RRC ID 4686
Author Tominaga A, Nagata M, Futsuki K, Abe H, Uchiumi T, Abe M, Kucho K, Hashiguchi M, Akashi R, Hirsch AM, Arima S, Suzuki A.
Title Enhanced nodulation and nitrogen fixation in the abscisic acid low-sensitive mutant enhanced nitrogen fixation1 of Lotus japonicus.
Journal Plant Physiol.
Abstract The phytohormone abscisic acid (ABA) is known to be a negative regulator of legume root nodule formation. By screening Lotus japonicus seedlings for survival on an agar medium containing 70 microM ABA, we obtained mutants that not only showed increased root nodule number but also enhanced nitrogen fixation. The mutant was designated enhanced nitrogen fixation1 (enf1) and was confirmed to be monogenic and incompletely dominant. The low sensitivity to ABA phenotype was thought to result from either a decrease in the concentration of the plant's endogenous ABA or from a disruption in ABA signaling. We determined that the endogenous ABA concentration of enf1 was lower than that of wild-type seedlings, and furthermore, when wild-type plants were treated with abamine, a specific inhibitor of 9-cis-epoxycarotenoid dioxygenase, which results in reduced ABA content, the nitrogen fixation activity of abamine-treated plants was elevated to the same levels as enf1. We also determined that production of nitric oxide in enf1 nodules was decreased. We conclude that endogenous ABA concentration not only regulates nodulation but also nitrogen fixation activity by decreasing nitric oxide production in nodules.
Volume 151(4)
Pages 1965-76
Published 2009-12
DOI 10.1104/pp.109.142638
PII pp.109.142638
PMID 19776164
PMC PMC2785972
MeSH Abscisic Acid / metabolism Abscisic Acid / pharmacology* Crosses, Genetic Flowers / drug effects Flowers / physiology Gene Expression Regulation, Plant / drug effects Genes, Dominant / genetics Genes, Plant / genetics* Lotus / drug effects* Lotus / genetics* Lotus / growth & development Lotus / microbiology Mutant Proteins / isolation & purification Mutant Proteins / metabolism Mutation / genetics* Nitric Oxide / metabolism Nitrogen Fixation / drug effects* Nitrogen Fixation / genetics Phenotype Plant Root Nodulation / drug effects* Plant Root Nodulation / genetics RNA, Messenger / genetics RNA, Messenger / metabolism Rhizobium / drug effects Rhizobium / physiology Root Nodules, Plant / drug effects Root Nodules, Plant / metabolism Symbiosis / drug effects Time Factors
IF 6.305
Times Cited 42
Lotus / Glycine Miyakojima MG-20