CATALASE ISOZYMES ARE USEFUL MARKERS OF DIFFERENTIATION IN MAIZE TISSUE-CULTURES

To examine the temporal pattern of catalase expression during callus i nduction, cultures obtained from immature embryos and leaves of severa l maize inbred lines at several times after explanting were evaluated. The results indicate that irrespective of the primary explant used, C AT-1 is the predominant isozyme in established callus. Catalase expres sion during the regeneration phase in the absence of auxin was assayed in the cultures. CAT-2 was found to be the isoform specific to this d evelopmental time. The results indicate that different catalase isozym es are expressed at tissue culture level and callus initiation and sub sequent plant regeneration can be easily monitored by means of catalas e isozymes.