NBCL1 and NBCL2 regulate legume development
The transcriptional co-regulators NBCL1 and NBCL2 redundantly coordinate aerial organ development and root nodule identity in legumes
Medicago truncatula NODULE ROOT1 (MtNOOT1) and Pisum sativum COCHLEATA1 (PsCOCH1) are orthologous genes belonging to the NOOT-BOP-COCH-LIKE (NBCL) gene family. NBCL genes encode key transcriptional co-regulators of plant development. In Mtnoot1 and Pscoch1 mutants, development of stipules, flowers and symbiotic nodules is impaired. MtNOOT2 and PsCOCH2 represent the unique paralogs of MtNOOT1 and PsCOCH1, respectively. In M. truncatula, MtNOOT1 and MtNOOT2 are required for the establishment and maintenance of symbiotic nodule identity.
Unlike NBCL1 genes, the role of NBCL2 genes in aerial development of legumes is not known. To better understand the roles of these genes in legumes, we used nbcl single and double mutants from M. truncatula and P. sativum.
In a study published in Journal of Experimental Botany, the IPS2 SYMUNITY team shows that Mtnoot2 and Pscoch2 single mutants develop wild-type stipules, flowers and symbiotic nodules. However, the number of flowers is increased, and pods and seeds are smaller compared to the wild type. In addition, compared with the corresponding nbcl1 single mutants, nbcl1nbcl2 double mutants of M. truncatula and P. sativum show a significant alteration in the development of stipules, inflorescences, flowers, and nodules. Remarkably, in nbcl double mutants of M. truncatula and P. sativum, stipules are transformed into a range of aberrant compound leaf-like structures.
