MOLECULAR-CLONING OF A SULFOTRANSFERASE IN ARABIDOPSIS-THALIANA AND REGULATION DURING DEVELOPMENT AND IN RESPONSE TO INFECTION WITH PATHOGENIC BACTERIA

A cDNA clone (RaRO47) encoding a sulfotransferase (ST) has been isolat ed from Arabidopsis cell suspensions. The deduced polypeptide of 302 a mino acids is highly related to plant flavonol sulfotransferases (FSTs ), characterized for the first time in Flaveria, and also to STs from animal tissue. The expression of the Arabidopsis ST gene(s) correspond ing to RaR047 was examined during different developmental stages. It w as found that, at the level of steady-state mRNA, expression of gene(s ) encoding this ST was rapidly induced in the aerial parts of young se edlings, and during growth of Arabidopsis cell cultures. No expression could be detected in roots. Treatment of Arabidopsis seedlings with h ormonal or stress-related compounds, showed that RaR047 mRNA accumulat ion was more particularly induced in response to salicylic acid and me thyl jasmonate. Furthermore, in the leaves of mature plants or in cell suspensions, accumulation of RaR047 mRNA was observed upon infection with bacterial pathogens. This expression was observed preferentially in response to avirulent pathogens causing an hypersensitive reaction, as compared to virulent pathogens, which lead to disease.