PII Overexpression in Lotus japonicus Affects Nodule Activity in Permissive Low-Nitrogen Conditions and Increases Nodule Numbers in High Nitrogen Treated Plants.
We report here the first characterization of a GLNB1 gene coding for the PII protein in leguminous plants. The main purpose of this work was the investigation of the possible roles played by this multifunctional protein in nodulation pathways. The Lotus japonicus LjGLB1 gene shows a significant transcriptional regulation during the light-dark cycle and different nitrogen availability, conditions that strongly affect nodule formation, development, and functioning. We also report analysis of the spatial profile of expression of LjGLB1 in root and nodule tissues and of the protein's subcellular localization. Transgenic L. japonicus lines overexpressing the PII protein were obtained and tested for the analysis of the symbiotic responses in different conditions. The uncoupling of PII from its native regulation affects nitrogenase activity and nodule polyamine content. Furthermore, our results suggest the involvement of PII in the signaling of the nitrogen nutritional status affecting the legumes' predisposition for nodule formation.
1 Institute of Biosciences and Bioresources, CNR, Via P. Castellino 111, Napoli, Italy;
Enrica
E
D'Apuzzo
Vladimir Totev
VT
Valkov
Aurora
A
Parlati
Selim
S
Omrane
Ani
A
Barbulova
Maria Martha
MM
Sainz
Marco
M
Lentini
Sergio
S
Esposito
Alessandra
A
Rogato
Maurizio
M
Chiurazzi
D018506:Gene Expression Regulation, Plant / Q000502:physiology; D000070116:Lotus / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism*; D051922:PII Nitrogen Regulatory Proteins / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D017440:Photoperiod; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D053204:Root Nodules, Plant / Q000378:metabolism*
D051922:PII Nitrogen Regulatory Proteins; D010940:Plant Proteins; D009584:Nitrogen