Inhibition of plant growth by mevinolin and reversal of this inhibition by isoprenoids

Mevinolin completely inhibited the growth of seedlings and cell cultures of Solanum xanthocarpum Schrader & Wendl. (S. surattense Burm.f.) at 100 mu M and 50 mu M concentrations respectively. Exogenously supplied acetate could not negate the inhibition but mevalonate, squalene and cholesterol could bring about revesal of inhibition when supplied exogenously. Analysis of the steroidal contents of mevinolin treated tissues showed reduction of free sterols to less than 50% of the control. Mevinolin at 5.0 mu M concentration severely inhibited (40%) 3-hydroxy 3-methylglutaryl CoA reductase (HMGR) in vitro. However, mevinolin at lower concentrations could not bring about significant influence an the pigment levels. The present study concludes that mevinolin inhibits growth of plants by inhibiting isoprenoid synthesis, mainly the steroid metabolism by inhibiting the 3-hydroxy 3-methylglutaryl CoA reductase, the gateway enzyme of isoprenoid pathway.