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瓜类细菌性果斑病是世界范围的检疫性细菌病害,病原菌为西瓜嗜酸菌,带菌种子为主要侵染源。病原细菌在寄主表面的定殖能力与其致病能力关系密切,而趋化性是决定定殖能力的关键因素之一,研究不同物质对西瓜嗜酸菌趋化性的影响对防治瓜类细菌性果斑病具有重要意义。本文采用毛细管法,研究了碳源、氨基酸、有机酸及其他物质对西瓜嗜酸菌趋化性的影响。结果表明,所测碳源中,麦芽糖、葡萄糖、乳糖、蔗糖和半乳糖均显著促进西瓜嗜酸菌的趋化性;所测氨基酸中,L-精氨酸、L-天冬氨酸、L-组氨酸、L-谷氨酸、L-亮氨酸、L-缬氨酸、L-谷氨酰胺和L-丙氨酸显著促进西瓜嗜酸菌的趋化性;所测有机酸中,琥珀酸、半乳糖醛酸和酒石酸显著促进西瓜嗜酸菌的趋化性;氯化钠、硫酸镁等对西瓜嗜酸菌的趋化性无显著影响。 相似文献
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连江县是福州市西瓜主要产区,每年种植西瓜130 hm2,西瓜细菌性叶斑病及西瓜细菌性果斑病是本县西瓜的主要病害.西瓜细菌性叶斑病在本县发生普遍,病株率20%~100%,严重影响西瓜生产. 相似文献
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瓜类细菌性果斑病是瓜类作物上重要的种传细菌性病害,其病原菌西瓜噬酸菌Acidovorax citrulli为我国进境植物检疫性有害生物,种子种苗带菌是病害长距离传播的重要来源,种子种苗的快速检测对病害综合防控具有重要的意义。根据寄主的差异西瓜噬酸菌分为两个组,Ⅱ组菌株比Ⅰ组菌株具有更高的铜制剂敏感性,因此,西瓜噬酸菌的分组检测可为病害田间防治中铜制剂的精准使用提供科学依据,避免化学农药的过量施用。本研究筛选了现有的西瓜噬酸菌种间特异性引物和种内分组特异引物,建立并优化了一个多重PCR体系,实现了通过一步试验,就能够准确将西瓜噬酸菌与近缘种和其他植物病原细菌区分开来,并直接鉴定到西瓜噬酸菌不同组。该多重体系可以从带菌种子浸泡液和感病植物组织研磨液中直接检测到西瓜噬酸菌的不同组,且稳定性好,具有应用于生产实践的潜力。 相似文献
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不同药剂对海南省甜瓜细菌性果斑病病原菌的室内药效测定 总被引:2,自引:0,他引:2
采用含毒介质法对引起甜瓜细菌性果斑病(Bacterial Fruit Blotch of melon)的病原菌西瓜嗜酸菌(Acidovorax citrulli)进行了室内药效测定,评价测定的8种药剂对海南省5个甜瓜主栽区(昌江县、东方市、乐东县、陵水县和三亚市)细菌性果斑病病原菌的抑菌效果,试验结果表明,8种药剂对细菌性果斑病病原菌的抑菌效果各不相同,且相同药剂对不同地区的病原菌抑菌效果也不同,其中,噻霉酮对细菌性果斑病病原菌的抑菌效果最好,抗生素类药剂的抑菌效果普遍较好,如农用链霉素、中生菌素和春雷霉素,而氢氧化铜和琥胶肥酸铜等铜制剂室内效果最差。该试验筛选的对西瓜嗜酸菌(A.citrulli)抑菌效果较好的药剂,可为细菌性果斑病的防治提供参考。 相似文献
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哈密瓜果斑病是严重危害瓜类的种传细菌性病害,其病原菌为嗜酸菌属西瓜种(Acidovorax citrulli)。本文首先用Bioedit软件建立瓜类果斑病菌全氨基酸序列本地资源库,运用比较基因组学的方法,通过大量查找嗜酸菌属、欧文氏菌属、假单胞菌属、黄单胞菌属、劳尔氏菌属、土壤杆菌属、木质部小菌属中的致病基因和参考文献中已报道的致病基因,下载相关致病基因的氨基酸序列,与瓜类果斑病菌的全氨基酸序列进行localblast,取E<10-5的为候选基因,得到果斑病菌中与致病性相关的基因,并对未知蛋白进行产物预测。同时,根据已经公布的靶标基因,用同样的比对方法,得到果斑病菌中潜在的靶标基因。本研究通过保守估计,得到77个致病性相关蛋白,预测了其中7个未知蛋白的产物,得到46个靶标蛋白。致病基因和靶标基因的分析预测,对以后研究此类基因提供了指导作用,为更好地防治该病害提供了理论基础。 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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由西瓜嗜酸菌(Acidovorax citrulli)引起的细菌性果斑病是一种毁灭性的种传病害,可为害多种葫芦科作物并造成重大经济损失。该病原菌为检疫性有害生物,种子带菌是田间病害发生的最重要初侵染来源,因此,种子健康检测成为病害综合防控过程中的重要环节。Bio-PCR是当前种子携带细菌检测的常用方法,而特异性引物的选择和使用是检测的关键。本研究使用已报道的7对引物对17株西瓜嗜酸菌、10株嗜酸菌属其它种的菌株和6株其它属的植物病原细菌进行了Bio-PCR检测,筛选出对西瓜嗜酸菌特异性最好的引物为SEQID4m/SEQID5。研究表明:使用该引物对西瓜嗜酸菌MH21纯菌菌悬液的检测限度为102 CFU·mL-1;在人工添加菌悬液的模拟带菌西瓜种子中,使用ASCM和EBBA两种半选择性培养基结合引物SEQID4m/SEQID5进行Bio-PCR检测,ASCM对种子中带菌量的检测限度可达到0.01 CFU·g-1,EBBA对种子中带菌量的检测限度为0.1 CFU·g-1。 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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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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Flávio H. V. Medeiros Iale S. F. Moraes Edson B. da Silva Neto Elineide B. Silveira Rosa de Lima R. Mariano 《Phytoparasitica》2009,37(5):453-460
Plant beneficial bacteria (PBB) have shown potential for disease control and are particularly important in the management
