JIP60, A METHYL JASMONATE-INDUCED RIBOSOME-INACTIVATING PROTEIN INVOLVED IN PLANT STRESS REACTIONS

Plant tissues treated with the naturally occurring cyclopentanone comp ound methyl jasmonate or exposed to stress causing in planta jasmonate accumulation express distinctive proteins and, concomitantly, reduce the synthesis of most preexisting proteins. One of the recently identi fied jasmonate-induced proteins, designated JIP60, in barley is a ribo some-inactivating protein that cleaves polysomes of both animal and pl ant origin into their ribosomal subunits. By attacking foreign and sel f ribosomes, respectively, JIP60 appears to be both a defense protein and a potent regulator of protein synthesis in stressed plant tissues.