Abstract
It was reported that exogenous apply of jasmonic acid (JA) affected nodulation in L. japonicus. It is also shown that expression of JA-dependent VSP gene is induced by nitrogen in soybeans. Therefore, it is suggested that quantity of JA changes depending on nitrogen in L. japonicus, which in turn regulates nodulation. Thus, we tried to reveal relation between JA and control of nodulation caused with nitrogen.
The numbers of nodules and the quantity of heme b in L. japonicus (MG-20) that were grown with 50 μM or 5 mM KNO3 after inoculation of Mesorhizobium loti were measured. As a result, plants grown with 50 μM KNO3 had the largest number of nodules and the highest quantity of heme b. In contrast, both the values decreased with 5 mM KNO3. Therefore, it was revealed that nitrogen control nodulation in L. japonicus.
Next, in the EST database, a gene homologous to allene oxide synthase (AOS) could be found. Its function was examined after expression of it in E. coli. Thereafter, the change of expression of LjAOS was monitored with the plants grown at different concentration of KNO3 after inoculation. Expression of AOS gene little changed dependent on concentration of KNO3.
