Nucleoside 5'-Phosphoramidates Control the Phenylpropanoid Pathway in Suspension-Cultured Cells.

It is known that cells contain various uncommon nucleotides such as dinucleoside polyphosphates (NpN's) and adenosine 5'-phosphoramidate (NH-pA) belonging to nucleoside 5'-phosphoramidates (NH-pNs). Their cellular levels are enzymatically controlled. Some of them are accumulated in cells under stress, and therefore, they could act as signal molecules. Our previous research carried out in and grape () showed that NpN's induced the expression of genes in the phenylpropanoid pathway and favored the accumulation of their products, which protect plants against stress. Moreover, we found that NH-pA could play a signaling role in seedlings. Data presented in this paper show that exogenously applied purine (NH-pA, NH-pG) and pyrimidine (NH-pU, NH-pC) nucleoside 5'-phosphoramidates can modify the expression of genes that control the biosynthesis of both stilbenes and lignin in cv. Monastrell suspension-cultured cells. We investigated the expression of genes encoding for phenylalanine ammonia-lyase (), cinnamate-4-hydroxylase (), 4-coumarate:coenzyme A ligase (), chalcone synthase (), stilbene synthase (), cinnamoyl-coenzyme A:NADP oxidoreductase (), and cinnamyl alcohol dehydrogenase (). Each of the tested NH-pNs also induced the expression of the -resveratrol cell membrane transporter gene and caused the accumulation of -resveratrol and -piceid in grape cells as well as in the culture medium. NH-pC, however, evoked the most effective induction of phenylpropanoid pathway genes such as , , , and . Moreover, this nucleotide also induced at short times the accumulation of -benzoylputrescine (BenPut), one of the phenylamides that are derivatives of phenylpropanoid and polyamines. The investigated nucleotides did not change either the lignin content or the cell dry weight, nor did they affect the cell viability throughout the experiment. The results suggest that nucleoside 5'-phosphoramidates could be considered as new signaling molecules.