**40. Defense-related enzymes**

A new class of bacteriocin (class IId) stimulates plant growth in a way analogous to Nod fac‐ tors which have been shown to provoke aspects of plant disease resistance. Cut stems of soybean seedlings at the first trifoliate stage were exposed to the bacteriocin solutions Phe‐ nylalanine ammonia lyase (PAL) activity, superoxide dismutase (SOD) activity, and one APX isozyme (28kDa isoform) level in bacteriocins thuricin 17 (T17)-treated leaves peaked at 72h after treatment. At 72h post-treatment, compared with the control, guaiacol peroxidase (POD) activity in leaves exposed to T17 and bacteriocin bacthuricin F4 (BF4) rose by 72.7 and 91.3%, respectively; ascorbate peroxidase (APX) activity increased by 52.3 and 49.6%; and SOD activity was elevated by 70.5 and 60.2%, respectively. The 33-kDa polyphenol oxi‐ dase isozyme was induced strongly by both bacteriocins. Thus class IId bacteriocins can act as an inducer of plant disease defense-related enzymes and may employ mechanisms simi‐ lar to Nod factors [43].
