Photorespiratory metabolism and nodule function: behavior of Lotus japonicus mutants deficient in plastid glutamine synthetase.
Mol Plant Microbe Interact
; 25(2): 211-9, 2012 Feb.
Article
en En
| MEDLINE
| ID: mdl-22007601
ABSTRACT
Two photorespiratory mutants of Lotus japonicus deficient in plastid glutamine synthetase (GS(2)) were examined for their capacity to establish symbiotic association with Mesorhizobium loti bacteria. Biosynthetic glutamine synthetase (GS) activity was reduced by around 40% in crude nodule extracts from mutant plants as compared with the wild type (WT). Western blot analysis further confirmed the lack of GS(2) polypeptide in mutant nodules. The decrease in GS activity affected the nodular carbon metabolism under high CO(2) (suppressed photorespiration) conditions, although mutant plants were able to form nodules and fix atmospheric nitrogen. However, when WT and mutant plants were transferred to an ordinary air atmosphere (photorespiratory active conditions) the nodulation process and nitrogen fixation were substantially affected, particularly in mutant plants. The number and fresh weight of mutant nodules as well as acetylene reduction activity showed a strong inhibition compared with WT plants. Optical microscopy studies from mutant plant nodules revealed the anticipated senescence phenotype linked to an important reduction in starch and sucrose levels. These results show that, in Lotus japonicus, photorespiration and, particularly, GS(2) deficiency result in profound limitations in carbon metabolism that affect the nodulation process and nitrogen fixation.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Plastidios
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Nódulos de las Raíces de las Plantas
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Mesorhizobium
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Lotus
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Glutamato-Amoníaco Ligasa
Idioma:
En
Revista:
Mol Plant Microbe Interact
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BOTANICA
/
MICROBIOLOGIA
Año:
2012
Tipo del documento:
Article
País de afiliación:
España