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为有效防控瓠瓜果斑病,自浙江省象山县田间采集具有典型果斑病症状的瓠瓜样本,对其进行病原菌分离、形态观察、致病性测定及分子生物学鉴定,并利用特异性引物PL1/PL2 PCR扩增和基质辅助激光解吸电离飞行时间质谱（matrix assisted laser desorption ionization time-of-flight massspectrometry,MALDI-TOF-MS）技术对其病原菌进行亚群鉴定。结果表明：瓠瓜果斑病田间典型症状是发病叶片和果实上病斑由水渍状小斑点逐渐发展为伴有黄色晕圈的褐色不规则病斑,果实腐烂、有臭味。通过菌体形态和培养特性观察、PCR鉴定、16S rDNA序列分析和7个看家基因的系统发育分析将其病原菌鉴定为西瓜噬酸菌Acidovorax citrulli。从瓠瓜上分离的菌株均属于西瓜噬酸菌亚群I,从西瓜上分离的菌株均属于西瓜噬酸菌亚群II。 相似文献
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小麦白粉病菌对温度不同敏感性菌株的寄生适合度研究 总被引：2，自引：0，他引：2
利用离体叶片接种法,将12个对温度不同敏感性的小麦白粉病菌株分别在18℃和22℃条件下的流行组分（潜育期、侵染几率、单病斑累积产孢量和病斑日扩展面积）和寄生适合度进行了测定。结果表明,对温度不同敏感性菌株的流行组分在18℃和22℃条件下均存在显著性差异,且单病斑累积产孢量与病斑日扩展面积的相关性最高。各供试菌株在22℃条件下的寄生适合度均低于18℃条件下的寄生适合度。在两温度条件下,对温度低敏感性菌株平均寄生适合度高于对温度高敏感性菌株,特别是在较高温度下这种趋势更为明显。 相似文献
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为探明温度对梨树腐烂病菌生长、病斑扩展及产毒素水平的影响,采用常规生物学方法和高效液相色谱法,测定了该病菌强致病力菌株LXS240101在不同温度下的菌丝生长、病斑扩展及产毒素水平。结果表明:菌株LXS240101最适宜的生长温度为25~30℃;在5~35℃范围内,梨树离体枝条接种梨树腐烂病菌后均能发病并导致病斑扩展,25℃时病斑扩展速度最快,面积达4.45cm2,5℃和35℃时病斑扩展速度缓慢,面积不足0.3 cm2。该菌株在梨树树皮培养基中最适宜的产毒素温度为20℃,10~25℃条件下可产生5种毒素,而在其它温度下仅产生3~4种;接种该菌株的梨树离体枝条5℃条件下未检测到间苯三酚和对羟基苯甲酸,且毒素总量最低,其余温度下均可检测到5种毒素,最适宜的产毒素温度为10℃,毒素总量可达224.14μg/g干组织。 相似文献
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DHN黑色素是许多植物病原真菌的致病相关因子,为明确黑色素在玉米大斑病菌致病过程中的作用,采用三环唑和紫外线复合诱变的方法获得了黑色素缺失的6个突变菌株,对突变菌株的生长量、产孢量、HT-毒素活性、致病力进行测定。结果显示,突变菌株产毒能力变化不大,但生长量下降,产孢量和致病力显著下降或完全丧失,野生型菌株的产孢量和侵染频率分别是突变菌株的30～50倍和5倍。突变菌株与黑色素共培养后,菌株M01-23a和M01-23b恢复了致病力,但病斑面积和侵染频率较小。玉米大斑病菌黑色素与致病力具有一定的相关性。 相似文献
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根据93个单病斑中分离的227个单孢菌株样品的分析，研究了来自同一定殖系统(同一病斑)中稻瘟病菌不同单孢菌株(同源菌株)的遗传变异。在致病性分析的样品中，仅有5个病斑分离的10个单孢菌株在所有鉴别品种上表现同源菌株有完全相同的致病反应，并且有完全相同的DNA指纹图谱带型；另有13个病斑上分离的32个单孢菌株的同源菌株不仅属于不同的生理小种，而且在1～3个单基因品种上也有不同的致病反应。用rep—PCR指纹图谱和致病型分析67个病斑的157个单孢样品中的同源菌株具有完全相同的DNA指纹图谱；13个病斑中分离的27个单孢样品中同源菌株具有显著差异的指纹图谱；8个病斑分离的27个单孢菌株样品中同一来源样品中部分样品有相同的指纹图谱带型，部分样品却有不同的指纹图谱。同源菌株之间有完全相同致病性其指纹图谱亦相同或有很小的差异；通常，致病性差异很大的同源菌株其指纹图谱差异也很大。作者认为来自同一定殖系统中的不同单孢菌株存在的遗传变异与病菌的异核现象或自然状态下不同遗传背景菌株同时侵染造成同一病斑有关。 相似文献
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2013-2014年吉林省、黑龙江省烟区首次大面积发生烟草靶斑病,损失严重。采集吉林省柳河县、黑龙江省林口县和宾县的烟草靶斑病病叶进行分离纯化,得到了12个菌株。将所获菌株分别与立枯丝核菌标准融合群菌株AG-2、AG-3、AG-4进行对峙培养,结果表明:此12个菌株均与立枯丝核菌AG-3标准菌株发生融合反应,不与其他融合群发生融合;随机选取3个县各1个代表性菌株,提取菌丝基因组DNA并对其ITS序列进行分析与比对,菌株HLJ-2、JL-1、HLJ-7的ITS序列与辽宁省烟草靶斑病菌菌株LF-2、LJT-8(AG-3融合群)的同源性达99%~100%,因此推断,吉林省、黑龙江省烟草靶斑病菌与辽宁省烟草靶斑病菌应属于同一个融合群,即立枯丝核菌AG-3融合群(Rhizoctonia solani AG-3)。根据各菌株在鉴别寄主上表现的抗性不同,可将吉林省、黑龙江省所有菌株分为3个致病类型,即致病类型Ⅰ、致病类型Ⅱ和致病类型Ⅲ。同一省份不同菌株间致病力有差异,黑龙江省菌株3种致病类型均有,以致病类型Ⅱ为主;吉林省菌株只有致病类型Ⅰ和致病类型Ⅱ。分别选取3个省的强致病力菌株,用离体叶片接种法鉴定了我国21个主栽烟草品种对靶斑病的室内抗病性,结果表明:没有免疫或抗病品种,‘龙江981’、‘NC297’对供试的3个强致病力菌株均表现中抗,‘中烟202’、‘云烟97’、‘NC55’、‘KRK26’和‘G28’分别对不同菌株表现中抗。 相似文献
