Colonization and Competition Dynamics of Plant Growth-Promoting/Inhibiting Bacteria in the Phytosphere of the Duckweed Lemna minor
Colonization and Competition Dynamics of Plant Growth-Promoting/Inhibiting Bacteria in the Phytosphere of the Duckweed Lemna minor
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DOI：
10.1007/s00248-018-1306-x
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发表时间：
2019-02-01
影响因子：
3.6
通讯作者：
Ike, Michihiko
中科院分区：
文献类型：
--
作者：
Ishizawa, Hidehiro;Kuroda, Masashi;Ike, Michihiko
尽管水生植物相关细菌在宿主植物生长和水生环境中的营养循环中发挥着重要作用，但其植物定殖模式却很少被了解。研究了一种植物生长促进细菌（PGPB）和两种植物生长抑制细菌（PGIB）在水生植物浮萍（Lemna minor）中的定殖和竞争动态。单独接种L.较小，每种细菌菌株以每毫克（植物鲜重）约10（6）个细胞迅速定殖，并在整个7天培养时间内保持相似的群体。二元共接种试验结果表明，无论接种比例（99：1-1：99）和接种顺序如何，PGPB菌株Aquitalea magnusonii H3均能竞争性地排斥PGIB菌株Acinetobacter ursingii M3，且H3与PGIB菌株Asticcacaulis excentricus M6几乎以1：1的比例共存。我们还发现A. magnusonii H3的促生作用可能与其优异的竞争定殖能力有关，即使在接种量很少的情况下，也能克服两株PGIB菌株的负效应。这些实验结果表明，水生植物的细菌定殖存在一个恒定的生态平衡状态。
Despite the considerable role of aquatic plant-associated bacteria in host plant growth and nutrient cycling in aquatic environments, the mode of their plant colonization has hardly been understood. This study examined the colonization and competition dynamics of a plant growth-promoting bacterium (PGPB) and two plant growth-inhibiting bacteria (PGIB) in the aquatic plant Lemna minor (common duckweed). When inoculated separately to L. minor, each bacterial strain quickly colonized at approximately 10(6) cells per milligram (plant fresh weight) and kept similar populations throughout the 7-day cultivation time. The results of two-membered co-inoculation assays revealed that the PGPB strain Aquitalea magnusonii H3 consistently competitively excluded the PGIB strain Acinetobacter ursingii M3, and strain H3 co-existed at almost 1:1 proportion with another PGIB strain, Asticcacaulis excentricus M6, regardless of the inoculation ratios (99:1-1:99) and inoculation order. We also found that A. magnusonii H3 exerted its growth-promoting effect over the negative effects of the two PGIB strains even when only a small amount was inoculated, probably due to its excellent competitive colonization ability. These experimental results demonstrate that there is a constant ecological equilibrium state involved in the bacterial colonization of aquatic plants.