Glutathione and homoglutathione play a critical role in the nodulation process of Medicago truncatula.
Legumes form a symbiotic interaction with bacteria of the Rhizobiaceae family to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. This process involves the recognition of the bacterial Nod factors by the plant which mediates the entry of the bacteria into the root and nodule organogenesis. We have examined the importance of the low molecular weight thiols, glutathione (GSH) and homoglutathione (hGSH), during the nodulation process in the model legume Medicago truncatula. Using both buthionine sulfoximine, a specific inhibitor of GSH and hGSH synthesis, and transgenic roots expressing GSH synthetase and hGSH synthetase in an antisense orientation, we showed that deficiency in GSH and hGSH synthesis inhibited the formation of the root nodules. This inhibition was not correlated to a modification in the number of infection events or to a change in the expression of the Rhizobium sp.-induced peroxidase rip1, indicating that the low level of GSH or hGSH did not alter the first steps of the infection process. In contrast, a strong diminution in the number of nascent nodules and in the expression of the early nodulin genes, Mtenod12 and Mtenod40, were observed in GSH and hGSH-depleted plants. In conclusion, GSH and hGSH appear to be essential for proper development of the root nodules during the symbiotic interaction.
Frendo
Pierre
P
Interactions Plantes-Microorganismes et Santé Végétale, UMR CNRS-INRA-Université de Nice-Sophia Antipolis, 400, Route des Chappes, BP167, 06903 Sophia-Antipolis Cedex, France.
Harrison
Judith
J
Norman
Christel
C
Hernández Jiménez
María Jesús
MJ
Van de Sype
Ghislaine
G
Gilabert
Alain
A
Puppo
Alain
A
D019328:Buthionine Sulfoximine / Q000494:pharmacology; D016373:DNA, Antisense / Q000235:genetics; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism*; D005981:Glutathione Synthase / Q000037:antagonists & inhibitors / Q000235:genetics; D046913:Medicago truncatula / Q000254:growth & development / Q000378:metabolism* / Q000382:microbiology*; D009586:Nitrogen Fixation; D010453:Peptide Synthases / Q000037:antagonists & inhibitors / Q000235:genetics; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D013559:Symbiosis
D016373:DNA, Antisense; C402172:homoglutathione; D019328:Buthionine Sulfoximine; D010453:Peptide Synthases; C402171:homoglutathione synthase; D005981:Glutathione Synthase; D005978:Glutathione