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近年来,在湖北省油莱上发生一种病害,油菜抽薹后,主轴上产生暗绿色水渍状长条斑,病部溢出大量乳黄色粘稠物,后为黑褐色腐烂,其主轴萎缩卷曲,角果干秕、枯死。被害维管束变褐,髓部变黄。叶片上很少见病斑。从这种病株上分离到了致病细菌,经全面、系统鉴定,确定为黑腐病黄色单胞杆菌[Xanthomonas campestris(Pammel)Dowsom]。由黑腐病菌引起的上述症状,国内外未曾报道过。另外,对来自六种十字花科寄生的七个黑腐病菌株,作了致病力比较测定,结果差异显著,以油莱两个黑腐病菌株致病力最强,表明可能存在不同生理型。 相似文献
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ABSTRACT The role of watermelon blossom inoculation in seed infestation by Acidovorax avenae subsp. citrulli was investigated. Approximately 98% (84/87) of fruit developed from blossoms inoculated with 1 x 10(7) or 1 x 10(9) CFU of A. avenae subsp. citrulli per blossom were asymptomatic. Using immunomagnetic separation and the polymerase chain reaction, A. avenae subsp. citrulli was detected in 44% of the seed lots assayed, despite the lack of fruit symptoms. Furthermore, viable colonies were recovered from 31% of the seed lots. Of these lots, 27% also yielded seedlings expressing bacterial fruit blotch symptoms when planted under conditions of 30 degrees C and 90% relative humidity. A. avenae subsp. citrulli was detected and recovered from the pulp of 33 and 19%, respectively, of symptomless fruit whose blossoms were inoculated with A. avenae subsp. citrulli. The ability to penetrate watermelon flowers was not unique to A. avenae subsp. citrulli, because blossoms inoculated with Pantoea ananatis also resulted in infested seed and pulp. The data indicate that watermelon blossoms are a potential site of ingress for fruit and seed infestation by A. avenae subsp. citrulli. 相似文献
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甜瓜细菌性果斑病菌致病性突变体筛选与hrcR基因的克隆 总被引：2，自引：0，他引：2
细菌性果斑病(Bacterial Fruit Blotch,BFB)是西瓜和甜瓜的重要病害。本实验从发病甜瓜果实上分离得到致病菌株MH21,经鉴定为燕麦食酸菌西瓜亚种(Acidovorax avenae subsp. citrulli)。利用转座子Mini-Tn5构建MH21菌株的突变体库,Southern印迹杂交结果显示Mini-Tn5在菌株MH21染色体上可随机、单拷贝插入。通过浸种处理甜瓜种子进行突变体的致病性检查,筛选得到1株致病性完全丧失的突变体M543。对M543中转座子插入基因的克隆和测序表明其突变基因为燕麦食酸菌Ⅲ型分泌系统(TTSS)中的保守基因hrcR。推测菌株MH21中hrcR基因编码的蛋白定位于细菌内膜,是分泌通道主要成分之一。hrcR基因互补菌株的致病性检查结果显示其致病力恢复到野生型的84%。研究同时发现hrcR基因突变后MH21菌株丧失了在烟草上诱导过敏性坏死反应的能力。本研究从遗传学角度说明TTSS是西甜瓜果斑病菌致病性的重要因子。 相似文献
