Project description:Analysis of the nitrate-responsive transcriptome during root nodule symbiosis in wild type, the Ljnin mutants, the nrsym1 mutants, the nrsym2 mutants, and the nrsym1 nrsym2 double mutants of Lotus japonicus
Project description:Key genes involved in symbiosis have been lost in nonmycorrhizal plants such as Arabidopsis thaliana. We studied the effects on gene expression in A. thaliana expressing an abbreviated, functional version of one of genes, the transcription factor Interacting Protein of DMI3 (IPD3-min), under low nutrient conditions in the presence and absence of a mycorrhizal fungi, Rhizophagus. We conducted the same transcriptome analysis with a cyclops-4 knockout mutant in Lotus japonicus to compare with the expression profile of a mycorrhizal host model lacking IPD3.
Project description:Drought is one of the major environmental factors limiting biomass and seed yield production in agriculture. In this research we focused on plants from Fabaceae family, which have a unique ability for establishment of symbiosis with nitrogen-fixing bacteria, and are relatively susceptible to water limitation. We present the changes in nitrogenase activity and global gene expression occurring in Medicago truncatula and Lotus japonicus root nodules during water deficit. Our results prove a decrease in the efficiency of nitrogen fixation as well as extensive changes in plant and bacterial transcriptomes shortly after watering cessation. We show for the first time that not only symbiotic plant component, but also Sinorhizobium meliloti and Mesorhizobium loti bacteria residing in the root nodules of M. truncatula and L. japonicus, respectively, adjust their gene expression in response to water shortage. Although our results demonstrate that both M. truncatula and L. japonicus root nodules are susceptible to water deprivation, they indicate significant differences in plant and bacterial response to drought between tested species, which may be related to various type of root nodules formed by these species.
