Response of PAL Activity to Phytophthora sojae Inoculation in Glycine soja

Phytophthora root and stem rot caused by Phytophthora sojae is a destructive disease in soybean production regions all around the world.Some protective enzymes begin to be active when soybean is infected by P.sojae.Of the enzymes,phenylalanine ammonia-lyase(PAL)is a key and rate-limiting enzyme in phenyl propane metabolize pathway which could produce kinds of antimicrobial products.There is abundant wild soybean in China,but there are few reports on the relationship about PAL and resistance of wild soybean to P.sojae.In this paper,4 resistant wild soybeans and 4 susceptible wild soybeans were inoculated with zoospores of P.sojae race 1 as treatment and those inoculated with water as control.The PAL activity in roots,stems,and leaves were measured after inoculation of 0,12,24,36,48,60,and 72 h in the treatment and control respectively.The results indicated that the PAL activity in roots and stems of resistant wild soybeans was higher than that of the control at most of the stages of pathogenetic process,but was lower than that of control for susceptible wild soybean.The change range of PAL activity in leaves of both susceptible and resistant wild soybeans were relatively low compared with that of control.