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ABSTRACT To assess the diversity of Acidovorax avenae subsp. citrulli, 121 strains from watermelon, cantaloupe, and pumpkin were compared using pulse field gel electrophoresis of SpeI-digested DNA and gas chromatographic analysis of fatty acid methyl esters. Twenty-nine unique DNA fragments resulted from DNA digestion, and 14 distinct haplotypes were observed. Based on cluster analysis, two subgroups, I and II, were recognized, which accounted for 84.8% (eight haplotypes) and 15.2% (six haplotypes) of the strains, respectively. Results of cellular fatty acid analysis varied quantitatively and qualitatively for the A. avenae subsp. citrulli strains and supported the existence of the two subgroups. Group I includes strains from cantaloupe and pumpkin as well as the ATCC type strain, which was first described in the United States in 1978, whereas group II represents the typical watermelon fruit blotch-causing strains that appeared in the mainland United States in 1989. Knowledge of the two A. avenae subsp. citrulli groups may be useful in screening for watermelon fruit blotch resistance. 相似文献
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Biological Control to Protect Watermelon Blossoms and Seed from Infection by Acidovorax avenae subsp. citrulli 总被引：1，自引：0，他引：1
ABSTRACT The efficacy of biological control seed treatments with Pseudomonas fluorescens (A506), Acidovorax avenae subsp. avenae (AAA 99-2), and an unidentified gram-positive bacterium recovered from watermelon seed (WS-1) was evaluated for the management of bacterial fruit blotch (BFB) of watermelon. In growth chamber and greenhouse experiments, seed treated with AAA 99-2 displayed superior disease suppression, reducing BFB transmission by 96.5%. AAA 99-2, P. fluorescens A506, and Kocide also suppressed the epiphytic growth of A. avenae subsp. citrulli when applied to attached watermelon blossoms 5 h prior to inoculation. Watermelon blossom protection reduced seed infestation by A. avenae subsp. citrulli. From blossoms treated with 0.1 M phosphate buffered saline (PBS), 63% of the resulting seed lots were infested with A. avenae subsp. citrulli. In contrast, for blossoms protected with WS-1, Kocide, P. fluorescens A506, and AAA 99-2, the proportion of infested seed lots were 48.3, 21.1, 24.1, and 13.8%, respectively. The effect of blossom treatments on seed lot infestation was statistically significant (P = 0.001) but WS-1 was not significantly different from PBS. These findings suggest that blossom protection with biological control agents could be a feasible option for managing BFB. 相似文献
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本文利用群体感应信号报告菌Agrobacterium tumefaciens NTL4(pZLR4),在LB报告平板上对燕麦食酸菌西瓜亚种的19个菌株进行了初步检测,发现18个菌株有群体感应信号产生.用琼脂条法对菌株Pslb-94进一步检测,证实菌株Pslb-94存在群体感应系统.提取了该菌株信号物质,反相薄层层析(TLC)检测证明该菌株能产生群体感应信号分子. 相似文献
