NIN-Like Protein Transcription factors regulate leghemoglobin genes in legume nodules
Résumé
Leghemoglobins enable endosymbiotic N2-fixation in legume nodules by channelling O2 for bacterial respiration while maintaining a microoxic environment to protect O2-sensitive nitrogenase. We show that the NIN-like Protein (NLP) transcription factors NLP2 and Nodule Inception (NIN) directly activate expression of leghemoglobins through a promoter motif resembling a 'double' version of the Nitrate Responsive Elements (NREs) targeted by other NLPs that has conserved orientation and position across legumes. CRISPR-KO of the NRE-like element resulted in strongly decreased expression of the associated leghemoglobin. Our findings indicate that the origins of the NLP-leghemoglobin module for O2-buffering in nodules can be traced to an ancient pairing of NLPs with non-symbiotic hemoglobins that function in hypoxia.
Domaines
Sciences du Vivant [q-bio]| Origine | Fichiers produits par l'(les) auteur(s) |
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