Comprehensive Screening of Arabidopsis Mutants Suggests the Lysine Histidine Transporter 1 to Be Involved in Plant Uptake of Amino Acids

Svennerstam, Henrik; Ganeteg, Ulrika; Bellini, Catherine; Näsholm, Torgny

doi:10.1104/pp.106.092205

Cited by 151 publications

(165 citation statements)

References 31 publications

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“…utes to the root import of several amino acids (19,20), might also be involved in m-tyrosine uptake from the medium. Inhibition of the shikimate pathway enzyme 3-deoxy-Darabino-heptulosonic acid 7-phosphate synthase by m-tyrosine in E. coli (21) suggested that similar effects could produce toxicity in plants.…”

Section: Resultsmentioning

confidence: 99%

Grass roots chemistry: meta -Tyrosine, an herbicidal nonprotein amino acid

Bertin

Weston²,

Huang

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

178

185

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Fine fescue grasses displace neighboring plants by depositing large quantities of an aqueous phytotoxic root exudate in the soil rhizosphere. Via activity-guided fractionation, we have isolated and identified the nonprotein amino acid m-tyrosine as the major active component. m-Tyrosine is significantly more phytotoxic than its structural isomers o-and p-tyrosine. We show that mtyrosine exposure results in growth inhibition for a wide range of plant species and propose that the release of this nonprotein amino acid interferes with root development of competing plants. Acid hydrolysis of total root protein from Arabidopsis thaliana showed incorporation of m-tyrosine, suggesting this as a possible mechanism of phytotoxicity. m-Tyrosine inhibition of A. thaliana root growth is counteracted by exogenous addition of protein amino acids, with phenylalanine having the most significant effect. The discovery of m-tyrosine, as well as a further understanding of its mode(s) of action, could lead to the development of biorational approaches to weed control.allelopathy ͉ festuca ͉ rhizosphere ͉ root ecology ͉ Arabidopsis R oot exudation of small molecules plays a major role in plant ecosystems and is often associated with the development of competitive advantage through allelopathy (1, 2). Juglone, a highly phytotoxic naphthoquinone produced by black walnut (Juglans nigra L.), and sorgoleone, a substituted quinone from sorghum (Sorghum spp.), are two classic examples of potently active allelochemicals deposited via the plant's living root system ( Fig. 1) (3). Elucidation of the structures and mode of action of previously unknown root-derived phytotoxins could lead to new biorational approaches to weed control.Because of their stress tolerance and disease resistance, fescue (Festuca spp.) grasses are commonly used in landscape, roadside, and pasture settings, as well as for conservation purposes (4, 5). The unusual ability of many fine leaf fescue species to outcompete other plants is well known, and previous investigations suggested that fescue root exudates have phytotoxic properties (4). Here, we report the isolation, identification, and biological activity of m-tyrosine, a potent, structurally unusual broadspectrum phytotoxin exuded by the roots of some fine leaf fescue grasses. Results and DiscussionIn an initial field evaluation of 80 fine fescue cultivars, 8 cultivars with strong weed suppressive potential were identified and their allelopathic potential in laboratory settings was confirmed (4). Based on both field and laboratory results, we selected ''Intrigue,'' a common Chewing's fescue cultivar (Festuca rubra L. ssp. commutata), for further studies.To identify the allelopathic compound(s) contained in Intrigue root exudates, we developed an activity-guided separation scheme based on the inhibition of lettuce (Lactuca sativa L.) radicle elongation in a filter paper-based assay. By using this assay, we compared the phytotoxicity of root surface washes (hexanes, dichloromethane, methanol, and water) prepared from 2-w...

