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Combined phosphate and nitrogen limitation generates a nutrient stress transcriptome favorable for arbuscular mycorrhizal symbiosis in M edicago truncatula
Author(s) -
Bonneau Laurent,
Huguet Stéphanie,
Wipf Daniel,
Pauly Nicolas,
Truong HoaiNam
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12234
Subject(s) - symbiosis , medicago truncatula , rhizophagus irregularis , strigolactone , biology , nutrient , transcriptome , phosphate , phosphorus , botany , arbuscular mycorrhizal , gene , arabidopsis , biochemistry , chemistry , gene expression , ecology , genetics , mutant , organic chemistry , bacteria
Summary Arbuscular mycorrhizal ( AM ) symbiosis is stimulated by phosphorus ( P ) limitation and contributes to P and nitrogen ( N ) acquisition. However, the effects of combined P and N limitation on AM formation are largely unknown. M edicago truncatula plants were cultivated in the presence or absence of R hizophagus irregularis (formerly G lomus intraradices ) in P ‐limited ( LP ), N ‐limited ( LN ) or combined P ‐ and N ‐limited ( LPN ) conditions, and compared with plants grown in sufficient P and N . The highest AM formation was observed in LPN , linked to systemic signaling by the plant nutrient status. Plant free phosphate concentrations were higher in LPN than in LP , as a result of cross‐talk between P and N . Transcriptome analyses suggest that LPN induces the activation of NADPH oxidases in roots, concomitant with an altered profile of plant defense genes and a coordinate increase in the expression of genes involved in the methylerythritol phosphate and isoprenoid‐derived pathways, including strigolactone synthesis genes. Taken together, these results suggest that low P and N fertilization systemically induces a physiological state of plants favorable for AM symbiosis despite their higher P status. Our findings highlight the importance of the plant nutrient status in controlling plant–fungus interaction.