Regulation of betaine synthesis by precursor supply and choline monooxygenase expression in Amaranthus tricolor

Journal of Experimental Botany
Nazmul H BhuiyanTeruhiro Takabe

Abstract

In plants, betaine is synthesized upon abiotic stress via choline oxidation, in which choline monooxygenase (CMO) is a key enzyme. Although it had been thought that betaine synthesis is well regulated to protect abiotic stress, it is shown here that an exogenous supply of precursors such as choline, serine, and glycine in the betaine-accumulating plant Amaranthus tricolor further enhances the accumulation of betaine under salt stress, but not under normal conditions. Addition of isonicotinic acid hydrazide, an inhibitor of glycine decarboxylase, inhibited the salinity-induced accumulation of betaine. Salt-induced accumulation of A. tricolor CMO (AmCMO) and betaine was much slower in roots than in leaves, and a transient accumulation of proline was observed in the roots. Antisense expression of AmCMO mRNA suppressed the salt-induced accumulation of AmCMO and betaine, but increased the level of choline approximately 2- 3-fold. This indicates that betaine synthesis is highly regulated by AmCMO expression. The genomic DNA, including the upstream region (1.6 kbp), of AmCMO was isolated. Deletion analysis of the AmCMO promoter region revealed that the 410 bp fragment upstream of the translation start codon contains the sequence respo...Continue Reading

Citations

Mar 18, 2010·Yi chuan = Hereditas·Li-Ping ZhuQiu-Li Li
Aug 25, 2015·Plant Physiology and Biochemistry : PPB·Nana YamadaTeruhiro Takabe
Oct 16, 2010·Plant, Cell & Environment·Tony H H Chen, Norio Murata
Jul 26, 2016·Frontiers in Plant Science·Yongxue ZhangBing Yu
Mar 23, 2019·Frontiers in Plant Science·Maria Grazia AnnunziataPetronia Carillo

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