Sevilla M, Burris R H, Gunapala N, Kennedy C
Department of Plant Pathology, University of Arizona, Tucson 85721, USA.
Mol Plant Microbe Interact. 2001 Mar;14(3):358-66. doi: 10.1094/MPMI.2001.14.3.358.
The ability of the nitrogen-fixing bacterial endophyte Acetobacter diazotrophicus strain PAl5 to enhance the growth of sugarcane SP70-1143 was evaluated in the growth chamber, greenhouse, and field by comparing plants inoculated with wild-type and Nif mutant MAd3A in two independent experiments. The wild-type and Nif mutant strains colonized sugarcane plants equally and persisted in mature plants. In N-deficient conditions, sugarcane plants inoculated with A. diazotrophicus PAl5 generally grew better and had a higher total N content 60 days after planting than did plants inoculated with mutant MAd3A or uninoculated plants. These results indicate that the transfer of fixed N from A. diazotrophicus to sugarcane might be a significant mechanism for plant growth promotion in this association. When N was not limiting, growth enhancement was observed in plants inoculated with either wild-type or Nif- mutants, suggesting the additional effect of a plant growth promoting factor provided by A. diazotrophicus. A 15N2 incorporation experiment demonstrated that A. diazotrophicus wild-type strains actively fixed N2 inside sugarcane plants, whereas the Nif- mutants did not.
在生长室、温室和田间通过比较接种野生型和固氮酶突变体MAd3A的甘蔗SP70 - 1143植株，在两个独立实验中评估了固氮内生细菌重氮营养醋杆菌菌株PAl5促进甘蔗生长的能力。野生型和固氮酶突变体菌株对甘蔗植株的定殖能力相同，并能在成熟植株中持续存在。在缺氮条件下，接种重氮营养醋杆菌PAl5的甘蔗植株在种植60天后通常生长得更好，总氮含量也高于接种突变体MAd3A的植株或未接种的植株。这些结果表明，重氮营养醋杆菌固定的氮向甘蔗的转移可能是这种共生关系中促进植物生长的一个重要机制。当氮不成为限制因素时，接种野生型或固氮酶突变体的植株均观察到生长增强，这表明重氮营养醋杆菌提供了一种促进植物生长的因子的额外作用。一项¹⁵N₂掺入实验表明，重氮营养醋杆菌野生型菌株能在甘蔗植株内积极固定N₂，而固氮酶突变体则不能。
