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Opening the black box: outcomes of interactions between arbuscular mycorrhizal ( AM ) and non‐host genotypes of M edicago depend on fungal identity, interplay between P uptake pathways and external P supply
Author(s) -
FACELLI E.,
DUAN T.,
SMITH S E.,
CHRISTOPHERSEN H M.,
FACELLI J M.,
SMITH F A.
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12237
Subject(s) - arbuscular mycorrhizal fungi , host (biology) , genotype , identity (music) , microbiology and biotechnology , genetics , biology , physics , gene , horticulture , inoculation , acoustics
We investigated the physiology that underlies the influence of arbuscular mycorrhizal ( AM ) colonization on outcomes of interactions between plants. We grew M edicago truncatula A17 and its AM ‐defective mutant dmi1 in intragenotypic (two plants per pot of the same genotype, x2) or intergenotypic (one plant of each genotype, 1 + 1) combinations, inoculated or not with R hizophagus irregularis (formerly G lomus intraradices ) or G igaspora margarita . We measured plant growth, colonization, contributions of AM and direct P uptake pathways using 32 P , and expression of plant P i transporter genes at two levels of P supply. A17 (x2) responded positively to inoculation only at low P . The response was enhanced with 1 + 1 even at high P where colonization in A17 was reduced. With R . irregularis P uptake by the AM pathway was unaffected by P supply, whereas with G . margarita , the AM pathway was lower at high P , and direct uptake higher. Gene expression varied and was unrelated to P uptake through the two pathways. There was no evidence of plant control of P uptake via R . irregularis at high P but there was via G . margarita . Importantly, growth responses of plant genotypes grown alone did not predict outcomes of intergenotypic interactions.