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Section: Resultsmentioning

confidence: 99%

Grass roots chemistry: meta -Tyrosine, an herbicidal nonprotein amino acid

Bertin

Weston²,

Huang

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

178

185

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“…The lht1 mutant displayed accelerated leaf senescence (Svennerstam et al, 2007). Particularly when grown under a long photoperiod (16 h), early senescence was exclusively associated with old leaves, and the senescing leaves showed an enhanced oxidative burst, as detected by 3,3-diaminobenzidine (DAB) staining (see Supplemental Figures 6A to 6D online).…”

Section: The Lht1 Phenotypes Are Associated With Altered Redox Statusmentioning

confidence: 99%

Amino Acid Homeostasis Modulates Salicylic Acid–Associated Redox Status and Defense Responses inArabidopsis

et al. 2010

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The tight association between nitrogen status and pathogenesis has been broadly documented in plant–pathogen interactions. However, the interface between primary metabolism and disease responses remains largely unclear. Here, we show that knockout of a single amino acid transporter, LYSINE HISTIDINE TRANSPORTER1 (LHT1), is sufficient for Arabidopsis thaliana plants to confer a broad spectrum of disease resistance in a salicylic acid–dependent manner. We found that redox fine-tuning in photosynthetic cells was causally linked to the lht1 mutant-associated phenotypes. Furthermore, the enhanced resistance in lht1 could be attributed to a specific deficiency of its main physiological substrate, Gln, and not to a general nitrogen deficiency. Thus, by enabling nitrogen metabolism to moderate the cellular redox status, a plant primary metabolite, Gln, plays a crucial role in plant disease resistance.

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“…Plant roots can take up amino acids (Wright, 1962) and the ecological significance of this ability has been recognized (Chapin et al, 1993;Näsholm et al, 1998;Schmidt and Stewart, 1999). Studies with Arabidopsis (Arabidopsis thaliana) mutants atlht1 and ataap1 provided molecular evidence that amino acid transporters facilitate uptake of amino acids into roots (Hirner et al, 2006;Lee et al, 2007;Svennerstam et al, 2007). In addition to amino acids, more complex organic N sources may also be important.…”

mentioning

confidence: 99%

AtPTR1 and AtPTR5 Transport Dipeptides in Planta

Komarova

Thor²,

Gubler³

et al. 2008

Plant Physiol.

164

138

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Transporters for di-and tripeptides belong to the large and poorly characterized PTR/NRT1 (peptide transporter/nitrate transporter 1) family. A new member of this gene family, AtPTR5, was isolated from Arabidopsis (Arabidopsis thaliana). Expression of AtPTR5 was analyzed and compared with tissue specificity of the closely related AtPTR1 to discern their roles in planta. Both transporters facilitate transport of dipeptides with high affinity and are localized at the plasma membrane. Mutants, double mutants, and overexpressing lines were exposed to several dipeptides, including toxic peptides, to analyze how the modified transporter expression affects pollen germination, growth of pollen tubes, root, and shoot. Analysis of atptr5 mutants and AtPTR5-overexpressing lines showed that AtPTR5 facilitates peptide transport into germinating pollen and possibly into maturating pollen, ovules, and seeds. In contrast, AtPTR1 plays a role in uptake of peptides by roots indicated by reduced nitrogen (N) levels and reduced growth of atptr1 mutants on medium with dipeptides as the sole N source. Furthermore, overexpression of AtPTR5 resulted in enhanced shoot growth and increased N content. The function in peptide uptake was further confirmed with toxic peptides, which inhibited growth. The results show that closely related members of the PTR/NRT1 family have different functions in planta. This study also provides evidence that the use of organic N is not restricted to amino acids, but that dipeptides should be considered as a N source and transport form in plants.

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Comprehensive Screening of Arabidopsis Mutants Suggests the Lysine Histidine Transporter 1 to Be Involved in Plant Uptake of Amino Acids

Cited by 151 publications

References 31 publications

Grass roots chemistry: meta -Tyrosine, an herbicidal nonprotein amino acid

Grass roots chemistry: meta -Tyrosine, an herbicidal nonprotein amino acid

Amino Acid Homeostasis Modulates Salicylic Acid–Associated Redox Status and Defense Responses inArabidopsis

AtPTR1 and AtPTR5 Transport Dipeptides in Planta

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