A recent study on leguminous plants has uncovered the function of IRON MAN (IMA) peptides in facilitating the collection of iron into root blemishes during rhizobial symbiosis. This process is essential for nitrogen fixation, a key aspect of plant growth and nitrogen homeostasis. Credit: SciTechDaily.comIMA peptides in legumes improve iron acquisition for nitrogen fixation, offering insights into sustainable farming practices.Leguminous plants have a mechanism (rhizobial symbiosis) to effectively acquire nitrogen, which is an essential macronutrient for growth, through the nitrogen-fixing germs rhizobia. Root blemishes are organs on plant roots that help with the cooperative relationship. Rhizobia colonizes these nodules and fix nitrogen by converting nitrogen from air into ammonia. Iron is needed for the enzymes that catalyze nitrogen fixation; however, where and how iron is transferred to the blemish and utilized for nitrogen fixation is largely unknown.Discovering the Role of IMA PeptidesIn this study, utilizing the legume design plant Lotus japonicus, a transcriptome analysis was carried out based upon the nitrogen status in the plant body during the rhizobial symbiosis process. IRON MAN (IMA) peptides including roughly 50 amino acids were determined, which work systemically (shoot and root systems) to gather iron into the nodules following rhizobial infection.Insights from Comparative AnalysisFurthermore, the function of IMA peptides was analyzed in L. japonicus and Arabidopsis thaliana, a plant devoid of rhizobial symbiosis. In both plant species, the IMA peptides kept nitrogen homeostasis by getting iron in reaction to increased nitrogen concentrations in the plant body, therefore managing plant growth.The research group previously recognized a system for regulating rhizobial symbiosis in reaction to the existence of nitrogen in the soil. This research study constructs on previous research studies by clarifying the underlying system of iron acquisition in reaction to nitrogen, which offers further insight into the mechanisms of plant adaptation to the environment.Contributions to Sustainable Agricultural PracticesThese findings are assuring for the advancement of new innovations that contribute to a sustainable society by maximizing the capacity of plants for microbial symbiosis in regards to nutrient use.Reference: “IMA peptides manage root nodulation and nitrogen homeostasis by supplying iron according to internal nitrogen status” by Momoyo Ito, Yuri Tajima, Mari Ogawa-Ohnishi, Hanna Nishida, Shohei Nosaki, Momona Noda, Naoyuki Sotta, Kensuke Kawade, Takehiro Kamiya, Toru Fujiwara, Yoshikatsu Matsubayashi and Takuya Suzaki, 29 January 2024, Nature Communications.DOI: 10.1038/ s41467-024-44865-4This research was supported by Ministry of Education, Culture, Sports, Science and Technology KAKENHI grants (JP20H05908 and JP23H02495 to T.S.); JSTMirai Program (JPMJMI20E4) to T.S.