Elucidation of the microbial complex having a causal role in the development of apple replant disease in Washington
Elucidation of the microbial complex having a causal role in the development of apple replant disease in Washington
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DOI：
10.1094/phyto.1998.88.9.930
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发表时间：
1998-09-01
期刊：
影响因子：
3.2
通讯作者：
Mazzola, M
中科院分区：
文献类型：
--
作者：
Mazzola, M
进行了系统研究以阐明不同土壤微生物群在苹果重植病害发生中的作用。通过使用半选择性杀菌剂和土壤巴氏灭菌，减少了目标微生物的数量。细菌与该疾病无关，因为抗生素氯霉素的使用减少了土壤中的细菌数量，但未能改善苹果移植物的生长，而在巴氏灭菌温度下实现了生长的促进，不会改变从苹果根部回收的细菌群落的属性。在所调查的 9 个果园中，有 8 个果园的穿透短体线虫数量低于损害阈值水平，在所测试的 5 个重植土壤中，有 4 个使用杀线虫剂未能促进苹果生长，表明植物寄生线虫在疾病发展中作用较小或没有作用。杀菌剂苯醚甲环唑或甲霜灵的施用促进了所有五种重新种植土壤中苹果的生长，氟二恶腈在两种测试土壤中的效果也是如此。土壤巴氏灭菌促进了苹果的生长，并导致从这些处理过的土壤中生长的苹果幼苗的根部分离出的真菌群落的组成发生了特定的变化。从田间有症状的树木中始终分离出Cylindrocarpon destructans、Phytophthora cactorum、Pythium spp. 和Rhizoctonia solani，它们对苹果具有致病性。然而，腐霉属和丝核菌成分的组成以及该真菌复合体的任何一种成分对疾病发展的相对贡献在研究果园中各不相同。这些发现清楚地表明真菌是华盛顿州苹果重植病的主要致病因子。
Systematic studies were conducted to elucidate the role of different soil microbial groups in the development of apple replant disease. Populations of targeted microorganisms were reduced by the application of semiselective biocides and soil pasteurization. Bacteria were not implicated in the disease, because application of the antibiotic chloramphenicol reduced soil populations of bacteria but failed to improve growth of apple transplants, while enhanced growth was achieved at pasteurization temperatures that did not alter attributes of the bacterial community recovered from apple roots. Populations of Pratylenchus penetrans were below the damage threshold level in eight of nine orchards surveyed, and nematicide applications failed to enhance apple growth in four of five replant soils tested, indicating that plant parasitic nematodes have a minor role or no role in disease development. Application of the fungicide difenconazole or metalaxyl enhanced growth of apple in all five replant soils, as did fludioxinil in the two soils tested. Soil pasteurization enhanced growth of apple and resulted in specific changes in the composition of the fungal community isolated from the roots of apple seedlings grown in these treated soils. Cylindrocarpon destructans, Phytophthora cactorum, Pythium spp., and Rhizoctonia solani were consistently isolated from symptomatic trees in the field and were pathogenic to apple. However, the composition of the Pythium and Rhizoctonia component and the relative contribution of any one component of this fungal complex to disease development varied among the study orchards. These findings clearly demonstrate that fungi are the dominant causal agents of apple replant disease in Washington state.