vanBrassica campestris var.rapa werden geïnoculeerd met een suspensie van rustsporen vanPlasmodiophora brassicae. De rustsporen waren afkomstig uit verouderd ziek callusweefsel. Elektronenmicroscopisch onderzoek werd verricht aan de cortex van de hoofdwortel van vatbare planten in de periode die vooraf gaat aan de ontwikkeling van ziektesymptomen (10–13 dagen na inoculatie). Tien dagen na inoculatie werden amoebe-achtige structuren in de cortex gevonden (Fig. 1–4). Herhaaldelijk werden gaten in de celwand van de cortex gevonden (Fig. 5). De waardplantkern en kernlichaampje vertoonden een hypertrofische reactie terwijl de tonoplast vaak kapot was (Fig. 3). Deze resultaten vormen een aanwijzing dat de parasiet in de vorm van een amoebe door de celwand dringt en de celinhoud van de cortex verstoort. Dertien dagen na inoculatie werden de eerste secondaire plasmodiën in het binnenste gedeelte van de cortex of in de mergstraalcellen van de hoofdwortel gevonden (Fig. 6). Vanaf dat moment traden de typische knolvoetsymptomen op.Uit elektronen-microscopisch onderzoek van de resistente variëteit bleek dat negen dagen na inoculatie zoösporangien en secondaire zoösporen aanwezig waren in de wortelharen van de zijwortels (Fig. 7–9). Twee tot vier dagen later werden een groot aantal dode waardplantcellen in de buitenste cortexcellen van de hoofdwortel gevonden, terwijl het binnenste gedeelte van de cortex geen veranderingen vertoonde (Fig. 10 en 11). Deze resultaten wijzen er op dat in de resistente variëteit een overgevoeligheidsreactie in de cortex opgetreden is waardoor verdere groei vanPlasmodiophora brassicae verhinderd werd.     

Dissemination of Plasmodiophora brassicae in livestock manure detected by qPCR

The present study was performed to investigate whether Plasmodiophora brassicae can be disseminated by livestock manure. A quantitative PCR (qPCR) assay was developed and used to detect and quantify P. brassicae in manure samples from naturally and artificially infested chickens and pigs. In naturally infested manure, quantifiable levels of infestation were observed in 7 out of the 28 samples, ranging from 10³ to 10⁷ resting spores per g of manure. The vast majority of the resting spores (76–91%) were viable, as determined by a dual fluorescence viability assay. Clubroot symptoms developed on plants inoculated with P. brassicae resting spores isolated from all seven qPCR‐positive samples. Artificially infested manure samples were produced by feeding chickens and pigs on P. brassicae‐contaminated feed. The levels of infestation were 10³ resting spores per g of manure for both chicken and pig manure sampled 24 and 48 h after feeding, respectively. Spore viability was >80% for both samples, and the disease severity indices were both >40 as indicated by bioassay. This showed that resting spores can survive the digestive tracts of chickens and pigs, and retain strong pathogenicity. The findings indicate that manure dissemination is possible for P. brassicae. Farmers should avoid feeding livestock on P. brassicae‐contaminated feed or applying infested manure as fertilizer on land intended for crucifer crops.     

Pathogenicity of Plasmodiophora brassicae populations from small, spheroid, resistant-type clubroot galls on roots of clubroot-resistant cultivars of Chinese cabbage (Brassica rapa L. subsp. pekinensis)

A resistant type of small, spheroid clubroot galls (SSGs) containing resting spores formed on the root surface of clubroot-resistant (CR) cultivars of Chinese cabbage (Brassica rapa L. subsp. pekinensis) inoculated with an avirulent population of Plasmodiophora  brassicae. Populations isolated from the SSGs severely affected a common (susceptible) cultivar but did not have the typical pathogenicity on CR cultivars, indicating similarity in pathogenicity between SSG and original spore populaions. Populations pathogenic on CR cultivars were not detected from SSGs. Therefore, the ability of the avirulent population among the SSGs to form resting spores may need to be considered to achieve clubroot control in common cultivars of crucifers.