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New subspecies-specific primers for the detection of Acidovorax avenae subsp. citrulli ( Aac ), the seedborne bacterium which causes bacterial fruit blotch of cucurbits, were designed based on PCR fragments obtained in ERIC- and BOX-PCR profiles of Aac strains. PCR with both primer sets identified 30 strains from different locations and hosts, but did not amplify DNA from other closely related species and subspecies assessed, with the exception of DNA of one strain of A. avenae subsp. avenae , which was amplified by one of the primer sets, named BX-S. This primer set, based on a BOX-PCR fragment, performed under high-stringency conditions without losing its detection sensitivity. The primers were also evaluated for their ability to detect the pathogen in contaminated watermelon and melon seed samples. The BX-S primers facilitated the detection of the pathogen from washings of 5000-seed samples with 0·02% infestation. This primer set was also assessed for detection using immunomagnetic separation polymerase chain reaction (IMS-PCR) and was shown to be as sensitive as a previously described primer set (AACF2/R3), detecting 0·02% infestation in seed samples. This highly specific and sensitive primer set could be used to improve PCR-based detection of this important pathogen. 相似文献
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瓜类果斑病菌(Acidovorax avenae subsp.citrulli,Aac)是瓜类作物上重要的病原细菌,为我国进境植物检疫性有害生物。胶体金免疫层析试纸条方便快捷,应用广泛。该方法使用不当会出现假阳性问题,仅适用于病原菌的初筛检测。本研究将Aac胶体金免疫层析方法(GICA)与PCR技术相结合,建立了GICA-PCR检测方法。检测结果表明,该方法在蛋白与核酸2个层面上从发病西瓜叶片上检测到瓜类果斑病菌,有效解决了试纸条检测的假阳性问题,提高了瓜类果斑病菌检测的准确性,值得推广应用。 相似文献
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免疫凝聚试纸条和TaqMan探针实时荧光PCR检测西瓜细菌性果斑病菌比较研究 总被引：7，自引：0，他引：7
以西瓜细菌性果斑病菌(Acidovorax avenae subsp.citrulli)菌悬液和田间采集的病组织为试材,研究了免疫凝聚试纸条和实时荧光PCR技术检测的灵敏度和适应性。结果表明,免疫凝聚试纸条检测灵敏度为106 cfu/mL,具有简便、快速、易操作特点,适用于田间快速检测和病害诊断;TaqMan探针实时荧光PCR检测灵敏度达103~4 cfu/mL,比传统PCR检测灵敏度(105 cfu/mL)提高了10~100倍,且不需要琼脂糖凝胶电泳、溴化乙锭染色和Southern杂交。但需要昂贵的仪器和试剂,适用于室内检测及相关研究。 相似文献
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种子引发处理对无籽西瓜幼苗生长的影响和对细菌性果斑病菌消毒的效果 总被引：2，自引：0，他引：2
种子出苗率低和传带细菌性果斑病菌是制约三倍体无籽西瓜生产的主要原因。本试验利用KMnO4、CuSO4和ZnSO4的不同浓度溶液对无籽西瓜种子进行不同时间引发处理, 通过滤纸发芽试验, 观测其对种子发芽和幼苗生长的促进作用;借助平板法测定引发溶液对细菌性果斑病菌FC247的抑制作用, 免疫凝聚试纸条和传统PCR检测引发处理对种子人工接菌FC247的消毒效果。结果表明:0.1% CuSO4溶液引发处理4 h和0.2% ZnSO4溶液引发处理24 h, 分别比未引发处理的无籽西瓜种子发芽率提高71.1%和73.3%, 并能显著提高发芽整齐度和幼苗素质;同时, 引发溶液对细菌性果斑病菌有显著抑制作用, 并对人工接菌种子表现出-定程度的消毒效果。 相似文献