Long-term agricultural practices are assumed to shape the rhizosphere microbiome of crops with implications for plant health. In a long-term field experiment, we investigated the effect of different tillage and fertilization practices on soil and barley rhizosphere microbial communities by means of amplicon sequencing of 16S rRNA gene fragments from total community DNA. Differences in the microbial community composition depending on the tillage practice, but not the fertilization intensity were revealed. To examine whether these soil and rhizosphere microbiome differences influence the plant defense response, barley (cultivar Golden Promise) was grown in field or standard potting soil under greenhouse conditions and challenged with Blumeria graminis f. sp. hordei (Bgh). Amplicon sequence analysis showed that preceding tillage practice, but also aboveground Bgh challenge significantly influenced the microbial community composition. Expression of plant defense-related genes PR1b and PR17b was higher in challenged compared to unchallenged plants. The Bgh infection rates were strikingly lower for barley grown in field soil compared to potting soil. Although previous agricultural management shaped the rhizosphere microbiome, no differences in plant health were observed. We propose therefore that the management-independent higher microbial diversity of field soils compared to potting soils contributed to the low infection rates of barley.

中文翻译：

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耕作塑造了大麦的土壤和根际微生物组-但对大白粉病的敏感性却不高。sp。霍尔迪

长期的农业实践被认为会影响作物的根际微生物组，从而影响植物健康。在一项长期的田间试验中，我们通过从总群落DNA扩增16S rRNA基因片段的扩增子，研究了不同耕作和施肥方式对土壤和大麦根际微生物群落的影响。揭示了取决于耕作实践的微生物群落组成的差异，但未发现施肥强度。为了检查这些土壤和根际微生物组差异是否影响植物防御反应，在田间或标准盆栽土壤中于温室条件下种植大麦（栽培品种Golden Promise）并用Blumeria graminis f攻击。sp。大麦（BGH）。扩增子序列分析表明，之前的耕作实践以及地上Bgh挑战均显着影响微生物群落组成。与未挑战的植物相比，被挑战的植物防御相关基因PR1b和PR17b的表达更高。与盆栽土壤相比，在田间土壤中生长的大麦的Bgh感染率要低得多。尽管先前的农业管理影响了根际微生物组，但未观察到植物健康方面的差异。因此，我们提出，与盆栽土壤相比，田间土壤的与管理无关的较高微生物多样性造成了大麦的低感染率。