Disruption of ureide degradation affects plant growth and development during and after transition from vegetative to reproductive stages

Hiroshi Takagi, Shunsuke Watanabe, Shoma Tanaka, Takakazu Matsuura, Izumi C. Mori, Takashi Hirayama, Hiroshi Shimada, Atsushi Sakamoto

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)

    Abstract

    Background: The ureides allantoin and allantoate are major metabolic intermediates of purine catabolism with high nitrogen-to-carbon ratios. Ureides play a key role in nitrogen utilization in ureide-type legumes, but their effects on growth and development in non-legume plants are poorly understood. Here, we examined the effects of knocking out genes encoding ureide-degrading enzymes, allantoinase (ALN) and allantoate amidohydrolase (AAH), on the vegetative-to-reproductive transition and subsequent growth of Arabidopsis plants. Results: The ureide-degradation mutants (aln and aah) showed symptoms similar to those of nitrogen deficiency: early flowering, reduced size at maturity, and decreased fertility. Consistent with these phenotypes, carbon-to-nitrogen ratios and nitrogen-use efficiencies were significantly decreased in ureide-degradation mutants; however, adding nitrogen to irrigation water did not alleviate the reduced growth of these mutants. In addition to nitrogen status, levels of indole-3-acetic acid and gibberellin in five-week-old plants were also affected by the aln mutations. To test the possibility that ureides are remobilized from source to sink organs, we measured ureide levels in various organs. In wild-type plants, allantoate accumulated predominantly in inflorescence stems and siliques; this accumulation was augmented by disruption of its catabolism. Mutants lacking ureide transporters, ureide permeases 1 and 2 (UPS1 and UPS2), exhibited phenotypes similar to those of the ureide-degradation mutants, but had decreased allantoate levels in the reproductive organs. Transcript analysis in wild-type plants suggested that genes involved in allantoate synthesis and ureide transport were coordinately upregulated in senescing leaves. Conclusions: This study demonstrates that ureide degradation plays an important role in supporting healthy growth and development in non-legume Arabidopsis during and after transition from vegetative to reproductive stages.

    Original languageEnglish
    Article number287
    JournalBMC Plant Biology
    Volume18
    Issue number1
    DOIs
    Publication statusPublished - Nov 20 2018

    Keywords

    • Allantoate
    • Allantoin
    • Arabidopsis thaliana
    • Catabolic pathway
    • Nitrogen remobilization
    • Phytohormone
    • Purine base
    • Ureide transport

    ASJC Scopus subject areas

    • Plant Science

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