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Herbaspirillum colonization increases growth and nitrogen accumulation in aluminium‐tolerant rice varieties
Author(s) -
Gyaneshwar Prasad,
James Euan K.,
Reddy Pallavolu M.,
Ladha Jagdish K.
Publication year - 2002
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2002.00371.x
Subject(s) - axenic , diazotroph , nitrogenase , inoculation , oryza sativa , nitrogen fixation , biology , bacteria , microbial inoculant , horticulture , colonization , botany , microbiology and biotechnology , biochemistry , genetics , gene
Summary• Varieties of rice ( Oryza sativa ) differing in tolerance to aluminium (Al) were evaluated for their N‐fixation ability after inoculation with a gusA ‐marked strain of Herbaspirillum seropedicae Z67. • Under axenic conditions, by 30 d, inoculation resulted in enhanced nitrogenase activity, d. wt, total N and total C content only in the Al‐tolerant varieties, and one (cv. Moroberekan) showed significantly more 15 N 2 incorporation than an Al‐sensitive variety (‘IR45’). There were no differences in the number of the bacteria colonizing the different varieties, but the Al‐tolerant ones secreted larger amounts of C in their root exudates, and bacteria colonizing the roots of cv. Moroberekan strongly expressed gusA and NifH proteins. • Under glasshouse conditions, by 30 d, inoculation resulted in increased growth of both cvs IR45 and Moroberekan, but the latter showed significantly greater nitrogenase activity and 15 N dilution. In a long‐term experiment, by 120 d, cv. Moroberekan showed a significant increase in N content after inoculation. • Herbaspirilla were localized on and within roots and aerial parts of cvs Moroberekan and IR45 under both growth conditions. The role of N fixation in growth promotion of rice by H. seropedicae is discussed in terms of availability of C.