Transport and Retention of Phytophthora capsici Zoospores in Saturated Porous Media
Transport and Retention of Phytophthora capsici Zoospores in Saturated Porous Media
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DOI：
10.1021/acs.est.6b01784
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发表时间：
2016-09-06
影响因子：
11.4
通讯作者：
Zhang, Wei
中科院分区：
文献类型：
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作者：
Jeon, Sangho;Krasnow, Charles S.;Zhang, Wei
辣椒疫霉是一种重要的植物病原菌，可侵染多种主要蔬菜作物。水分诱导的辣椒疫霉的运输被认为是疾病暴发和随后的作物损失的一个重要因素。然而，目前对控制辣椒疫霉游动孢子在多孔介质中传播的因素知之甚少，这阻碍了我们对其在环境中扩散的了解，也阻碍了污染灌溉水过滤技术的发展。在pH 7.7+/-0.5或4.0+/-0.3的Na+/-0.5或4.0+/-0.3的Na+或Ca~(2+)背景溶液中，结合XDLVO相互作用能计算和微观可视化，研究了氧化铁涂层砂(IOCs)和未涂层砂填充的饱和色谱柱中辣椒疫霉游动孢子的迁移和保留。在pH 4.0和7.7时，IOCS中游动孢子的包裹率明显高于未涂膜的沙子，这可能是由于游动孢子与颗粒表面之间的静电引力增加所致。在pH 7.7时，由于强烈的表面附着、孔应变和粘附性相互作用，IOCS和未涂覆的沙子中游动孢子的去除率分别高达99%和96%。游动的双鞭毛虫游动孢子比包囊游动孢子更容易运输，因此造成了更大的传播和感染风险。这项研究对自然土壤中疫霉游动孢子的环境运输以及具有成本效益的工程过滤系统具有广泛的意义。
Phytophthora capsici is an important plant pathogen capable of infecting several major vegetable crops. Water-induced P. capsici transport is considered to be a significant contributor to disease outbreaks and subsequent crop loss. However, little is known about factors controlling P. capsici zoospore transport in porous media, thus impeding our understanding of their environmental dispersal and development of filtration techniques for contaminated irrigation water. This study investigated the transport and retention of P. capsici zoospores in saturated columns packed with iron-oxide-coated sand (IOCS) or uncoated sand in Na+ or Ca2+ background solution at pH 7.7 +/- 0.5 or 4.0 +/- 0.3, in combination with XDLVO interaction energy calculations and microscopic visualizations. Significantly more encysted zoospores were retained in IOCS than in uncoated sand, and at pH 4.0 than at pH 7.7, which likely resulted from increased electrostatic attraction between zoospores and grain surface. At pH 7.7, up to 99% and 96% of the encysted zoospores were removed in IOCS and uncoated sand, respectively, due to a combination of strong surface attachment, pore straining, and adhesive interactions. Motile biflagellate zoospores were more readily transported than encysted zoospores, thus posing a greater dispersal and infection risk. This study has broad implications in environmental transport of Phytophthora zoospores in natural soils as well as in cost-effective engineered filtration systems.