Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands.
Appl Environ Microbiol. 2013 Jan;79(1):263-72. doi: 10.1128/AEM.02546-12. Epub 2012 Oct 26.
Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA and chiA genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.
几丁质改良是一种很有前途的土壤管理策略，可能会增强土壤对植物病原体的抑制能力。然而，我们对添加的几丁质的影响知之甚少，包括在降解过程中可能发生的假定演替。我们在中度酸性土壤中进行了一项实验，在该实验中，除了 pH 值外，还改变了几丁质的水平。几丁质酶活性的检测显示出对添加粗几丁质的快速反应，酶活性的峰值出现在第 7 天。基于 16S rRNA 和 chiA 基因的 PCR-变性梯度凝胶电泳（DGGE）分析表明，在添加几丁质和改变 pH 值后，基于系统发育和功能的细菌群落的结构发生了变化。焦磷酸测序分析表明：（i）土壤中 chiA 基因类型的多样性非常巨大；（ii）在不同的流行土壤 pH 值下，不同的 chiA 基因类型被添加的几丁质选择。有趣的是，与 Actinobacteria 相比，革兰氏阴性细菌在添加几丁质后的立即反应中（基于 16S rRNA 基因丰度和 chiA 基因类型）发挥了主要作用。这项研究的结果增强了我们对土壤细菌群落对几丁质的反应的理解，对于理解土壤抑制性和从土壤中挖掘新的酶都有一定的作用。
