Nutritional regulation of ANR1 and other root-expressed MADS-box genes in Arabidopsis thaliana

The ANR1 MADS-box gene in Arabidopsis thaliana (L.) Heynh. has previously been identified as a key regulator of lateral root growth in response to signals from external nitrate (NO3(-)). We have used quantitative real-time PCR to investigate the responsiveness of ANR1 and 11 other root-expressed MADS-box genes to fluctuations in the supply of N, P and S. ANR1 expression in roots of hydroponically grown Arabidopsis plants was specifically regulated by changes in the N supply, being induced by N deprivation and rapidly repressed by N re-supply. This pattern of N responsiveness differs from the NO3(-)-inducibility of ANR1 previously observed in Arabidopsis root cultures [H.M. Zhang and B.G. Forde (1998) Science 279:407-409]. Seven of the other MADS-box genes responded to N…