Long-term monoculture reduces the symbiotic rhizobial biodiversity of peanut
Long-term monoculture reduces the symbiotic rhizobial biodiversity of peanut
复制标题
长期单一栽培降低了花生共生根瘤菌的生物多样性
DOI：
10.1016/j.syapm.2020.126101
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发表时间：
2020-09-01
影响因子：
3.4
通讯作者：
Li, Yan
中科院分区：
文献类型：
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作者：
Shao, Shuai;Chen, Mingna;Li, Yan
长期单一栽培降低了花生的产量和品质，甚至导致微生物群落的变化。然而，LTM对花生根瘤菌群落的影响尚不清楚。在本研究中，我们从6块不同单作种植年限的样地中分离并鉴定了花生根瘤菌。分析了各样点花生根瘤菌群落结构和多样性指数，并评价了土壤特征与花生根瘤菌群落的相关性，以阐明土壤特征对花生根瘤菌群落的影响。对代表性菌株的竞争能力进行了分析。从6个样地共分离得到283株菌株。确定了19个recA单倍型，并将其归为8个慢生根瘤菌基因种，每个样本中以B. liaoningense和B. ottawawense为优势类群。随着培养时间的延长，根瘤菌群落多样性指数呈下降趋势，优势类群辽宁白僵菌和加拿大白僵菌显著富集。速效钾（AK）、速效磷（AP）、速效氮（AN）、总氮（TN）和有机碳（OC）随单作时间的延长而逐渐增加。土壤有机质、全氮、速效钾和速效钾是影响根瘤菌基因种分布的主要土壤特征。竞争性结瘤试验表明，辽宁白僵菌具有较强的竞争能力，这与其较高的分离频率是一致的。本研究揭示了土壤特征和根瘤菌的竞争能力决定了共生根瘤菌群落的形成，并为根瘤菌群落的形成和生物地理特性提供了信息。(C) 2020 Elsevier GmbH版权所有。
Long-term monoculture (LTM) decreases the yield and quality of peanut, even resulting in changes in the microbial community. However, the effect of LTM on peanut rhizobial communities has still not been elucidated. In this study, we isolated and characterized peanut rhizobia from 6 sampling plots with different monoculture cropping durations. The community structure and diversity index for each sampling site were analyzed, and the correlations between a peanut rhizobium and soil characteristics were evaluated to clarify the effects on peanut rhizobial communities. The competitive abilities among representative strains were also analyzed. A total of 283 isolates were obtained from 6 sampling plots. Nineteen recA haplotypes were defined and were grouped into 8 genospecies of Bradyrhizobium, with B. liaoningense and B. ottawaense as the dominant groups in each sample. The diversity indexes of the rhizobial community decreased, and the dominant groups of B. liaoningense and B. ottawaense were enriched significantly with extended culture duration. Available potassium (AK), available phosphorus (AP), available nitrogen (AN), total nitrogen (TN) and organic carbon (OC) gradually increased with increasing monoculture duration. OC, TN, AP and AK were the main soil characteristics affecting the distribution of rhizobial genospecies in the samples. A competitive nodulation test indicated that B. liaoningense presented an excellent competitive ability, which was congruent with its high isolation frequency. This study revealed that soil characteristics and the competitive ability of rhizobia shape the symbiotic rhizobial community and provides information on community formation and the biogeographic properties of rhizobia. (C) 2020 Elsevier GmbH. All rights reserved.