Open AccessComparison of Benefit to Sugarcane Plant Growth and 15N2 Incorporation Following Inoculation of Sterile Plants with Acetobacter diazotrophicus Wild-Type and Nif¯ Mutant Strains
Author(s) -
Myrna Sevilla,
R. H. Burris,
Nirmala Gunapala,
Christina Kennedy
Publication year - 2001
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.2001.14.3.358
Subject(s) - inoculation , mutant , biology , wild type , horticulture , endophyte , botany , microbiology and biotechnology , biochemistry , gene
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 15 N 2 incorporation experiment demonstrated that A. diazotrophicus wild-type strains actively fixed N 2 inside sugarcane plants, whereas the Nif¯ mutants did not.