Endophytic colonization of rice (Oryza sativa L.) by the diazotrophic bacterium Burkholderia kururiensis and its ability to enhance plant growth
Endophytic colonization of rice (Oryza sativa L.) by the diazotrophic bacterium Burkholderia kururiensis and its ability to enhance plant growth
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DOI：
10.1590/s0001-37652008000300009
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发表时间：
2008-09-01
期刊：
影响因子：
--
通讯作者：
Mendonça-Previato, Lucia
中科院分区：
文献类型：
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作者：
Mattos, Katherine A.;Pádua, Vania L.M.;Mendonça-Previato, Lucia
库鲁里伯克霍尔德氏菌（Burkholderia kururiensis）是一种最初从受污染的含水层环境中分离的固氮细菌，与水稻内生菌“B”具有高度的相似性。brasilensis”种。这项工作评估了B的能力。kururiensis内生定殖水稻幼苗通过监测不同组织的根接种植物的细菌生长在不同的媒体，电子显微镜和16 S rDNA分析的存在。用电镜观察接种苗的根、茎、叶，发现B. B. kururiensis定殖主要在根毛区，表明内生定殖主要通过内皮层，然后扩散到木质部导管中，这是导致气生部分的可能途径。虽然对细菌生长本身无关紧要，但添加氮源是内生菌定殖的限制因素。由于内生定殖与增强的植物发育直接相关，因此B产生植物激素生长素/吲哚-3-乙酸。用含有生长素应答报告基因（DR 5-GUS）的转基因水稻植株测定kururiensis。我们的研究结果表明植物伴生B产生生长素的能力。kururiensis，其可能对植物发育具有刺激作用，如通过DR 5-GUS的激活所证明的。我们在此首次证明了B的能力。kururiensis内生定殖水稻..促进植物生长和水稻产量。
Burkholderia kururiensis is a diazotrophic bacterium originally isolated from a polluted aquifer environment and presents a high level of similarity with the rice endophyte "B. brasilensis" species. This work assessed the ability of B. kururiensis to endophytically colonize rice plantlets by monitoring different tissues of root-inoculated plants for the presence of bacterial growth in different media, electron microscopy and by 16S rDNA analysis. Observations of roots, sterns and leaves of inoculated rice plantlets by electron microscopy revealed B. kururiensis colonization predominantly on root hair zones, demonstrating endophytic colonization primarily through the endodermis, followed by spreading into xylem vessels, a possible pathway leading to aerial parts. Although indifferent for the bacterial growth itself, addition of a nitrogen source was a limiting factor for endophytic colonization. As endophytic colonization was directly associated to an enhanced plant development, production of phytohormone auxin/indole-3-acetic acid by B. kururiensis was assayed with transgenic rice plantlets containing an auxin-responsive reporter (DR5-GUS). Our findings suggest the ability of auxin production by plant-associated B. kururiensis which may have a stimulatory effect on plant development, as evidenced by activation of DR5-GUS. We hereby demonstrate, for the first time, the ability of B. kururiensis to endophytically colonize rice.. promoting both plant growth and rice grain yield.