Aims

Arbuscular Mycorrhizal Fungi (AMF) are ubiquitous soil microorganisms playing a vital role in the functioning of agricultural ecosystems. Although AMF are generally considered to have a low host specificity, it has been suggested that modern plant breeding has selected crop genotypes that are more selectively associated with AMF, possibly resulting in modern high yielding varieties (HYV) having a lower AMF diversity than traditional crop varieties. Whether this is true for paddy rice varieties under field conditions is not known so far. Here, we aimed at comparing differences of AMF communities among modern HYV and traditional rice varieties.

Methods

We collected root and soil samples of five Bangladeshi rice varieties (two traditional and three modern HYV) from 40 different rice fields and quantified AMF richness, diversity and community composition through high throughput amplicon sequencing of the small subunit (SSU) of the ribosomal RNA cistron.

Results

Overall, 75 AMF OTUs, distributed over six AMF families with Glomeraceae as predominant family were found. After accounting for differences in soil conditions, we found that AMF diversity significantly differed among the five varieties and was higher in the traditional than modern varieties. The composition and structure of the AMF communities were distinct between the traditional and modern varieties. An indicator species analysis detected 9 OTUs significantly associated with traditional rice varieties, whereas no indicator OTUs were found for the modern HYV.

Conclusions

We conclude that modern breeding coupled with high fertilizer application rates provide a plausible explanation for the reduced AMF diversity and the different AMF community composition between Bangladeshi modern HYV and traditional varieties.

中文翻译：

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孟加拉国现代高产水稻品种与传统水稻品种的丛枝菌根真菌群落比较

目的

丛枝菌根真菌（AMF）是普遍存在的土壤微生物，在农业生态系统的功能中起着至关重要的作用。尽管通常认为AMF具有较低的宿主特异性，但已有研究表明，现代植物育种已选择了与AMF选择性更高相关的农作物基因型，可能导致现代高产品种（HYV）的AMF多样性低于传统农作物品种。到目前为止，对于田间条件下的水稻品种是否如此还不清楚。在这里，我们旨在比较现代高产栽培稻和传统水稻品种之间的AMF群落差异。

方法

我们从40个不同的稻田中收集了五个孟加拉稻品种（两个传统品种和三个现代HYV品种）的根和土壤样品，并通过核糖体RNA顺反子小亚基（SSU）的高通量扩增子测序，定量了AMF的丰富度，多样性和群落组成。

结果

总体上，发现了75个AMF OTU，分布在六个以伞形科为主要科的AMF家族中。在考虑了土壤条件的差异之后，我们发现五个品种之间的AMF多样性显着不同，并且传统品种比现代品种更高。AMF社区的组成和结构在传统品种和现代品种之间是截然不同的。指标物种分析检测到9个与传统水稻品种显着相关的OTU，而现代HYV没有发现指标OTU。

结论

我们得出的结论是，现代育种加上较高的肥料施用量为孟加拉国现代高产杂交种与传统品种之间减少的AMF多样性和不同的AMF群落组成提供了合理的解释。