of bacterial diseases, which are poorly controlled by conventional methods. In melon, bacterial fruit blotch caused by Acidovorax citrulli is a seedborne disease that is particularly destructive under certain conditions. PBB strains were screened for their ability
to protect seeds and leaves from bacterial fruit blotch, and their antibiosis activity and plant colonization were studied.
When Bacillus sp. RAB9 was applied to infected seeds, it reduced the area under the disease progress curve (AUDPC) by 47% and increased
the incubation period (the time between inoculation and the first visible symptoms) by 35%. Three of the selected strains
(JM339, MEN2 and PEP91) displayed antibiosis against A. citrulli. The RAB9Rif-Nal mutant colonized seeds epiphytically and roots and stems endophytically. Paenibacillus lentimorbus MEN2 sprayed on melon seedlings protected leaves, and when challenged with A. citrulli, it reduced the AUDPC (by 88%), disease index (by 81%) and incidence (by 77%). Given that the production of both melon seedlings
and commercially grown greenhouse melons is increasing, biocontrol strategies may well be integrated into bacterial blotch
management programs. 相似文献
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Watermelon seeds can become infested by Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits via penetration of the ovary pericarp or by invasion of the pistil. This study investigated the effect of these invasion pathways on A. citrulli localization in seeds. Seed samples (n = 20 or 50 seeds/lot) from pistil- and pericarp-inoculated lots were dissected into testa, perisperm-endosperm (PE) layer, and embryo tissues and tested for A. citrulli by species-specific polymerase chain reaction (PCR) and by plating on semiselective media. Less than 8% of the testa samples were A. citrulli-positive regardless of the method of seed inoculation. Additionally, the difference in percentages of contaminated testae between the two seed lot types was not significant (P = 0.64). The percentage of A. citrulli-positive PE layer samples as determined by real-time PCR assay was significantly greater for seeds from pistil-inoculated lots (97%) than for seeds from pericarp-inoculated lots (80.3%). The mean percentage of A. citrulli-positive embryo samples was significantly greater for seeds from pistil-inoculated lots (94%) than for seeds from pericarp-inoculated lots (≈8.8%) (P = 0.0001). Removal of PE layers and testae resulted in a significant reduction in BFB seed-to-seedling transmission percentage for seeds from pericarp-inoculated lots (14.8%) relative to those from pistil-inoculated lots (72%). Additionally, using immunofluorescence microscopy, A. citrulli cells were observed in the PE layers and the cotyledons of pistil-inoculated seeds but only in the PE layers of pericarp-inoculated seeds. These results suggest that pericarp invasion results in superficial contamination of the testae and PE layers while pistil invasion results in the deposition of A. citrulli in seed embryos. 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