Functional NIN persists in non-nodulating plants: Rethinking the loss of symbiosis

Certain plants, including legumes, form specialized root organs known as nodules. These plants establish symbiotic relationships with nitrogen-fixing bacteria and utilize atmospheric nitrogen. This process, termed "root nodule symbiosis," is an important biological function that can reduce reliance on chemical nitrogen fertilizers. At the genetic level, previous studies, primarily on legumes, have demonstrated that the transcription factor nodule inception (NIN) is essential for root nodule symbiosis. This finding has led to the prevailing view that the loss of the NIN gene is primarily responsible for nodulation loss.