The Auxin Conjugate Hydrolase Family of Medicago truncatula and Their Expression During the Interaction with Two Symbionts

Campanella, James J.; Smith, Stephanie M.; Leibu, Dora; Wexler, Shiri; Ludwig‐Müller, Jutta

doi:10.1007/s00344-007-9027-2

Cited by 85 publications

(65 citation statements)

References 54 publications

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“…detect 4-chloro-IAA, phenylacetic acid, and the auxin conjugates IAA-phenylalanine, IAA-tryptophan, IAA-leucine, IAA-isoleucine, IAA-valine, or IAA-aspartate in any of the root segments. These auxin metabolites were targeted for quantification because a previous study suggested their presence in M. truncatula based on enzyme feeding assays (Campanella et al, 2008). The detection limits for these auxins are shown in Supplemental Table 1 and are below the concentrations measured for some of these auxins in other studies (Schneider et al, 1985;Kowalczyk and Sandberg, 2001;Matsuda et al, 2005).…”

Section: Resultsmentioning

confidence: 99%

“…However, we cannot exclude the importance of other auxins that were not detectable or not measured in our assays. While we concentrated on auxin amino acids conjugates, which were previously suggested to be present in M. truncatula (Campanella et al, 2008), a number of other auxin conjugates exist in plants that could contribute to the dynamics of auxin breakdown, storage, and activity (Korasick et al, 2013). In addition, it is likely that the GH3:GUS reporter construct does not reflect the exact localization and activity of all different auxins in the root.…”

Section: Discussion Cytokinin Signaling Is Required For Increased Auxmentioning

confidence: 99%

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Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

et al. 2015

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Initiation of symbiotic nodules in legumes requires cytokinin signaling, but its mechanism of action is largely unknown. Here, we tested whether the failure to initiate nodules in the Medicago truncatula cytokinin perception mutant cre1 (cytokinin response1) is due to its altered ability to regulate auxin transport, auxin accumulation, and induction of flavonoids. We found that in the cre1 mutant, symbiotic rhizobia cannot locally alter acro-and basipetal auxin transport during nodule initiation and that these mutants show reduced auxin (indole-3-acetic acid) accumulation and auxin responses compared with the wild type. Quantification of flavonoids, which can act as endogenous auxin transport inhibitors, showed a deficiency in the induction of free naringenin, isoliquiritigenin, quercetin, and hesperetin in cre1 roots compared with wild-type roots 24 h after inoculation with rhizobia. Coinoculation of roots with rhizobia and the flavonoids naringenin, isoliquiritigenin, and kaempferol, or with the synthetic auxin transport inhibitor 2,3,5,-triiodobenzoic acid, rescued nodulation efficiency in cre1 mutants and allowed auxin transport control in response to rhizobia. Our results suggest that CRE1-dependent cytokinin signaling leads to nodule initiation through the regulation of flavonoid accumulation required for local alteration of polar auxin transport and subsequent auxin accumulation in cortical cells during the early stages of nodulation.

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Section: Resultsmentioning

confidence: 99%

Section: Discussion Cytokinin Signaling Is Required For Increased Auxmentioning

confidence: 99%

Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

et al. 2015

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“…As to quaternary structures, all aforementioned HmrA relatives form dimers. Indole-3-acetatic acid amino acid hydrolase crystallized as monomers, but dimerization in solution has not been ruled out for this amidohydrolase (52). Dimerization involves the same region of the ODs in all cases, and it occurs through formation of an overall open sandwich of antiparallel strands and four helices as found in HmrA dimers (see above).…”

Section: Parameters Valuesmentioning

confidence: 99%

Structural and Functional Analyses Reveal That Staphylococcus aureus Antibiotic Resistance Factor HmrA Is a Zinc-dependent Endopeptidase

Botelho

Guevara

Marrero

et al. 2011

Journal of Biological Chemistry

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HmrA is an antibiotic resistance factor of methicillin-resistant Staphylococcus aureus. Molecular analysis of this protein revealed that it is not a muramidase or ␤-lactamase but a nonspecific double-zinc endopeptidase consisting of a catalytic domain and an inserted oligomerization domain, which probably undergo a relative interdomain hinge rotation upon substrate binding. The active-site cleft is located at the domain interface. Four HmrA protomers assemble to a large ϳ170-kDa homotetrameric complex of 125 Å . All four active sites are fully accessible and ϳ50 -70 Å apart, far enough apart to act on a large meshwork substrate independently but simultaneously. In vivo studies with four S. aureus strains of variable resistance levels revealed that the extracellular addition of HmrA protects against loss of viability in the presence of oxacillin and that this protection depends on proteolytic activity. All of these results indicate that HmrA is a peptidase that participates in resistance mechanisms in vivo in the presence of ␤-lactams. Furthermore, our results have implications for most S. aureus strains of known genomic sequences and several other cocci and bacilli, which harbor close orthologs. This suggests that HmrA may be a new widespread antibiotic resistance factor in bacteria.

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“…Gene families encoding auxin amidohydrolases and their regulation by interacting microorganisms have been described in Brassica rapa (25) and Medicago truncatula (26). In Arabidopsis, they form a 7-gene family (IAR3, ILL1, ILL2, ILL3, ILL5, ILL6, and ILR1) with several members known to cleave auxin-amino acid conjugates (27).…”

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confidence: 99%

The Amidohydrolases IAR3 and ILL6 Contribute to Jasmonoyl-Isoleucine Hormone Turnover and Generate 12-Hydroxyjasmonic Acid Upon Wounding in Arabidopsis Leaves

Widemann

Miesch

Lugan

et al. 2013

Journal of Biological Chemistry

112

143

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Background:The plant hormone jasmonoyl-isoleucine (JA-Ile) undergoes oxidative catabolism mediated by cytochrome P450 enzymes. Results: Two amidohydrolases catalyze the cleavage of JA-Ile conjugates and generate 12OH-JA during Arabidopsis wound response. Conclusion: IAR3 and ILL6 define an additional pathway for JA-Ile turnover and establish a biosynthetic route for 12OH-JA. Significance: New enzymatic steps unravel the complexity in jasmonate metabolism.

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The Auxin Conjugate Hydrolase Family of Medicago truncatula and Their Expression During the Interaction with Two Symbionts

Cited by 85 publications

References 54 publications

Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

Structural and Functional Analyses Reveal That Staphylococcus aureus Antibiotic Resistance Factor HmrA Is a Zinc-dependent Endopeptidase

The Amidohydrolases IAR3 and ILL6 Contribute to Jasmonoyl-Isoleucine Hormone Turnover and Generate 12-Hydroxyjasmonic Acid Upon Wounding in Arabidopsis Leaves

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