Facultad de Estudios Superiores Iztacala, Laboratorio de Genómica Funcional de Leguminosas, Universidad Nacional Autónoma de México, Tlalnepantla, Estado de México, 54090, Mexico.
New Phytol. 2023 Feb;237(4):1082-1085. doi: 10.1111/nph.18627. Epub 2022 Dec 4.
Legumes form a symbiotic association with rhizobia and fix atmospheric nitrogen in specialized root organs known as nodules. It is well known that salt stress inhibits root nodule symbiosis by decreasing rhizobial growth, rhizobial infection, nodule number, and nitrogenase activity in diverse legumes. Despite this knowledge, the genetic and molecular mechanisms governing salt stress's inhibition of nodulation and nitrogen fixation are still elusive. In this Viewpoint, we summarize the most recent knowledge of the genetic mechanisms that shape this symbiosis according to the salt levels in the soil. We emphasize the relevance of modulating the activity of the transcription factor Nodule Inception to properly shape the symbiosis with rhizobia accordingly. We also highlight the knowledge gaps that are critical for gaining a deeper understanding of the molecular mechanisms underlying the adaptation of the root nodule symbiosis to salt-stress conditions. We consider that filling these gaps can help to improve legume nodulation and harness its ecological benefits even under salt-stress conditions.
豆科植物与根瘤菌形成共生关系，并在专门的根器官（称为根瘤）中固定大气氮。众所周知，盐胁迫通过降低根瘤菌的生长、根瘤菌的侵染、根瘤的数量和固氮酶活性来抑制各种豆科植物的根瘤共生。尽管有这些认识，但控制盐胁迫抑制结瘤和固氮的遗传和分子机制仍然难以捉摸。在本观点中，我们根据土壤中的盐分总结了塑造这种共生关系的遗传机制的最新知识。我们强调了调节转录因子根瘤起始的活性的重要性，以相应地正确塑造与根瘤菌的共生关系。我们还强调了关键的知识空白，这些空白对于深入了解根瘤共生适应盐胁迫条件的分子机制至关重要。我们认为，填补这些空白可以帮助提高豆科植物的结瘤能力，并利用其生态效益，即使在盐胁迫条件下也是如此。
