Nitrogen (N) is an essential component of various biomolecules, such as amino acids and nucleic acids. A major source of N to land plants is the inorganic ion nitrate (NO3−). To uptake NO3− from the soil, plants rely on the activity of sophisticated NO3− transporter (NRT) systems in roots (Vidal et al., 2020). However, under limiting N conditions, some plants evolved the remarkable ability to acquire atmospheric N. Legumes, for example, establish symbiotic relationships with N-fixing soil bacteria from the genus Rhizobia to form highly specialized structures, called nodules, in their roots (reviewed in Roy et al., 2020). In nodules, rhizobia fix atmospheric N at the expense of photosynthetic products provided by plants. Although beneficial under N limiting conditions, nodulation is energetically expensive to plants and, thus, tightly regulated. Members of the NLP family of transcriptional factors suppress nodulation in legumes by orchestrating gene expression in response to N supply. Despite recent advances in understanding the genetic cascades required for nodulation, the molecular mechanisms underlying the switch between N acquisition strategies remain unclear. In this issue of The Plant Cell, Misawa and colleagues (Misawa et al., 2022) uncover a transcriptional cascade involving NLPs and an NRT controlling the interplay between NO3− uptake and nodulation in the legume Lotus japonicus. Their findings expand our understanding of how plants control nodulation and may substantiate efforts on the development of sustainable strategies to improve plant performance.
|Number of pages||2|
|Journal||The Plant cell|
|Early online date||21 Feb 2022|
|Publication status||Published - 1 May 2022|