Two S-adenosylmethionine synthetase-encoding genes differentially expressed during adventitious root development in Pinus contorta.

Abstract:

:Two S-adenosylmethionine synthetase (SAMS) cDNAs, PcSAMS1 and PcSAMS2, have been identified in Pinus contorta. We found that the two genes are differentially expressed during root development. Thus, PcSAMS1 is preferentially expressed in roots and exhibits a specific expression pattern in the meristem at the onset of adventitious root development, whereas PcSAMS2 is expressed in roots as well as in shoots and is down-regulated during adventitious root formation. The expression of the two SAMS genes is different from the SAMS activity levels during adventitious root formation. We conclude that other SAMS genes that remain to be characterized may contribute to the observed SAMS activity, or that the activities of PcSAMS1 and PcSAMS2 are affected by post-transcriptional regulation. The deduced amino acid sequences of PcSAMS1 and PcSAMS2 are highly divergent, suggesting different functional roles. However, both carry the two perfectly conserved motifs that are common to all plant SAMS. At the protein level, PcSAMS2 shares about 90% identity to other isolated eukaryotic SAMS, while PcSAMS1 shares less than 50% identity with other plant SAMS. In a phylogenetic comparison, PcSAMS1 seems to have diverged significantly from all other SAMS genes. Nevertheless, PcSAMS1 was able to complement a Saccharomyces cerevisiae sam1 sam2 double mutant, indicating that it encodes a functional SAMS enzyme.

journal_name

Plant Mol Biol

journal_title

Plant molecular biology

authors

Lindroth AM,Saarikoski P,Flygh G,Clapham D,Grönroos R,Thelander M,Ronne H,von Arnold S

doi

10.1023/a:1010637012528

subject

Has Abstract

pub_date

2001-06-01 00:00:00

pages

335-46

issue

3

eissn

0167-4412

issn

1573-5028

journal_volume

46

pub_type

杂志文章