Mutation of Arabidopsis Copper-Containing Amine Oxidase Gene AtCuAO? Alters Polyamines, Reduces Gibberellin Content and Affects Development.

ABSTRACT: Polyamines (PAs) are essential metabolites in plants performing multiple functions during growth and development. Copper-containing amine oxidases (CuAOs) catalyse the catabolism of PAs and in Arabidopsis thaliana are encoded by a gene family. Two mutants of one gene family member, AtCuAO?, showed delayed seed germination, leaf emergence, and flowering time. The height of the primary inflorescence shoot was reduced, and developmental leaf senescence was delayed. Siliques were significantly longer in mutant lines and contained more seeds. The phenotype of AtCuAO? over-expressors was less affected. Before flowering, there was a significant increase in putrescine in AtCuAO? mutant leaves compared to wild type (WT), while after flowering both spermidine and spermine concentrations were significantly higher than in WT leaves. The expression of GA (gibberellic acid) biosynthetic genes was repressed and the content of GA1, GA7, GA8, GA9, and GA20 was reduced in the mutants. The inhibitor of copper-containing amine oxidases, aminoguanidine hydrochloride, mimicked the effect of AtCuAO? mutation on WT seed germination. Delayed germination, reduced shoot height, and delayed flowering in the mutants were rescued by GA3 treatment. These data strongly suggest AtCuAO? is an important gene regulating PA homeostasis, and that a perturbation of PAs affects plant development through a reduction in GA biosynthesis.

SUBMITTER: Alharbi B 

PROVIDER: S-EPMC7589035 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature