Changes in ginsenosides and soil biodiversity related to management of ginseng replant disease

种植者都知道，在一种作物之后，不可能在同一个花园里种植人参。通常，新作物会很快死于根腐病，俗称补种病。再植疾病的持续性以几十年为单位来衡量。由于再植疾病，以前没有种植人参的合适的桑迪土壤变得稀缺。据估计，在未来20至30年内，安大略将不会有更适合人参生产的土地。与此同时，从他们的家庭农场到田地旅行长达一个小时，以及由于搬到越来越边缘的土地而导致的产量下降，估计该行业每年要花费4000万美元。补种疾病并不像以前的人参园中持续存在的特定致病生物那么简单。相反，越来越多的证据表明，人参园土壤化学和微生物生物学的关键变化发生在收获后，使人参园不适合第二茬人参。人参皂苷是由人参制成的化合物，为植物提供了一些药用特性。已知这些化合物会释放到土壤中，并且可以被土传微生物改变。我们假设，芦荟苷是由常驻土壤微生物生物转化，创造了一个土壤环境，其中高度致命的形式的生物体，包括再植疾病复合体可以建立。为了解决这一假设，在本提案中，我们将建立人参皂苷和田间土壤中微生物组之间的关系，在新花园中种植人参期间，以及在最近收获的花园中。我们还将监测特定土壤处理对田间和温室土壤微生物组和糖苷的影响。我们将确定与再植疾病期间根腐病水平增加相关的关键生物和皂苷类型，并建立用于土壤样品中常规鉴定的分子标记（例如，以确定田地是否有再植疾病的风险）。最后，我们建议确定生物体的独特基因特征，并将其作为选择性管理干预的潜在目标。

It is well known by growers that after one crop, it is not possible to plant ginseng in the same gardens. Frequently, the new crop will quickly succumb to root rot disease colloquially referred to as replant disease. The persistence of replant disease is measured in decades. Due to replant disease, suitable sandy soils on which ginseng has not been grown previously are becoming scarce. It is estimated that there will not be any more suitable land for ginseng production in Ontario in the next 20 to 30 years. In the meantime, travel to fields up to an hour from their home farms and decreased yields from moving to increasingly marginal land costs the industry an estimated $40 million/yr. Replant disease is not as simple as the persistence of specific disease-causing organisms in former ginseng gardens. Instead, there is growing evidence that critical changes in both soil chemistry and microorganism biology in ginseng gardens occur post-harvest and render ginseng gardens unsuitable for a second crop of ginseng. Ginsenosides are chemical compounds made by ginseng that provide the plant with some of its medicinal properties. These compounds are known to be released into the soil, and can be modified by soil-borne microorganisms. We hypothesize that ginsenosides are biotransformed by resident soil microbes, creating a soil environment in which highly virulent forms of the organisms that comprise the replant disease complex can establish. To address this hypothesis in the present proposal we will establish the relationship between ginsenosides and the microbiome in field soil, during cultivation of ginseng in a new garden, as well as in a recently harvested garden. We will also monitor the impact of specific soil treatments on the soil microbiome and ginsenosides in the field and the greenhouse. We will identify key organisms and types of ginsenosides associated with increasing levels of root rot during replant disease and establish molecular markers for their routine identification in soil samples (e.g., to determine whether a field is at risk for replant disease). Finally, we propose to identify unique gene features of identified organisms and use them as potential targets for selective management intervention.